Test Material Research Articles

Design and validation of a method for evaluating medical device cleanliness by recovering and quantifying residual proteins on stainless plates

We recently reported a method for recovering and quantifying residual proteins bound to surfaces of various medical instruments via thermal coagulation under neutral pH and room temperature. The method effectively recovered and solubilised coagulated proteins at high temperatures in dry and humid conditions, with a protein recovery rate of > 90%. This study validated the previous method by comparing residual protein recovery from test samples using a conventional extraction solution (1% SDS, [pH 11.0]) and proposed solution (1% SDS, 10 mM TCEP, and 10 mM HEPES [pH 7.0]). To mimic soiled medical equipment, pseudo-blood-contaminated stainless steel plates were prepared. Residual protein was recovered using conventional and proposed solutions under varying temperature and humidity conditions. Quantitative protein recovery limits were determined at nine facilities. Compared with the conventional solution, the proposed solution recovered proteins more effectively from samples processed at temperatures > 60 °C. However, low recovery rates were observed for samples processed at 95 °C, possibly owing to differences in protein adhesion due to sample and plate-surface properties. Our findings present a method for quantifying residual proteins on medical instruments exposed to high temperatures during use or disinfection. Further studies should standardise test soiling conditions, materials, and solutions to evaluate cleaning methods.

Tissue-engineered oral epithelium for dental material testing: towards in vitro biomimetic models.

Tissue-engineered oral epithelium for dental material testing: towards in vitro biomimetic models.

Effect of potassium fulvate on continuous tobacco cropping soils and crop growth

Long-term continuous cropping of tobacco causes dysbiosis of soil microbial communities, the imbalance of soil nutrients, and the increase of pathogenic bacteria, which will slow the growth and development of tobacco plants, reduce the production quality, and cause significant losses to tobacco production and tobacco farmers. The application of Potassium fulvic acid can not only provide nutrients, but also inhibit the propagation of pathogens in soil along with raising the amount of organic matter in the soil, which is an effective way to improve soil health. In this experiment, Tobacco variety SNT60 was used as the test material, and 6 treatments were set up by pot test, they were: no fertilisation control group (CK), tobacco special fertiliser (NPK), 3.45 g/kg of potassium fulvic acid fertiliser (T1), 4.65 g/kg of potassium fulvic acid fertiliser (T2), 5.85 g/kg of potassium fulvic acid fertiliser (T3), 7.05 g/kg of potassium fulvic acid fertiliser (T4), Ten replications were set up for each treatment and the soil and fertiliser were mixed and potted before transplanting, 70% as basal fertiliser and 30% as supplementary fertiliser. We also analyzed soil properties, soil microorganisms and agronomic traits of tobacco plants in different treatments to provide reference for mitigating tobacco succession barrier. The test results are as follows: 4.65 g/kg of potassium fulvic acid fertiliser (T2) treatment was the best, soil organic matter, quick nitrogen, phosphorus, potassium, pH, soil catalase, soil sucrase, and soil urease content, compared to CK control, increased by 22.04%, 43.12%, 96.21%, 381.79%, 25.43%, 91.69%, 262.07% and 93.16%. In terms of microbial community, application of potassium fulvic acid fertiliser significantly increased the relative abundance of Ascomycetes, Chlorobacterium, Bacillus, Proteobacteria and Tephritobacterium in the soil. Meanwhile, 4.65 g/kg of potassium fulvic acid fertiliser (T2) promoted the growth of tobacco plants, improved leaf photosynthetic capacity, and enhanced plant disease resistance. This experiment provides practical measures to improve the microbial community of tobacco continuous cropping soils and to reduce the incidence of diseases.

Specifics of Experimental and Fem Approaches in Structural Integrity Assesment of Penstock Made of HSLA Steel

Taking into account the history of problems concerning high-strength low-alloyed (HSLA) steel used for manufacturing of penstocks (partly presented by authors in previous studies), this paper is oriented toward specifics on structural integrity assessment of construction in question. Experimental testing of parent material, i.e. HSLA steel, such as microstructure analysis, impact toughness testing and hardness measuring provide insight into characteristics of parent material properties. Considering geometry of penstock and specific requirements, finite element method (FEM), i.e. ABAQUS, was used to assess the structural integrity of penstock as a whole, specific the longitudinal welded joint under the different internal (working) pressure. It should be emphasized that a slight undermatching effect was investigated by FEM approach in this case. Focus is being put on plastic deformation investigation on aforementioned welded joint under maximum internal pressure of 120 bar.

