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Automated analysis of microplastics is essential due to the labor-intensive, time-consuming, and error-prone nature of manual methods. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy offers valuable molecular information about microplastic composition. However, efficient data analysis tools are required to effectively differentiate between various types of microplastics due to the large volume of spectral data generated by ATR-FTIR. In this study, we propose a machine learning (ML) approach utilizing ATR-FTIR spectroscopy data for accurate and efficient classification of undegraded and aged polyethylene terephthalate (PET) microplastics (MPs). We evaluate seven ML algorithms, including Random Forest (RF), Gradient Boosting (GB), Decision Tree (DT), k-Nearest Neighbors (k-NN), Logistic Regression (LR), Support Vector Machine (SVM), and Multi-Layer Perceptron (MLP), to assess their performance. The models were optimized using fivefold cross-validation and evaluated using multiple metrics such as confusion matrix, accuracy, precision, recall (sensitivity), and F1-score. The experimental results demonstrate exceptional performance by RF, GB, DT, and k-NN models, achieving an accuracy of 99% in correctly classifying undegraded and aged PET MPs. The proposed approach capitalizes on the potential of ATR-FTIR spectra to discern distinct chemical signatures of undegraded and aged PET particles, enabling precise and reliable classification. Furthermore, the method offers the benefit of automating the classification process, streamlining the analysis of environmental samples. It also presents the advantage of providing an effective means for method standardization, facilitating more automated and optimized extraction of information from spectral data. The method's versatility and potential for large-scale application make it a valuable contribution to the field of MP environmental research. [ABSTRACT FROM AUTHOR]

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Most scientific studies on microplastic (MP) pollution report their results as number of particles (e.g., particles/m2, particles/m3, particles/kg dw). An important limitation of this expression is to consider all MP particles as environmentally equivalent, regardless of their size, volume, mass, or specific surface area. Using a theoretical approach, we advocate that including such morphological attributes reveals significant differences in results of supposedly equivalent samples that consider only the number of particles. Our goal is to present how particle size and shape produce different results for hypothetical samples with the same number of particles. Therefore, from these examples we expect to stimulate the debate and contribute to improve accuracy and comparability of studies on MP pollution. [ABSTRACT FROM AUTHOR]

Simple Summary: The environmental issue posed by the distribution of plastic is largely due to their fragmentation into micro- and nanoplastics (MNPs), which are spread across aquatic, atmospheric, and terrestrial ecosystems. The discovery that these particles can easily accumulate in aquatic organisms and edible plants has rapidly drawn global attention to their potential impact on human health. Therefore, based on the One Health approach, this paper will first provide an overview of soil contamination as well as human exposure routes and toxicity pathways of MNPs. It then describes the significant role of livestock animals as a critical link between soil and human exposure, focusing on the lack of the available literature and on the role of livestock animals as reservoirs and carriers of MNP contamination along the food chain. The lack of a standardized method to detect, quantify, and characterize plastic particles in different matrices prevents the determination of their realistic load. For this reason, the development of a database where researchers can document data, both on MNP characteristics and assessment procedures, is also suggested with the perspective of training, in the future, artificial intelligence (AI) tools capable of predicting the most abundant/dangerous polymer(s) and help in guiding decisions to reduce risks to global health. Plastic pollution is a global diffuse threat, especially considering its fragmentation into microplastics (MPs) and nanoplastics (NPs). Since the contamination of the aquatic environment is already well studied, most studies have now focused on the soil. Moreover, the number of studies on the exposure routes and toxic effects of MNPs in humans is continuously increasing. Although MNPs can cause inflammation, cytotoxicity, genotoxicity and immune toxicity in livestock animals, which can accumulate ingested/inhaled plastic particles and transfer them to humans through the food chain, research on this topic is still lacking. In considering farm animals as the missing link between soil/plant contamination and human health effects, this paper aims to describe their importance as carriers and vectors of MNP contamination. As research on this topic is in its early stages, there is no standard method to quantify the amount and the characteristics of MNPs in different matrices. Therefore, the creation of a common database where researchers can report data on MNP characteristics and quantification methods could be helpful for both method standardization and the future training of an AI tool for predicting the most abundant/dangerous polymer(s), thus supporting policy decisions to reduce plastic pollution and perfectly fitting with One Health principles. [ABSTRACT FROM AUTHOR]

