Chemical Analysis Research Articles

Expansion in low calcium fly ash-based geopolymer concrete: chemical factors influenced by silica fume and NaOH concentration

Geopolymer technology offers a sustainable alternative to energy-intensive cement production, potentially reducing dependence on natural resources and mitigating environmental impact. Silica fumes (SF) are mostly used to enhance the fresh, hardened, and durable performance of geopolymers. However, their influence on geopolymerization may result in the expansion of the geopolymer mortar (GPM) due to reaction with alkaline liquid. In this study, the effect of NaOH concentration, particle size and dosage of SF, alkaline liquid-to-binder ratio, Na2SiO3-to-NaOH ratio, and sand-to-binder ratio on the expansion behavior of a low calcium fly ash (FA)-based GPM was investigated. FA-based GPMs were tested using two distinct SFs with varying particle sizes (SF1 = 9.5 µm and SF2 = 16.2 µm) and two varying dosages of SF (2.5% and 5%). Physical observations of GPMs revealed that NaOH concentration, particle size and dosage of SF are crucial factors that significantly impact the expansion which is concomitant with a reduction in compressive strength. Analytical techniques such as X-ray diffraction (XRD), Rietveld analysis, Fourier transform infrared spectroscopy (FTIR), and Thermo Gravimetric Analysis (TGA) were employed to comprehensively investigate reaction product(s) that led to the expansion of such GPMs. The chemical analysis confirmed the presence of excess analcime in the mortars fabricated by blending SF1 and FA at 12 M NaOH concentration. This study is the first to report the expansion of low calcium FA-based GPMs blended with a SF of particle size 9.5 µm. These findings emphasize the significance of selecting the appropriate SF particle size to prevent expansion and ensure optimal compressive strength in geopolymer applications.

Assessing the Optimal Antibacterial Action of Lavandula stoechas L., Thymus zygis L., and Eucalyptus camaldulensis Dehnh Essential Oils

The use of combined essential oils (EOs) is a new technique that can improve their preservative effects while minimizing their sensory impact in foods. The aim of this study was to determine the chemical profile of three essential oils (EOs) extracted from Lavandula stoechas L. (Ls), Thymus zygis L. (Tz), and Eucalyptus camaldulensis Dehnh (Ec) and to evaluate their synergistic antibacterial activity for optimal inhibition against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus using an augmented Simplex centroid mixing scheme. The essential oils were extracted by hydrodistillation and analyzed via gas chromatography–mass spectrometry. Anti-bacterial potency was evaluated by disk diffusion. Chemical analysis revealed the main compounds in Lavandula stoechas (Ls) essential oil: camphor (36.15%), followed by fenchone (16.57%) and Z-8-hydroxy linalool (8.28%). The Thymus zygis (Tz) essential oil is dominated by δ-terpineol (27.64%), δ-3-carene (15.7%), and thymol (14.17%). In contrast, the Eucalyptus camaldulensis (Ec) essential oil contains mainly 1,8-cineole (43.61%), γ-terpinene (11.71%), and α-terpineol (10.58%). The optimal mixture is the binary association of 40% E. camaldulensis EO and 60% T. zygis EO, which provides an effective inhibition diameter (ID) of 13.37 mm to inhibit S. aureus. Furthermore, the formulation of 27% and 73% EOs of E. camaldulensis and T. zygis, respectively, corresponds to the mixture required to achieve the optimum inhibition diameter (ID = 11.55 mm) against E. coli. In addition, the mixture of 29% EO of E. camaldulensis and 71% EO of T. zygis is the optimum mixture to inhibit B. subtilis, with an inhibition diameter of 12.31 mm. These findings highlight the potency of antibacterial formulations of these essential oils and suggest that they might be used as substitutes for conventional drugs to prevent the development of bacteria responsible for serious infections and food spoilage.

