Chemical Analysis Research Articles

Designing the public works values

What are public works, and under what conditions can they be considered a “common value” recognized by the community? The contributions to issue n. 28 of TECHNE Journal delve into these conditions, offering critical reflections and research advancements that examine cities, buildings, places, and public services from the perspective that «the entire urban space must be regarded as something produced, owned, and transformed collectively» (Marella, 2024). There are three main areas of reflection and proposal: the first involves the methods and procedural and design tools that can be employed for the recovery and adaptive reuse of public works facing functional obsolescence, abandonment, and/or decay; the second addresses the regenerative processes of public spaces and entire urban sectors with a focus on usability and environmental sustainability; and the third concerns the participatory design of public works as a vital lever for the creation of social value. This set of design actions is well-supported by analytical and evaluative tools that guide the decision-making process, all driven by an interest in optimizing the socio-economic, cultural, and environmental benefits that can result from more effective and efficient public works production and management processes, especially in response to evolving social demands.

Analytical Challenges in Novel Pentavalent Meningococcal Conjugate Vaccine (A, C, Y, W, X)

Multivalent meningococcal conjugate vaccines are a significant focus for the scientific community in light of the WHO’s mission to defeat meningitidis by 2030. Well-known meningococcal vaccines such as MenAfriVac, Nimenrix, Menveo, and MenQuadfi are licensed in various parts of the world and have been successful. Recently, the World Health Organization (WHO) qualified MenFive (meningococcal A, C, Y, W, and X) conjugate vaccine, further enhancing the battery of vaccines against meningitis. The antigenic nature of the current and new serogroups, the selection of carrier proteins, and the optimal formulation of these biomolecules are pivotal parameters for determining whether a biological preparation qualifies as a vaccine candidate. Creating appropriate quality control analytical tools for a complex biological formulation is challenging. A scoping review aims to identify the main challenges and gaps in analyzing multivalent vaccines, especially in the case of novel serogroups, such as X, as the limited literature addresses these analytical challenges. In summary, the similarities in polysaccharide backbones between meningococcal serogroups (C, Y, W sharing a sialic backbone and A, X sharing a phosphorous backbone) along with various conjugation chemistries (such as CNBr activation, reductive amination, CDAP, CPIP, thioether bond formation, N-hydroxy succinimide activation, and carbodiimide-mediated coupling) resulting into a wide variety of polysaccharide -protein conjugates. The challenge in analyzing carrier proteins used in conjugation (such as diphtheria toxoid, tetanus toxoid, CRM diphtheria protein, and recombinant CRM) is assessing their purity (whether they are monomeric or polymeric in nature as well as their polydispersity). Additional analytical challenges include the impact of excipients, potential interference from serogroups, selection and establishment of standards, age-dependent behavior of biomolecules indicated by molecular size distributions, and process-driven variations. This article explains the analytical insights gained (polysaccharide content, free saccharide, free proteins, MSD) during the development of the MenFive vaccine and highlights the crucial gaps and challenges in testing.

Peru’s leadership in the Lima Group: emergence and failure (2015–2021)

This research seeks to understand the factors that enabled Peru, a medium-sized country in Latin America, to take on a leadership role in the creation and development of the Lima Group—a multilateral mechanism whose main objective was to find a resolution to the democratic crisis in Venezuela—as well as the subsequent failure of this leadership. Using the analytical tools provided by Neoclassical Realism, this study argues that Peru’s leadership was made possible not only by the growing importance of the Venezuelan crisis on the international agenda since 2015 but also by changes in regional and global power dynamics. These shifts allowed a country like Peru to exercise such leadership and garner greater interest from the United States. Additionally, the presence of a favorable domestic political climate and clear national interests led the Peruvian government to view this leadership as beneficial, not only for the region but also for Peru itself. However, despite the Venezuelan crisis remaining on the international agenda due to Nicolás Maduro’s continued hold on power, the hardening of the U.S. stance on Venezuela and political changes at the regional level since 2018 fractured the Lima Group and undermined Peru’s leadership. Moreover, domestically, political changes led to heightened instability, weakening Peru’s external position. Finally, the surge in Venezuelan migration and the onset of the COVID-19 pandemic shifted the priorities of Peru’s foreign policy, diminishing its focus on the Venezuelan crisis and contributing to the failure of its leadership.

