Sample Material Research Articles

A novel fast analytical method for the determination of N-nitroso vonoprazan in vonoprazan tablets and raw materials using LC-ESI-MS/MS

ABSTRACT The presence of N-nitrosamine contaminants in pharmaceuticals, particularly N-nitroso vonoprazan (NVP), poses significant health risks due to their genotoxic and carcinogenic properties. This study describes a novel, rapid analytical method for detecting and quantifying NVP in vonoprazan tablets and raw materials. The NVP was separated and quantified using an LC-ESI-MS/MS system with ESI ionisation and an Exion LC Sciex 5500-QTrap. The system utilised an ACE 3 C18-PFP column with dimensions of 4.6 mm × 150 mm and 3.0 µm. It achieved a high correlation coefficient (R2 = 0.9955) and met linearity and accuracy criteria. The method was developed and validated using ICH guidelines and against standard solutions, and it demonstrated high precision, accuracy, and specificity. The method validation results showed that the quantification is accurate, with an RSD of less than 10% and LOD and LOQ values of 0.5 and 1.0 ng/mL, respectively. The analysis of 150 vonoprazan tablets and 100 raw material samples revealed low levels of NVP, mostly falling below the FDA’s Acceptable Daily Intake limit of 96 ng/day. This novel approach provides a powerful and dependable tool for ensuring the safety and quality of vonoprazan-based pharmaceuticals.

Static headspace-gas chromatography with mass spectrometry for the assessment of the bioaccumulation of volatile organic compounds associated with microplastics in animal tissues

BackgroundThe excessive increase in the production of plastics worldwide and their mismanagement have turned these materials into a threat to the environment and living organisms. Plastics undergo erosion and degradation processes releasing additives, monomers of their formulation, and even generating one of the most worrying emerging pollutants: microplastics. These contaminants have been found in both aquatic and terrestrial ecosystems, so it is clear the need to develop a methodology to determine the accumulation of these pollutants and their associated compounds in living organisms. ResultsThis work presents a new combination of static headspace with gas chromatography coupled to mass spectrometry (SHS-GC-MS) for the determination of volatile organic compounds (VOCs) associated with microplastic materials in animal tissue samples. A total of 48 samples were analysed, corresponding to different organs (brain, heart, fat, liver, muscle, lung, kidney) of lamb, pig, rabbit, turkey, chicken, and beef, and 60 VOCs related to the presence of plastics were tentatively identified. Moreover, the identity of 25 VOCs was confirmed and they were also quantified, with contents in the 1.12–920 ng g−1 range. The application of chemometric tools allowed to evaluate the relationship between the type of animal organ and the presence of contaminants associated with microplastics, showing a tendency towards a greater accumulation in kidney and liver. Verification of the origin of the VOCs found was carried out by means of a thermogravimetric analysis - mass spectrometry study. SignificanceThe developed analytical approach generates useful and valuable information to better understand the exposure pathways of microplastics and their associated compounds, as well as the related migration and accumulation processes may happen in animal organs. This methodology has demonstrated high sensitivity, precision, robustness, and automation, as well as minimal sample handling.

Evaluation of interferents in sampling materials for analysis of post-explosion residues (explosive emulsion/ANFO) using gas chromatography-mass spectrometry (GC/MS).

Chemical analysis aimed at identifying post-explosion residues is critical for investigating crimes or accidents involving explosives, establishing it as a vital area of forensic chemistry. In general, only trace amounts remain in samples analyzed for this purpose, making the presence of interferents a constant concern. Therefore, understanding the materials used from collection to sample preparation is essential for this type of analysis. This study focuses on organic contaminants in collection and laboratory materials analyzed by gas chromatography/mass spectrometry (GC/MS), complementing a previous study by Mauricio etal. (2020), which addressed inorganic contaminants in materials used for similar purposes in ion chromatography (IC). No prior studies have specifically investigated the potential organic interferences introduced by various materials commonly used in forensic laboratories for sample pre-processing, storage, and evidence collection in this context. Plastic films, bottle caps, disposable gloves, syringes, swabs, disposable cups, plastic tubes, and plastic pipettes were examined. GC/MS analyses revealed that certain materials, particularly syringe plungers, gloves, and plastic films, can interfere with the detection of post-explosion residues from explosive emulsions and ANFO (ammonium nitrate-fuel oil). These findings emphasize the importance of evaluating materials for potential interferences prior to sample collection and processing to minimize contamination risks. This study provides significant insights into how commonly used laboratory materials can impact forensic analysis, thereby enhancing the reliability of post-explosion residue analysis and supporting more accurate forensic investigations.