The Influence of Tourist Attraction and Digital Marketing on Return Visit Interest with Tourist Satisfaction as a Mediating Variable in Tinalah Tourism Village, Kulonprogo Regency

The objectives of this study include: (1) To determine the effect of tourist attraction on tourist satisfaction at Tinalah tourist attraction, Kulonprogo Regency. (2) To determine the effect of digital marketing on tourist satisfaction at Tinalah Tourism Village, Kulonprogo Regency. (3) To determine the effect of tourist satisfaction on interest in visiting again at Tinalah Tourism Village, Kulonprogo Regency. (4) To determine the effect of tourist attraction on return visit interest in Tinalah Tourism Village, Kulonprogo Regency, which is mediated by tourist satisfaction. (5) To determine the effect of digital marketing on return visit interest in the Tourism Village, Kulonprogo Regency, which is mediated by tourist satisfaction. The research design used in this research was quantitative research design. The population used in this study were tourists visiting Tinalah Tourism Village, Tinalah, Kulonprogo Regency with a large and unknown number. The sampling technique used in this study is non probability sampling by purposive sampling. The respondents who met the criteria were tourists who had visited Tinalah Tourism Village with a maximum limit of the last three months. The research sample amounted to 150 people. The data collection procedure in this study is to use the questionnaire method. The analytical tool used is Patial Least Square (PLS), which is a variance-based SEM, with SmartPLS 2.0 software. Based on the results of the analysis discussed in the previous chapter, the following conclusions can be given: (1) Attractiveness of tourist objects has a positive effect on tourist satisfaction in Tinalah Tourism Village, Kulonprogo Regency. (2) Digital marketing has a positive effect on tourist satisfaction in Tinalah Tourism Village, Kulonprogo Regency. (3) Tourist satisfaction has a positive effect on interest in visiting again at Tinalah Tourism Village, Kulonprogo Regency. (4) Tourism attraction has a positive effect on interest in visiting again at Tinalah Tourism Village, Kulonprogo Regency, which is mediated by tourist satisfaction. (5) Digital marketing has a positive effect on interest in visiting again at Tinalah Tourism Village, Kulonprogo Regency, which is mediated by tourist satisfaction.

A multiple biomolecules-based rapid life detection protocol embedded in a rover scientific subsystem for soil sample analysis

The study of whether life exists, is extinct, or not depends on various sophisticated experimental studies, as many different signatures of life can be used. The experimental procedures that can be performed to identify life can be further restricted by time, resources, and mobility constraints. Therefore, any research analyzing the presence of extraterrestrial life must be precise and unambiguous. This research focuses on the objective of the extraterrestrial life detection domain and seeks to provide an efficient protocol that can produce life detection decisions based on empirical data obtained through chemical analysis under time and resource-constrained conditions. While the majority of existing frameworks in this field are designed to identify biomolecules, our goal is to accomplish the same with minimal operational expense and mission complexity. We argue that the thoughtful integration of multiple biomolecular detections with lesser complexity and a robust framework can improve overall mission performance by satisfying the necessary time and resource constraints. In this study, a rapid multiple biomolecules-based life detection protocol (MBLDP-R) from soil samples is developed from scratch and embedded in an operational scientific rover subsystem targeted for planetary analysis missions. The study uses artificial biomolecule samples and simulated extraterrestrial environments to illustrate the suggested protocol’s end-to-end process. First, we list a few significant biomolecules, including lipids, proteins, carbohydrates, nucleic acids, ammonia, and pigments. Then, a weighted qualitative test scoring is applied to sort out the best test method for the finally selected biomolecules which are used as operational analogue to showcase the protocol’s in-situ analysis and decision-making capabilities. Based on the suitable biomolecules, a scientific exploration subsystem is developed, and the implemented protocol is built to perform onboard sample analysis. Evaluation results show that: (1) the proposed MBLDP-R protocol could effectively predict the classes with an average f1-score of 98.65% (macro) and 90.00% (micro), (2) the area under the Receiver Operating Characteristics (AUC-ROC) curve shows the sample categories to be correctly predicted 92% of the time (97% for Extant, 88% for Extinct, and 92% in the case of NPL), and (3) the protocol is time-efficient with an average completion time of 17.60 min, demonstrating the protocol’s rapid nature in detecting biosignatures in soil samples. The research outcome yields useful additional data for related future studies, particularly in the design of scientific frameworks for mission-specific requirements with limited resources while also serving as a reference point for constraint evaluation methods for similar systems.