Text Comment Classification and Sentiment Analysis Model Based on LSTM

This study addresses the challenge of sentiment analysis and text classification in user-generated comments, an essential task for understanding public opinion in the digital age. With the widespread adoption of social media, the sheer volume of text data has increased exponentially, thereby necessitating advanced analytical tools. The study integrates Long Short-Term Memory (LSTM) networks with attention mechanisms to develop a model adept at both classifying and analyzing the sentiment of textual comments. The research methodology commences with data cleaning, tokenization, and feature extraction, subsequently followed by the implementation of a bidirectional LSTM architecture augmented with an attention mechanism. The model underwent rigorous training and testing on a comprehensive dataset, yielding high accuracy rates in sentiment analysis and text classification. The results underscore the model’s proficiency in capturing sentiment nuances and underscore its potential for deployment in e-commerce and content recommendation systems, emphasizing the practical implications of this research for enhancing decision-making processes in businesses and among policymakers.

NcPlantDB: a plant ncRNA database with potential ncPEP information and cell type-specific interaction.

The field of plant non-coding RNAs (ncRNAs) has seen significant advancements in recent years, with many ncRNAs recognized as important regulators of gene expression during plant development and stress responses. Moreover, the coding potential of these ncRNAs, giving rise to ncRNA-encoded peptides (ncPEPs), has emerged as an essential area of study. However, existing plant ncRNA databases lack comprehensive information on ncRNA-encoded peptides (ncPEPs) and cell type-specific interactions. To address this gap, we present ncPlantDB (https://bis.zju.edu.cn/ncPlantDB), a comprehensive database integrating ncRNA and ncPEP data across 43 plant species. ncPlantDB encompasses 353 140 ncRNAs, 3799 ncPEPs and 4 647 071 interactions, sourced from established databases and literature mining. The database offers unique features including translational potential data, cell-specific interaction networks derived from single-cell RNA sequencing and Ribo-seq analyses, and interactive visualization tools. ncPlantDB provides a user-friendly interface for exploring ncRNA expression patterns at the single-cell level, facilitating the discovery of tissue-specific ncRNAs and potential ncPEPs. By integrating diverse data types and offering advanced analytical tools, ncPlantDB serves as a valuable resource for researchers investigating plant ncRNA functions, interactions, and their potential coding capacity. This database significantly enhances our understanding of plant ncRNA biology and opens new avenues for exploring the complex regulatory networks in plant genomics.

Three-dimensional trust: disentangling trust relations in the context of converted asylum seekers

ABSTRACT Forced migration always involves dramatic life changes, but with converted asylum seekers, these changes become especially devastating. Conversion entails building relationships with local religious groups while former social ties usually get severed. Typically, forced migrants seek support from friends, family and relatives. For converted asylum seekers, these bases of security often turn into sources of psychological violence and threats. We examine how converted asylum seekers and members of the congregations they join experience and make sense of trust. We have interviewed representatives of both groups to understand the role of trust in their relationships and in relation to other actors involved in the asylum process. Methodologically, we test Frederiksen’s distinction between three dimensions of trust (relations, objects and situations) on an empirical case and develop this analytical tool further. The findings emphasize the complex and dynamic role that proximity, affects and temporality play in relation to trust. Theoretically, we offer a definition of trust that emphasizes affects and ascribed moral agency instead of belief in the good will of another toward oneself.