Amorphous silica, a specialised silicate adsorbent is extensively extracted from agricultural residues for application in various environmental domains. Wheat straws are a rich source of silica that have earlier been overlooked however demand for value addition. The study presents an innovative approach to extracting silica from wheat straw and standardising the extraction process to produce clean product. The sodium silicate solution and the amorphous silica synthesis were obtained by modifying the template mediated sol–gel method. Optimum temperature, concentration and pH were identified for the cleaner production of silica with maximum yield and favourable adsorbent characteristics. The crystallographic properties analysed by the X-Ray Diffraction revealed the amorphous nature of silica extracted from ash at 650 °C for 4 h. The structure of phytolith present in the wheat straw was observed in the form of articulated elongate undulate epidermal phytolith under scanning electron microscopy. The Energy Dispersive X-ray spectrum exhibited higher amount of silica (Si %) of 70.10% with a minimal percentage of potassium (9.96%). The sharp bend at 1025 cm−1 is attributed to the siloxane (Si–O-Si) vibrations in Fourier transform infrared spectroscopic graph of amorphous silica. The specific surface area measurements of amorphous silica showed type II isotherm curve with a hysteresis of H3 type. The optimum conditions derived to produce amorphous silica were 3 M NaOH and 3 M H2SO4 at pH 9. [ABSTRACT FROM AUTHOR]

Plastic pollution is a global diffuse threat, especially considering its fragmentation into microplastics (MPs) and nanoplastics (NPs). Since the contamination of the aquatic environment is already well studied, most studies have now focused on the soil. Moreover, the number of studies on the exposure routes and toxic effects of MNPs in humans is continuously increasing. Although MNPs can cause inflammation, cytotoxicity, genotoxicity and immune toxicity in livestock animals, which can accumulate ingested/inhaled plastic particles and transfer them to humans through the food chain, research on this topic is still lacking. In considering farm animals as the missing link between soil/plant contamination and human health effects, this paper aims to describe their importance as carriers and vectors of MNP contamination. As research on this topic is in its early stages, there is no standard method to quantify the amount and the characteristics of MNPs in different matrices. Therefore, the creation of a common database where researchers can report data on MNP characteristics and quantification methods could be helpful for both method standardization and the future training of an AI tool for predicting the most abundant/dangerous polymer(s), thus supporting policy decisions to reduce plastic pollution and perfectly fitting with One Health principles.

Life cycle assessments conducted in the last decade on forest-derived solid biofuels contain key insights to assess the environmental impact of such fuels under different contexts. This paper reports on the results of a systematic review of 87 studies that applied life cycles assessment on five types of solid biofuels: firewood, charcoal, wood chips, briquettes, and pellets. By considering the particularities of the countries in which the studies were conducted, biomass sources, end-uses and life cycle methodological choices, and key insights were derived about the global distribution of studies and what existing works can contribute to general understanding of the sustainability of wood-based fuels. First, most life cycles assessment focus on modern solid biofuels in developed countries, only 13% were on traditional solid biofuels such as firewood and charcoal in developing countries. Secondly, there are remarkable inconsistencies across studies in how they report and define their system boundaries. Thirdly, global warming potential is the most widely applied impact category. A meta-analysis of a subset of the studies (N = 26) revealed that, in general, forest-derived solid biofuels have lower global warming potential than fossil-based alternatives. Given the global imbalance of life cycle assessment efforts on forest-derived solid biofuels, there is need to mobilize capacities in order to increase applications in developing nations. However, persistent low uptake of standardized application and reporting in life cycle assessment studies perpetuates oft-mentioned limitations for cross-study comparisons. An approach to standardize system boundaries is proposed to partially address these limitations. [ABSTRACT FROM AUTHOR]