Use of zoohumus extracts in soybean cultivation under regulated agroecosystem conditions

A model experiment was conducted in the laboratory conditions of the climate chamber to study the effect of liquid extract of black soldier fly zoohumus prepared in different ways on the growth rates and germination of seeds of the early ripening soybean variety EN Argenta. The zoohumus suspension was used in all variants at a dose of 0.2% (2000 ppm). As an additional background, a complex fertilizer containing the necessary plant nutrients in the form of various mineral salts was added. Analysis of the experimental data showed that the highest percentage of plant germination was recorded in the variant with the introduced aqueous suspension of zoohumus without centrifugation and without sterilization, and amounted to 94%. Against the background of pure organic matter, an increase in shoot biomass by an average of 22% was recorded. However, here the variant with sterilization, but without centrifugation of the zoohumus suspension, stood out. Against the background of the organomineral environment, the weight and height of the plants were higher, but stagnation in growth was noted, probably due to oversaturation in the feeding regime and the formation of chelate complexes of prolonged absorption. Thus, an aqueous suspension of zoohumus obtained by sterilization without additional centrifugation is the best way to prepare samples of raw materials for further use in sterile experiments. Centrifugation reduces the amount of enzymes and nutritional compounds, which negatively affects the quality of the suspension, and additional sterilization releases an additional amount of low-molecular compounds into the environment, which can feed microorganisms.

Consideration of spectral interference in total reflection X-ray fluorescence analysis using a limited number of calibration samples: Case study of ocean polymetallic nodules

A novel approach for quantitative analysis in total-reflection X-ray fluorescence (TXRF) which can be employed for the samples with complex matrices inducing overlapping spectral signals in the scenario of limited availability of standard samples is proposed. The approach is based on the least squares (LS) decomposition of real spectra into the weighted sum of simulated individual element subspectra and requires only a single sample of matrix-matched reference material. Oceanic polymetallic nodules and crusts, having complex mineral matrix and containing high concentrations of overlapping elements, were chosen to demonstrate the feasibility of the approach in quantification of 11 elements. The comparison of the results obtained with LS decomposition, internal standard and linear calibration with three standard samples was performed. It was demonstrated that the performance of the proposed approach and of the linear calibration was better than that of internal standard for most of the elements; however, the proposed method requires only a single standard sample.

Resistive Heating and Thermal Decomposition of an Additively Manufacturable Electrically Conductive Explosive

AbstractThe ability to transmit electrical signals through high explosive charges without using dense metal conductors could enable continuous monitoring of explosive charges with internally embedded sensors. With the sensor materials themselves being energetic, the impact on the intended detonation performance of the charge can be minimized. Embedded sensors enable real time, in‐situ measurements of conditions relevant to ageing assessments. Additionally, dynamic material property sensing can provide detonation performance data, enabling measurement of dynamic shock position. One proposed method to allow for electronic signal transfer through high explosives is to use electrically conductive explosive composites consisting of an electrically conductive polymer binder mixed with high explosive crystals. These conductive energetic pathways also serve as independently reactive elements and can provide additional functionality via dynamic sensor removal through resistive heating and subsequent decomposition. This work discusses the resistive heating of a previously developed, poly (3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) based, electrically conductive extrudable explosive composite. Experimental samples of the conductive explosive material were subjected to a range of direct current applications and the resulting heating and decomposition of the material is discussed.

Bibliometric Analysis of the 100 Most-Cited Articles on the Methods of Shade-Matching in Dentistry.