Analysis of GCRV Pathogenesis and Therapeutic Measures Through Proteomic and Metabolomic Investigations in GCRV-Infected Tissues of Grass Carp (Ctenopharyngodon idella).

Hemorrhagic disease caused by grass carp reovirus (GCRV) infection is a major problem affecting the grass carp aquaculture industry. Therefore, inhibiting the spread of GCRV infection is of great economic significance. Herein, we sequenced five tissues (gill, liver, intestine, kidney, and muscle) from grass carp before and after GCRV infection using data-independent acquisition proteomic and untargeted metabolomic technologies, and quantitatively identified 10,808 proteins and 4040 metabolites. Then, we analyzed the differentially expressed proteins (DEPs) and metabolites (DEMs) before and after GCRV infection in the five tissues. Gene ontology analysis revealed that the five tissue DEPs were enriched in metabolic, including carbohydrate and lipid metabolic processes. Chemical taxonomy analysis showed that the categories of DEMs mainly included carbohydrates and lipids, such as fatty acids, glycerophospholipids, steroids, and their derivatives. Both the proteomic and the metabolomic data showed that GCRV affected the carbohydrate and lipid metabolism in the host. Shared pathway analysis was performed at both the protein and metabolic levels, showing significant enrichment of the glycolysis and pentose phosphate pathways (p < 0.001). Further analysis of glycolysis and pentose phosphate pathway inhibitors revealed that these two pathways are important for GCRV replication. As the kidney was the most affected among the five tissues, we analyzed the butanoate metabolism in the kidney, which revealed that most of the differentially expressed proteins and differently expressed metabolites in the butanoate metabolism were related to the TCA cycle. Further investigation showed that fumaric acid, an intermediate product in the TCA cycle, significantly inhibited GCRV replication in the CIK cells (p < 0.001), and that this inhibitory effect may be related to its induction of interferon system activation. The addition of fumaric acid to feed increased the survival rate of juvenile grass carp by 19.60% during GCRV infection, and protected the tissues of those infected with GCRV, making it a potential anti-GCRV feed additive. Our results provide new perspectives on GCRV pathogenesis and antiviral strategies for grass carp.

Phenolics in soymilk manufactured from black and Proto soybeans by two continuous-ultrahigh-temperature-processing technologies inhibit DU145-prostate cancer cell proliferation through apoptosis.

Plant genotypes and processing technologies affect health properties of foods. How thermal processes with different sterilization values influence polyphenols in soymilk manufactured from different genotypes, particularly black soybean has not been well characterized. This study's aims were to investigate how one- and two-phase ultrahigh temperature (UHT) processing technologies, with wide differences of lethality (F0 158.5 and 6.35, respectively), affected anti-prostate cancer DU145-cell properties of black soymilk compared to light-yellow-Proto soymilk. Phenolics were extracted from soymilk and used for chemical, cell cycle and apoptosis analyses. Total isoflavones and genistein in black soymilk were significantly higher than Proto soymilk by either processing methods. Compared to one-phase processing, two-phase produced higher gallic acid in both soybeans, and higher oxygen radical absorbance capacity (ORAC) in black soymilk. Soymilk processed from both genotypes by both UHT methods inhibited DU145 cells. Two-phase-UHT processed black soymilk was more effective than one-phase UHT-processed soymilk. IC50 values (mg/mL) of black and yellow soy extracts against prostate cancer cells differed only by 11%-25%, which were lower than the differences of total isoflavone (29%-33%) or genistein (>50% between two beans). The mechanism by which soymilk inhibited DU145 cell proliferation was through apoptosis as evidenced by cell cycle analyses and expressions of caspase-3, Bcl-2, and PARP-1 proteins. Antioxidant properties, isoflavones, and phenolic acids were negatively correlated with prostate-cancer-cell inhibition IC50 (p<0.05) with ORAC having the highest coefficient (r=-0.98). Overall, two-phase-UHT processing of soybean would produce soymilk products with a higher health benefit than a one-phase UHT method. PRACTICAL APPLICATION: This study characterized the potential prostate cancer prevention effect of soymilk's phenolic extract in black soybean and compared with yellow soybean. The crude extract can be prepared much less costly than purified isoflavones and has potential to be developed into a dietary supplement. This study shows differences of soymilks made by continuous high-temperature processing of two soybean types and can serve as a scientific foundation for future clinical research and commercialization.

