Sample Volume Research Articles

Investigation of Coal Structure and Its Differential Pore–Fracture Response Mechanisms in the Changning Block

The deep coal seams in the southern Sichuan region contain abundant coalbed methane resources. Determining the characteristics and distribution patterns of coal structures in this study area, and analyzing their impact on pore and fracture structures within coal reservoirs, holds substantial theoretical and practical significance for advancing coal structure characterization methods and the efficient development of deep coalbed methane resources. This paper quantitatively characterizes coal structures through coal core observations utilizing the Geological Strength Index (GSI) and integrates logging responses from different coal structures to develop a quantitative coal structure characterization model based on logging curves. This model predicts the spatial distribution of coal structures, while nitrogen adsorption data are used to analyze the development of pores and fractures in different coal structures, providing a quantitative theoretical basis for accurately characterizing deep coal seam features. Results indicate that density, gamma, acoustic, and caliper logging are particularly sensitive to coal structure variations and that performing multiple linear regression on logging data significantly enhances the accuracy of coal structure identification. According to the model proposed in this paper, primary-fragmented structures dominate the main coal seams in the study area, followed by fragmented structures. Micropores and small pores predominantly contribute to the volume and specific surface area of the coal samples, with both pore volume and specific surface area increasing alongside the degree of coal fragmentation. Additionally, the fragmentation of coal structures generates more micropores, enhancing pore volume and suggesting that tectonic coal has a greater adsorption capacity. This study combines theoretical analysis with experimental findings to construct a coal structure characterization model for deep coal seams, refining the limitations of logging techniques in accurately representing deep coal structures. This research provides theoretical and practical value for coal seam drilling, fracturing, and reservoir evaluation in the southern Sichuan region.

Cryo-electron tomography: en route to the molecular anatomy of organisms and tissues.

Cryo-electron tomography (cryo-ET) has become a key technique for obtaining structures of macromolecular complexes in their native environment, assessing their local organization and describing the molecular sociology of the cell. While microorganisms and adherent mammalian cells are common targets for tomography studies, appropriate sample preparation and data acquisition strategies for larger cellular assemblies such as tissues, organoids or small model organisms have only recently become sufficiently practical to allow for in-depth structural characterization of such samples in situ. These advances include tailored lift-out approaches using focused ion beam (FIB) milling, and improved data acquisition schemes. Consequently, cryo-ET of FIB lamellae from large volume samples can complement ultrastructural analysis with another level of information: molecular anatomy. This review highlights the recent developments towards molecular anatomy studies using cryo-ET, and briefly outlines what can be expected in the near future.

A Cu/β-cyclodextrin/reduced graphene oxide nanocomposite for efficient and multi-aflatoxin detection in rice, ginger and bean samples.

Aflatoxins (AFs) are some of the most important mycotoxins or fungal toxins that cause contamination of food products and are considered a threat to human and animal health. An efficient Cu/β-cyclodextrin/reduced graphene oxide nanocomposite (Cu/β-CD/rGO) has been prepared and applied as a new solid-phase extraction adsorbent for the separation and preconcentration of four AFs (B1, B2, G1, and G2) using high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The successful synthesis of the prepared nanocomposite was confirmed using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The impacts of pH, amount of adsorbent, sample volume, desorption solvent volume, and salt concentration on the recovery of AFs were precisely investigated and optimized by central composite design (CCD). Under the optimal conditions, the introduced method demonstrated good linearity in the range of 0.4-5.4, 0.08-1.08, 0.4-5.4, and 0.08-1.08 ng g-1 for AFs B1, B2, G1 and G2, respectively. The limits of detection and quantification for the four AFs were obtained in the range of 0.06-0.53 and 0.20-1.62 ng g-1, respectively. The accuracy of the method was evaluated using recovery measurements in spiked real samples such as rice, bean, and ginger samples, and satisfactory recoveries were obtained in the range of 83.5-109.0% with good precision (RSDs between 2.4 and 8.6%). The results of this research revealed that our developed method is sensitive, highly effective, and convenient to perform for the trace analysis of AFs in different real samples.

