Reliable Test Method Research Articles

Bees can be trained to identify SARS-CoV-2 infected samples.

ABSTRACTThe COVID-19 pandemic has illustrated the need for the development of fast and reliable testing methods for novel, zoonotic, viral diseases in both humans and animals. Pathologies lead to detectable changes in the volatile organic compound (VOC) profile of animals, which can be monitored, thus allowing the development of a rapid VOC-based test. In the current study, we successfully trained honeybees (Apis mellifera) to identify SARS-CoV-2 infected minks (Neovison vison) thanks to Pavlovian conditioning protocols. The bees can be quickly conditioned to respond specifically to infected mink's odours and could therefore be part of a wider SARS-CoV-2 diagnostic system. We tested two different training protocols to evaluate their performance in terms of learning rate, accuracy and memory retention. We designed a non-invasive rapid test in which multiple bees are tested in parallel on the same samples. This provided reliable results regarding a subject's health status. Using the data from the training experiments, we simulated a diagnostic evaluation trial to predict the potential efficacy of our diagnostic test, which yielded a diagnostic sensitivity of 92% and specificity of 86%. We suggest that a honeybee-based diagnostics can offer a reliable and rapid test that provides a readily available, low-input addition to the currently available testing methods. A honeybee-based diagnostic test might be particularly relevant for remote and developing communities that lack the resources and infrastructure required for mainstream testing methods.

Pulsed eddy current testing for gap measurement of metal casing

A pulsed eddy current testing (PECT) method is proposed to measure the gap of non-ferromagnetic metal casing. Firstly, the detection sensitivity to the casing gap of the voltage signal induced respectively by time-harmonic excitation current and by pulsed excitation current are calculated theoretically and compared. Then the advantages of PECT method for gap measurement are discussed. Secondly, the difference curve of the time-domain induced voltage signal between two gaps near the nominal value is presented. And the value of the induced voltage signal corresponding to the peak time of the difference curve is extracted to serve as the signal characteristic. Furthermore, using a calibrated casing, the function relationship between the signal characteristic and the casing gap is derived by curve fitting. Finally, the casing gap can be determined rapidly through the induced voltage at the peak time. This paper provides a reliable non-destructive testing method for the casing gap measurement, and compared with the existing sinusoidal ECT method, the PECT method can significantly improve the signal-to-noise ratio and the detection sensitivity to the casing gap.

Different Antimicrobial Susceptibility Testing Methods to Determine Vancomycin Susceptibility and MIC for Staphylococcus aureus with Reduced Vancomycin Susceptibility.

The methods and results obtained using commercialized automation systems used for antimicrobial susceptibility testing are not entirely consistent. Therefore, we evaluated different antimicrobial susceptibility testing methods to determine vancomycin susceptibility and minimum inhibitory concentration (MIC) for Staphylococcus aureus with reduced vancomycin susceptibility (SA-RVS). A total of 128 clinical isolates of S. aureus were tested, including 99 isolates showing an MIC of ≥2 µg/mL using the VITEK2 system (VITEK2). Antimicrobial susceptibility tests were performed using the Sensititre system (Sensititre), Phoenix M50 system (Phoenix), and MicroScan WalkAway 96 Plus system (MicroScan). Vancomycin MICs were determined using the broth microdilution method (BMD) and Etest. Essential agreement and category agreement for each method were compared with BMD results as the reference method. The BMD and Etest showed complete essential agreement (100%). VITEK2, Sensititre, and Phoenix showed high essential agreement (>99%), while MicroScan showed the lowest essential agreement (92.2%). The MIC MICs determined via Etest, VITEK2, and MicroScan tended to be higher than that determined via BMD. When comparing BMD with Etest, the category agreement was 93.8% and minor errors were observed for eight isolates. VITEK2, Sensititre, and Phoenix showed category agreements of 96.1%, 96.1%, and 99.2%, respectively, while MicroScan showed the lowest category agreement of 85.2%. The determination of vancomycin susceptibility and MIC for S. aureus varied among the methods. Caution should be taken when interpreting RVS and intermediate results for S. aureus. For confirmation of SA-RVS results, it would be appropriate to test with BMD or a more reliable testing method.