Applying Cross-Validated Psychometric Models to the Bavarian Reading Test (BYLET)

Abstract: In this study, we compared three different models of reading comprehension on a large dataset of more than 6,500 students. We compared two models representing four comprehension processes as well as the influence of text difficulty to a one-factor model by applying multi-dimensional item response models to the newly developed Bavarian reading test (BYLET). Cross-validation indicated the best generalizability for the one-factor model, but factor loadings and global model fit showed some evidence for the influence of text difficulty measured by word and sentence length and the process structure. All psychometric models tested had a good fit, as indicated by global fit indices and loading patterns. The general factor scores point to reliability and validity. We conclude that theories of reading comprehension processes also apply to some extent to the measurement of reading comprehension as a trainable skill and that the general factor score of the BYLET is suitable for a reading comprehension screening between grades two and six. The study is preregistered. The analysis code is available at https://osf.io/xw9bv/?view_only=21549993ef79426eb4006ef82415f25c . Test materials can be sent to interested researchers on request.

The value of patch testing with plants "as is" in diagnosing plant sensitization.

The number of commercially available plant allergens/extracts is limited and therefore patch testing with fresh/dried plant material may be a necessary supplement in diagnosing plant allergy. To evaluate the usefulness of patch testing with plants "as is" compared to patch testing with commercial and in-house produced plant test materials and to report on species eliciting positive patch test reactions. Consecutive eczema patients, who were patch tested between January 2019 and December 2023 and who had at least one positive reaction to a plant allergen and/or extract and/or plant "as is" were included in the study. A total 57 out of 1893 patients tested (3%) were sensitised to plants. Compositae plants were the most frequent sensitizers, followed by tomato, tulipalin A, falcarinol, and Philodendron plants. In 12 patients (21%), the diagnosis was based on patch testing with fresh plants only. Occupational sensitization occurred in 32%. Other sensitizers included Hydrangea, Pelargonium zonale, and Monstera. A large minority of plant-sensitised patients would have been undiagnosed without patch testing with plants "as is." Most of the culprit plants were known sensitizers, but not commercially available, and these and new species taken into cultivation makes patch testing with fresh plants unavoidable and worthwhile.

Landslide Analysis with Incomplete Data: A Framework for Critical Parameter Estimation

Landslides are one of the most common geohazards, posing significant risks to infrastructure, recreation, and human life. Slope stability analyses rely on detailed data, accurate materials testing, and careful model parameter selection. These factors are not always readily available, and estimations must be made, introducing uncertainty and error to the final slope stability analysis results. The most critical slope stability parameters that are often missing or incompletely constrained include slope topography, depth to water table, depth to failure plane, and material property parameters. Though estimation of these values is common practice, there is limited guidance or best practice instruction for this important step in the analysis. Guidance is provided for the estimation of: original and/or post-failure slope topography via traditional methods as well as the use of open-source digital elevation models, water table depth across variable hydrologic settings, and the iterative estimation of depth to failure plane and slope material properties. Workflows are proposed for the systematic estimation of critical parameters based primarily on slide type and scale. The efficacy of the proposed estimation techniques, uncertainty quantification, and final parameter estimation protocol for data-sparse landslide analysis is demonstrated via application at a landslide in Colorado, USA.

High-Throughput Computational Screening of Metal Sulfides for the Chemical Looping Elemental Decomposition of H2S.

Hydrogen sulfide is a significant byproduct of oil and gas production and is typically recovered as elemental sulfur, a low-value commodity. In recent years, there have been efforts to upgrade H2S through elemental decomposition to S and H2, an essential energy carrier in a sustainable economy. Among the promising approaches is thermocatalytic looping, which involves a sulfide-based redox pair. Unfortunately, the search for sulfides capable of facilitating this conversion is progressing slowly, and primarily focusing on monometallic sulfides. With a few notable exceptions, the field of bimetallic sulfide remains largely unexplored. In this study, a machine learning framework is employed to explore the material space of mono and bimetallic sulfides. The workflow begins by mining sulfides from the Materials Project database, allowing the workflow to be benchmarked using formation enthalpies derived from established density functional theory calculations. Through the machine learning framework, the number of bimetallic sulfide redox pairs considered is expanded from 102 cases in the Materials Project database to 105 cases. This expansion allows for the identification trends that can serve as guidelines for future research and helps prioritize materials for experimental testing.