Electrochemical immunosensing of Crohn's disease biomarkers using diazonium salt-grafted crystalline nanocellulose/carbon nanotube-modified electrodes.

Thefirst dual immunosensoris reportedfor the determination of IL-12 and IL-23, two relevant biomarkers of Crohn's disease (CD). The strategy relies on the selective capture of the targets by the respective antibodies which were covalently immobilized onto SPCEs modified with crystalline nanocellulose (CNC) and multi-walled carbon nanotubes (MWCNTs) followed by conjugation with a detector antibody labelled with poly-HRP-Strept and amperometric transduction using the H2O2/HQ system. The combination of CNC, a nanomaterial scarcely exploited in immunosensing, with MWCNTs enables the preparation of a novel dual immunosensor for the determination of CD biomarkers in clinical samples, including faeces. The developed bioplatform exhibits a high reproducibility and selectivity allowing the simultaneous determination of IL-12 and IL-23 using a smaller sample volume and in a much shorter assay time than those reported for each target with commercial ELISA kits. The dual immunosensor was successfully applied to the analysis of raw serum and faeces spiked with IL-12 and IL-23 at the expected levels in patients with severe CD.

Dispersive solid phase extraction of 18 PFAS from environmental water samples using a novel MOF-polymeric monolith composite followed by High-Resolution mass spectrometry analysis

Metal-organic frameworks (MOFs) have been broadly coupled with many pretreatment techniques due to their remarkable attributes including high porosity, significantly increased specific surface area, and chemical stability, but their nanoscale dimensions make their handling challenging. To overcome this, a novel MOF-polymeric monolith composite was synthesized and studied as a novel sorbent material in an analytical technique. A rapid and efficient method for the extraction of a mixture of 18 per- and poly-fluoroalkyl (PFAS) compounds from environmental water samples was established based on MOF-polymeric monolith composite assisted dispersive solid phase extraction (d-SPE). The analytical methodology was carried out with the aid of liquid chromatography tandem high-resolution mass spectrometry. Several parameters influencing the extraction efficiency were comprehensively evaluated and optimized. The optimization was based on two processes: the one-variable-at-a-time approach (OVAT) and the central composite design (CCD). Preliminary studies were conducted and the extraction and elution time, as well as the sample volume were evaluated by adopting OVAT approach. The optimal parameters were found to be 15 min for extraction time, 5 min for the elution time and 10 mL as sample volume. Under the optimum conditions, the sample pH, sorbent amount and eluent volume were all evaluated under the design of experiments (DoE). ANOVA demonstrated the suitability of the suggested model with a p-value of less than 0.05 and various diagnostic tests validate the well-fitting results. The software extracted the optimal conditions which were pH = 7, sorbent amount = 10 mg and eluent volume = 750 μL. The method was subsequently validated with respect to accuracy, linearity detection limits and reproducibility. The proposed method presented recoveries over 70 %, method detection limits 1–46 ng/L and relative standard deviations <20 %. Before the implementation of the method in real samples, the “green” character was evaluated using the ComplexGAPI index, indicating the satisfactorily “green” character of the new MOF-based dSPE-LC-HRMS method. Finally, the efficacy of the method for determining PFASs in four environmental water matrices was tested using several matrices of varying complexity, including wastewater effluent, river water, marine water, and runoff.