Report of RILEM TC 267-TRM phase 2: optimization and testing of the robustness of the R3 reactivity tests for supplementary cementitious materials

The results of phase 1 of an interlaboratory test, coordinated by the RILEM TC 267-TRM “Tests for Reactivity of Supplementary Cementitious Materials” showed that the R3 (rapid, relevant, reliable) test method, by measurement of heat release or bound water, provided the most reliable and relevant determination of the chemical reactivity of supplementary cementitious materials (SCMs), compared to other test methods. The phase 2 work, described in this paper aimed to improve the robustness of the test procedure and to develop precision statements for the consolidated test procedure. The effect of the pre-mixing and mixing conditions, and the impact of the mix design on the test method robustness were assessed and fixed for optimal conditions to carry out the R3 heat release test. The effect of the drying step was evaluated to define the R3 bound water test procedure in more detail. Finally, the robustness of the consolidated final test methods was determined by an interlaboratory study to define the precision statements.

Indirect Efficiency Measurement Method for Line-Start Permanent Magnet Synchronous Motors

Despite the great potential and the high performance of energy-efficient line-start permanent magnet synchronous motors (LSPMSMs), their developers face a great deal of difficulties, one of which is the lack of reliable and accurate testing methods for such electrical machines. In this paper, we propose a new method for indirectly determining the efficiency of LSPMSM through the summation of individual loss components. The standard input-output method usually used for these machines is based on torque measurement, requires expensive measuring equipment, and, as a rule, has great uncertainty. Contrarily, the proposed method does not require direct measurement of torque and mechanical power on the shaft and is less sensitive to measurement uncertainties. The theoretical substantiation of the proposed method and its experimental verification using a commercially available four-pole LSPMSM with a rated power of 0.55 kW are presented. Satisfactory convergence of the experimental results obtained using the standard input-output method and using the proposed indirect method is shown.

Clinical Study for Objectification of Abdominal Examination with Functional Dyspepsia - Epigastric Diagnosis using Algometer

Objectives: Using algometer, measure the pressure pain threshold (PPT) of the epigastric pain(心下痞硬) and calculate the cut-off value, and this can serve as the basis for prognostic diagnosis of functional dyspepsia so we would like to evaluate its diagnostic value.Methods: We investigated 353 patients with functional dyspepsia symptoms who admitted Gangnam Weedahm Oriental Hospital from February 1, 2021 to February 27, 2021. At the time of the patient's visit, an oriental medical doctor measured the pressure at the first pain point on the Algometer of (CV14), twice each, at 1minute intervals. The ROC (receiver operating characteristic) curve and the optimal cut-off value derived through the diagnosis of the (CV14) PPT value for epigastric pain(心下痞硬) and the gold standard of oriental medical doctor, it was evaluated through.Results: In 353 patients, the area under the ROC curve (AUC) was 0.909 (p=0). In addition, the optimal cutting value was 10.05 (kg/cm2), which was statistically significant. Additionally, the sensitivity of the Algometer's PPT measurement was 0.704 and the specificity was 0.884. As a result, if the PPT value of the Algometer exceeds 10.05 (kg/㎠) in terms of the optimal cutting value, it can be seen that epigastric pain(心下痞硬) is lost.Conclusion: Algometer's PPT value measurement can be a reliable test method for quantification of epigastric pain(心下痞硬) diagnosis and can be useful as an objective indicator.

Establishment of a Direct PCR Assay for Simultaneous Differential Diagnosis of African Swine Fever and Classical Swine Fever Using Crude Tissue Samples.

African swine fever (ASF) and classical swine fever (CSF) are contagious swine diseases that are clinically indistinguishable from each other; hence, reliable test methods for accurate diagnosis and differentiation are highly demanded. By employing a buffer system suitable for crude extraction of nucleic acids together with an impurity-tolerant enzyme, we established a multiplex assay of real-time reverse-transcription polymerase chain reaction (rRT-PCR) for simultaneous detection of ASF virus (ASFV), CSF virus (CSFV) and swine internal control derived genes in a sample without the need for prior purification of viral nucleic acids. We applied this method to test serum and tissue samples of infected pigs and wild boars and compared the statistical sensitivities and specificities with those of standard molecular diagnostic methods. When a serum was used as a test material, the newly established assay showed 94.4% sensitivity for both and 97.9 and 91.9% specificity for ASFV and CSFV detection, respectively. In contrast, the results were 100% identical with those obtained by the standard methods when a crude tissue homogenate was used as a test material. The present data indicate that this new assay offers a practical, quick, and reliable technique for differential diagnosis of ASF and CSF where geographical occurrences are increasingly overlapping.

Factors affecting employee commitment of office staff in Ho Chi Minh City

This paper examined the factors affecting the commitment of office staff in Ho Chi Minh City (HCMC). The data is collected through questionnaires from 253 office staff; the SPSS software is used to analyse data through Cronbach’s Alpha reliability testing method, Exploratory Factor Analysis (EFA), and regression analysis. The research results revealed that training and development opportunities, salary and bonuses, and employee benefits are three critical factors that positively affect the commitment of office staff to the enterprise. The study provides implications or strategies for managers to improve their human resource management and enhance long-term employee commitment. Besides, the study also provides recommendations for future research.