Increasing accuracy in predicting mode I fracture toughness of rock structures: a comparative analysis of the rock engineering system method

The investigation of crack initiation and expansion is vital for the stability of structures. The Mode I fracture toughness (KIc) of rocks is a key property used to predict crack propagation in tension and hydraulic fracturing. Various methods have been introduced to determine KIc, but results differ due to factors like sample dimensions, crack geometry, groove type, and loading conditions. The cracked chevron notched Brazilian disc (CCNBD) sample is commonly used in laboratory tests for its easy preparation. This study employs the rock engineering system (RES) technique to overcome the challenges of time-consuming and costly laboratory tests and the uncertainty in traditional methods (analytical, numerical, experimental, laboratory, regression). Using 88 CCNBD rock samples proposed by ISRM, input parameters include thickness of the disc specimen (B), uniaxial tensile strength (σt), initial crack length (α0), radius of the disc specimen (R), crack length (αB), and the length of the final crack (α1). The RES-based model used 70 data points (80% of the dataset) for development, and 18 data points (20%) for evaluation. Regression analysis compared the performance of the RES method, using statistical indicators such as squared correlation coefficient (R2), mean square error (MSE), and root mean square error (RMSE) to measure accuracy. The RES-based method outperformed other regression techniques, demonstrating significantly enhanced accuracy. This highlights the effectiveness and superior performance of the RES method in estimating fracture toughness, particularly for CCNBD samples, showcasing its potential as a robust analytical tool.

A Critical Evaluation of Network Approaches for Studying Species Interactions

Ecological networks of species interactions are popular and provide powerful analytical tools for understanding variation in community structure and ecosystem functioning. However, network analyses and commonly used metrics such as nestedness and connectance have also attracted criticism. One major concern is that observed patterns are misinterpreted as niche properties such as specialization, whereas they may instead merely reflect variation in sampling, abundance, and/or diversity. As a result, studies potentially draw flawed conclusions about ecological function, stability, or coextinction risks. We highlight potential biases in analyzing and interpreting species-interaction networks and review the solutions available to overcome them, among which we particularly recommend the use of null models that account for species abundances. We show why considering variation across species and networks is important for understanding species interactions and their consequences. Network analyses can advance knowledge on the principles of species interactions but only when judiciously applied.

Insights into the Structure and Dynamics of Proteins from 19F Solution NMR Spectroscopy.

19F NMR spectroscopy has recently witnessed a resurgence as an attractive analytical tool for the study of the structure and dynamics of biomolecules in vitro and in cells, despite reports of its applications in biomolecular NMR since the 1970s. The high gyromagnetic ratio, large chemical shift dispersion, and complete absence of the spin 1/2 19F nucleus from biomolecules results in background-free, high-resolution 19F NMR spectra. The introduction of 19F probes in a few selected locations in biomolecules reduces spectral crowding despite its increased line width in comparison to typical 1H NMR line widths and allows rapid site-specific measurements from simple 1D spectra alone. The design and synthesis of novel 19F probes with reduced line widths and increased chemical shift sensitivity to the surrounding environment, together with advances in labeling techniques, NMR methodology, and hardware, have overcome several drawbacks of 19F NMR spectroscopy. The increased interest and widespread use of 19F NMR spectroscopy of biomolecules is gradually establishing it as a sensitive and high-resolution probe of biomolecular structure and dynamics, supplementing traditional 13C/15N-based methods. This Review focuses on the advances in 19F solution NMR spectroscopy of proteins in the past 5 years, with an emphasis on novel 19F tags and labeling techniques, NMR experiments to probe protein structure and conformational dynamics in vitro, and in-cell NMR applications.

Pathological Changes and CYP1A1 Expression as Biomarkers of Pollution in Sarpa Salpa and Diplodus Sargus.