Validated kinetic modelling of ladle furnace process for predicting inclusions in API steel grade

A kinetic model of ladle furnace (LF) process is developed in C++ format using the FactSage database and ChemApp subroutines. The model considers all the process parameters such as ferroalloy and slag dissolution, wire additions, electrical arcing, steel/slag reactions, reoxidation due to slag eye opening, heat exchange between metal/slag, and refractory dissolution. Further, a correlation for inclusion removal rate was developed as a function of argon flow rate, using discrete phase method (DPM) in Computational Fluid dynamics (CFD). Lollypop samples from steel bath and slag samples were collected from the plant for API steel grade for chemical analysis and inclusion characterisation. At LF_in, the inclusions found were mostly alumina spinel with very low amount of Mg (∼3%), followed by spinel at intermediate stage having ∼15 wt. % of Mg and after Ca treatment, inclusions transformed into CaS and Calcium Aluminate type of inclusions. Overall inclusion weight fraction varied from 136 ppm at LF_in to 93 ppm at LF_out. The model calculations were found to give very good prediction for steel and slag chemistry, and inclusion global composition as compared to the plant results. Predicted temperature was found with an accuracy of ± 5 oC, while the calculated inclusion weight fraction was having an accuracy of ±12 ppm.

Comparison Among Food By-Products to Improve the Shelf Life of a Fresh Burger Based on Shelled Shrimps

Pomegranate peels, fig peels, and by-products from turnip greens were used as novel ingredients in burgers based on shelled shrimps. With the aim, a control without any by-products and three fortified samples with 7.5% (w/w) by-product were realized. To verify the benefic effects of by-product addition on the chemical quality of burgers, total phenols, total flavonoids, and antioxidant activity were measured in both the control and fortified samples. In addition, during storage under refrigerated conditions, the microbiological proliferation of the main spoilage bacteria, the pH, and the sensory acceptability were properly monitored in all the samples. Results from chemical analyses confirmed that the nutritional level of shrimp-based burgers enriched with by-products was better than that of the control. Burgers with peels from pomegranate recorded the best results (2.67 ± 0.24 mg GAE/g dw, 1.62 ± 0.21 mg QE/g dw, and 12.63 ± 0.41 mg Trolox/g dw for total phenols, flavonoids, and antioxidant activity, respectively). From the microbiological point of view, the bacterial proliferation was always more rapid in the control than in the other samples. Among the by-products, the pomegranate peels better delayed the spoiling phenomena, even though mesophilic and psychrotrophic bacteria grew abundantly and rapidly in all the products, thus reducing the differences among samples. All the burgers maintained sensory acceptability for more than two weeks, regardless of the by-product addition. Considering both microbiological stability and sensory properties, the shelf life of this product was calculated to be around 1 week for the control burger, 8.5 days for both burgers with fig peels and by-products from turnip greens, and 9 days for the shrimp-based burger fortified with pomegranate peels.

Editorial: Harmonization of protocols investigating natural products: the role of chemical analysis from in vitro studies to clinical research

Editorial: Harmonization of protocols investigating natural products: the role of chemical analysis from in vitro studies to clinical research

A Reactivity Study of 4-Hydroxy-2H-chromene-2-thione and 4-Hydroxy-2H-thiochromene-2-thione with tert-Butyl Nitrite and Aromatic Amines: An Environmentally Benign Synthesis of New Hydrazone Derivatives

AbstractThe synthesis of biologically active coumarin-based hydrazone derivatives is achieved through a one-pot, three-component reaction of 4-hydroxy-2H-chromene-2-thiones with aniline derivatives and tert-butyl nitrite under solvent- and catalyst-free conditions in yields of 76–86%. Similarly, the reactions of 4-hydroxydithiocoumarins with aniline derivatives and tert-butyl nitrite under identical conditions provided the corresponding hydrazone products in 79–85% yield through a four-component reaction. It is observed in both cases that the C=S group at the C2 position is converted into a C=O moiety. However, the intermediate products derived from 4-hydroxydithiocoumarin react further with another aniline molecule leading to thioesters. 4-Hydroxy-2H-chromene-2-thione and 4-hydroxydithiocoumarin exhibit distinct reactivity pathways, resulting in the formation of two different types of product. In addition, quantum chemical analysis of the mechanistic steps show that this reaction is exergonic. This protocol offers broad substrate scope and tolerates various functional groups, leading to high product yields in short reaction times.