Considerable work has been done on method standardization for experimental characterization of column packings used in absorption processes. A detailed framework for determination of packing hydraulics as well as gas- and liquid-side volumetric mass transfer coefficients (k G a and k L a) has been established. Packing characterization experiments in large diameter columns result in high equipment and operating costs. Accurate extrapolation of packing properties from experiments in smaller diameter columns would therefore be highly desirable. However, diameter influence is currently not completely understood, making further work necessary. In this work, experiments for the determination of k G a and k L a values were carried out and evaluated independently in two plants (inner diameters 422 and 150 mm). Results from measurements conducted with three metal packings RSP 250Y, RMP N 250X and RMP N 250Y are in good agreement with existing literature data. k G a was found to be dependent on column diameter with larger diameters leading to increased k G a values. The overall effect (approx. 15 %) is consistent with previous works, suggesting the possibility of deriving appropriate scaling factors once the findings are validated by a larger sample size. No clear dependence of k L a values on diameter was found with deviations significantly smaller than for k G a measurements. [Display omitted] • Three column packings are surveyed using standardized methodology. • Results from two different column diameters (150 and 422 mm) are compared. • k G a values are found 15 % lower at the smaller column diameter. • No influence of column diameter on k L a values is observed. [ABSTRACT FROM AUTHOR]

Standardised molecular methods are available for the detection of norovirus from water and specific food items. Detection of norovirus from stool samples also relies on molecular methods, but differences exist between nucleic acid extraction, reverse transcription, and amplification strategies recommended by the ISO 15216-1:2017, and those employed in clinical laboratories. Here, we conduct a direct comparison of two methods for the detection and quantitation of norovirus from a stool sample and from artificially contaminated swabs. We also compare use of linear dsDNA standards as recommended in ISO 15216:2017 against an in vitro-transcribed single-stranded RNA (ssRNA) for estimation of norovirus genome copy number. Our results show that the two methods have comparable sensitivity for the detection of norovirus RNA from a clinical sample or swab. The use of a ssRNA standard revealed that quantitation performed against a linear dsDNA standard consistently underestimated the genome copy numbers by 1.5 to 2 log due to the relative inefficiency of the reverse transcription step. This has important implications for the estimation of the sensitivity of norovirus detection methods, comparability of results across sites, and assessment of viral loads that may be clinically significant or estimated to constitute infectious doses. [ABSTRACT FROM AUTHOR]

The advancing field of nanoscience has produced lower mass, smaller size, and expanded chemical composition nanoparticles over recent years. These new nanoparticles have challenged traditional analytical methods of qualification and quantification. Such advancements in nanoparticles and nanomaterials have captured the attention of toxicologists with concerns regarding the environment and human health impacts. Given that nanoparticles are only limited by size (1–100 nm), their chemical and physical characteristics can drastically change and thus alter their overall nanotoxicity in unpredictable ways. A significant limitation to the development of nanomaterials is that traditional regulatory and scientific methods used to assess the biological and environmental toxicity of chemicals do not generally apply to the assessment of nanomaterials. Significant research effort has been initiated, but much more is still needed to develop new and improved analytical measurement methods for detecting and quantitating nanomaterials in biological and environmental systems. [ABSTRACT FROM AUTHOR]

Global deterioration of marine ecosystems, together with increasing pressure to use them, has created a demand for new, more efficient and cost-efficient monitoring tools that enable assessing changes in the status of marine ecosystems. However, demonstrating the cost-efficiency of a monitoring method is not straightforward as there are no generally applicable guidelines. Our study provides a systematic literature mapping of methods and criteria that have been proposed or used since the year 2000 to evaluate the cost-efficiency of marine monitoring methods. We aimed to investigate these methods but discovered that examples of actual cost-efficiency assessments in literature were rare, contradicting the prevalent use of the term “cost-efficiency.” We identified fve different ways to compare the cost-efficiency of a marine monitoring method: (1) the cost–benefit ratio, (2) comparative studies based on an experiment, (3) comparative studies based on a literature review, (4) comparisons with other methods based on literature, and (5) subjective comparisons with other methods based on experience or intuition. Because of the observed high frequency of insufficient cost–benefit assessments, we strongly advise that more attention is paid to the coverage of both cost and efficiency parameters when evaluating the actual cost-efficiency of novel methods. Our results emphasize the need to improve the reliability and comparability of cost-efficiency assessments. We provide guidelines for future initiatives to develop a cost-efficiency assessment framework and suggestions for more unified cost-efficiency criteria. [ABSTRACT FROM AUTHOR]