The purpose of this bibliometric analysis is to identify the 100 most cited articles and delve into citation metrics to gain insights into the evolving trends in shade-matching methods in dentistry. Following PRISMA guidelines, two reviewers conducted a structured search in Scopus using keyword-based search strings. The top 100 articles were selected based on predefined criteria, and their bibliometric data were extracted. Harzing's Publish Or Perish and VOSviewer were used to generate the bibliographic network. Between 1989 and 2017, the top 100 articles were published and obtained citations ranging from 560 to 48. Twenty-eight articles received over 100 citations, deemed classic. The Journal of Prosthetic Dentistry and the United States of America were the primary contributors. In-vitro experimental studies employing restorative material samples were prevalent, with spectrophotometers being the favored method of color analysis. Using Python, Spearman's correlation coefficient resealed positive correlations between citation count and age of publication (r = 0.16, p = 0.12) and between citation count and the impact factor of the journal (r = 0.35, p < 0.05). However, a negative correlation was observed between citation density and age of publication (r = -0.46, p < 0.05). This study demonstrated a significant upward trajectory of citation count in shade-matching in dentistry, reflecting high-quality scientific contributions.

Cyclic Voltammetry Study and Solar Light Assisted Photocatalytic Activity of the CeFeO3/CeO2/Fe2O3 Composite.

The semiconducting nature of CeFeO3/CeO2/Fe2O3 nanocomposite has permitted the degradation of the organic toxic dye methylene blue under the irradiation of ultraviolet and visible light portions of solar radiation. Fullprof-assisted Rietveld refinement analysis, performed using the Match software, has revealed the orthorhombic nature of CeFeO3. In addition, in the synthesized material, the cubic phase byproduct CeO2 was found due to the highly oxidizing nature of the cerium element. This occurred due to 6 min microwave irradiation because the microwave-assisted technique offered random distribution of heating during the supply of 800-W power for 30 s, followed by 12 cycles. Additionally, the presence of Fe2O3 was also confirmed through Match software-assisted Rietveld refinement analysis through phase matching. During the synthesis, a certain portion of the synthesized CeFeO3 experienced overheating, leading to phase transformation from CeFeO3 into Fe2O3 and CeO2. The unit cell compositions of CeFeO3, CeO2, and Fe2O3 were found in the sample material with 35.54%, 52.43%, and 12.03%, respectively. The appearance of a fingerprint absorption region in the FTIR spectrum around 577.36 and 535.38 cm-1 further confirmed the similarity of these values (577.36 and 535.38 cm-1) to those obtained from the calculated values obtained by substituting Rietveld refined bond length parameters. The fourth step process in the thermal analysis curve (TGA) revealed the oxidation process, which led to the destruction of the CeFeO3 phase, causing the transformation of CeFeO3 into two byproducts (CeO2 and Fe2O3). This oxidation process permitted in an observable weight gain, which is observed in the thermal analysis curve (TGA). A cyclic voltammetry study (the experimentally measured current-voltage characteristic curve) revealed slightly distorted semirectangular CV curves, confirming the pseudo-capacitive behavior of the synthesized composite.

Implementation of the course “good chemistry: methodological, ethical and social implications” – a case study

Abstract The article describes the practical implementation of the course titled “Good Chemistry: Methodological, Ethical, and Social Implications” available on the EuChemS e-learning platform. This MOOC course has been used in various ways at several European universities and through blended learning at Jagiellonian University in Krakow (Poland), which is discussed in this article. Since the groups of students participating in the course were not large and it is worth taking a closer look/insight at this issue, the case study method was used. Sample materials and activities for this course are presented. The survey responses of lecturers and students, as well as the activities and posts of Jagiellonian University in Krakow students on the remote learning platform, were analyzed. The strengths and weaknesses of the course were identified, and the need for continuous efforts by lecturers to develop ethical attitudes, critical thinking, and communication skills in students, especially in the field of socioscientific issues, was emphasized.

Spectral in situ ellipsometer for thin layer measurements in thermonuclear fusion applications.