Enrichment of polyphenols from Cinnamomum camphora seed kernel by macroporous adsorption resins and evaluation of its antioxidant and enzyme inhibitory activities

The Cinnamomum camphora seed kernel (CCSK) has potential as a natural source of bioactive phenolics. However, there is limited information on the recovery and characteristics of polyphenols from the by-product of CCSK after oil extraction. In this study, an efficient macroporous adsorption resin technology was established to enrich polyphenols from CCSK (CCSK-P). HJ-18 resin was found as the most appropriate adsorbent because of its highest adsorption/desorption capacity for CCSK-P. The pseudo-second-order kinetic and Freundlich isotherm models better described the whole adsorption process. The adsorption process was spontaneous, physical, and dominated by multilinear intraparticle diffusion. The optimum enrichment procedure of CCSK-P on HJ-18 resin was as follows: for adsorption, loading flow rate and sample volume were 1.5 BV/h, and 4.79 BV, respectively; for desorption, the eluent type, elution flow rate and volume were 80% ethanol, 3.0 BV/h and 8 BV, respectively. After one-step large-scale enrichment, the total polyphenol content of CCSK-P was increased 7.11-fold with a recovery of 81.07%. Moreover, enriched CCSK-P showed significantly higher scavenging ability against DPPH radical and ABTS radical and higher inhibitory activity against α-amylase and α-glucosidase. In conclusion, CCSK-P was well enriched by HJ-18 resin and exhibited good antioxidant and enzyme inhibition activity, which may be applied in the food, cosmetic and pharmacy industries. This study provides a meaningful guidance for the industrial enrichment of polyphenols from CCSK.

Starch-modified nickel ferrite nanoparticles as a magnetic nano-bio adsorbent for the extraction and determination of lead in water and Moringa oleifera samples

In this work, nickel ferrite magnetic nanoparticles were synthesized using a facile hydrothermal method. The surface modification of the prepared nanoparticles was carried out using cross-linked starch as a good stabilizer and biopolymer. The as-prepared nickel ferrite-starch nano-bio composite was characterized using numerous techniques, and introduced as a novel adsorbent. The initial experimental results indicated that the adsorbent has a good capability to extract lead ions (Pb(II)) from aqueous solutions. Hence, the adsorbent was applied for dispersive magnetic solid-phase extraction of Pb(II) before flame atomic absorption spectrometric detection. Some variables affecting the extraction efficiency such as sample volume (250.0mL), pH (6.5), type and eluent concentration (0.3molL1 nitric acid), amount of the adsorbent (200mg), extraction time (15min), and desorption time (15min) were investigated and optimized. Moreover, the adsorption capacity (35.50mgg1), stability and reusability (80 extraction/desorption cycles), and selectivity of the adsorbent towards the analyte were studied. In the optimized conditions, the linear dynamic range of the constructed calibration graph is between 0.5 and 140.0ngmL1. The limit of detection and limit of quantification of the method are 0.12 and 0.40ngmL1, respectively. The average intra-day and inter-day relative standard deviations (for n=6 and 5.0, 50.0 and 100.0ngmL1 Pb(II) concentration) are 2.02% and 3.72%, respectively. To validate the method, the certified reference material NIST SRM 1643e was analyzed, and the method was used for the pre-concentration and determination of lead ions in different sections of Moringa oleifera medicinal plant and several water samples. The acceptable relative recovery values between 98.0 and 102.7% were attained for the spiked samples, approving the ignorable matrix effect of the method.

Customizable Microfluidic Devices: Progress, Constraints, and Future Advances.