Microstructure and properties of underwater in-situ wire-based laser additive manufactured duplex stainless steel

ABSTRACT A novel underwater in-situ wire-based laser additive manufacturing (ULAM) technology is proposed for the in-service repair of underwater components in nuclear power plant. Duplex stainless steel (DSS) obtained in air and underwater environments were analysed using material characterisation and testing methods. The effects of underwater additive environments on the microstructure evolution, mechanical properties and corrosion resistance of the specimens were investigated. The results show that the laser heat input is consumed to balance the heat loss of the water-cooled base material during the underwater laser additive manufacturing process, leading to a reduction in the heat input to the molten pool. Underwater specimen exhibit a two-phase balance, with small ferrite grain boundary angles, resulting in better tensile strength and corrosion resistance. Laser reheat treatment leads to a phase change in microstructure, which can enhance the microhardness and the tensile strength. The ULAM system can meet the requirements of actual engineering for cladding layer.

Penetrative Fracture Behavior of Monolayer Graphene Oxide: Nanoscale Experiment and Molecular Dynamics Simulation

Abstract Graphene, a two-dimensional material, is expected to be employed as a next-generation component for structural and functional applications because of its light weight and excellent mechanical properties. For applications requiring lightness and impact resistance, preventing penetrative damage upon particle impact is critical for applications in mechanical protection. However, graphene is known to have high defect sensitivity. Graphene oxide (GO) may be a better candidate, as functional groups (e.g., hydroxy and epoxy groups) bonded to the C–C network in GO result in better deformability, ductility, and durability compared to graphene. For mechanical applications, it is crucial to understand the fracture behavior, especially the penetrative fracture behavior, of GO membranes. This study characterizes the penetration behavior and fracture morphology of GO membranes subjected to particle impact. Nanoscale experiments were conducted using an atomic force microscope and laser-induced particle impact test for GO. These material testing methods employ nanoscale spheres to induce particle penetration, with the former experiment conducted under quasi-static loading and the latter under dynamic loading. Additionally, molecular dynamics simulations were performed to elucidate the fracture mechanisms of GO. Finally, cyclic fatigue experiments and simulations revealed that GO’s ductility provides resistance to catastrophic failure, indicating its durability. These comprehensive investigations provide valuable insights into the fracture properties of GO membranes under impact penetration.

Experimentation of Heat-Insulating Materials for Surrounding Rocks in Deep Mines and Simulation Study of Temperature Reduction

With the increasing depletion of shallow resources, mining has gradually shifted to deeper levels, and the high-temperature problem of deep mining has restricted the efficient and safe development of mining. In this study, five types of thermal insulation materials for surrounding rocks with different ratios were produced using tailings, P.O.32.5 clinker, aluminum powder, glass beads, quick lime, and slaked lime as test materials. Based on the uniaxial compression test, the thermal constant analysis test, and numerical simulation analysis technology, the change rule of mortar compressive strength and thermal conductivity was analyzed, and the cooling effect of surrounding-rock thermal insulation materials with different ratios was discussed. The results showed that the compressive strength of the surrounding-rock thermal insulation materials ranged from 0.39 to 0.53 MPa, and the thermal conductivity ranged from 0.261 to 0.387 W/(K·m), with the compressive strength of ratio E being the largest and the thermal conductivity of ratio A being the lowest. In the numerical simulation analysis results, the thermal insulation layer thickness was taken as a value of 10 cm when, at this time, the best thermal insulation effect and economic benefits involved a temperature reduction of 0.9 K. In the case of changing the thermal conductivity and inlet wind speed, the original temperature of the rock temperature reduction was also very clear, with maximum reductions of 0.92 K, 0.92 K, and 1.42 K.

