Sequential Test Research Articles

Assessing the Neurotoxicity of a Sub-Optimal Dose of Rotenone in Zebrafish (Danio rerio) and the Possible Neuroactive Potential of Valproic Acid, Combination of Levodopa and Carbidopa, and Lactic Acid Bacteria Strains.

Parkinson’s disease (PD) is an enigmatic neurodegenerative disorder that is currently the subject of extensive research approaches aiming at deepening the understanding of its etiopathophysiology. Recent data suggest that distinct compounds used either as anticonvulsants or agents usually used as dopaminergic agonists or supplements consisting of live active lactic acid bacteria strains might alleviate and improve PD-related phenotypes. This is why we aimed to elucidate how the administration of rotenone (ROT) disrupts homeostasis and the possible neuroactive potential of valproic acid (VPA), antiparkinsonian agents (levodopa and carbidopa – LEV+CARB), and a mixture of six Lactobacillus and three Bifidobacterium species (PROBIO) might re-establish the optimal internal parameters. ROT causes significant changes in the central nervous system (CNS), notably reduced neurogenesis and angiogenesis, by triggering apoptosis, reflected by the increased expression of PARKIN and PINK1 gene(s), low brain dopamine (DA) levels, and as opposed to LRRK2 and SNCA compared with healthy zebrafish. VPA, LEV/CARB, and PROBIO sustain neurogenesis and angiogenesis, manifesting a neuroprotective role in diminishing the effect of ROT in zebrafish. Interestingly, none of the tested compounds influenced oxidative stress (OS), as reflected by the level of malondialdehyde (MDA) level and superoxide dismutase (SOD) enzymatic activity revealed in non-ROT-exposed zebrafish. Overall, the selected concentrations were enough to trigger particular behavioral patterns as reflected by our parameters of interest (swimming distance (mm), velocity (mm/s), and freezing episodes (s)), but sequential testing is mandatory to decipher whether they exert an inhibitory role following ROT exposure. In this way, we further offer data into how ROT may trigger a PD-related phenotype and the possible beneficial role of VPA, LEV+CARB, and PROBIO in re-establishing homeostasis in Danio rerio.

Effect of framework Al pairing on NO storage properties of Pd-CHA passive NOx adsorbers

Three Pd/H-CHA samples were prepared containing 53.0 %, 10.8 % and 6.5 % paired Al sites at near fixed Si/Al ratio and similar Pd loading. According to H2 temperature-programmed reduction, Pd was present almost exclusively as isolated cations in the two samples containing the higher concentrations of paired Al sites, whereas in the other sample PdO was also present. Simulated lean cold start tests on the fresh samples conducted in a microflow reactor showed that the sample containing PdO stored the lowest amount of NOx. When tested with CO/H2, the sample containing 53.0 % paired Al sites showed significantly better storage capacity than the other samples and deactivated less rapidly upon sequential tests. Experiments using lean gasoline engine exhaust revealed similar trends. This study showed that a high concentration of paired Al sites in Pd/H-CHA is beneficial for NOx storage capacity, thermal durability, and minimizing deactivation in the presence of CO/H2.

Transient nonlinear vibration characterization of building materials in sequential impact scale experiments

Characterizing standard building materials such as concrete is challenging primarily because of the broad range of constituent component sizes within the material itself. Concrete, the most ubiquitous building material, contains critical components that span at least three orders of magnitude of physical size. This work introduces a nondestructive sequential impact test to extract transient nonlinear vibration behaviors that provide statistically significant holistic characterization of a heterogeneous building material, neat cement paste, on a centimeter scale sample. The sensitivity of the single impact vibration combined with the repeatability of the new sequential apparatus enables the extraction of statistically distinct transient nonlinear (slow dynamic) material memory behaviors. Experimental results on neat cement paste prisms and borosilicate glass blocks across several environmental states and damage conditions reveal an underlying phenomenon of transient nonlinear behaviors. Material damage and moisture state significantly affect the proper interpretation of the transient nonlinear material behaviors. The presented testing procedure and observations, supported by historical experiments, confirm that sequential impact reports a consistent transient nonlinear vibration behavior, and the measured behavior can identify damaged heterogeneous building materials.