The field of microfluidics encompasses the study of fluid behavior within micro-channels and the development of miniature systems featuring internal compartments or passageways tailored for fluid control and manipulation. Microfluidic devices capitalize on the unique chemical and physical properties exhibited by fluids at the microscopic scale. In contrast to their larger counterparts, microfluidic systems offer a multitude of advantages. Their implementation facilitates the investigation and utilization of reduced sample, solvent, and reagent volumes, thus yielding decreased operational expenses. Owing to their compact dimensions, these devices allow for the concurrent execution of multiple procedures, leading to expedited experimental timelines. Over the past two decades, microfluidics has undergone remarkable advancements, evolving into a multifaceted discipline. Subfields such as organ-on-a-chip and paper-based microfluidics have matured into distinct fields of study. Nonetheless, while scientific progress within the microfluidics realm has been notable, its translation into autonomous end-user applications remains a frontier to be fully explored. This paper sets forth the central objective of scrutinizing the present research paradigm, prevailing limitations, and potential prospects of customizable microfluidic devices. Our inquiry revolves around the latest strides achieved, prevailing constraints, and conceivable trajectories for adaptable microfluidic technologies. We meticulously delineate existing iterations of microfluidic systems, elucidate their operational principles, deliberate upon encountered limitations, and provide a visionary outlook toward the future trajectory of microfluidic advancements. In summation, this work endeavors to shed light on the current state of microfluidic systems, underscore their operative intricacies, address incumbent challenges, and unveil promising pathways that chart the course toward the next frontier of microfluidic innovation.

Application of semi-quantitative loop-mediated isothermal amplification for gene expression study in Expi293 cells.

BACKGROUND: Mammalian cell cultures play a key role in the pharmaceutical industry, requiring constant monitoring of the cell conditions during fermentation. In addition to monitoring of the physical-chemical parameters, it is important to evaluate the internal state of cells, for which gene expression analysis is used. Currently, quantitative reverse transcription polymerase chain reaction (qPCR) is the dominant method. However, the loop-mediated isothermal amplification (LAMP) technique also attracts attention due to its high specificity, sensitivity and reaction rate. LAMP is becoming a promising tool for rapid analysis of gene expression, especially under the conditions of limited biological material or a large volume of samples. AIM: Development of a technique for quantifying the expression level of target genes in human cell culture Expi293. METHODS: For LAMP, a recombinant large fragment of Bacillus stearothermophilus DNA polymerase (Bst-pol) was obtained, purified, and optimal reaction conditions were determined. SYBR Green I and LUCS13 were used as intercalating dyes. The amplification parameters for different concentrations of the enzyme and the dye were analyzed. Standard SYBR Green I kits were used for qPCR. Both methods were compared when analyzing the expression of IGF 1, FGF2 and EIF3i genes in cell lines with an increased expression level of these genes. RESULTS: It has been shown that using LUCS13 dye provides the classic S-shape of the signal accumulation curve in LAMP, while using SYBR Green I dye causes artifacts. The optimal concentration of Bst-pol was 40 ng/µl. When comparing the two methods, it was found that LAMP has greater sensitivity, allows determining gene expression with an accuracy comparable to qPCR, demonstrating a shorter reaction time (up to 35 minutes). CONCLUSION: Although quantitative PCR remains the main method for assessing the level of gene expression, loop-mediated isothermal amplification offers a number of advantages that make it an attractive alternative for various biotechnological purposes. Due to its high speed, ease of execution and accessibility, as well as high sensitivity and specificity, LAMP is a valuable technique for rapid analysis of gene expression during cell culture monitoring.

Sustainable liquid-liquid microextraction and determination of inorganic arsenic species in nut-based beverages using hydrophobic natural deep eutectic solvents

Arsenic (As) is a carcinogenic, mutagenic, and toxic element, making its determination in food and beverages essential for assessing its impact on human health. Since the total As content alone does not provide adequate information on toxicity and bioavailability, it is crucial to develop methods for the speciation of As(III) and As(V). The aim of this work was to develop an efficient and selective method for the determination of inorganic As (iAs) species in complex samples such as nut-based beverages. This method involves the application of a hydrophobic natural deep eutectic solvent (HNADES) in the vortex-assisted liquid-liquid microextraction (VA-LLME) technique based on the solidification of floating droplets. The As(III) species was complexed with ammonium pyrrolidinedithiocarbamate (APDC) and extracted using 50μL of HNADES capric acid:lauric acid (CAP:LAU) (2:1). Then, As(III) species was determined by hydride generation atomic fluorescence spectrometry (HG-AFS). Optimization of the sample volume, HNADES volume, vortex stirring time, and cooling time was performed using a multivariate study. The method contributes to the development of a more environmentally friendly analytical approach and offers several advantages, including 100% As(III) extraction efficiency, low limits of detection (0.11μgL⁻¹ for As(III) and 0.30μgL⁻¹ for As(V)), and excellent selectivity.