Exploring residual stress analysis in the machining of hypoeutectic high chromium white cast iron alloys through the hole-drilling method

Abstract High chromium white cast irons (HCWCIs), ASTM A352, Type A and Class III, i.e., 25%Cr iron in as-cast condition consists of proeutectic austenite (γ-Fe), transformed martensite (α-Fe) and discontinuous Cr-rich, i.e., M7C3/ (Cr, Fe)7C3 type of carbides, which are hard and brittle in nature. Fully annealed thermal treatment was performed to improve iron’s machinability leading to fully pearlitic matrix with minor retained γ-Fe content. Eutectic (Cr, Fe)7C3 type of carbides are not affected by heat treatment processes. Resulting from corresponding manufacturing process, the magnitude and distribution of residual stresses (RSs) in as-cast and after machining were measured using hole-drilling method (HDM), as they are known to be harmful to corrosion and fatigue resistance. Furthermore, general metallurgical material characterisation was performed in as-cast and heat-treated conditions. As a result, this study revealed hardness variation, 547 and 555BHN in as-cast as compared to 327BHN in heat-treated condition. Furnace and actual cast component chemical analysis revealed a slight variation, especially between carbon (C) and chromium (Cr). Furthermore, eutectic type of carbides and precipitated secondary, i.e., (Cr, Fe)23C6 type of carbides within fully pearlitic matrix with minor amounts of retained γ-Fe were detected within the dominant matrix, i.e., pearlitic matrix in as-annealed condition. Detected magnitude and distributions of RSs on heat-treated sample resulted in higher tensile stresses in the surface and compressive in the interior as compared to sample in as-cast condition. Thus, this study was successfully in measuring RSs in as-cast and upon machining of hypoeutectic irons of HCWCI alloys using HDM.

Organohalogenochromism: Toward Colorimetric Detection of Volatile Organic Halogen Compounds

A significant hypsochromic or bathochromic shift of photoabsorption bands of dyes may be observed only in halogenated solvents. Such specific solvatochromism is termed organohalogenochromism (OHC), which has been recently recognized as a photophysical phenomenon. However, few studies have been carried out on the elucidation of OHC and thus there is a limited insight into the mechanism for expression of OHC, although the phenomenon not only is of a great scientific interest in photochemistry, photophysics, analytical chemistry, and synthetic organic chemistry but also has great potential for development of colorimetric detection technique for organohalogen compounds; this technique is expected to be facile operation and simple analysis with sufficient accuracy, high sensitivity, and fast response, and thus allows visualization and real‐time monitoring for toxic volatile organohalogen compounds (VOHCs). In this Concept, we first review OHC of dyes which have been reported so far. Second, the elucidation of OHC based on the interactions between dye and organohalogen molecules are discussed. In particular, we propose the explanation for a pronounced OHC of donor‐π‐acceptor‐type cationic dye from the viewpoint of halogen bond (XB) between halogenated solvents and counter anion of cationic dye. Moreover, an application of organohalogenochromic dyes to colorimetric sensors for VOHCs is presented.

Urban Community Participation In Dealing With The Covid-19 Pandemic Through Environment-Based On Covid-19 Handling Policies In The City Of Mataram

The city of Mataram is an area that has a high number of Covid-19 cases in West Nusa Tenggara Province. Covid-19 has seriously impacted all aspects of life, from health, economy, society, culture, and tourism to religious rituals. This study aims to analyze the policies for handling Covid-19 in Mataram City. Second, analyze the form of community participation in efforts to deal with Covid-19 in Mataram City. This study uses the participation theory of Cohen and Uphoff as an analytical tool. This research is qualitative research with a descriptive approach. In- depth interviews, observation, and documentation employed data collection techniques. The results of this study indicate that this environment-based policy for handling Covid-19 effectively suppresses the spread of Covid-19 in Mataram City. This policy is implemented by involving the participation of all elements of government, local leaders, and the community. Community participation in handling Covid-19 starts with high public awareness of Covid-19, then implementing health protocols. Community participation is also seen in the formulation of policies for handling Covid-19, the movement to join a Task Force (Satgas), carrying out self- help movements to help each other, and being involved in evaluating the handling of Covid-19 in the City of Mataram.