Effects of New Zealand Blackcurrant Extract on Sequential Performance Testing in Male Rugby Union Players.

Previous studies on performance effects by New Zealand blackcurrant (NZBC) extract used mainly a single exercise task. We examined the effects of NZBC extract in a battery of rugby union–specific tests including speed, agility and strength testing. University male rugby union players (n = 13, age: 21 ± 2 years, height: 182 ± 6 cm, body mass: 87 ± 13 kg) completed two full familiarisations and two experimental visits in an indoor facility. The study had a double blind, placebo-controlled, randomised, crossover design. For the experimental visits, participants consumed NZBC extract (210 mg/day of anthocyanins for 7 days) or placebo with a 7-day wash-out. Testing order was the running-based anaerobic sprint test, the Illinois agility test, seated medicine ball (3 kg) throw, and handgrip strength. With NZBC extract, there may have been an effect for average sprint time to be faster by 1.7% (placebo: 5.947 ± 0.538 s, NZBC extract: 5.846 ± 0.571 s, d = −0.18 (trivial), p = 0.06). However, with NZBC extract there may have been reduced slowing of sprint 2 (d = −0.59 (moderate), p = 0.06) and reduced slowing for sprint 6 (d = −0.56 (moderate), p = 0.03). In the Illinois agility test, there may have also been an effect for the mean time to be faster by 1.6% (placebo: 18.46 ± 1.44 s, NZBC extract: 18.15 ± 1.22 s, d = −0.24 (small), p = 0.07). The correlation between the %change in average sprint time and %change in mean agility time was not significant (Pearson R2 = 0.0698, p = 0.383). There were no differences for the seated medicine ball throw distance (p = 0.106) and handgrip strength (p = 0.709). Intake of NZBC extract in rugby union players seems to improve tasks that require maximal speed and agility but not muscle strength. NZBC blackcurrant extract may be able to enhance exercise performance in team sports that require repeated movements with high intensity and horizontal change of body position without affecting muscle strength.

Order selection with confidence for finite mixture models

The determination of the number of mixture components (the order) of a finite mixture model has been an enduring problem in statistical inference. We prove that the closed testing principle leads to a sequential testing procedure (STP) that allows for confidence statements to be made regarding the order of a finite mixture model. We construct finite sample tests, via data splitting and data swapping, for use in the STP, and we prove that such tests are consistent against fixed alternatives. Simulation studies and real data examples are used to demonstrate the performance of the finite sample tests-based STP, yielding practical recommendations of their use as confidence estimators in combination with point estimates such as the Akaike information or Bayesian information criteria. In addition, we demonstrate that a modification of the STP yields a method that consistently selects the order of a finite mixture model, in the asymptotic sense. Our STP is not only applicable for order selection of finite mixture models, but is also useful for making confidence statements regarding any sequence of nested models.

Virtual–real fusion maintainability verification based on adaptive weighting and truncated spot method

Maintainability is an important general quality characteristic of products. Insufficient maintainability will lead to long maintenance time and high maintenance cost, thus affecting the availability of products. Maintainability verification is an important means to ensure maintainability meets design requirements. However, the cost of traditional real maintainability verification method is very high, and the virtual maintenance method has insufficient verification accuracy due to the lack of large maintenance force feedback when the human body is moving. In order to reduce the evaluation error and test sample size, the paper conducts maintainability verification based on the mixed physical and virtual maintainability test scenarios. Aiming at the problem that traditional methods are difficult to deal with the real test information and synchronous virtual simulation information in the test process, this study proposes a virtual–real fusion maintainability evaluation algorithm based on adaptive weighting and truncated SPOT (Sequential Posterior Odd Test) method. It can weigh real test information and virtual human simulation information adaptively to obtain a virtual–real fusion maintainability test sample. Then, the SPOT method is used to evaluate the maintainability of small samples. The adjustment of valve clearance, replacement of air filter element and replacement of starting motor maintenance tasks of ship engine are taken as examples for demonstration. The virtual–real fusion and virtual maintainability verification methods are respectively used for verification, and compared with the physical maintenance scenario constructed by 3D printing, indicating that the accuracy of virtual–real fusion maintainability test verification is 89%, while the virtual maintainability verification is only 33%.