Utilization and validation of dried blood spot-based metabolomics in plasma-derived diagnostic models

Metabolomics has rapidly advanced in life sciences, enhancing our understanding of physiological conditions. Plasma stands out as a predominant sample type in metabolomics studies. Dried blood spot (DBS) has been recognized as a valuable strategy due to its unique characteristics, such as minimal invasiveness, small sample volume, and easy transport. Most large cohort studies construct the diagnostic model using plasma-based metabolomics rather than DBS. However, the comparability of metabolite measurements between DBS and plasma samples, as well as the integration of DBS-based metabolomics into established plasma-derived diagnostic models, remains unclear. We collected plasma and DBS samples from the same 12 healthy controls under fasting and non-fasting conditions and performed ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS)-based metabolomics. We identified 277 metabolites present in both plasma and DBS samples, with 229 (82.7 %) showing a strong correlation between the two sample types. Furthermore, pre-processing datasets from plasma and DBS samples before combining them effectively diminished inconsistencies between plasma- and DBS-based metabolomics without compromising the inherent classification within the data. For the clinical application, the plasma samples were obtained from the gastric cancer patients (n = 204) and the healthy controls (n = 128) to serve as the training cohorts. Additionally, DBS samples were collected from different participants of gastric cancer (n = 19) and healthy controls (n = 12) to validate the diagnostic model. Finally, DBS-based metabolomics were integrated into established plasma-derived gastric cancer diagnostic models, yielding an area under the ROC curve (AUC) of 0.934. Overall, incorporating DBS-based metabolomics into an established plasma-derived diagnostic model holds promise, offering valuable opportunities and insights for diagnostic research and clinical practice.

Small volume solid phase extraction method for comprehensive analysis of neonicotinoids, their metabolites, and related pesticides in water

Neonicotinoid insecticides (NEOs) such as clothianidin, imidacloprid, and thiamethoxam are used worldwide. The occurrence of their degradates, for instance, clothianidin-n-desmethyl (CLO-N-DES), clothianidin-urea (CLOU), imidacloprid urea (IMIU) and olefin (IMIO), as well as thiamethoxam urea (THXU), have seldom been documented in water due to the lack of a sensitive analytical method. In this study, a method only requiring 12 mL of water sample was developed and validated to quantify 8 NEOs, 13 metabolites, and 3 related insecticides using solid phase extraction (SPE) coupled with HPLC-MS/MS. The method demonstrated good linearity (r2 > 0.99), with limits of detection (LOD) ranging from 0.16 to 1.21 ng/L and limits of quantification (LOQ) from 0.54 to 4.03 ng/L in water samples. Validation showed accuracy between 70 and 130 % and precision below 15 % for most analytes. The method's performance was comparable to, or better than, existing methods, with the advantage of requiring much smaller sample volumes. Using this method, we monitored the occurrence and seasonal variability of NEOs and their metabolites in various surface water and groundwaters matrices from across Iowa. For example, analysis of water samples from private wells across three Iowa counties detected several NEOs, with notable findings including the first detection of flupyradifurone (FLU) in Iowa well water. Surface water analysis from five locations revealed frequent detection of NEOs and their metabolites, with some concentrations exceeding U.S. EPA chronic toxicity benchmarks for freshwater invertebrates. In addition, this is the first study to demonstrate the occurrence of CLO-N-DES, CLOU, and THX-U in US surface water. The study helps advance analytical methods for NEOs and their metabolites while also highlighting their widespread occurrence in Iowa waters and associated ecological risks, emphasizing the need for more comprehensive monitoring of these compounds.