A Novel PCR-Free Ultrasensitive GQD-Based Label-Free Electrochemical DNA Sensor for Sensitive and Rapid Detection of Francisella tularensis

Biological warfare agents are infectious microorganisms or toxins capable of harming or killing humans. Francisella tularensis is a potential bioterrorism agent that is highly infectious, even at very low doses. Biosensors for biological warfare agents are simple yet reliable point-of-care analytical tools. Developing highly sensitive, reliable, and cost-effective label-free DNA biosensors poses significant challenges, particularly when utilizing traditional techniques such as fluorescence, electrochemical methods, and others. These challenges arise primarily due to the need for labeling, enzymes, or complex modifications, which can complicate the design and implementation of biosensors. In this study, we fabricated Graphene Quantum dot (GQD)-functionalized biosensors for highly sensitive label-free DNA detection. GQDs were immobilized on the surface of screen-printed gold electrodes via mercaptoacetic acid with a thiol group. The single-stranded DNA (ssDNA) probe was also immobilized on GQDs through strong π−π interactions. The ssDNA probe can hybridize with the ssDNA target and form double-stranded DNA, leading to a decrease in the effect of GQD but a positive shift associated with the increase in DNA concentration. The specificity of the developed system was observed with different microorganism target DNAs and up to three-base mismatches in the target DNA, effectively distinguishing the target DNA. The response time for the target DNA molecule is approximately 1010 s (17 min). Experimental steps were monitored using UV/Vis spectroscopy, Atomic Force Microscopy (AFM), and electrochemical techniques to confirm the successful fabrication of the biosensor. The detection limit can reach 0.1 nM, which is two–five orders of magnitude lower than previously reported methods. The biosensor also exhibits a good linear range from 105 to 0.01 nM and has good specificity. The biosensor’s detection limit (LOD) was evaluated as 0.1 nM from the standard calibration curve, with a correlation coefficient of R2 = 0.9712, showing a good linear range and specificity. Here, we demonstrate a cost-effective, GQD-based SPGE/F. tularensis DNA test suitable for portable electrochemical devices. This application provides good perspectives for point-of-care portable electrochemical devices that integrate sample processing and detection into a single cartridge without requiring a PCR before detection. Based on these results, it can be concluded that this is the first enzyme-free electrochemical DNA biosensor developed for the rapid and sensitive detection of F. tularensis, leveraging the nanoenzyme and catalytic properties of GQDs.

Composition of Donkey Meat (Equus Asinus) from the Puno Region, Peru

Objective: To determine the proximate chemical composition of donkey meat (Equus asinus) considering the variables of animal class (young and adult) and commercial cut (shoulder, rib and leg) with the purpose of nutritionally assessing it as an alternative source of red meat. Theoretical Framework: Donkey meat is characterized by a low intramuscular fat content and could be used as a valid alternative to other species of red meat such as beef and sheep in the Puno region, Peru. However, little is known about the nutritional quality of meat from donkeys that are slaughtered at the main equine slaughterhouse in southern Peru. Method: Muscle tissue samples were taken from the following muscles: deltoid, Longissimus dorsi and biceps femoris representing the commercial cuts of shoulder, rib and leg, respectively. Chemical analysis (moisture, protein, fat and ash) was performed following the protocols established for meat by the Association of Official Analytical Chemists (AOAC), in the Bromatology Laboratory of the Faculty of Veterinary Medicine and Zootechnics of UNA-Puno. Data analysis was performed in a randomized complete block design (DBCA) and the LSD significance test (α=0.05). Results and Discussion: The proximate chemical composition of donkey meat is as follows: moisture 73.79%, protein 19.23%, fat 4.53% and ash 1.20%. The animal class (young and adult) and the commercial cut (shoulder, rib and leg) have a significant effect on the moisture and fat content (p≤0.05), with an inverse relationship between the two; but there is no effect on the protein and ash content (p>0.05). Implications of the research: It was possible to demonstrate that the meat of donkeys from the Puno region has a similar composition to the red meat of other domestic species, so it can be a good alternative to replace red meat. Originality/Value: This study contributes to the literature by knowing the chemical composition of donkey meat from the Puno region, Peru for consumption purposes as a substitute for red meat or for the preparation of meat by-products.