Backward Sequential Significance Testing in Survival Trials

In survival studies the treatment effect on the hazard ratio may not extend over the entire observation time, yet the effect over a shorter time may be medically important. If the analysis using all events over the observation time does not show a significant benefit, then post hoc analyses at earlier times, which show nominal significance, would only be viewed as post hoc and suggestive of an effect. Therefore, it would be advantageous to incorporate a shorter duration of treatment effect into the study design. A backward sequential logrank procedure, with testing at the end of study and if not significant then sequentially at prespecified earlier time points with a prespecified distribution of Type I error, is proposed. Critical values and power are obtained by simulation for repeated logrank tests at prespecified times and α distribution. When the treatment effect does not extend over the entire observation period the backward logrank testing procedure is more powerful compared to the power of a single logrank test at the end of the study.

Tracy-Widom Distribution for Heterogeneous Gram Matrices With Applications in Signal Detection

Detection of the number of signals corrupted by high-dimensional noise is a fundamental problem in signal processing and statistics. This paper focuses on a general setting where the high-dimensional noise has an unknown complicated heterogeneous variance structure. We propose a sequential test which utilizes the edge singular values (i.e., the largest few singular values) of the data matrix. It also naturally leads to a consistent sequential testing estimate of the number of signals. We describe the asymptotic distribution of the test statistic in terms of the Tracy-Widom distribution. The test is shown to be accurate and have full power against the alternative, both theoretically and numerically. The theoretical analysis relies on establishing the Tracy-Widom law for a large class of Gram type random matrices with non-zero means and completely arbitrary variance profiles, which can be of independent interest.

Plasma levels of multiple cardiovascular- and inflammation-related proteins analysed for associations with disease activity and anti-cyclic citrullinated peptide status in active early rheumatoid arthritis.

To compare plasma levels of 92 cardiovascular- and inflammation-related proteins (CIRPs) and to analyse for associations with anti-cyclic citrullinated peptide (anti-CCP) status and disease activity in early and treatment-naive rheumatoid arthritis (RA). Olink CVD-III-panel was used to measure 92 CIRP plasma levels in 180 early, treatment-naive, and highly inflamed RA patients from the OPERA trial. CIRP plasma levels as well as correlation between CIRP plasma levels and RA disease activity were compared between anti-CCP groups. CIRP level-based hierarchical cluster analysis was performed in each anti-CCP group separately. The study included 117 anti-CCP-positive and 63 anti-CCP-negative RA patients. Among the 92 CIRPs measured, the levels of chitotriosidase-1 (CHIT1) and tyrosine-protein-phosphatase non-receptor-type substrate-1 (SHPS-1) were increased and those of metalloproteinase inhibitor-4 (TIMP-4) decreased in the anti-CCP-negative group compared to anti-CCP-positive group. The strongest associations with RA disease activity were found for interleukin-2 receptor-subunit-alpha (IL2-RA) and E-selectin levels in the anti-CCP-negative group and for C-C-motif chemokine-16 levels (CCL16) in the anti-CCP-positive group. None of the differences passed the Hochberg sequential multiplicity test, however, the CIPRs were interacting and thus the prerequisites of the Hochberg procedure were not fulfilled. CIRP level-based cluster analysis identified two patient clusters in both anti-CCP groups. Demographic and clinical characteristics were similar in the two clusters for each anti-CCP group. In active and early RA, the findings regarding CHIT1, SHPS-1 TIMP-4, IL2-RA, E-selectin, and CCL16 differed between the two anti-CCP groups. In addition, we identified two patient clusters that were independent of the anti-CCP status.