A simple Magnetic-aided microfluidic screening approach for rabies virus via rolling circle amplification

Rabies, being a fatal neurologic disease, is one of the neglected tropical diseases. Timely post-exposure prophylaxis is the key to healthcare, demanding an early diagnosis towards the much-envisaged ‘One Health’ measures. Despite being a disease with almost 100 % mortality cases, no significant progress has been made towards its early and accurate diagnosis. Herein, we report a simple microfluidic device based on magnetic trapping, without any complex design, in order to specifically screen rabies virus from biofluids. For this, we exploit Rolling Circle Amplification (RCA), a highly recommended isothermal nucleic acid amplification test (NAAT), with rapid and robust point-of-care diagnosis capabilities. This specific molecular assay was used for sensitive detection down to 2.69 fM and 14.5 fM for N- and L-gene targets, respectively. COMSOL simulations have accelerated experimental optimization time, resulting in effective capture and detection of magnetically-coupled amplicons. Fluorescently-tagged RCA products mixed with magnetic microparticles (M−RCPs) showed a clearly distinguishable signal between rabies vaccine strain and blood samples of healthy dogs. This simple technique presents a scalable proof-of-concept prototype for a highly specific ‘yes-or-no’ detection method for rabies virus, using a minimal sample volume and extendable for sensitive-cum-specific screening of other pathogens using tunable molecular probes.

Establishment and Validation of Sandell-Kolthoff Method for Saliva Iodine Determination.

Saliva iodine is a useful biochemical marker for evaluating iodine status and controlling iodine-related diseases. This study aims to establish and validate a simple, reliable, and low-cost Sandell-Kolthoff (S-K) method for the determination of iodine in saliva. The method was established by considering the digestion solution type, concentration, dosage, digestion time and temperature, the volume of saliva samples, glass tube size, dosage of arsenious acid solution and ammonium ceric sulfate solution, and warm bath time. Then, the effectiveness of the method was examined by the linearity of the standard curve, detection limit, precision, and accuracy. The 1.5mL 1 Mol/L ammonium persulfate solution at 100°C for 90min, the 200 μL saliva sample, glass tubes of 15mm × 120mm, 2.5mL arsenious acid solution, 0.3mL ammonium ceric sulfate solution, and 15min for warm bath was selected to determine saliva iodine. In terms of validation of the S-K method, the linearity method has the linear range of the standard curve from 0 to 300μg/L and the coefficient of determination ≥ 0.999; the detection limit, when the volume of saliva samples was 0.2mL, was 4.6μg/L; for precision, the relative standard deviation was from 0.3 to 2.8%; and for accuracy, the total recovery rate ranged from 92.8 to 107.0%. This S-K method is easy to operate, has good precision and accuracy, and can be used as a method to determine saliva iodine. It has great potential practical value in disease prevention, clinical auxiliary diagnosis, and experimental research.

Experimental study of supercritical CO2-H2O-coal interactions and the effect on coal spontaneous imbibition characteristics

The interaction among supercritical CO2 (ScCO2)–H2O-coal can impact the pore structure of coal, thereby bringing about changes in the spontaneous imbibition (SI) characteristics of coal. This is of great significance for the effect of hydraulic fracturing and the increase in coalbed methane production. The changes in pore structure and imbibition characteristics of coals with different degrees of metamorphism after ScCO2-H2O treatment were studied using nuclear magnetic resonance technology. The experimental results indicate that ScCO2-H2O treatment can increase porosity, enhance pore connectivity, and significantly increase the imbibition rate. It also alters the proportion of different pores. The proportion of micropores, microfractures and fractures increases, while the proportion of small pores, mesopores and large pores decreases. This change is more significant in low-rank coal. During SI, the main contribution to the imbibition volume of coal samples is consistent with the proportion of pore structure; hence, there are differences in the extent of changes in the SI characteristics between low-rank and high-rank coals. The numerous etched pores produced by ScCO2-H2O treatment exhibit self-similarity, reducing the roughness and complexity of the pores while enhancing connectivity. The emergence of a large number of microfractures and fractures has a minor impact on the change in SI volume and rate but affects the mode of SI.