Practice of Presidential Threshold in the Implementation of Presidential and Vice Presidential General Elections and Its Implications on the Political Rights of Citizens and Political Parties in Indonesia

The presidential threshold is a rule that becomes a political requirement for a political party to carry presidential and vice presidential candidates. The existence of this rule can potentially cause restrictions on citizens in running for president and restrictions on political parties in carrying their candidates to the presidency and vice presidency. The presidential threshold journey in coloring the elections in Indonesia has also undergone material testing and a lawsuit by the Constitutional Court. Therefore, this study aims to discuss the practice of the Presidential threshold in the implementation of elections in Indonesia and its relation to the political rights of citizens and political parties in Indonesia. This study is a field research study with a study into the field and using a non-doctrinal approach that is the enactment of law. Primary Data was obtained by interview techniques to the KPU RI, political parties, and legal experts. Furthermore, the secondary data consists of primary, secondary, and tertiary legal materials. This legal research uses descriptive analysis to obtain research results. The results showed that the practice of Presidential threshold has existed since the enactment of the first presidential and vice presidential elections. The political rights of citizens and political parties do not necessarily disappear, they only become conditional. Political parties also have the same opportunity to nominate the president and vice president by carrying their own or joining and forming coalitions with other parties.

Short Communication: Rotavirus Group A Occurrence in Rural Water Source Samples in a Midwest Region State of Brazil, Comparing Wet and Dry Seasons

Identified as a potential reference pathogen by the WHO Guidelines for Drinking-Water Quality, Rotavirus (RV) is among the main enteric viruses that cause waterborne diseases. The aim of this study was to identify and correlate the presence of RV in collective and individual water sources of rural communities in the state of Goiás, within the seasons in which the collections were made (rainy and dry seasons). For this, 86 water samples in the dry period and 160 samples in the rainy period were collected. Concentration of water samples, extraction of viral genetic material and molecular tests were performed. When analyzing the presence of RV in the samples, taking into consideration the period studied, RV was found to be more prevalent in the dry season (54.7%) than in the rainy season (20%), showing a strong statistical association with the dry season (p-value < 0.001). The presence of pathogenic microorganisms in water is a public risk issue, enabling the emergence of outbreaks, endemics and epidemics. In the present research, there was an association between the presence of Rotavirus and the dry period of the year when compared to the rainy period.

Comparative analysis of cyto-genotoxicity of zinc using the comet assay and chromosomal abnormality test.

In this study, the toxicity of the trace element zinc (Zn) in Allium cepa L. test material was examined. Toxicity was investigated in terms of physiological, cytogenetic, biochemical, and anatomical aspects. Germination percentage, root length, weight gain, mitotic index (MI), micronucleus (MN) frequency, chromosomal abnormalities (CAs), malondialdehyde (MDA), proline and chlorophyll levels, superoxide dismutase (SOD) and catalase (CAT) enzyme activities, and meristematic cell damage were used as indicators of toxicity. Additionally, the comet test was used to measure the degree of DNA damage. Four groups of A. cepa bulbs-one for control and three for applications-were created. While the bulbs in the treatment groups were germinated with Zn at concentrations of 35, 70, and 140mg/L, the bulbs in the control group were germinated with tap water. Germination was carried out at room temperature for 72h and 144h. When the allotted time was over, the root tips and leaf samples were collected and prepared for spectrophotometric measurements and macroscopic-microscopic examinations. Consequently, Zn treatment led to significant reductions in physiological indicators such as weight gain, root length, and germination percentage. Zn exposure caused genotoxicity by decreasing the MI ratios and increasing the frequency of MN and CAs (p < 0.05). Zn promoted various types of CAs in root tip cells. The most observed of CAs was the sticky chromosome. Depending on the dose, Zn was found to cause an increase in tail lengths in comet analyses, which led to DNA damage. Exposure to Zn led to a significant decrease in chlorophyll levels and an increase in MDA and proline levels. It also promoted significant increases in SOD and CAT enzyme activities up to 70mg/L dose and statistically significant decreases at 140mg/L dose. Additionally, Zn exposure caused different types of anatomical damage. The most severe ones are epidermis and cortex cell damage. Besides, it was found that the Zn dose directly relates to all of the increases and decreases in physiological, cytogenetic, biochemical, and anatomical parameters that were seen as a result of Zn exposure. As a result, it has been determined that the Zn element, which is absolutely necessary in trace amounts for the continuation of the metabolic activities of the organisms, can cause toxicity if it reaches excessive levels.