Ellipsometry is widely used to characterize the thickness and optical parameters of thin films deposited, for example, in industrial processes. It is based on the measurement of polarization change upon reflection of, for example, visible light at a material sample. Commercially available devices are designed for stationary applications and often rely on precise geometric adjustment of the optical setup to maximize the measurement precision. In this work, a simplified spectral ellipsometer is proposed and tested with the aim of flexible implementation in space-limited applications in thermonuclear fusion research: on the one hand, as a hand-held device for large thickness scans of coatings deposited on first-wall components inside the vacuum vessel of fusion experiments and, on the other hand, for in situ monitoring of plasma deposited coatings on diagnostic vacuum windows, reducing their transmission in the optical spectral range, which hampers spectroscopic diagnostics in long-pulse plasma experiments. The simplicity of the hardware setup is partially compensated by complex Bayesian inference of the coating parameters, which incorporates all uncertainties of the measurement and the model and provides a quantitative assessment of the final uncertainties of inferred coating parameters. The Bayesian inference based on synthetic observations is also used to optimize the diagnostic design, identifying the limiting parameters and quantifying their impact on final accuracy. For real-time analysis of layer thickness on first-wall components in fusion devices measured with the hand-held device, a neural network based analysis has been implemented, and promising test results are presented.

Thermal characterization of Xenon-Arc flash lamp heating system for automated fiber placement (AFP) of thermoplastic composites

In this study, a systematic experimental and simulations-based characterization of key thermal aspects of the arc-flash lamp based AFP heating is presented. Ex-situ measurements of heat flux output from the flash lamp as well as the resulting temperature field on a material sample are carried out in a geometry representative of actual manufacturing conditions, using a heat flux sensor and infrared thermography. A thermal simulation model is developed to predict the temperature field resulting from the measured heat flux data. Good agreement is found between experimental data and simulation predictions. This work contributes towards developing a fundamental understanding of heat transfer processes during AFP manufacturing. Data presented here may be of broad benefit to AFP-related research, and may contribute towards process design and optimization in order to further expand the capabilities of this promising additive manufacturing technology.

Assessment of Vocal Characteristics Associated With Chronic Rhinosinusitis Using Machine-Learning Techniques Based on Long-Term Average Spectrum of Voice

Objectives and BackgroundRhinosinal structures play a significant role in human speech production, particularly the production of nasal voices. Pathologies within these structures can affect vocal characteristics, facilitating the detection of rhinosinal diseases through acoustic analyses of voice samples. Material and MethodsVoice samples of a phonemically balanced passage, oral passage, and nasal sentences in Taiwan Mandarin from 77 healthy participants and 39 patients with radiologically confirmed CRS were obtained. The power spectra of vocal signals were averaged to obtain each speaker's long-term average spectra (LTAS). These LTAS power values were then used to train machine learning models, including supportive vector machine, multi-layer perceptions (MLP), decision trees, random forests (RF), gradient boosting decision trees, and convolutional neural networks to detect chronic rhinosinusitis (CRS). ResultsThe energy of LTAS from 90 to 300 Hz of the CRS patients was notably lower than the healthy participants (p < 0.05, independent sample t-test). Conversely, the power within the frequency range of 420–3630 Hz was significantly greater in CRS patients than in the healthy participants (p <0.05, independent sample t-test). MLP and RF models were most effective, achieving an accuracy of approximately 0.9. These models demonstrate potential as non-invasive screening tools for CRS, requiring minimal instrumentation and enabling automated analysis. ConclusionsThe findings of this study present an opportunity for remote screening and early detection of CRS. Further testing on other rhinosinal diseases with larger-scale datasets for model training is imperative for broader applications. Nonetheless, the current results demonstrate that these models and methodologies are effective for detecting rhinosinusitis.

Study on the Ratio and Model Test of Similar Materials of Heavily Weathered Granite.