In a marine ecosystem, the most sensitive organisms to environmental changes, mainly to anthropic pressures, are fishes and invertebrates. Therefore, they are considered the ideal targets to indirectly evaluate the health of an entire ecosystem. Teleost fishes, particularly those that occupy the highest trophic levels, can accumulate toxic substances through their diet. In this study, we used two fish species with sedentary behavior and trophic habits, Diplodus sargus and Sarpa salpa, caught in two areas at different anthropic pressures divided into the Gulf of Naples (Na) and the Gulf of Salerno (Sa). This study aimed to correlate the pathological alterations in target organs in both species with known concentrations of polychlorinated biphenyls (PCBs) and heavy metals (lead and cadmium) to the expression of CYP1A1. Histological examination took into consideration circulatory disorders, increase in melanomacrophages (MMs) number, inflammation in kidney and hepatopancreas and gonadal stage maturation. Next, the pathological and morphological changes found were compared to immunohistochemical expression of CYP1A1 in the same samples. Chemical analysis of PCBs, based on 28, 52, 101, 138, 153, and 180 congeners, and heavy metals, were performed on hepatopancreas and muscle samples. Higher median values of PCBs concentration were detected in both species in the Salerno area (8.1 ng/g in Diplodus sargus muscles and 51.1 ng/g in Sarpa salpa hepatopancreas, respectively), although the values were consistently below the legal limits. No critical values were found for lead and cadmium. Therefore, we hypothesized that CYP1A1 and pathological alterations were more expressed in fish from Salerno area. The pathological changes showed a statistically significant difference in inflammation of the kidneys (p < 0.0001) between S. salpa of both Gulfs. In addition, we found a statistically significant difference in the assessment of the increase in MMs/MMCs (p = 0.0384) and circulation disorders (p = 0.0325) of hepatopancreas in D. sargus of both Gulfs. As not all the variables considered showed statistical significance, the analysis of the results does not fully support the correlation between the highest levels of contaminants found in the Salerno area and the expression of CYP1A1. Our data could be a starting point for future studies to better correlate the role of CYP1A1 to pollutants, considering this is the first study involving two of the most common species in the Mediterranean Sea. Thus, future studies could include other species to improve and increase records.

GGR Handbook of Rock and Mineral Analysis Chapter 1 (Part 2) Sampling as Part of the Measurement Process

This chapter (Sampling as Part of the Measurement Process) is a contribution to the Geostandards and Geoanalytical Research Handbook of Rock and Mineral Analysis – an online textbook that is a fully revised and updated edition of A Handbook of Silicate Rock Analysis (P. J. Potts, 1987, Blackie, Glasgow).Chapter 1 (Part 2) forms part of Section 1 of the handbook dealing with fundamentals of measurement and instrument design. The geochemical measurement process is considered to begin when the primary sample is taken from the sampling target, rather than when that sample arrives at the laboratory. This integration of sampling within the measurement procedure enables both sampling and chemical analysis to be optimised in order to achieve a measurement procedure that is fit for its intended geochemical purpose. The key metric in judging this fitness for purpose, and hence validating a measurement procedure, is the uncertainty of each measurement value. This measurement uncertainty is explained, together with methods to estimate and express it in a way that includes the contribution from sampling, with a worked example. The resultant more realistic estimates of measurement uncertainty are shown to improve the reliability of the geochemical interpretation of measurement values.

Phytochemical Profiling and Anti-VanA Activity of Pulegone Extracted from Ziziphora tenuior Flower Against Vancomycin-Resistant Enterococci: an In Silico Approach.

Ziziphora tenuior is a herb known for its potent pharmaceutical activities. However, the specific compounds of the flowers of this herb have not been fully studied yet. This study used GC-MS to conduct a chemical analysis of the methanol and dichloromethane extracts of Z. tenuior flowers. Additionally, it sought to assess the potential antibacterial activity of the extracts against vancomycin-resistant enterococci (VRE) bacteria by predicting the interactions between one of the most prevalent compounds in the extracts and the D-alanyl-D-lactate ligase (VanA) protein, which is responsible for enterococci resistant to vancomycin. The results revealed a total of 15 compounds in the methanolic extract and 12 compounds in the dichloromethane extract. Among these, 5-methyl-2-(1-methylethylidene)-cyclohexanone, also known as pulegone, constituting 52.6 % of the methanolic extract and 34.6 % of the dichloromethane extract, was the most abundant compound in the extracts. Furthermore, the in-silico analysis demonstrated that pulegone exhibited significant interactions with VanA, as indicated by docking energy values of -7 kcal/mol and the formation of one hydrogen bond. The study suggests that pulegone shows promise as an antibacterial agent against VRE by potentially interacting with VanA protein and serving as a key inhibitor in fighting vancomycin resistance.