Life cycle assessment and design of LignoBlock: A lignin bound block on the path towards a green transition of the construction industry

Lignin-based biopolymer-bound soil composites (BSCs) are a new class of sustainable construction materials that utilize a bio-based biopolymer — lignin — as a binder. Prior use of lignin suggests that lignin is a promising candidate for the development of bio-based construction materials. Inspired by these applications, lignin-based BSCs were developed using lignoboost lignin, lignoforce lignin, alkali lignin, and hydrolysis lignin. Uni-axial compressive testing of lignin-based BSC shows that the compressive strength for these BSCs range from 1.6–8.1 MPa, which makes them appropriate for low compressive strength construction applications. We performed a life cycle assessment (LCA) of lignin-based BSC, with the functional unit being a CMU-sized block (V=6423cm3). The major advantage of BSC lies in the elimination of ordinary portland cement, which is common to many construction materials, including many forms of concrete. Furthermore, the use of lignin in lignin-based BSC results in carbon sequestration (lignin ≈ 60 wt% carbon), potentially making construction materials made from lignin-based BSC carbon negative. Additionally, a design guide for estimating the life cycle carbon footprint of lignin-based BSC for a required compressive strength was developed. By utilizing the results from material tests and the LCA, designers are now able to use lignin effectively in construction applications, as they can now design lignin-based BSC for a target compressive strength with a full understanding of the life cycle carbon footprint implications.

Enhancing Manufacturing Processing Stability and Efficiency with Linear-Regression Analysis: Modeling on a Flow-Drill Screw (FDS) Joining Process

The instability (in processing time) in the flow-drill screwing process is undesired but inescapable due to variations in material property, gauge, and process parameters. A substantial number of materials and lab labor need to be used to test and control the variability of the real manufacturing joining process. To enhance the stability and efficiency of the screwing process, this study seeks multi-disciplinary collaboration by applying linear-regression modeling. Six hundred and forty-eight data points were collected and split into an 80% training set for model building and a 20% test set for model validation. A multiple linear-regression model was built. The results indicated that, compared to variable base level (6000 rpm rotational speed and 1100 N downforce), higher rotational speed (8000 rpm, 7000 rpm), greater downforce (1200 N, 1300 N), and their interaction were significantly associated with passage (processing) time, while the switch point did not significantly affect passage time. The interaction plot and effect size were adopted to provide measurements of the effect magnitude on processing time. The coefficient of determination indicated that 86% of the variability in the passage time can be explained by this model. Statistical analysis, such as data visualization, statistical modeling, and other data-driven analysis methods, can be used to detect underlying relationships between variables, investigate variations, and make predictions in the manufacturing process. The outcomes from the data-driven analysis can benefit from improving the economical manufacturing system, refining the processing setting, and reducing test material costs, labor, and lead time.

Foliar spraying exogenous ABA resists chilling stress on adzuki beans (Vigna angularis).

Adzuki bean, an important legume crop, exhibits poor tolerance to low temperatures. To investigate the effect of exogenous abscisic acid (ABA) on the physiological metabolism and yield resistance of adzuki bean under low-temperature stress, we conducted a potted experiment using Longxiaodou 4 (LXD 4) and Tianjinhong (TJH) as test materials and pre-sprayed with exogenous ABA at flowering stage continuously for 5 days with an average of 12°C and an average of 15°C, respectively. We found that, compared with spraying water, foliar spraying exogenous ABA increased the activities of antioxidants and the content of non-enzymatic antioxidants, effectively inhibited the increase of malondialdehyde (MDA), hydrogen peroxide (H2O2) content, O2-· production rate. Exogenous ABA induced the activation of endogenous protective mechanisms by increasing antioxidant enzymes activities such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), as well as elevated levels of non-enzymatic antioxidants including ascorbic acid (ASA) and glutathione (GSH). Moreover, the yield loss of 5.81%-39.84% caused by chilling stress was alleviated by spraying ABA. In conclusion, foliar spraying exogenous ABA can reduce the negative effects of low-temperature stress on the yield of Adzuki beans, which is essential to ensure stable production of Adzuki beans under low-temperature conditions.