To study the bearing characteristics of rock-socketed single piles on the southeast coast of Fujian Province, we conducted similar material ratio tests and single pile model tests. Initially, based on the mechanical parameters of strongly weathered granite, 10 groups of similar material samples were prepared using iron concentrate powder, barite powder, and quartz sand as aggregates, with rosin and alcohol as the cementing agents and gypsum as the modulating agent. Through triaxial testing and range and variance analysis, it was determined that the binder concentration has the most significant impact on the material properties. Consequently, Specimen 1 was selected as the simulation material. In the model test, the strongly weathered granite stratum was simulated using the ratio of Specimen 1. A horizontal load was applied using a pulley weight system, and the displacement at the top of the pile was measured with a laser displacement meter, resulting in a horizontal load-displacement curve. The results indicated that the pile foundation remained in an elastic state until a displacement of 2.5 mm. Measurements of the horizontal displacement and bending moment of the pile revealed that the model pile behaves as a flexible pile; the bending moment initially increases along the pile length and then decreases, approaching zero at the pile's bottom. The vertical load test analyzed the relationship between vertical load and settlement of the single pile, as well as its variation patterns. This study provides an experimental basis for the design of single pile foundations in weathered granite formations on the southeast coast of Fujian Province and aids in optimizing offshore wind power engineering practices.

АДГЕЗИВНАЯ АКТИВНОСТЬ МИКРООРГАНИЗМОВ К СТОМАТОЛОГИЧЕСКИМ МАТЕРИАЛАМ ДЛЯ 3D ПЕЧАТИ И ВАКУУМНОЙ ФОРМОВКИ

Relevance: The adhesive activity of the oral microbiome to new generation materials is the subject of study by the global medical community, and the issue of choosing structural materials is still being discussed in the scientific community and is of a controversial nature. Objective: To study the adhesion of representatives of the oral microbiome to samples of modern dental materials under experimental conditions (in vitro). Materials and methods: Samples of photopolymer resins for 3D printing: Dental Crown LCD, Dental Sand A1-A2, Dental Clear Pro, (n=30), (1-3 groups), thermoforming plates for vacuum forming: EV Gasket Bleaching 080, Bioplast multicolor 3.0*123 mm, Bioplast color 3.0*125 mm (n=30), (groups 4-6); clinical isolates of the microbiome as test strains: Staphylococcus aureus, Streptococcus oralis, Neisseria subflava, Actinomyces oris, Candida albicans (n=5). Research methods: experimental, microbiological, cultural, analytical and statistical. Results: The degree of adhesion of representatives of the oral microbiome to the studied structural materials is in the range from 0 to 4.91 (Ia) and depends on both the species composition of the microbiome and the physico-chemical properties of the materials. The high adhesion index for all microbiota groups was noted for vacuum forming materials (4.91), and the lowest was Dental Crown LCD (0), which makes it possible to recommend it for practical use. Conclusions: The choice of structural material should be made, including taking into account the adhesive activity of the oral microbiome in order to reduce the risk of complications. It is recommended to give preference to materials with a low adhesive activity index.

Best Management Practices to Mitigate Contamination of Karstic Aquifers from Emergency Fire-Control Runoff

We propose best management practices to increase karstic aquifer drinking water supplies’ resilience to potential hazardous material impacts where first responders and public safety officials suspect emergency firefighting runoff has entered the subsurface in the aquifer recharge zone. Karstic aquifers are unique because of their direct openings to the land’s surface, which allows contaminants in runoff or other surface waters to rapidly enter the subsurface and impact aquifer water quality. In the United States, 20% of the land surface is karst, and about a third of the groundwater used for drinking comes from karstic aquifers. Proposed best management practices emphasize on-site, real-time evaluation of the transport and fate of HAZMAT that may enter the subsurface and focus on water quality sampling, runoff and groundwater flow modeling, nontoxic dye tracing, and related studies for use in planning before and during an event and after emergency response has ended. We recommend best management practices for evidence-based screening of high-risk sites to facilitate placement of hazardous material sampling devices and emergency responder deployment. The best management practices, tools, curricula, and training described combine with earlier work by the authors to provide a comprehensive menu of actions to (1) help first responders prevent or limit flushing of hazardous material into a karstic aquifer; (2) help emergency management officials understand the consequences of contamination and issue data-driven geographically focused health and safety risk communications; and (3) help provide health and safety officials with relevant science- and data-based information that can help mitigate human and environmental health risks.

Impact Absorption Power of Polyolefin Fused Filament Fabrication 3D-Printed Sports Mouthguards: InVitro Study.