Fixation of Tripotassium Citrate Flame Retardant Using a Sorbitol and Citric Acid Wood-Modification Treatment.

Wood modification has been explored in various ways to enhance dimensional stability and reduce flammability, with a focus on environmentally friendly treatments to meet market demands. This study aimed to investigate the efficacy of new, potential fire-retardant materials. Specifically, the study examined the combination of tripotassium citrate (TPC), a water-soluble and bio-based fire retardant, with sorbitol and citric acid (SorCA), an eco-friendly thermosetting resin previously studied. While TPC is known to control combustion, its application in wood modification has not been thoroughly researched. To assess the fixation and flammability of these fire retardants, tests were conducted on Scots Pine (Pinus sylvestris L.), including chemical analysis, dimensional stability, mechanical properties, flame retardancy, and leaching tests. The combination of SorCA and TPC showed high weight percent gain (WPG) values; however, leaching and anti-swelling efficiency (ASE) tests revealed challenges in fixation stability. The dynamic mechanical properties were reduced, whereas the static strength values were in the same range compared with untreated wood. While TPC exhibited high flame retardancy prior to leaching, its efficacy diminished post-leaching, underscoring challenges in fixation and the need for improved retention strategies. Bunsen burner tests conducted on leached specimens indicated enhanced performance even under severe leaching conditions as per the EN 84:2020 procedure. However, cone calorimetry measurements showed less favorable outcomes, emphasizing the necessity for further investigation into optimizing TPC retention and enhancing treatment efficacy.

Insights into Martian bedform migration: Results from Gale, Jezero and Pasteur craters

AbstractAn attempt is made in this study to advance the understanding of the sand movement on Mars by studying the bedform migration at Gale, Jezero and Pasteur craters. The study on the grain size distribution at Gale Crater using Curiosity rover (MAHLI and APXS) observations reveals that the grains with smaller diameters (~50–150 μ) are more prone to migration and vice‐versa, which gives an idea of the necessary requirements that initiate bedform migration. The chemical analysis of the surface materials at the Gale crater revealed elevated concentrations of P2O5, SO3, Cl and Zn in soil compared to sand and active transportation processes for sand but not soil. The comprehensive chemical makeup of the Martian soil (inactive bedforms) and sand (active bedforms) is characterized by its basaltic nature, with enriched volatile elements such as sulphur, chlorine and zinc, and the presence of minerals like plagioclase, pyroxene and olivine due to the cohesive nature of inactive bedforms. Physical weathering and wind flow velocity play a pivotal role in the formation of different sedimentary bodies, impacting grain size distribution and mineralogy. The effect of dust‐lifting on surface features is studied by analysing Perseverance‐MEDA observations at the Jezero crater to understand the short‐term changes in the bedform. These events are found to involve the redistribution of only a small amount of materials and, thereby, changing surface features on Mars over a short period. To detect the bedform migration in the Pasteur crater, several HiRISE images acquired over different time intervals were used. The changes in the ripple crest (~0.29–1.18 m/Earth year) and dune slip face suggest new grain flow events. In the Pasteur crater, extensive changes in sand deposits near the dunes signify a widespread bedform migration. The stronger north‐westerly and north‐easterly winds dominate these changes. Thus, the bedform migration in the three tropical craters exhibits significant variability driven by localized aeolian processes. This variability is crucial for understanding Mars' geological history, current surface dynamics and eventually, helps in planning future missions.

