Test Method Research Articles

Issues of physical development among the Mongolian youth

At the beginning of the research, we proposed the goal of studying the modern trends in physical education at the Mongolian University of Science and Technology through analysis and comparative assessments. As a result of the study, it was observed that comprehensive education in England, sports education using technical and technological advances in Australia, sports teaching for happiness in Japan and China and skills education and physical education in Mongolia are the dominant teaching approaches. In the course of the analysis, it has been found out that there is a lack of attitude towards physical education in Mongolia, and we have determined the extent to which it has been effective through a test study. One of the main goals of our work is to study the issue of physical development of the Mongolian youth in years past. The article presents the results of the unprecedented physical development test of the first-year students enrolled in the Mongolian University of Science and Technology from 2008 to 2018. We used the “Test to Determine the Level of Physical Development and Fitness of the Population”. Actually, this test named after the President of Mongolia Mr. Tsakhiagiin Elbegdorj has been implemented at the national level. During the test, height, weight, speed, strength, flexibility and endurance of students were studied by the movement test method. The test was evaluated according to the approved methodologyю. And as a result, we used quantitative and statistical research methods, performed reliability and statistical tests for each questionnaire and data obtained and analyzed the correlation of factors. If we look at physical development levels of all students, there were 14 percent with poor results and 44 percent with insufficient ones. The physical development of the majority of participants (58 percent) was rated below the sufficient level (17 points) that a person of that age should have. In terms of gender, 53 percent of male students and 65 percent of female students had insufficient physical development. According to the data of a sociological questionnaire survey of students participating in the test, 58.1 percent did not exercise or play sports. It was an interesting observation that coincided with the result that 58.0 percent of the test participants had insufficient physical development. According to our research, the majority of Mongolian students and young people had a low level of physical fitness, and one of every six students had weight problems. This may indicate that the approach to teaching skills development and physical education is somewhat ineffective. The theoretical and practical significance of the research is that the current situation regarding physical development of students and youth can be determined and the results can serve as a basis for making detailed policies and decisions for the development of physical activity and sports among young people. Today, students and youth are the most important segment of the population that drives the economy and human development of Mongolia, so it is important to cultivate a healthy and physically fit nation relying on the fact that physical activity and sports should be available for all people.

Performance Characterization of the Field Aged Asphalt Pavement Materials at Mortar Scale: Testing Method Optimization and Rheology Analysis

Performance evaluation at the asphalt mortar scale offers increased sensitivity to aging and is less affected by extraction processes comparated to asphalt mixture. Despite these benefits, there is currently a lack of standardized methods for directly processing mortar samples obtained from field mixtures. This study aims to improve and validate a manufacturing procedure for aged mortar specimens derived from field aging cores, and to evaluate the field damage level of asphalt paving materials at the mortar scale. A novel approach was developed that incorporates warm sieving, compaction, coring, and cutting to manufacture mortar specimens suitable for Dynamic Shear Rheometer (DSR) tests. This study selected mortar specimens with different service ages and conducted rheological tests, including frequency sweep tests and modified Multiple Stress Creep Recovery (MSCR) tests, to assess their rheological performance. And the significance test of all the indcies were conducted to select suitable indcies.The results show the proposed aged mortar manufacture approach can prepare eligible mortar specimens for rheology tests. The rheology test results show that several indices can distinguish different mortar types and service ages, and the indices of surface layer mortar follow a linear relationship with service age. The linear viscoelastic zone (LVE), representative shear modulus (G0), and unrecovered creep compliance at 1.6kPa (Jnr1.6) and 3.2kPa (Jnr3.2) are identified as effective indices for evaluating the behavior of field aged mortar because of their effectiveness, lower variability, and better distinction.