11.H. Round table: Making the case for public investment in health

Abstract Across the European Union (EU), public budgets are facing pressures and policy makers are becoming increasingly concerned about how to adequately and sustainably fund their health systems to keep up with need and demand. In recognition of this, in 2022 a Technical Support Instrument (TSI) project funded by the Directorate-General for Structural Reform Support (DG REFORM) was launched together with three European Union (EU) Member States with the goal of strengthening capacity to make the case for public investments in health. To support these efforts, the European Observatory on Health Systems and Policies (OBS) conducted an exercise to map relevant analytical approaches and tools for making the case for public investment in health. As a contribution to this workshop, OBS will present the key results from this exercise, including a framework that has been designed to support health policy makers, advisors and advocates by providing five key lines of argument and selected examples of tools, data, indicators and methods that can be used to successfully make the case for public funding for health. This will be complemented by two presentations on country experiences (in Austria and Malta) of navigating negotiations between health and finance and securing public funding for health. These will highlight both successes and challenges in practice. By looking at examples from MS on making the case for public investment in health, these presentations will frame the panel discussion that follows. The chairs will facilitate a discussion closely engaging the audience on how to build better narratives and exchanges which facilitate trust and alignment between health and finance stakeholders in the pursuit of strengthening the capacity to make the case for public investment in health. The workshop will highlight five lines of argument and practical examples of tools, data, indicators and methods that can be used to support the case for public investment in health. It will also focus on the important enablers (e.g. cooperation, communication, transparency, accountability, trust) for successful budget negotiations and discuss how these can be facilitated. Key messages • Budget cases for public funds for health tend to be most successful when they align well with the goals and objectives of finance stakeholders, and certain narratives and arrangements can foster this. • Data and evidence can help steer decision makers to make good choices (or at least avoid bad ones), but other factors serve as the fuel to push the budget case for health forward successfully. Speakers/Panelists Rebecca Forman European Observatory on Health Systems and Policies, London, UK Jonathan Cylus European Observatory on Health Systems and Policies, London, UK Stefan Eichwalder Ministry of Health, Vienna, Austria Neville Calleja Department of Health Information and Research, G’Mangia, Malta

Experimental Investigation and Chemical Kinetics Analysis of Carbon Dioxide Inhibition on Hydrogen-Enriched Liquefied Petroleum Gas (LPG) Explosions

The utilization of hydrogen-enriched liquefied petroleum gas (LPG) is an effective means of reducing carbon emissions, but the special physical and chemical properties of hydrogen have raised concerns among the public. To delve into the intricate chemical kinetic mechanisms governing the inhibitory effect of CO2 on the explosion of hydrogen-enriched LPG, this study systematically investigated the influence of varying CO2 concentrations (3%, 6%, and 9%) on the explosion characteristics of hydrogen-enriched LPG (hydrogen ratio ranging from 0 to 0.5) within a 20 L spherical explosion chamber. Subsequently, a chemical kinetic analysis was conducted, focusing on the explosion reaction dynamics of the H2/LPG/CO2/Air mixture, encompassing temperature sensitivity assessments and the production rates of key free radicals. The findings reveal that although hydrogen incorporation does not significantly alter the maximum explosion pressure of LPG, it markedly accelerates the explosion reaction rate, posing a challenge for CO2 in effectively inhibiting the explosion of hydrogen-enriched LPG. CO2 functions as a stabilizing third body within the reaction system, diminishing the collision frequency among free radicals, hydrogen molecules, hydrocarbon molecules, and oxygen molecules, thereby slowing down the reaction rate. As the proportion of hydrogen increases, the concentration of ·H radicals, known for their high reactivity, escalates, rapidly completing the propagation phase of the chain reaction and intensifying the overall generation rates of critical free radicals, including ·H, ·O, and ·OH. Notably, the key reaction H+O2⇋O+OH, which governs the reaction temperature, undergoes significant enhancement, further accelerating the explosion reaction rate and ultimately diminishing the inhibitory efficacy of CO2 against the hydrogenated LPG explosion. Furthermore, as the amount of hydrogen added increases, hydrogen’s competitiveness for oxygen within the reaction system markedly improves, attenuating the oxidation of hydrocarbons. Concurrently, the alkane recombination reaction, exemplified by C3H6+CH3(+M)⇋sC4H9(+M), is strengthened. These insights provide valuable understanding of the complex interactions and mechanisms during the explosion of hydrogen-enriched LPG in the presence of CO2, with implications for the safe application of hydrogen-enriched LPG.