Marine plastic pollution is an environmental contaminant of significant concern. There is a lack of consistency in sample collection and processing that continues to impede meta-analyses and large-scale comparisons across time and space. This is true for most taxa, including seabirds, which are the most studied megafauna group with regards to plastic ingestion research. Consequently, it is difficult to evaluate the impacts and extent of plastic contamination in seabirds fully and accurately, and to make inferences about species for which we have little or no data. We provide a synthesized set of recommendations specific for seabirds and plastic ingestion studies that include best practices in relation to sample collection, processing, and reporting, as well as highlighting some “cross-cutting” methods. We include guidance for how carcasses, regurgitations, and pellets should be handled and treated to prevent cross-contamination, and a discussion of what size class of microplastics can be assessed in each sample type. Although we focus on marine bird samples, we also include standardized techniques to remove sediment and biological material that are generalizable to other taxa. Lastly, metrics and data presentation of ingested plastics are briefly reviewed in the context of seabird studies.

Antimicrobial resistance (AMR) surveillance of mycoplasmas of veterinary importance has been held back for years due to lack of harmonized methods for antimicrobial susceptibility testing (AST) and interpretative criteria, resulting in a crucial shortage of data. To address AMR in ruminant mycoplasmas, we mobilized a long-established clinical surveillance network called “Vigimyc.” Here we describe our surveillance strategy and detail the results obtained during a 2-year monitoring period. We also assess how far our system complies with current guidelines on AMR surveillance and how it could serve to build epidemiological cut-off values (ECOFFs), as a first attainable criterion to help harmonize monitoring efforts and move forward to clinical breakpoints. Clinical surveillance through Vigimyc enables continuous collection, identification and preservation of Mycoplasma spp. isolates along with metadata. The most frequent pathogens, i.e., M. bovis and species belonging to M. mycoides group, show stable clinicoepidemiological trends and were included for annual AST. In the absence of interpretative criteria for ruminant mycoplasmas, we compared yearly minimum inhibitory concentration (MIC) results against reference datasets. We also ran a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis on the overall service provided by our AMR surveillance strategy. Results of the 2018–2019 surveillance campaign were consistent with the reference datasets, with M. bovis isolates showing high MIC values for all antimicrobial classes except fluoroquinolones, and species of the Mycoides group showing predominantly low MIC values. A few new AMR patterns were detected, such as M. bovis with lower spectinomycin MICs. Our reference dataset partially complied with European Committee on Antimicrobial Susceptibility Testing (EUCAST) requirements, and we were able to propose tentative epidemiological cut-off values (TECOFFs) for M. bovis with tilmicosin and spectinomycin and for M. mycoides group with tilmicosin and lincomycin. These TECOFFs were consistent with other published data and the clinical breakpoints of Pasteurellaceae, which are often used as surrogates for mycoplasmas. SWOT analysis highlighted the benefit of pairing clinical and antimicrobial resistance surveillance despite the AST method-related gaps that remain. The international community should now direct efforts toward AST method harmonization and clinical interpretation.

Quantification of cyclophosphamide, palcitaxel and etoposide in water sample using simple analytical technique is challenging. In this study, we have developed a simple, sensitive, robust and accurate method for the detection and quantification of cyclophosphamide, etoposide, and paclitaxel using high‐performance liquid chromatography and validated the same. The analytical conditions were achieved by the high‐performance liquid chromatography system on a C18 column (250 mm × 4.6 mm × 5 µm) under isocratic mode. The retention time for cyclophosphamide, paclitaxel and etoposide were 2:40.1, 3:32.3 and 3:49.3 min respectively. We validated the method by evaluating system sensitivity and linearity. We anticipate the method to be useful in quantification of cyclophosphamide, paclitaxel and etoposide in water sample. [ABSTRACT FROM AUTHOR]

The article discusses the current prospects for herbal medicines in treatment practice, specifically, in the therapy of acute respiratory infections (ARI). The authors highlight the properties, characteristic features, principles and objectives of the phytotherapeutic method. Based on their own experience and analysis of a number of experimental and clinical reports, the use of Umckalor, the Pelargonium sidoides extract (Pelargonium sidoides EPs 7630), is substantiated in the treatment of ARI and its complications in children.