Construction d’une méthodologie d’évaluation clinique des dispositifs médicaux grâce aux outils de simulation et illustration à travers trois études

European regulations have recently moved towards more stringent requirements for demonstrating the safety and performance of medical devices (MDs). To apply an innovative testing method using medical simulation to the evaluation of three medical devices at different stages of their life cycle. The methodology for evaluating DMs using simulation is based on seven stages: definition of the context, training, construction of a scenario to test the DM, validation of the scenario, realization of the scenario, evaluation of the scenario by the players and validation and exploitation of the results. Our evaluation methodology enabled us to assess three DMs at different stages of their development: a respiratory protection device at the initial stage (prototype definition), a respiratory protection mask (prototype optimization) and bottle adapters (post-marketing). Simulation is a valuable tool for evaluating DM. The proposed methodology enables it to be used and adapted to different contexts. It responds to the specificities of clinical evaluation of this class of products, and helps to better anticipate certain risks.

NIR spectroscopy for quality assessment and shelf-life prediction of kiwifruit

In this study, a non-destructive quality testing method along with shelf-life prediction of Xu Xiang ready-to-eat kiwifruit were developed using near-infrared spectroscopy (NIR) techniques. Several traditional quality indicators (hardness, soluble solids content, and dry matter) were evaluated. Partial least squares regression (PLS) was used to predict the intrinsic quality attributes of the samples. Competitive adaptive reweighted sampling algorithm (CARS) and uninformative variable elimination (UVE) algorithm were used to select the characteristic wavelengths. Prediction models for hardness, soluble solids content and dry matter were developed. The results showed that the prediction ability of the models could be improved by screening the characteristic wavelengths of CARS and UVE. Among them, the CARS-SNV-PLS model based on soluble solids had the best prediction ability (RMSEP of 0.430 and Rp2 of 0.958). Then, an NIR-based residual shelf-life prediction model was obtained by linking the measured quality indicators to the residual shelf-life, which was well validated with an RMSEP of 1.64 and an Rp2 of 0.939. Therefore, this study demonstrated the potential of combining CARS, SNV, and PLS for the non-destructive testing of ready-to-eat kiwifruit to provide technical support and solution.

Antibacterial activity study of Urea-Trimesic acid and 2, 3-dihydro-1,5- benzodiazepine-picric acid based cocrystals

The antibacterial activity of two cocrystals of Urea-Trimesic acid (1) and 2,3-dihydro-1,5- benzodiazepine-Picric acid (2) is reported. Cocrystals 1 and 2 show antibacterial effects with Escherichia coli and Staphylococcus aureus via the Disk Diffusion Test method with the zone of inhibition as comparable to the positive control Chloramphenicol whereas the individual coformers are found to be less potent under the same condition. The insilico molecular docking has been used to acquire binding modes and binding affinities for both the cocrystals 1 and 2 and the respective of conformers where the protein structure (d-lactate dehydrogenase) (DLDH) of E. coli and Staphylococcus aureus show remarkable binding affinity with cocrystals 1 and 2 as compared to the respective coformers.

The effectiveness of a proposed strategy in light of anchored instruetion learning on achievement among middle school students

The research aims to identify the effectiveness of a proposed strategy in light of Anchored instruetion Learning in achieving achievement among middle school students. To achieve the aim of the research, the two researchers adopted an experimental research approach with two groups (experimental and control) with a post-test, and the null hypothesis was developed: There is no statistically significant difference at the level of significance (0.05) between the average scores of the experimental group students who studied according to the proposed strategy and the scores of the control group students who studied according to the normal method in the achievement test. The research sample consisted of (60) fifth-grade science students at Al-Suyuti Preparatory School affiliated with the General Directorate of Education of Baghdad Al-Karkh II. The sample was distributed into two groups: The experimental group consisted of (30) students who studied according to the proposed strategy. 2. The control group consisted of (30) students who studied in the usual way. The two research groups were rewarded on the variables (previous achievement, chronological age, previous knowledge, intelligence, and mathematical culture). After that, an achievement test was constructed, consisting of (30) objective, multiple-choice items. Appropriate statistical analyzes were conducted, and the psychometric properties of the test were verified. The results resulted The students in the experimental group who studied with the proposed strategy outperformed the students in the control group who studied in the usual way. In light of the results, a set of conclusions, recommendations and proposals were reached.