Effect of Equal Volume Replacement of Fine Aggregate with Fly Ash on Carbonation Resistance of Concrete.

Concrete is prepared by substituting an equal volume of fly ash for fine aggregate, and the effect of substitution rate on its carbonation resistance is studied. Using a rapid carbonation test, the distribution law of the internal pH value of concrete with fly ash as fine aggregate (CFA) along the carbonation depth under different substitution rates (10%, 20%, 30%, and 40%) after carbonation is studied and compared with the test results of phenolphthalein solution. Then, to further clarify the damage mechanism of fly ash replacing fine aggregate on concrete carbonation, the changes in the pore structure and micromorphology of CFA after carbonation are studied by means of mercury intrusion pressure and electron microscope scanning tests. The results indicate that the carbonation depth of CFA increases gradually with increasing carbonation time. In particular, in the later stage of carbonation, the carbonation rate of concrete decreases significantly with an increase in the substitution rate. The carbonation depth XC of CFA measured by phenolphthalein solution is approximately 0.24–0.39 times of the complete noncarbonation depth measured by the pH method. The pH value test is a reliable test method that can reveal the carbonation mechanism of CFA. Carbonation can significantly reduce the proportion of more harmful holes in concrete with a large amount of fly ash, but it can also increase the proportion of less harmful and harmful holes. In general, the pore size distribution and micromorphology of concrete can be improved by replacing fine aggregates with fly ash.

Experimental Evaluation of Shear Properties of Lightweight PVC Core for Marine Application Using Digital Image Correlation System

Sandwich structures are well-known and frequently used solutions in marine applications, especially when structural stiffness is required. An important part of the sandwich structure is the core, which usually carries shear loads. Therefore, choosing a reliable test method and knowing the exact shear properties of the particular core used in the structural design is beneficial for every engineer. Shear properties of the FlexyFoam M-55, a closed-cell, lightweight PVC foam with an apparent density of 60 kg/m3, have been investigated according to the ASTM C273 standard, using the tensile and compressive loading of metal supporting plates glued to the PVC foam sample. A digital image correlation (DIC) technique was used to monitor the crack propagation, and the appearance of secondary stresses at the foam-adhesive interface and strain field for the representative sample was presented. Displacement was measured using the testing machine sensors and compared to the measurements from the DIC technique. Specimen manufacturing details, surface preparation, and the gluing sequence were described, and measuring equipment and experiment settings were presented. Stress-strain curves have been presented and shear modulus and ultimate shear strength of the foam were compared for each test approach. The results were discussed and compared with the manufacturer’s data, as well as with foams of similar densities. The well-established approach in testing the core material was discussed, and recommendations were given to improve the testing procedure.

Identifying SARS-COV-2 infected patients through canine olfactive detection on axillary sweat samples; study of observed sensitivities and specificities within a group of trained dogs.

There is an increasing need for rapid, reliable, non-invasive, and inexpensive mass testing methods as the global COVID-19 pandemic continues. Detection dogs could be a possible solution to identify individuals infected with SARS-CoV-2. Previous studies have shown that dogs can detect SARS-CoV-2 on sweat samples. This study aims to establish the dogs’ sensitivity (true positive rate) which measures the proportion of people with COVID-19 that are correctly identified, and specificity (true negative rate) which measures the proportion of people without COVID-19 that are correctly identified. Seven search and rescue dogs were tested using a total of 218 axillary sweat samples (62 positive and 156 negative) in olfaction cones following a randomised and double-blind protocol. Sensitivity ranged from 87% to 94%, and specificity ranged from 78% to 92%, with four dogs over 90%. These results were used to calculate the positive predictive value and negative predictive value for each dog for different infection probabilities (how likely it is for an individual to be SARS-CoV-2 positive), ranging from 10–50%. These results were compared with a reference diagnostic tool which has 95% specificity and sensitivity. Negative predictive values for six dogs ranged from ≥98% at 10% infection probability to ≥88% at 50% infection probability compared with the reference tool which ranged from 99% to 95%. Positive predictive values ranged from ≥40% at 10% infection probability to ≥80% at 50% infection probability compared with the reference tool which ranged from 68% to 95%. This study confirms previous results, suggesting that dogs could play an important role in mass-testing situations. Future challenges include optimal training methods and standardisation for large numbers of detection dogs and infrastructure supporting their deployment.

Gold Nanoparticles and Plant Pathogens: An Overview and Prospective for Biosensing in Forestry.