Floor live load survey and modelling by house VR viewing and public registration information

Reliable live load value is a prerequisite for the safety design of civil structures, and the quantity of samples is the key data foundation for live load modelling. The traditional walk-in survey approach has encountered challenges such as low efficiency, high costs, and potential privacy concerns, resulting in a limited collection of live load samples and a halt in load surveys over the past three to four decades. To address these issues, this paper proposes a new online survey approach for floor live load sampling. The new approach uses a panoramic VR (virtual reality) house viewing system, available and open-access on many real estate trading websites, to collect load amplitude samples. Additionally, it utilizes public information systems, including real estate transactions and national enterprise credit system, to collect live load duration samples. The practical implementation of this novel approach yields a substantial volume of samples, with 1883 and 4676 load amplitude samples, and 121,561 and 46,353 duration samples obtained for office and residential buildings, respectively, constituting the largest live load sample set reported to date. Statistical analysis reveals that design live load values derived from the new samples are higher than the recommended values in the current code, due to a notable increase in the standard deviation of load amplitude and a significant decrease in the load duration. Overall, the proposed approach presents a novel, efficient, and convenient method for live load modelling.

Microplastic accumulation in one-year freshwater ice: A four-year monitoring study reveals winter dynamics of microplastics

Microplastic research has reached a point where microplastics (MPs) have been found in virtually every environment studied. However, MP studies of freshwater ice are scarce, and the winter dynamics of MPs are less understood. Measuring MPs from one-year freshwater ice samples can aid understanding seasonal MP fluxes in freshwater systems. In this study we explored the same four sites close to urban/suburban areas over four subsequent years. We collected a total of 48 ice samples across all the years and sites with an average sample volume of 2.9 to 5.0 L of liquid water. In addition, we sampled an annually laminated section of bottom sediments representing these four years in seasonal resolution. MP concentrations varied considerably between years and samples, being 1–44 MPs/L in all the ice samples. The MPs found in ice were small with a mean (± average) size of 142 ± 177 μm. In total, 9 different polymer types were identified: the most common types being polypropylene, polyethylene and polyethylene terephthalate. We found that MPs accumulate to one-year freshwater ice, because the MP concentrations found from ice are one to two orders of magnitude higher than concentrations from surfaces waters in the same area. This further confirms that ice acts as a temporal repository for MPs in the aquatic freshwater systems. Our study also indicates that the properties of MPs were relatively similar in all sites around the city. The accumulation of MPs in sediments was highest during the spring flood periods, when MPs were released from the ice and snow at the catchment area of the sediment samples. We highlight the importance of monitoring to collect representative MP data from various environmental compartments.

Rapid quantification of isovaleraldehyde in sake by HPLC with post-column fluorescent derivatisation

Why was the work done: Elevated levels of isovaleraldehyde (3-methylbutanal) in sake gives rise to an unfavourable aroma of ‘mureka’ or ‘stuffy smell’. The concentration of isovaleraldehyde is typically higher in unpasteurised than pasteurised sake. Controlling the concentration of isovaleraldehyde in unpasteurised sake remains a major challenge for quality control. As existing methods for the quantification of isovaleraldehyde in sake require specialised sample preparation, there is a need for a simple and precise method. How was the work done: High-performance liquid chromatography with fluorescence detection and post-column derivatisation (HPLC-PCD-FLD) for determining the isovaleraldehyde content in sake has been developed with optimisation of the separation of peaks and derivatisation of aldehyde compounds. The new method was compared with the established method of headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). What are the main findings: The limit of quantification of the new method was 87 µg/L, and accordingly, the HPLC-PCD-FLD method could determine the concentration of isovaleraldehyde in sake below the reported threshold level. The precision of the HPLC-PCD-FLD method for the analysis of sake containing isovaleraldehyde (&gt; threshold level) either matched or was superior to the HS-SPME-GC-MS method. Why is the work important: The new approach requires only particle removal for sample preparation, with an rapid analysis time (&lt;1 h per sample), and requires a smaller sample volume (≈ 100 µL) than the alternative method (10 mL). These improvements contribute to a simpler and more efficient workflow for routine analysis of isovaleraldehyde in the quality control of sake.