Numerical characterisation of reaction forces’ contribution to initial stiffness in speed-lock beam-to-upright connections

This article presents a detailed numerical model of speed-lock (boltless) beam-to-upright connections in steel storage pallet rack systems. The model is capable of predicting initial stiffness and characterising the reaction forces of connector-to-upright interactions. The study examines nine configurations, combining three types of uprights and three types of beams with a common connector. Initially, experimental tests were conducted using the monotonic cantilever test method according to EN 15512 standard, with initial stiffness calculated using a standardised version of the initial stiffness method. Subsequently, a numerical analysis was developed through a finite element model based on the experimental setup. The model introduces new geometric details, evaluating each impact on behaviour, particularly on initial stiffness. Results show that numerical accuracy improves with detailed components such as inclined tabs, more detailed perforations, and 3D weld modelling. The contribution of reaction forces of connector-to-upright interactions to initial stiffness was analysed, considering the impact of the rotation centre’s position. It was found that a lower rotation centre position reduces the connector-to-upright lateral contact contribution while increasing tab-to-slot interaction contributions. The impact of beam height and beam weld position on initial stiffness was also analysed, with results showing that increasing these variables consistently led to increased initial stiffness. Finally, the rotation centre’s position was shown to evolve throughout the test, redefining the contribution of interactions. It clarified that connector-to-upright lateral interaction and tab1-to-slot1 and tab2-to-slot2 interactions have the highest contributions. This information is valuable for rack manufacturers to improve, optimise, and ensure the safety of their designs.

Discovery and Analysis of the Relationship between Organic Components in Exhaled Breath and Bronchiectasis.

The prevalence of patients with bronchiectasis (BE) has been rising in recent years, which increases the substantial burden on the family and society. Exploring a convenient, effective, and low-cost screening tool for the diagnosis of BE is urgent. We expect to identify the accuracy of breath biomarkers(BBs) for the diagnosis of BE through breathomics testing and explore the association between BBs and clinical features of BE.
Method: Exhaled breath samples were collected and detected by high-pressure photon ionization time-of-flight mass spectrometry(HPPI-TOF MS) in a cross-sectional study. Exhaled breath samples were from 215 patients with BE and 295 control individuals. The potential BBs were selected via the machine learning method. The overall performance was assessed for the BBs-based BE detection model. The significant BBs between different subgroups such as the severity of BE, acute or stable stage, combined with hemoptysis or not, with or without Nontuberculous Mycobacterium (NTM), Pseudomonas aeruginosa (P.a) isolation or not, and the BBs related to the number of involved lung lobes and lung function were discovered and analyzed.
Results: The top 10 BBs based machine learning model achieved an area under the curve (AUC) of 0.940, sensitivity of 90.7%, specificity of 85%, and accuracy of 87.4% in BE diagnosis. Except for the top ten BBs, other BBs were found also related to the severity, acute/stable status, hemoptysis or not, NTM infection, P.a isolation, the number of involved lobes, and three lung functional paramters in BE patients.
Conclusions: BBs-based BE detection model showed good accuracy for diagnosis. BBs have a close relationship with the clinical features of BE. The breath test method may provide a new strategy for bronchiectasis screening and personalized management.

Clinical Trail Number: NCT05293314&#xD.

A novel random-effect Birnbaum-Saunders distribution for reliability assessment considering accelerated mechanism equivalence

ABSTRACT Birnbaum-Saunders (B-S) distribution has been widely used in reliability assessment of products. However, the basic B-S distribution fails in characterizing the variation of damage caused by different units. In this paper, a novel random-effect B-S distribution which considers the unit heterogeneity is proposed. First, the novel distribution incorporates the inverse gamma distribution into the shape parameter of B-S distribution, and statistical inferences of the novel distribution are thoroughly investigated. Then, an extension of the proposed B-S distribution is developed to handle accelerated life test (ALT) data. In order to ensure the validity of ALTs, a coefficient of variation hypothesis test method employing the necessary condition for mechanism equivalence of the proposed distribution is executed. To estimate the parameters of the novel B-S distribution with explanatory variables, a two-step algorithm combining analogue least square and expectation maximization (ALS-EM) is proposed based on the data with constant coefficients of variation. A simulation is conducted to verify the effectiveness of the proposed ALS-EM method. Finally, two actual engineering cases are utilized to show the advantages of the random-effect B-S distribution in terms of goodness-of-fit and reliability assessment precision.