Plant diseases and their diagnoses are currently one of the global challenges and cause significant impact to the economy of farmers and industries depending on plant-based products. Plant pathogens such as viruses, bacteria, fungi, and pollution caused by the nanomaterial, as well as other important elements of pollution, are the main reason for the loss of plants in agriculture and in forest ecosystems. Presently, various techniques are used to detect pathogens in trees, which includes DNA-based techniques, as well as other microscopy based identification and detection. However, these methodologies require complex instruments and time. Lately, nanomaterial-based new biosensing systems for early detection of diseases, with specificity and sensitivity, are developed and applied. This review highlights the nanomaterial-based biosensing methods of disease detection. Precise and time effective identification of plant pathogens will help to reduce losses in agriculture and forestry. This review focuses on various plant diseases and the requirements for a reliable, fast, and cost-effective testing method, as well as new biosensing technologies for the detection of diseases of field plants in forests at early stages of their growth.

A practical laboratory method to determine ceftazidime-avibactam-aztreonam synergy in patients with New Delhi metallo-beta-lactamase (NDM)–producing Enterobacterales infection

In response to infection with New Delhi metallo-beta-lactamase (NDM)-producing Enterobacterales, combination antimicrobial therapy with ceftazidime/avibactam (CAZ/AVI) plus aztreonam (ATM) has been explored. This study evaluated a practical laboratory method of testing for clinically significant synergy between CAZ/AVI+ATM in NDM-producing Enterobacterales. Minimum inhibitory concentrations (MICs) of clinical NDM-producing isolates were determined for ATM alone and CAZ/AVI+ATM using broth dilution. Restoration of the ATM breakpoint after the addition of CAZ/AVI was explored. A CAZ/AVI Etest/ATM disc method was compared with broth dilution. Of 43 isolates, 33 (77%) were ATM resistant (median [range] MIC=56 [16-512] mg/L). Addition of CAZ/AVI restored the ATM breakpoint (MIC <4 mg/L) in 29 of 33 resistant isolates (89%). Overall, the Etest/disc method correlated with the findings from broth dilution in 35 of 43 cases (81%). Etest/disc sensitivity was 77% and specificity 85%. Positive predictive value was 92% and negative predictive value 61%. CAZ/AVI+ATM demonstrated significant synergy in most ATM-resistant NDM-producing Enterobacterales. The Etest/disc method is a quick, reproducible, and reliable method of testing for clinically relevant synergy in the microbiology laboratory.

Developing Immunity Testing for SARS-CoV-2 and Other Novel Vaccines—Correlates of Immunogenicity Parameters with Protection

During the assessment and licensing of novel vaccines, as well as post licensure follow up, it is critical to have reliable immunogenicity testing methods that relate well to real life protection [...].

Rapid Detection and Antimicrobial Susceptibility Testing of Pathogens Using AgNPs-Invertase Complexes and the Personal Glucose Meter.

Rapid detection of pathogens and assessment of antimicrobial susceptibility is of great importance for public health, especially in resource-limiting regions. Herein, we developed a rapid, portable, and universal detection method for bacteria using AgNPs-invertase complexes and the personal glucose meter (PGM). In the presence of bacteria, the invertase could be released from AgNPs-invertase complexes where its enzyme activity of invertase was inhibited. Then, the enzyme activity of invertase was restored and could convert sucrose into glucose measured by a commercially PGM. There was a good linear relationship between PGM signal and concentration of E. coli or S. aureus as the bacteria model with high sensitivity. And our proposed biosensor was proved to be a rapid and reliable method for antimicrobial susceptibility testing within 4 h with consistent results of Minimum Inhibitory Concentrations (MICs) testing, providing a portable and convenient method to treat infected patients with correct antibiotics and reduce the production of antibiotic-resistant bacteria, especially for resource-limiting settings.

Non-Destructive Multi-Method Assessment of Steel Fiber Orientation in Concrete

Integration of fiber reinforcement in high-performance cementitious materials has become widely applied in many fields of construction. One of the most investigated advantages of steel fiber reinforced concrete (SFRC) is the deceleration of crack growth and hence its improved sustainability. Additional benefits are associated with its structural properties, as fibers can significantly increase the ductility and the tensile strength of concrete. In some applications it is even possible to entirely replace the conventional reinforcement, leading to significant logistical and environmental benefits. Fiber reinforcement can, however, have critical disadvantages and even hinder the performance of concrete, since it can induce an anisotropic material behavior of the mixture if the fibers are not appropriately oriented. For a safe use of SFRC in the future, reliable non-destructive testing (NDT) methods need to be identified to assess the fibers’ orientation in hardened concrete. In this study, ultrasonic material testing, electrical impedance testing, and X-ray computed tomography have been investigated for this purpose using specially produced samples with biased or random fiber orientations. We demonstrate the capabilities of each of these NDT techniques for fiber orientation measurements and draw conclusions based on these results about the most promising areas for future research and development.