This study aims to evaluate and compare the impact absorption capacities of thermoformed ethylene vinyl acetate (EVA) mouthguards and 3D-printed polyolefin mouthguards used in sports dentistry applications. The objective is to determine whether 3D-printed polyolefin mouthguards offer superior impact toughness compared to traditional EVA mouthguards commonly used in sports settings. Six material samples were assessed: five pressure-formed EVA mouthguards (PolyShok, Buffalo Dental, Erkoflex, Proform, and Drufosoft) and one 3D-printed synthetic polymer (polyolefin). The materials were evaluated using a modified American Society for Testing and Materials (ASTM) D256 Test Method A for Izod pendulum impact resistance of plastics. Polyolefin samples were 3D-printed using fused filament fabrication (FFF) technology. Notably, the FFF process included samples printed with notches placed either parallel or perpendicular to the build direction. This orientation served as a study factor, allowing for comparison of material behavior under different printing conditions. Impact testing was conducted using an Izod impact tester to assess the materials' performance under controlled impact conditions. The study achieved a high power (1.0) in power analysis, indicating strong sensitivity to detect significant differences. Among molded materials, PolyShok showed significantly lower impact toughness compared to others (p = 0.06). The mean impact absorption of EVA materials was 5.4 ± 0.3 kJ/m2, significantly lower than polyolefin materials, which demonstrated 12.9 ± 0.7 kJ/m2 and superior performance (p = 0.0). Horizontal-notched polyolefin samples exhibited higher impact strength compared to vertical-notched samples (p = 0.009). 3D-printed polyolefin mouthguards exhibited significantly higher impact toughness than thermoformed EVA mouthguards. While EVA materials demonstrated structural robustness, their lower impact resistance and observed tearing in other test specimens suggest the need for alternative testing standards to better reflect real-world conditions. 3D-printed mouthguards fabricated with build orientations perpendicular to the direction of impact demonstrate significantly enhanced impact absorption. Further research into manufacturing methods and testing protocols is recommended to optimize mouthguard performance under impact scenarios.

Development of Technology for Providing Antimicrobial Properties to Medical Disposable Masks.

Wearing masks to protect against communicable diseases is an effective tool used in many countries affected by the COVID-19 pandemic. The antibacterial activity, antibacterial efficiency, microbial purity, and breathability properties of medical disposable masks are very important. Ag is most commonly applied to antimicrobial textiles. In this work, three antimicrobial additives were used. Four compositions of the binders with antimicrobial additives were prepared and applied to one-layer non-woven PP material. The influence of the binder antimicrobial polymer coating on the breathability and antibacterial activity of the non-woven PP material was evaluated. The results show that the composition of the polyacrylic acid binder had the least effect on their breathability and samples with the silver chloride formulation showed the best antimicrobial response. Based on the microbiological and air permeability results of the samples of the one-layer non-woven material with coating, the samples of two layers and three layers of the medical mask model were prepared. Microbiological studies have shown that a three-layered medical mask model with silver chloride composition in the middle layer, on both sides of the model, has antibacterial efficiency against three pathogens (E. Coli, K. Pneumoniae, and S. Aureus). The performance of this medical mask model has been found to meet the requirements for type I medical masks according to the EN 14863 standard. Studies have shown that the microbial purity of the mask model is CFU/g < 3.