Determination of Aloin A, Aloin B, and Aloe-Emodin in Raw Materials and Finished Products Using HPLC Multi-Laboratory Validation Study, AOAC 2016.09, Final Action Status.

A multi-laboratory validation study was performed on AOAC Official Method of Analysis (OMA) 2016.09, for final action. Eight different laboratories throughout the world participated in the study tested the same set of 6 different laboratory samples of raw materials (commercial) and formulated products (commercial), and all the laboratories successfully generated results within the acceptance criteria. The intention of the study was to evaluate specificity, precision (variation), linearity/range, system suitability, limit of detection (LOD), and limit of quantitation (LOQ) by multiple laboratories to satisfy the requirement of moving the OMA 2016.09 to the final action status. Accuracy and ruggedness were already validated in earlier work of single laboratory validation (1), and it was not necessary to include these validation parameters in the multi-laboratory validation study. Laboratory samples containing Aloe were sent out to participating laboratories. Each lab followed AOAC 2016.09 (First Action status) to analyze contents of aloin A, aloin B, and aloe emodin using high performance liquid chromatography (HPLC) instrument. The results generated by each laboratory were collected and evaluated. The specificity results show that blank and matrix chromatograms do not contain major interfering peaks on the retention time of aloin A, aloin B, and aloe-emodin. The precision (variation) results of duplicated preparations are not more than 0.05 parts per million (ppm) different. The linearity/range results from six standards (10 parts per billion (ppb), 20 ppb, 40 ppb, 80 ppb, 160 ppb, and 500 ppb) have correlation coefficient (R) value of ≥ 0.999. The system suitability results meet the acceptance criteria to show the instrument validity. The limit of detection (LOD) results show that the signal-to-noise (S/N) ratio of 10 ppb standards for all three components are about 3. The limit of quantitation (LOQ) results show that the S/N ratio of 20 ppb standards for all three components are about 10. The validation parameters (specificity, precision (variation), linearity/range, system suitability, LOD, and LOQ) have been successfully analyzed, and it shows that the test method is suitable for its intended use. The test method has been successfully validated by the eight different laboratories around the world (US, UK, Germany, and Canada). Each of the laboratory is managed independently by the site lab management team. This multi-lab study validated the method of Determination of Aloin A, Aloin B, and Aloe-Emodin in Raw Materials and Finished Products Using high performance liquid chromatography (HPLC), and the method fits for its intended purpose.

Pediatric Epilepsy Genetic Testing Results and Long-term Seizure Freedom.

Objective: To determine whether there is a correlation of genetic diagnosis/result with long-term seizure freedom in pediatric epilepsy patients. Methods: This was a prospective and retrospective cohort study of children with epilepsy referred for genetic testing at a single center. The primary outcomes were presence and type of genetic diagnosis (pathogenic, benign, or variant of uncertain significance) and patient epilepsy status (seizure free, treatment failure, uncertain). Epilepsy gene panels were the primary method of genetic testing. Results: The prospective cohort had 22 patients followed for >11 years and for whom genetic testing was then performed; the retrospective cohort had 78 patients with previous genetic testing followed for >8 years. In the prospective cohort, one patient each of the seizure free or treatment failure groups had a pathogenic genetic variant; mean Combined Annotation Dependent Depletion (CADD) scores 22 and 24, respectively (P = .62). In the retrospective cohort, there was no difference in the number of variants (P = .97), the variant interpretations (P = .29 ClinVar, P = .39 lab interpretation) or mean CADD scores (P = .29) between the seizure-free, treatment failure, and uncertain epilepsy patients. Whole exome and genome sequencing identified pathogenic variants in 70% of patients with treatment failure but were not performed in seizure-free patients. Significance: Our findings show no correlation of the presence or type of epilepsy gene panel result with long-term seizure freedom in pediatric patients. The yield and specificity of pathogenic variants may be higher using whole exome and whole genome sequencing in patients with treatment-resistant epilepsy. Whole exome and whole genome sequencing, or more targeted understanding of specific variants, may be needed to improve the utility of pediatric epilepsy genetic testing.