Analysis of Mathematical Connection Ability and Self-Confidence on Junior High School Students

This research is motivated by the importance of students’ mathematical connection abilities and self-confidence in learning mathematics. Mathematical connection ability is an important factor in understanding mathematical concepts. The aim of this research is to analyze the level of students’ mathematical connection abilities and junior high school students’ self-confidence. The method used in this research is a descriptive-qualitative method. The research subjects were 37 students in class VIII-C of SMPN 3 Margahayu. The instruments used were four items of mathematical connection test material on the System of Two-Variable Linear Equations and non-tests of students’ confidence in learning mathematics. The results of the analysis show that the average score of all mathematical connection ability test questions in indicator 1 using relationships between mathematical topics is 5%, indicator 2 is understanding equivalent representations of the same concept (36%), indicator 3 uses mathematics in everyday life (52%), and indicator 4 uses mathematics in other subjects (27%). So the average is 30%. So the students’ mathematical connection ability is included in the low category. Most students are unable to solve problems with indicators using relationships between mathematical topics. This is shown by the results of the mathematical connection ability test; students did not connect optimally. But in learning mathematics, students already have good self-confidence.

Imbalanced specialty representation of USMLE and NBME test writers

PurposeThe United States Medical Licensing Examination (USMLE) is an examination series required for allopathic physician licensure in the United States (US). USMLE content is created and maintained by the National Board of Medical Examinations (NBME). The specialty composition of the USMLE and NBME taskforce members involved in the creation of examination content is currently unknown.MethodsUsing the 2021 USMLE and 2021 NBME Committees and Task Forces documents, we determined each member’s board-certified primary specialty and involvement in test material development committees who we dubbed “test writers”. Total active physicians by primary specialty were recorded from the 2020 Physician Specialty Data Report published by the Association of American Medical Colleges (AAMC). Descriptive statistics and chi-square analysis were used to analyze the cohorts.ResultsThe USMLE and NBME test writer primary specialty composition was found to be significantly different compared to the US active physician population (USMLE χ2[32] = 172, p < .001 and NBME χ2[32] = 200, p < .001). Only nineteen specialties were represented within USMLE test writers, with three specialties being proportionally represented. Two specialties were represented within NBME test writers. Obstetrics and Gynecology physicians were proportionally represented in USMLE but not within NBME test writers. Internal Medicine (IM) accounts for the largest percentage of all USMLE test writers (60/197, 30%) with an excess representation of 31 individuals.ConclusionsThere is an imbalance in the specialty representation of USMLE and NBME test writers compared to the US active physician population. These findings may have implications for the unbiased and accurate portrayal of topics in such national examinations; thus, future investigation is warranted.

Antiviral Effects of Ozonated Water for Handwashing Against SARS-CoV-2 Omicron Variant Using the E1052-20 Test Method of the American Society of Testing Materials International

ABSTRACT Alcohol-based hand rubs are generally recommended for infection control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Hand hygiene agents, including ozonated water (OW), have been used as an alternative because alcohol-based products may cause skin damage. A few reports are available on the virucidal activity of OW against SARS-CoV-2; therefore, this study examined the inhibitory effect of 0.4, 1.0, and 4.0 ppm OW on the Omicron variant infection to VeroE6 cells expressing transmembrane protease serine 2 by calculating the median tissue culture infectious dose (TCID50) using the E1052–20 test method of the American Society of Testing Materials International. Additionally, viral RNA copies were measured in culture supernatants of control or OW. Each OW concentration demonstrated ≥5.6 log10 TCID50 reduction, corresponding to ≥99.999% reduction of infectious virus, while the control phosphate-buffered saline showed no inactivation effect. More than 5 log10 copies/mL reduction of viral RNA was observed in the culture supernatant of each OW compared with the control. These findings suggest that exposure of SARS-CoV-2 to at least 0.4 ppm OW for 5 s is sufficient for viral inactivation and that OW can be used as an alternative hand hygiene agent to prevent SARS-CoV-2 infection.