Behavioral risk assessment of work-related musculoskeletal disorders among workers of petrochemical industries: protocol of a mixed method study

BackgroundMusculoskeletal disorders (MSDs) are one of the most common occupational diseases and the main cause of disability worldwide. Work-related musculoskeletal disorders (WMSDs) are one of the common health risks and the most important cause of absenteeism due to disability in various industries, including the petrochemical industry, in developed and developing countries. These disorders have important social economic, and significant financial consequences due to direct and hidden costs. Health behaviors play a role in both creating and preventing musculoskeletal disorders in employees. Therefore, by identifying the influencing factors on these behaviors, it is possible to strengthen and improve the preventive behaviors of musculoskeletal disorders through educational intervention programs. This study aims to assess the behavioral risk of work-related musculoskeletal disorders, and design and implement an educational intervention to teach effective behaviors in the prevention of musculoskeletal disorders in petrochemical industry workers.MethodsThis study is a mixed-method study implemented in four stages involving the qualitative study, the design and evaluation of an instrument, the design of an experimental randomized clinical trial, and the psychometric evaluation of the instrument and the evaluation of the program. The research community consists of employees working in the petrochemical industry. The volume of samples in the qualitative study with the purposeful sampling method, in the instrument design stage based on the available sampling method, and also in the experimental study, the samples are employees suffering from work-related musculoskeletal disorders, who were selected based on a simple random method from among the employees of the petrochemical industry. Then they will be divided into intervention and control groups. The instruments of this research include a demographic questionnaire, a researcher-made questionnaire for measuring behavior, and two auxiliary instruments including the visual analog scale (VAS) and the Quebec Disability Scale. Evaluation is done in 4 stages: pre-test, immediately, 3, and 6 months after the intervention of both groups. The obtained data will be analyzed using SPSS software.DiscussionMusculoskeletal disorders related (WMSDs) to work can harm employees’ health in various industries, including the petrochemical industry. This study attempts to evaluate the behavioral risk of work-related musculoskeletal disorders among petrochemical industry workers and design and implement an appropriate educational intervention program.Trial registrationIranian Registry of Clinical Trial (IRCT20240321061346N1). Registered on 2024–04-10.Ethics Status: Ethics code: IR.MODARES.REC.1402.251.

Novel Simple Approach for Production of Elastic Poly(propylene carbonate)

The simple approach of increasing the elastic properties of atactic poly(propylene carbonate) (PPC) with Mn = 71.4 kDa, ĐM = Mw/Mn = 1.86, and predominantly carbonate units (&gt;99%) is suggested by selecting the appropriate hot pressing temperature for PPC between 110 and 140 °C. Atactic PPC is synthesized through ring-opening copolymerization of (rac)-propylene oxide and CO2 mediated by racemic salen complex of Co(III). Hot pressing PPC results in the release of a small amount of propylene carbonate (PC), sufficient to lower the glass transition temperature from 39.4 to 26.1 °C. Consequently, increasing the pressing temperature from 110 to 140 °C generates materials with a reduced modulus of elasticity (from 1.94 to 0.09 GPa), yield strength (from 38 to 2 MPa) and increased tensile elongation (from 140 to 940%). Thermomechanical analysis has shown a significant expansion in sample volume by hundreds of percent within the 80–130 °C range. PPC also displays large, reversible deformations, which can be utilized by creating shape memory materials.