Application of CNVPLUS-array custom microarray in genetic analysis of spinal muscular atrophy

To assess the application value of CNVPLUS-array for the genetic analysis of Spinal muscular atrophy (SMA). From June 2021 to December 2022, CNVPLUS-array technique was employed to test the SMN1 and SMN2 genes among peripheral blood samples from 17 suspected SMA patients, 18 core families with suspected SMA, and 25 healthy individuals. The results were compared with those of multiple ligation-dependent probe amplification (MLPA) assay. Samples with inconsistent results were subjected to nested PCR or comprehensive analysis of SMA. CNVPLUS-array has identified 35 SMA patients, 36 carriers, and 25 healthy individuals. In comparison, MLPA has identified 34 SMA patients, 36 carriers, and 26 healthy individuals. The two methods demonstrated a high consistency (Kappa = 0.968, P < 0.001). Additionally, CNVPLUS-array has identified one patient with compound heterozygous variants of SMN1 and one carrier with a [2+0] genotype. CNVPLUS-array not only can accurately determine the copy numbers of SMN1 and SMN2 genes, but also identify point mutations in SMN1 and [2+0] carriers, which has offered a new method for the genetic testing of SMA.

Non-inferiority testing on the accuracy of two qualitative microbiological methods on paired binary data

Before implementing a new microbiological test method in pharmaceutical industry, it is required to assess whether it matches or surpasses the detection of microorganisms of the current microbiological method. The United Stated Pharmacopoeia Chapter 1223 (USP < 1223>) proposes two statistical approaches for testing non-inferiority of two qualitative microbiological methods when they can both test the same samples (paired design). The first approach compares the positive rates of the two methods. The non-inferiority test is not influenced by the performance of the methods alone, it is also affected by the spiked bacterial density. The second approach compares most probable numbers (MPNs) between the two methods, but the MPN assumes that the microbiological methods are perfect. To address the two abovementioned flaws, a generalized MPN (gMPN) approach is being proposed. Estimators for the accuracy, detection proportion, and bacterial density parameter are being derived using the method of moments. It will be shown that estimation of the accuracy and detection proportion has limited to no bias, but the bias for the bacterial density can become substantial. A test statistic for non-inferiority of accuracy, along with a sample size formula, is presented, showing nominal type I error and appropriate power. The proposed approach is demonstrated using real data.

Determination of critical local straining conditions for solidification cracking at laser beam welding by experimental and numerical methods

AbstractThe phenomenon of solidification cracking has been the subject of numerous research projects over the years. Great efforts have been made to understand the fundamentals of hot cracking. It is generally agreed that solidification cracks form in the solidification range between the liquidus and solidus temperatures under the combination of thermal, metallurgical and mechanical factors. There is still a need to determine the time‐resolved strain distribution in the crack‐sensitive region in order to analyse the local critical conditions for solidification cracking phenomena. This was a strong motivation for the development of a measurement system used in this study to estimate the local strains and strain rates in the zone where the solidification crack is expected to occur. The laser beam welding experiments were conducted using the Controlled‐Tensile‐Weldability test (CTW test) to apply an external strain condition during welding to generate solidification cracks. The CTW test is a test method for investigating the susceptibility of laser‐welded joints to solidification cracking, in which the sample can be subjected to a defined strain at a defined strain rate during welding.In combination with experimental investigations, numerical simulations provide spatially detailed and time‐dependent information about the strain development during the welding process, especially regarding the critical conditions for solidification cracking. Therefore, this tool was also used in the present study to evaluate the accuracy of measurement methods and to estimate experimentally derived values and their concrete influence on the formation of solidification cracks. By integrating experimental methods and numerical simulations, this study investigates the spatially resolved and temporally changing development of strain during welding, with a particular focus on the critical conditions that lead to the formation of solidification cracks. The use of numerical simulations serves a dual purpose by validating the accuracy of measurement methods and examining experimentally determined values for their actual influence on the formation of solidification cracks. A three‐dimensional finite element (FE) model implemented with ANSYS is used to simulate strains and stresses during welding. The credibility of the model was first established by validation using experimental temperature measurements. Subsequently, structural simulations were carried out under external load. The results of the simulations showed commendable agreement with the strain measurements performed using the developed technique.