In this chapter, the analytical workflow typically used for the development and validation of an analytical method tailored to food allergen detection and quantification is presented. The main steps defining the workflow are herein described and commented with specific notes about the critical issues that can be faced and common solutions to be adopted. References to guidelines and/or recommendation available from official bodies, as well as main papers from international consortia operating on the specific research field, are also reported, whenever possible. As such, this chapter may represent a practical guide to drive method development in the standardization of analytical methods for food allergen detection., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

For the past two decades, the need to shield strategic maritime interests, to tackle criminality and terrorism at or from the sea and to conserve valuable marine resources has been recognized at the highest political level. Acknowledging and accounting for the interplay between climate change, the vulnerability of coastal populations and the occurrence of maritime criminality should be part of any ocean governance process. Still, given the complex interactions between climate change and socio-economic components of the marine realm, it has become urgent to establish a solid methodological framework, which could lead to sound and effective decisions. We propose that any such framework should not be built from scratch. The adaptation of well tested, existing uncertainty-management tools, such as Cumulative Effect Assessments, could serve as a solid basis to account for the magnitude and directionality of the dependencies between the impacts of climate change and the occurrence of maritime criminality, offering spatial explicit risk evaluations. Multi-Criteria Decision Making could then be employed to better and faster inform decision-makers. These mechanisms could provide a framework for comparison of alternative mitigation and adaptation actions and are essential in assessing responses to tackle maritime crime in the context of climate change. [ABSTRACT FROM AUTHOR]

The re-emergence of swine dysentery ( Brachyspira-associated muco-haemorrhagic colitis) since the late 2000s has illuminated diagnostic challenges associated with this genus. The methods used to detect, identify, and characterize Brachyspira from clinical samples have not been standardized, and laboratories frequently rely heavily on in-house techniques. Particularly concerning is the lack of standardized methods for determining and interpreting the antimicrobial susceptibility of Brachyspira spp. The integration of laboratory data into a treatment plan is a critical component of prudent antimicrobial usage. Therefore, the lack of standardized methods is an important limitation to the evidence-based use of antimicrobials. This review will focus on describing the methodological limitations and inconsistencies between current susceptibility testing schemes employed for Brachyspira, provide an overview of what we do know about the susceptibility of these organisms, and suggest future directions to improve and standardize diagnostic strategies. [ABSTRACT FROM AUTHOR]

Microplastics are ubiquitous in the environment, are frequently ingested by organisms, and may potentially cause harm. A range of studies have found significant levels of microplastics in beach sand. However, there is a considerable amount of methodological variability among these studies. Methodological variation currently limits comparisons as there is no standard procedure for sampling or extraction of microplastics. We identify key sampling and extraction procedures across the literature through a detailed review. We find that sampling depth, sampling location, number of repeat extractions, and settling times are the critical parameters of variation. Next, using a case-study we determine whether and to what extent these differences impact study outcomes. By investigating the common practices identified in the literature with the case-study, we provide a standard operating procedure for sampling and extracting microplastics from beach sand. [ABSTRACT FROM AUTHOR]

Therapeutic Drug monitoring (TDM) is a multidisciplinary endeavor encompassing skills of the laboratory, clinical pharmacologists and physicians aimed at providing the best possible patient care via the individualization of drug therapy. The expanding role of liquid chromatography - tandem mass spectrometry (LC–MS/MS) in TDM is based on dramatic improvements in analytical instrumentation, thereby enabling unique specificity, extreme sensitivity, high throughput, the simultaneous analysis of multiple drugs and metabolites in a drop of blood within several minutes and the use of multiplexed platforms for the rapid determination of single analytes. However, analysis by LC–MS/MS does not automatically ensure reliable results and superiority over other assays. The aim of this article is to provide an overview of the current use, advantages, and challenges of LC–MS/MS methods in TDM services, to summarize ongoing issues, and to provide an outlook on new perspectives. [ABSTRACT FROM AUTHOR]