Health impacts methodology in the European Commission

Abstract The state of play in the implementation of health impacts methodology within European Commission impact assessments reveals both advancements and challenges. The Commission has acknowledged the significance of assessing health impacts and has provided a generic methodological description, as outlined in Tool #32 of the Better Regulation guidelines. However, translating this guidance into practical application encounters obstacles stemming from challenges intrinsic to the policy in question, a lack of skills and knowledge, data gaps, and complexities in establishing causal links. In EU policymaking, health impacts are consistently appraised in relevant Impact Assessments across various policy areas, but the methodological intricacy varies. In the fields of public health, occupational safety, and environmental protection, econometric modelling is often employed to quantify potential health impacts rigorously. This involves sophisticated analytical tools designed to capture the complexity of the interactions. Conversely, in areas where the link between policies and health outcomes is less direct (e.g. food safety) or where data limitations pose challenges, a more qualitative appraisal is applied. This acknowledges the limitations in precisely quantifying health impacts and focuses on providing a nuanced understanding of potential health effects based on available information.

Long-range enhancement for fluorescence and Raman spectroscopy using Ag nanoislands protected with column-structured silica overlayer

We demonstrate long-range enhancement of fluorescence and Raman scattering using a dense random array of Ag nanoislands (AgNIs) coated with column-structured silica (CSS) overlayer of over 100 nm thickness, namely, remote plasmonic-like enhancement (RPE). The CSS layer provides physical and chemical protection, reducing the impact between analyte molecules and metal nanostructures. RPE plates are fabricated with high productivity using sputtering and chemical immersion in gold(I)/halide solution. The RPE plate significantly enhances Raman scattering and fluorescence, even without proximity between analyte molecules and metal nanostructures. The maximum enhancement factors are 107-fold for Raman scattering and 102-fold for fluorescence. RPE is successfully applied to enhance fluorescence biosensing of intracellular signalling dynamics in HeLa cells and Raman histological imaging of oesophagus tissues. Our findings present an interesting deviation from the conventional near-field enhancement theory, as they cannot be readily explained within its framework. However, based on the phenomenological aspects we have demonstrated, the observed enhancement is likely associated with the remote resonant coupling between the localised surface plasmon of AgNIs and the molecular transition dipole of the analyte, facilitated through the CSS structure. Although further investigation is warranted to fully understand the underlying mechanisms, the RPE plate offers practical advantages, such as high productivity and biocompatibility, making it a valuable tool for biosensing and biomolecular analysis in chemistry, biology, and medicine. We anticipate that RPE will advance as a versatile analytical tool for enhanced biosensing using Raman and fluorescence analysis in various biological contexts.

Processing Next-Generation Mass Spectrometry Imaging Data: Principal Component Analysis at Scale.

Mass spectrometry imaging (MSI) is constantly improving in spatial resolving power, throughput and mass resolution. Although beneficial, these improvements increase data set size and content. The larger data requires correspondingly fast computer-based analyses. However, these analyses often do not scale well with increased data size. Principal component analysis (PCA) is an important analytical tool commonly used with MSI data; however, most PCA algorithms load and process the entire data set within random access memory (RAM) which is most often insufficient for large data sets. PCA algorithms that use less RAM than the data set exist but are usually much slower or sacrifice precision and are rarely used for MSI data processing. Incremental PCA (IPCA) is an alternative algorithm that avoids large RAM allocations while also preserving speed and analytical precision. Here, we demonstrate and benchmark the use of differing implementations of IPCA, PCA, and commercial software on large and often complex MSI data sets. We show that using an already-published Python-based IPCA algorithm, IPCA can be successfully applied to MSI data sets too large to fit with RAM. Furthermore, our benchmarks demonstrate that, contrary to expectations, IPCA is faster than all other tested PCA implementations on all large data sets that can be directly compared.