A new strategy in bioreactor scale-up and process transfer using a dynamic initial vvm according to different aeration pore size

Monoclonal antibody drugs have grown into a drug category with a market size of over $100 billion since the first product was launched on the market, which naturally creates a large demand for production. At the same time, the $100 billion market is distributed among more than 200 listed drugs, which indicates that the production demand for monoclonal antibody drugs is diverse. To meet this demand, major suppliers offer single-use bioreactors of all sizes. These single-use bioreactors with different specifications, especially the inconsistency of aeration pore sizes, pose great challenges for technology transfer and scale-up production, and the conventional scale-up strategies of constant Power input/volume ratio (P/V) and constant vessel volume per minute (vvm) can no longer meet the needs. This study simplified the selection of technical parameters in bioreactors based on the differences in aeration pore size. Innovatively combined the aeration pore sizes with initial aeration vvm, and comprehensively investigated the relationship between P/V, vvm and aeration pore size by designing experiments (DoE) using the orthogonal test method. The results showed a quantitative relationship between the aeration pore size and the initial aeration vvm in the P/V range of 20 ± 5 W/m3. The appropriate initial aeration was between 0.01 and 0.005 m3/min for aeration pore size ranging from 1 to 0.3 mm, which was the optimal incubation condition in the bioreactors. The choice of initial ventilation was most related to the final expression. Follow-up studies validated these findings in a 15 L glass bioreactor and a 500 L single-use bioreactor, and the results were consistent with expectations.

An Improved Test Method for Assaying the Inhibition of Bioflavonoids on Xanthine Oxidase Activity in vitro.

The difference on inhibitory effects of bioflavonoids inhibiting XOD activity assayed by varying test methods cause of us to be further in consideration. The reported test method creating a micro-environment surrounding XOD in the absence of ⋅O2 -, which is seemly different from the assay in vivo. So, the vitro test method for assaying XOD activity is necessary to be improved for selection of potential inhibitors in the presence of ⋅O2 -. The inhibitory results demonstrated that bioflavonoids of MY, DMY, QUE and LUT are capable to be on effective IC50 values, but others are not. As well, their resulting inhibitions determined by the improved test method are much less than that reported in the literature, indicating that their chemical affinities with XOD become weaker. Moreover, DMY assayed on the inhibitions of XOD in the improved test method performs to be a better inhibitor, as compared to the assay of the reported test methods. Abasing on the transformation of DMY into MY in the presence of ⋅O2 -, the good inhibition of DMY on XOD activity can be explained by the synergistic effect of MY.

Measurement of computed tomography modulation transfer function with a novel polymethyl methacrylate phantom.

A novel phantom for measuring the 10% and 50% values of the modulation transfer function (MTF) for computed tomography scanners (CT) was investigated. The phantom was constructed by drilling rows of holes of different sizes and frequencies into a small block of polymethyl methacrylate (PMMA). The MTF at a given frequency was determined from the ratio of the range of Hounsfield units within the rows of holes at different frequencies, and the difference in Hounsfield units between air and PMMA. A MTF curve was plotted from measurements at different frequencies and the 10% and 50% MTF values were obtained from a cubic spline interpolation. The MTF results obtained with the drilled hole phantom method were compared to a conventional method - using a thin wire and Spice-CT ImageJ Plugin- and with identical acquisition and reconstruction parameters. The drilled hole phantom measured the 50% MTF with reasonable accuracy but underestimated the 10% MTF by 8.2% on average. MTF measurements were reproducible for repeated image acquisitions and with different users analysing the images, and the phantom was able to accurately measure the change in MTF when measured on images using different reconstruction kernels. The tool may find application as a cheap, easy to use method for routine QC testing of CT scanners.