Research on characteristic parameters for multi-factor aging of stator bar insulation of pumped storage generator

The real stator bars of an 18kV pumped storage generator were taken as research objects. The multi-factor sequential aging tests of thermal cycling, electrothermal and vibration were carried out. The dielectric loss angle tangent (tanδ), capacitance (C), Δtanδ, ΔC and maximum partial discharge of the samples at different aging periods were measured. The variation of these parameters with aging time was summarized, and the aging mechanism was analysed. The results show that tanδ, Δtanδ, and ΔC increase overall with aging time, while the capacitance decreases slightly with aging time. The maximum partial discharge decreases gradually at beginning of aging, and then increases after aging of 4 periods. All of tanδ, Δtanδ, ΔC and maximum partial discharge increase obviously in the later stages of aging. They can be used as characteristic parameters for multi-factor aging of stator bars insulation of pumped storage generators, to evaluate the aging state of the insulation with epoxy mica.

Quick Multiband Spectrum Sensing for Delay-Constraint Cognitive UAV Networks

Unmanned aerial vehicles (UAVs) have gained much popularity for a wide variety of applications that do not require human operators, but also face the spectrum scarcity problem. To address this problem, a cognitive UAV network (CUAVN) framework based on cognitive radio (CR) technology is formulated in this article. On the basis of this, the sequential probability ratio test (SPRT) is used as a fundamental cooperative spectrum sensing (CSS) scheme to significantly reduce the average number of samples, but the uncertainty of its detection delay has a negative impact on the spectrum-sensing performance and the achievable throughput of CUAVNs, especially in the multiband spectrum sensing. Considering the location flexibility and uneven distribution density of UAVs, we design an intraframe CSS structure, with aim of achieving CSS between microsensing slots. Furthermore, a sequential maximal truncation (SMT) is proposed to realize a quick multiband spectrum sensing for delay-constraint CUAVNs. Compared to uniform tail truncation (UTT), simulation results show that the proposed quick multiband spectrum sensing with the help of SMT requires fewer sensing times in support of better sensing performance and achievable throughput, especially under a strict delay constraint.

Finite Blocklength Covert Communications: When the Warden Wants to Detect the Communications Quickly

If it is necessary to punish the legitimate transmitter Alice in time, warden Willie must make a corresponding decision before the end of the transmission. Therefore, in the binary hypothesis test framework, we consider the timeliness of Willie’s detection in covert communications for the first time. Specifically, we consider Willie adopting a truncated one-sided sequential probability ratio test (TOSPRT). By analogy with the KL divergence in the FSS detection framework, we demonstrate that the Chernoff information is a correct and reasonable metric as the covert constraint. The key indicators of the three-node model of finite blocklength covert communications are analyzed. Further, to maximize the communication rate between Alice and the receiver Bob, we optimize the transmission power and blocklength of Alice subject to the covert constraint. Theoretical analysis and simulation results show that the maximum covert information can be transmitted when the blocklength reaches the maximum.

Mismatched Binary Hypothesis Testing: Error Exponent Sensitivity

We study the problem of mismatched binary hypothesis testing between i.i.d. distributions. We analyze the tradeoff between the pairwise error probability exponents when the actual distributions generating the observation are different from the distributions used in the likelihood ratio test, sequential probability ratio test, and Hoeffding’s generalized likelihood ratio test in the composite setting. When the real distributions are within a small divergence ball of the test distributions, we find the deviation of the worst-case error exponent of each test with respect to the matched error exponent. In addition, we consider the case where an adversary tampers with the observation, again within a divergence ball of the observation type. We show that the tests are more sensitive to distribution mismatch than to adversarial observation tampering.

128P Precision genomics based targeted 12 gene biomarker and PD-L1 testing in advanced non-small cell lung cancer patients as an alternative to conventional EGFR, ALK, ROS-1 sequential testing in a tertiary care hospital

The standard of care in our hospital was conventional EGFR, ALK, ROS1 sequential testing and to treat with chemotherapy if no actionable genetic mutations were detected. With the evolving precision medicine based new targeted treatment for lung cancer patients, we planned a study to develop a new NGS-based assay to identify clinically relevant 12 genes most frequently mutated in non-small cell lung cancer to help patients to benefit from precision genomics based new targeted treatment approaches and to avoid chemotherapy use.