Data interpretation and comparison in enzyme assays can be challenging because of the complex nature of the environment and variations in methods employed. This letter provides an overview of common enzyme assays, the need for methods standardization, and solutions addressing some of the concerns in microplate fluorimetric assay approaches. [ABSTRACT FROM AUTHOR]

Despite considerable advances in the past decade, melanin research still suffers from the lack of universally accepted and shared nomenclature, methodologies, and structural models. This paper stems from the joint efforts of chemists, biochemists, physicists, biologists, and physicians with recognized and consolidated expertise in the field of melanins and melanogenesis, who critically reviewed and experimentally revisited methods, standards, and protocols to provide for the first time a consensus set of recommended procedures to be adopted and shared by researchers involved in pigment cell research. The aim of the paper was to define an unprecedented frame of reference built on cutting-edge knowledge and state-of-the-art methodology, to enable reliable comparison of results among laboratories and new progress in the field based on standardized methods and shared information. [ABSTRACT FROM AUTHOR]

After Hemoglobin A (HbA), therapeutic targets for monitoring diabetes therapy were recommended, first, National Glycohemoglobin Standardization Program (NGSP), then, the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) developed standardization initiatives. The aim of this article is to demonstrate the role of a proficiency testing (PT) programs in monitoring the long-term effect of these initiatives and the current status of HbA measurement. Measurement precision as a coefficient of variation (CV), measurement bias (bias), and satisfactory HbA result rates in proficiency testing (PT) surveys were evaluated using fresh single donor whole blood PT items and assigned values from a NGSP-certified secondary reference laboratory. Between 2000 and 2010, both CV and bias of the IC measurement method showed a decreasing trend. While the CV of the HPLC measurement method decreased, no significant change was observed in its bias. The rates of satisfactory HbA results in PT surveys were higher in HPLC users than IC users. In 2010, the average CVs in HPLC and IC groups were 2.6 and 3.4 %, biases were 2.7 and 1.8 %, and corresponding total error (TE) estimates were 7.8 and 8.5 %, respectively. These TE values were higher than the maximum permissible measurement error of 7 %, developed based on clinical use of the test. The NGSP and the IFCC networks have promoted improvements in HbA testing; however, tightening of NGSP method certification criteria seems to be necessary to achieve a maximum permissible measurement error of 7 %. [ABSTRACT FROM AUTHOR]

The members of the committee NMP 264 “Chemical analysis of non-oxidic raw and basic materials” of the German Standards Institute (DIN) have organized two interlaboratory comparisons for multielement determination of trace elements in silicon carbide (SiC) powders via direct solid sampling methods. One of the interlaboratory comparisons was based on the application of inductively coupled plasma optical emission spectrometry with electrothermal vaporization (ETV ICP OES), and the other on the application of optical emission spectrometry with direct current arc (DC arc OES). The interlaboratory comparisons were organized and performed in the framework of the development of two standards related to “the determination of mass fractions of metallic impurities in powders and grain sizes of ceramic raw and basic materials” by both methods. SiC powders were used as typical examples of this category of material. The aim of the interlaboratory comparisons was to determine the repeatability and reproducibility of both analytical methods to be standardized. This was an important contribution to the practical applicability of both draft standards. Eight laboratories participated in the interlaboratory comparison with ETV ICP OES and nine in the interlaboratory comparison with DC arc OES. Ten analytes were investigated by ETV ICP OES and eleven by DC arc OES. Six different SiC powders were used for the calibration. The mass fractions of their relevant trace elements were determined after wet chemical digestion. All participants followed the analytical requirements described in the draft standards. In the calculation process, three of the calibration materials were used successively as analytical samples. This was managed in the following manner: the material that had just been used as the analytical sample was excluded from the calibration, so the five other materials were used to establish the calibration plot. The results from the interlaboratory comparisons were summarized and used to determine the repeatability and the reproducibility (expressed as standard deviations) of both methods. The calculation was carried out according to the related standard. The results are specified and discussed in this paper, as are the optimized analytical conditions determined and used by the authors of this paper. For both methods, the repeatability relative standard deviations were <25%, usually ~10%, and the reproducibility relative standard deviations were <35%, usually ~15%. These results were regarded as satifactory for both methods intended for rapid analysis of materials for which decomposition is difficult and time-consuming. Also described are some results from an interlaboratory comparison used to certify one of the materials that had been previously used for validation in both interlaboratory comparisons. Thirty laboratories (from eight countries) participated in this interlaboratory comparison for certification. As examples, accepted results are shown from laboratories that used ETV ICP OES or DC arc OES and had performed calibrations by using solutions or oxides, respectively. The certified mass fractions of the certified reference materials were also compared with the mass fractions determined in the interlaboratory comparisons performed within the framework of method standardization. Good agreement was found for most of the analytes. [ABSTRACT FROM AUTHOR]