Biomimetic synthetic test system based on hydroxyapatite cement for adhesive strength evaluation of experimental mineral-organic bone adhesive materials.

The development of bone adhesive materials is a research field of high relevance for the advancement of clinical procedures. Despite this, there are currently no material candidates meeting the full range of requirements placed on such a material, such as biocompatibility, sufficient mechanical properties and bond strength under biological conditions, practical applicability in a clinical setting, and no adverse effect on the healing process itself. A serious obstacle to the advancement of the field is a lack in standardized methodology leading to comparable results between experiments and different research groups. Natural bone samples are the current gold-standard material used to perform adhesive strength experiments, however they come with a number of drawbacks, including high sample variability due to unavoidable natural causes and the impossibility to reliably recreate test conditions to repeat experiments. This paper introduces a valuable auxiliary test method capable of producing large numbers of synthetic test specimens which are chemically similar to bone and can be produced in different laboratories so to repeat experiments under constant conditions across laboratories. The substrate is based on a hydroxyapatite forming cement with addition of gelatine as organic component. Crosslinking of the organic component is performed to improve mechanical properties. In order to demonstrate the performance of the developed method, various experimental and commercial bone/tissue adhesive materials were tested and compared with results obtained by established methods to highlight the potential of the test system.

Exploring Innovative Methods in Maritime Simulation: A Ship Path Planning System Utilizing Virtual Reality and Numerical Simulation

In addressing the high costs, inefficiencies, and limitations of purely digital simulations in maritime trials for unmanned vessel path planning, this paper introduces a ship virtual path planning simulation test system. This system, unbound by temporal and spatial constraints, vividly showcases the navigational performance of vessels. After analyzing the virtual testing requirements for the autonomous navigation performance of unmanned surface vehicles (USVs), we established the overall framework of this system. Data-driven by a numerical simulation platform, the system achieves synchronized operation between physical and virtual platforms and supports interactive path planning simulations between USVs and the virtual testing system. Furthermore, to address the limitations of traditional ship trajectory planning evaluation, this paper develops a global path planning fitness evaluation function that comprehensively considers trajectory safety, navigation distance, and vessel stability, achieving optimal comprehensive routes through the particle swarm optimization algorithm. Test results indicate an average roll reduction of 14.31% in the planned routes, with a slight increase in navigation distance. By integrating two-dimensional curve simulation with three-dimensional visualization, this paper not only overcomes the limitations of purely physical and purely virtual simulations but also enhances the overall credibility and intuitiveness of the simulation. Experimental results validate the system’s effectiveness, providing a novel method for autonomous navigation testing and evaluation of USVs.

Endophytic fungal diversity and bioactive potentials: investigating antimicrobial and antioxidant activities.

This study investigates the colonization of endophytic fungi in nettle leaf tissues and evaluates their antibacterial and antioxidant activities. Using an inverted optical microscope, extensive fungal colonization was observed in all leaf parts, with hyphae prevalent in epidermal cells, parenchyma cells, and vascular tissues. 144 endophytic fungal isolates were isolated from 800 leaf fragments, indicating an 18% retention rate. ANOVA analysis revealed significant differences (p < 0. 001) in colonization frequencies among 20 subjects, with subject 3 showing the highest frequency (40%) and subject 11 the lowest (2. 5%). Ethyl acetate extracts of the three most abundant endophytic fungi demonstrated notable antibacterial activity against both Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Inhibition zones ranged from 9. 5 to 15. 16 mm, with minimum inhibitory concentrations (MICs) between 0. 19 to 25 mg/mL. Alternaria sp. exhibited the highest antimicrobial activity against MRSA. Antioxidant activity was assessed using the DPPH radical scavenging test and FRAP method. All extracts showed substantial free radical scavenging properties, with IC50 values close to those of standards like BHT. Alternaria sp. had the highest antioxidant activity, followed by Epicocum sp. and Ulocladium sp. The FRAP method confirmed high reducing potential, with Alternaria sp. again exhibiting the highest activity. These findings highlight the potential of endophytic fungi in nettle leaves as sources of antimicrobial and antioxidant agents, with significant implications for pharmaceutical and biotechnological applications.