The Influence of Distortions of the Prior Distribution on the Characteristics of the Sequential Test for Composite Hypotheses

The Influence of Distortions of the Prior Distribution on the Characteristics of the Sequential Test for Composite Hypotheses

Designing a Scale for Measuring Multicultural Self-Efficacy of High School Students

Assessing students’ multicultural self-efficacy was a challenging duty for high school counselors, particularly in conjunction with the understanding function of school counseling. The main objective of this development research was to design and validate a scale for measuring the multicultural self-efficacy of high school students. The 851 public high school students from seven regions of Indonesia participated as respondents. After reviewing pertaining literature, the study set 40 preliminary items about cultural insight, communication, cultural value, cultural awareness, and flexibility. A school counselor educator and a high school counselor experienced in the field examined its construct validity and suggested improving item clarity. The revised scale had sequential testing to determine its practicality, validity, and reliability values, namely the practicality test, the pilot test, and the main test. The results showed that 36 of 40 items met the validity and reliability criteria. In addition, most respondents were in significant agreement about the scale practicality. This evidence indicated that this assessment instrument was suitable for measuring the multicultural self-efficacy of high school students.

Concordance of SARS-CoV-2 Antibody Results during a Period of Low Prevalence.

ABSTRACTAccurate, highly specific immunoassays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed to evaluate seroprevalence. This study investigated the concordance of results across four immunoassays targeting different antigens for sera collected at the beginning of the SARS-CoV-2 pandemic in the United States. Specimens from All of Us participants contributed between January and March 2020 were tested using the Abbott Architect SARS-CoV-2 IgG (immunoglobulin G) assay (Abbott) and the EuroImmun SARS-CoV-2 enzyme-linked immunosorbent assay (ELISA) (EI). Participants with discordant results, participants with concordant positive results, and a subset of concordant negative results by Abbott and EI were also tested using the Roche Elecsys anti-SARS-CoV-2 (IgG) test (Roche) and the Ortho-Clinical Diagnostics Vitros anti-SARS-CoV-2 IgG test (Ortho). The agreement and 95% confidence intervals were estimated for paired assay combinations. SARS-CoV-2 antibody concentrations were quantified for specimens with at least two positive results across four immunoassays. Among the 24,079 participants, the percent agreement for the Abbott and EI assays was 98.8% (95% confidence interval, 98.7%, 99%). Of the 490 participants who were also tested by Ortho and Roche, the probability-weighted percentage of agreement (95% confidence interval) between Ortho and Roche was 98.4% (97.9%, 98.9%), that between EI and Ortho was 98.5% (92.9%, 99.9%), that between Abbott and Roche was 98.9% (90.3%, 100.0%), that between EI and Roche was 98.9% (98.6%, 100.0%), and that between Abbott and Ortho was 98.4% (91.2%, 100.0%). Among the 32 participants who were positive by at least 2 immunoassays, 21 had quantifiable anti-SARS-CoV-2 antibody concentrations by research assays. The results across immunoassays revealed concordance during a period of low prevalence. However, the frequency of false positivity during a period of low prevalence supports the use of two sequentially performed tests for unvaccinated individuals who are seropositive by the first test.IMPORTANCE What is the agreement of commercial SARS-CoV-2 immunoglobulin G (IgG) assays during a time of low coronavirus disease 2019 (COVID-19) prevalence and no vaccine availability? Serological tests produced concordant results in a time of low SARS-CoV-2 prevalence and no vaccine availability, driven largely by the proportion of samples that were negative by two immunoassays. The CDC recommends two sequential tests for positivity for future pandemic preparedness. In a subset analysis, quantified antinucleocapsid and antispike SARS-CoV-2 IgG antibodies do not suggest the need to specify the antigen targets of the sequential assays in the CDC’s recommendation because false positivity varied as much between assays targeting the same antigen as it did between assays targeting different antigens.