Biochemical methane potential (BMP) tests used to determine the ultimate methane yield of organic substrates are not sufficiently standardized to ensure reproducibility among laboratories. In this contribution, a standardized BMP protocol was tested in a large inter-laboratory project, and results were used to quantify sources of variability and to refine validation criteria designed to improve BMP reproducibility. Three sets of BMP tests were carried out by more than thirty laboratories from fourteen countries, using multiple measurement methods, resulting in more than 400 BMP values. Four complex but homogenous substrates were tested, and additionally, microcrystalline cellulose was used as a positive control. Inter-laboratory variability in reported BMP values was moderate. Relative standard deviation among laboratories (RSDR) was 7.5 to 24%, but relative range (RR) was 31 to 130%. Systematic biases were associated with both laboratories and tests within laboratories. Substrate volatile solids (VS) measurement and inoculum origin did not make major contributions to variability, but errors in data processing or data entry were important. There was evidence of negative biases in manual manometric and manual volumetric measurement methods. Still, much of the observed variation in BMP values was not clearly related to any of these factors and is probably the result of particular practices that vary among laboratories or even technicians. Based on analysis of calculated BMP values, a set of recommendations was developed, considering measurement, data processing, validation, and reporting. Recommended validation criteria are: (i) test duration at least 1% net 3 d, (ii) relative standard deviation for cellulose BMP not higher than 6%, and (iii) mean cellulose BMP between 340 and 395 NmLCH4 gVS−1. Evidence from this large dataset shows that following the recommendations—in particular, application of validation criteria—can substantially improve reproducibility, with RSDR < 8% and RR < 25% for all substrates. The cellulose BMP criterion was particularly important. Results show that is possible to measure very similar BMP values with different measurement methods, but to meet the recommended validation criteria, some laboratories must make changes to their BMP methods. To help improve the practice of BMP measurement, a new website with detailed, up-to-date guidance on BMP measurement and data processing was established. [ABSTRACT FROM AUTHOR]

The hemagglutination inhibition assay (HAI) is a classical method used worldwide in many analytical applications, including pathogen identification, vaccine production monitoring, and detection and characterization of pathogen-neutralizing antibodies (n-Ab). This is also a World Health Organization (WHO) reference method for the global surveillance of influenza viruses, which provides the information needed for the annual reformulation of the flu vaccine. HAI is a simple and inexpensive method that is performed without sophisticated equipment. However, it has to be carried out with fresh red blood cells (RBCs), a highly variable, unstable, and hard to mass-produce reagent, which impairs assay reproducibility. Here, we used the tests employed for influenza surveillance as a model to develop synthrocytes © , a synthetic reagent that could substitute animal erythrocytes in HAI. Contrary to previous examples exploiting sophisticated production paths to generate therapeutic synthetic RBCs, we founded production on the identification of microparticles able to generate different sedimentation patterns when agglutinated or not, which is the main requirement for HAI testing. Upon incorporation of influenza-binding receptors and optimization of production and assay conditions, synthrocytes succeeded in binding influenza A(H1N1) and B viruses as erythrocytes do, but were faster and more stable. Synthrocytes were finally employed in an HAI-like assay to detect the WHO reference reagents for influenza surveillance. Our results show that it is possible to substitute erythrocytes in classical HAI by a highly tuneable and potentially mass-produced synthetic reagent, which should facilitate worldwide HAI standardization with minimal equipment or training requirements.