No evidence for interstellar fireballs in the CNEOS database

Context. The detection of interstellar meteors, especially meteorite-dropping meteoroids, would be transformative, as this would enable direct sampling of material from other stellar systems on Earth. One candidate is the fireball observed by U.S. government sensors on January 8, 2014. It has been claimed that fragments of this meteoroid have been recovered from the ocean floor near Papua New Guinea and that they support an extrasolar origin. Based on its parameters reported in the Center for Near Earth Object Studies (CNEOS) catalog, the fireball exhibits a hyperbolic excess velocity that indicates an interstellar origin; however, the catalog does not report parameter uncertainties. Aims. To achieve a clear confirmation of the fireball’s interstellar origin, we assessed the underlying error distributions of the catalog data. Our aim was also to confirm whether the fragments of this meteoroid survived passage through the atmosphere and assess all conditions needed to unambiguously determine the fragments’ origin. Methods. We approached the investigation of the entire catalog using statistical analyses and modeling, and we provide a comprehensive analysis of the individual hyperbolic CNEOS cases. Results. We have developed several independent arguments indicating substantial uncertainties in the velocity and radiant position of the CNEOS events. We determined that all the hyperbolic fireballs exhibit significant deviations from the majority of the events in one of their velocity components, and we show that such mismeasurements can produce spurious parameters. According to our estimation of the speed measurement uncertainty for the catalog, we found that it is highly probable that such a catalog containing only Sun-bound meteors would show at least one event that appears highly unlikely to be Sun-bound. We also establish that it is unlikely that any fragments from a fireball traveling at the high inferred velocities could survive passage through the atmosphere. When assuming a much lower velocity, some fragments of this meteoroid could survive; however, they would be of a common Solar System origin and thus highly probable to be indistinguishable from the quantity of other local micrometeorites that have gradually accumulated on the sea floor. Conclusions. We conclude that there is no evidence in the CNEOS data to confirm or reject the interstellar origin of any of the nominally hyperbolic fireballs in the CNEOS catalog. Therefore, the claim of an interstellar origin for the fireball recorded over Papua New Guinea in 2014 remains unsubstantiated. We have also gathered arguments that refute the claim that the collected spherules from the sea floor originated in the body of this fireball.

Desorption efficiency and holding capacity of acid-treated filters for nicotine sampling in vape shops.

Efficient sampling materials are essential for assessing nicotine levels in vape shops and other settings where nicotine exposures may exist. Two different treatments of Whatman glass fiber type A (GF/A) filters (sodium bisulfate treated and citric acid treated) were evaluated for nicotine capture, desorption efficiency, and holding capacity using Gas Chromatography-Mass Spectrometry (GC-MS). The Filters were treated with 0.8mL of 0.1 M sodium bisulfate or citric acid solution and oven-dried (80 °C) for 30min. Nicotine was desorbed off the filters using a modified analytical method. The average nicotine desorption efficiency for sodium bisulfate-treated GF/A filters (98.4%) was significantly higher than that of citric acid-treated GF/A filters (60.9%) over a range of 1-100 µg nicotine. Sodium bisulfate-treated and citric acid-treated GF/A filters experienced a 10% nicotine breakthrough after being dosed with about 550 and 2,750 µg of nicotine, respectively compared to 75 µg for untreated GF/A filters. Citric acid-treated GF/A filters had a much greater nicotine-holding capacity, but nicotine desorption from citric acid-treated GF/A filters was below the recommended criteria. Therefore, we recommend that sodium bisulfate-treated GF/A filters are employed for sample of nicotine with the GC-MS method.

Detection of Double-Stranded RNA Intermediates During SARS-CoV-2 Infections of Syrian Golden Hamsters with Monoclonal Antibodies and Its Implications for Histopathological Evaluation of In Vivo Studies.

The SARS-CoV-2 pandemic has highlighted the challenges posed by the emergence and rapid global spread of previously unknown viruses. Early investigations on the pathogenesis of newly identified viruses are often hampered by a lack of appropriate sample material and conventional detection methods. In this study, viral replication within the lungs of SARS-CoV-2-infected Syrian golden hamsters was assessed by immunolabeling dsRNA intermediates with three different monoclonal antibodies in formalin-fixed, paraffin-embedded tissue samples. The presence of dsRNA was compared to viral antigen levels, viral titers, and genomic RNA replicates using three different variants of concern and an ancestral virus strain at a single time point and during the course of infection with an ancestral variant, and then validated using fluorescent 2-plex in situ hybridization. The results indicate that the detection of viral infection using anti-dsRNA antibodies is restricted to an early phase of infection with high viral replication activity. Additionally, the combined detection of dsRNA intermediates and viral antigens may help to bridge the interpretation gaps between viral antigen levels and viral titers at a single time point. Further testing in other viral infections or species is needed to assess the potential of dsRNA as an early marker for viral infections.