Experimental assessment on the dynamic mechanical response of rocks under cyclic coupled compression-shear loading

Rock engineering structures are quite susceptible to cyclic coupled compression-shear loading. Accurately characterizing the dynamic compression-shear behaviors of rocks is thus crucial for the construction safety and disaster prevention of rock engineering. In this study, a convenient and reliable testing method is proposed to characterize the fatigue mechanical response of rocks under cyclic coupled compression-shear loading: an inclined specimen under cyclic uniaxial loading. With the specimen axis inclining the loading direction, a cyclic shear component is introduced into rocks when subjected to cyclic uniaxial compression. Our method has certain distinct merits in the specimen preparation and experimental operation since no undesired loading devices are required. To demonstrate this method, 21 cyclic loading tests are conducted on inclined sandstone specimens with different tilting angles (i.e., 0°, 3°, 6° and 10°) and under different loading frequencies (i.e., 0.5, 1, 2, and 3 Hz). Based on experimental results, the influence of the tilting angle and loading frequency on the dynamic properties of rocks is revealed and a fatigue life prediction function is proposed. With increasing tilting angle of rock specimens or decreasing loading frequency, rock specimens are featured by an increase of nominal hysteresis energy density, leading to higher damage variable and lower fatigue life. Quite different from the axial splitting failure of right cuboid specimens along the loading direction, all inclined rock specimens (i.e., 3°, 6° and 10°) exhibit a prominent shear-dominated failure accompanied by localized tensile damage, and the shear component becomes more remarkable as the tilting angle increases. In addition, with a higher tilting angle or under lower loading frequency, the cyclically failed specimen is characterized by a higher degree of fragmentation.

Research of social expectations of university students in the dimensions of psychological well-being

The aim of the article is to argue theoretically and empirically study the relationship between social expectations and psychological well-being of university students. Methodological starting points of empirical research are outlined. Valid and reliable test methods are used to study the psychological content parameters of social expectations and psychological well-being. The results determined that the psychological features of social expectations and psychological well-being of student's youth are theoretically substantiated. It was found that the respondents have an average level of parameters of psychological well-being and social expectations, which indicates moderate life satisfaction and the presence of adequate orientation in the socio-psychological reality. The most formed components of psychological well-being are the balance of affect and meaningfulness, which indicates the awareness of their own lives by student’s youth. It is recorded that the respondents have the least formed - self-acceptance, positive attitude and autonomy.

The Separation of Cannabinoids on Sub-2 µm Immobilized Polysaccharide Chiral Stationary Phases.

The increased use and applicability of Cannabis and Cannabis-derived products has skyrocketed over the last 5 years. With more and more governing bodies moving toward medical and recreational legalization, the need for robust and reliable analytical testing methods is also growing. While many stationary phases and methods have been developed for this sort of analysis, chiral stationary phases (CSPs) are unique in this area; not only can they serve their traditional chiral separation role, but they can also be used to perform achiral separations. Given that mixtures of cannabinoids routinely contain enantiomers, diastereomers, and structural isomers, this offers an advantage over the strictly achiral-only analyses. This work presents the separation of a 10-cannabinoid mixture on several polysaccharide-based sub-2 µm CSPs with both normal-phase and reversed-phase ultra-high-performance liquid chromatography (UHPLC) conditions. Along with the separation of the mixture, appropriate single-peak identification was performed to determine the elution order and reported where applicable.

Trends in the epidemiology of dermatophytosis in the Middle East and North Africa region.

Dermatophytosis corresponds to a broad series of infections, mostly superficial, caused by a group of keratinophilic and keratinolytic filamentous fungi called dermatophytes. These mycoses are currently considered to be a major public health concern worldwide, particularly in developing countries such as those in the Middle East and North Africa (MENA) region. Here we compiled and discussed existing epidemiologic data on these infections in the MENA region. Most of the available studies were based on conventional diagnostic strategies and were published before the last taxonomic revision of dermatophytes. This has led to misidentifications, which might have resulted in the underestimation of the real burden of these infections in the MENA countries. Our analysis of the available literature highlights an urgent need for further studies based on reliable diagnostic tools and standard susceptibility testing methods for dermatophytosis, which represents a major challenge for these countries. This is crucial for guiding appropriate interventions and activating antifungal stewardship programs in the future.