Comparative degradation analysis of accelerated-aged and field-aged crystalline silicon photovoltaic modules under Indian subtropical climatic conditions

The understanding of the degradation modes in end-of-life (EoL) photovoltaic (PV) modules is essential to develop realistic and effective accelerated testing methods. In this paper, types of defects and degradations (D&Ds) observed in EoL field-aged modules (FAM) have been compared with the accelerated-aged modules (AAM) for their type and underlying mechanisms. For this purpose, the FAM exposed to outdoor environmental conditions for 20 years have been taken from two cities in India. The observed D&Ds in FAM were compared with modules subjected to the temperature and humidity accelerated tests as per IEC 61215-2 standards using visual inspection, electroluminescence imaging, microscopic inspection, and current-voltage measurement. Encapsulant discoloration and delamination were the dominant modes of degradation observed in the FAM from both locations. Further, thermo-mechanical and mechanical breakages were more pronounced qualitatively under accelerated testing conditions. On the other hand, different types of chemical-induced degradations impacting both metallization and interconnects have been observed in varying degrees within damp heat and humidity freeze subjected AAM and FAM. The loss in electrical parameters namely, short circuit current and fill factor has been observed to vary in FAM and AAM subjected to different stress conditions based on the loss incurring mechanism of dominant degradation modes. The comparative analysis highlights the need for the development of effective sequential aging tests which can take into account the actual mix of external environmental conditions responsible for the various mechanism of degradation in the PV modules.

СЕНСОРНЫЙ КОМПОЗИТ НАНОВОЛОКНА γ-Al2O3 / НАНОАЛМАЗЫ / Cu2+ С УВЕЛИЧЕННОЙ КАТАЛИТИЧЕСКОЙ АКТИВНОСТЬЮ ДЛЯ ДЕТЕКЦИИ ФЕНОЛОВ В ВОДНОЙ СРЕДЕ

A functionalized composite γ-Al2O3 nanofibers / nanodiamond / Cu2+ with improved sensor properties for the detection of phenols in an aqueous medium was obtained by chemical modification with copper ions of a new composite material based on alumina nanofibers and nanodiamonds. The chemical modification of the composite made it possible to increase its catalytic activity more than twice in the co-oxidation of phenols with 4-aminoantipyrine in the presence of H2O2. The obtained effect enabled to reduce the threshold of the minimum detectable concentration of analytes by half when they were tested using a functionalized composite. What was demonstrated by the example of the detection of phenol and 4-chlorophenol. It was shown that the obtained composite provides a linear response in a wide range of concentrations of phenol (0.25–100 μM) and 4-chlorophenol (0.5–25 μM). It is found that the adsorbed Cu2+ ions are firmly bound to composite surface, are not desorbed, and are not inactivated by co-oxidation reagents during repeated use of the composite. The applicability of a functionalized composite as a reusable sensor was shown in model experiments in the course of sequential multiple testing of phenol in aqueous samples. Comparative studies of the kinetics and isotherms of adsorption of Cu2+ ions on a composite material and an alumina matrix, and estimation their sorption capacity were also carried out in the work.

Facile coating of Co3O4 on open-cell metallic foam for N2O catalytic decomposition

Co3O4 coated on open-cell metallic foams, which can merge the catalytic activity of Co3O4 and advantages derived from the geometry of the support, are promising for environmental applications such as the decomposition of N2O (deN2O). This study demonstrates how it is possible to easily and reproducibly prepare a well-adhered layer of Co3O4 with a similar specific surface area as the materials prepared with the precipitation method (∼ 23 m2 g−1coating) and controlled thickness on FeCrAlloy open-cell foams of different porosity and dimension by the electrosynthesis of Co(OH)2 followed by thermal treatment (600 °C). The obtained structured catalysts show stable performance after three cycles of catalytic decomposition of N2O between 250 and 550 °C, with a similar T50 of approximately 460 °C, which is comparable to the combustion or precipitated catalysts but provides a lower pressure drop. Under the operating conditions with a sequential test, the presence of NO and/or O2 in the feed gas inhibits partially the catalytic activity of the structured catalysts while the presence of H2O shows a slight enhancement in the N2O conversion at a temperature above 450 °C.