Lead (Pb) Accumulation in Water, Sediment and Distribution of Macro-Invertebrates in Delimi River, Jos, Nigeria

Background: This study assessed the concentrations of lead (Pb) in the water column and sediment as well as macro-invertebrates in River Delimi with a view to determining its ability to support aquatic life. Methodology: Water and sediment samples were collected simultaneously between August and November 2019 at designated stations: A (Abattoir), B (British America bridge), and C (Farin Gada bridge). Composite method was employed to collect water samples from different points in each station in 250 ml capacity plastic bottles with screw caps. The plastic bottles had previously washed with detergent and finally rinsed using distilled water. The water samples were filtered using 0.4 mm Whatman filter paper. Samples were then digested with few drops of concentrated nitric acid (HNO3). Sediment samples were collected in decontaminated airtight polythene bags measuring 500_g each. Sub-samples of the material were sun-dried for three (3) days and homogenized by grinding in laboratory mortar and pestle and sieved (aperture 125 µm). Sediment samples were digested with 20 cm3 aqua regia (3HCl:1HNO3), filtrate were stored in glass bottles and transported to the laboratory for chemical analyses. Macroinvertebrates were collected using a D-frame kick-net (30) at each site over a three-minute period. The collected specimens were preserved in 70% formalin and transported to the laboratory for sorting, identification, and enumeration. Result: Showed that the concentration of lead (Pb) in all the water samples were found to be less than the permissible limit set by WHO/FAO except site WA3 (0.0874ppm) and WC3 (0.0678 ppm) which were higher than the permissible limit. The concentration of lead (Pb) in sediment was higher than the WHO/FAO permissible limit in all sampling stations which is most likely to pose serious health risks to macrobenthos. Also, 7 Micro-invertebrate taxa were identified in the sampling stations. Chironomidae, Eristalis Larva (Syrphidae), Tabanidae and Whirligig beetle (Gyrinidae) comprised more than 79% of the total abundance while stone fly Larva, hydrophilidae and beetle larva constituted the remaining. Conclusion: water samples suggest potential environmental contamination of lead in some locations while sediment samples indicate a significant contamination with lead, posing potential health risks to organisms living in the sediment, including macrobenthos.

Pedagogical responsiveness of mathematics instruction at inclusive secondary schools: A particularistic case study

This qualitative particularistic case study explores the perspectives and experiences of learners with visual and hearing impairments regarding the teaching of mathematics. Extreme-case sampling was employed to select four learners (three hearing impaired and one visually impaired) from the only two inclusive secondary schools in the northern part of Namibia. The study qualitative study utilised open-ended questionnaires and interviews. Verbatim quotes from the research participants were used as inferences to identify descriptors within the first-generation Cultural Historical Activity Theory, which served as a theoretical and analytical tool. The findings revealed that the activity system of learners with visual and hearing impairments exhibited tensions that negatively affected their performance in mathematics. Learners experienced marginal responsive pedagogy in mathematics classrooms due to teachers' lack of knowledge and pedagogical skills for delivering meaningful mathematical instruction. While learners without disabilities struggled with comprehension and effective communication skills, learners with visual and hearing impairments faced a lack of equipment to support the conceptualisation and visualisation of mathematical subject content. The authors emphasise the critical importance of addressing communication barriers and adapting teaching practices to support the learning and inclusion of visually and hearing-impaired learners in mathematics, with an emphasis on mathematical language that promotes a better understanding of mathematical concepts. Teacher training should also incorporate responsive pedagogy to enhance outcomes and foster a more inclusive learning environment that promotes academic success and positive social experiences for all learners. Recommendations at a policy level, including advocating for a decolonised curriculum were made.

How dark traits and regulatory focus manifest in online hotel reviews: a textual content analysis

ABSTRACT This study seeks to explore how Dark Triad of psychopathy, Machiavellianism, and narcissism interact with consumers’ regulatory focus (prevention-focus and promotion-focus) to influence online consumer reviews in the hotel industry. We conducted an empirical analysis of 1,185,940 hotel reviews from TripAdvisor.com, utilizing the textual content of online reviews and employing Language Inquiry and Word Count analytical tools. The research reveals a multifaceted link between regulatory focus and Dark Triad in online reviews. The results showed that individuals with a promotion focus tend to give higher ratings than those with a prevention focus. Dark Triad significantly influences how regulatory focus impacts online reviews. This study initiates a new academic dialogue on the interaction between regulatory focus and Dark Triad traits within online consumer behavior studies. It provides practical guidance for the hotel industry to refine their management and response strategies by acknowledging the impact of consumer personality traits on online reviews.

Food Security Challenges for Hospital Sustainability

Background: Food security and safety are becoming major concerns worldwide. Providing food security and safety in hospitals is particularly challenging since their populations are diverse in dietary and nutritional requirements and more vulnerable to foodborne illnesses. The aim of this research is to promote hospital sustainability by addressing food security and food safety. Method: This study uses a quantitative method with a bibliometric study approach. This research has 212 articles from the Scopus database. All the documents were collected simultaneously in August 2022. The selected article encompassed the years from 2017 to 2021, including document type, publication stage, source type, language, and subject area. The data was analyzed using VOSviewer and NVivo analytical tools. Results: The results of the studies on food security and safety increased from 2017-2022 with current trends in hospital sustainability, food waste, and waste management in food. Our study has identified four clusters: hospital food services, hospital sustainability, nutrition, and food safety. Food security is positively correlated with assessment, challenges, measurement, status, and sustainability (Pearson correlation score is 1). Disease control, proper waste management, and environmental health are all associated with food safety (Pearson correlation score ±0.79-0.64). Conclusion: Food safety and security are critical to achieve hospital sustainability, therefore awareness-raising efforts must continue. It is recommended that hospital stakeholders, food service providers; public and private sectors adopt policies and guidelines to disseminate information on food safety and security concerning hospital sustainability.

A Design and Safety Analysis of the “Electricity-Hydrogen-Ammonia” Energy Storage System: A Case Study of Haiyang Nuclear Power Plant

With the development of modernization, traditional fossil energy reserves are decreasing, and the power industry, as one of the main energy consumption forces, has begun to pay attention to increasing the proportion of clean energy generation. With the deepening of electrification, the peak-valley difference of residential electricity consumption increases, but photovoltaic and wind power generation have fluctuations and are manifested as reverse peak regulation. Thermal power plants as the main force of peak regulation gradually reduce the market share, making nuclear power plants bear the heavy responsibility of participating in peak regulation. The traditional method of adjusting operating power by inserting and removing control rods has great safety risks and wastes resources. Therefore, this paper proposes a new energy storage system that can keep the nuclear power plant running at full power and produce hydrogen to synthesize ammonia from excess power. A comprehensive evaluation model of energy storage based on z-score data standardization and objective parameter assignment AHP (analytic hierarchy process) analysis method was established to evaluate energy storage systems according to a multi-index system. With an AP1000 daily load tracking curve as the input model, the simulation model built by Aspen Plus V14 was used to calculate the operating conditions of the system. In order to provide a construction basis for practical engineering use, Haiyang Nuclear Power Plant in Shandong Province is taken as an example. The system layout scheme is proposed according to the local environmental conditions. The accident tree analysis method is combined with ALOHA 5.4.1.2 (Areal Locations of Hazardous Atmospheres) hazardous chemical analysis software and MARPLOT 5.1.1 geographic information technology. A qualitative and quantitative assessment of risk factors and the consequences of leakage, fire, and explosion accidents caused by hydrogen and ammonia storage processes is carried out to provide guidance for accident prevention and emergency rescue. The design of an “Electric-Hydrogen-Ammonia” energy storage system proposed in this paper provides a new idea for zero-carbon energy storage for the peak shaving of nuclear power plants and has a certain role in promoting the development of clean energy.

Combining array-assisted SERS microfluidic chips and machine learning algorithms for clinical leukemia phenotyping

The disease progression and treatment options of leukemia between different subtypes vary considerably, emphasizing the importance of phenotyping. However, early typing of leukemia remains challenging due to the lack of highly sensitive and specific analytical tools. Herein, we propose a SERS-based platform for the classification of acute lymphoblastic T-cell leukemia (T-ALL) and chronic myeloid leukemia (CML) through the combination of machine learning and microfluidic chips. The ordered arrays in microfluidic channels reshape the microscopic flow field and contacting interfaces, facilitating the uniform and efficient capture of tumor cells. To enable phenotypic analysis, spectrally orthogonal SERS aptamer nanoprobes were applied, providing composite spectral signatures of individual cells in accordance with surface protein expression. Further, machine learning algorithms were employed to analyze the SERS signatures automatically, resulting in an accuracy of 98.6 % for 73 clinical blood samples. The results demonstrate that this platform holds promising potential for clinical leukemia diagnosis and precision medicine.