Reference Test Research Articles

Removal of heavy metals from mine tailings by in-situ bioleaching coupled to electrokinetics

This work utilizes a combined biological-electrochemical technique for the in-situ removal of metals from polluted mine tailings. As the main novelty point it is proposed to use electrokinetics (EK) for the in-situ activation of a bioleaching mechanism into the tailings, in order to promote biological dissolution of metal sulphides (Step 1), and for the subsequent removal of leached metals by EK transport out of the tailings (Step 2). Mine tailings were collected from an abandoned Pb/Zn mine located in central-southern Spain. EK-bioleaching experiments were performed under batch mode using a lab scale EK cell. A mixed microbial culture of autochthonous acidophilic bacteria grown from the tailings was used. Direct current with polarity reversal vs alternate current was evaluated in Step 1. In turn, different biological strategies were used: biostimulation, bioaugmentation and the abiotic reference test (EK alone). It was observed that bioleaching activation was very low during Step 1, because it was difficult to maintain acidic pH in the whole soil, but then it worked correctly during Step 2. It was confirmed that microorganisms successfully contributed to the in-situ solubilization of the metal sulphides as final metal removal rates were improved compared to the conventional abiotic EK (best increases of around 40% for Cu, 162% for Pb, 18% for Zn, 13% for Mn, 40% for Ni and 15% for Cr). Alternate current seemed to be the best option. The tailings concentrations of Fe, Al, Cu, Mn, Ni and Pb after treatment comply with regulations, but Pb, Cd and Zn concentrations exceed the maximum values. From the data obtained in this work it has been observed that EK-bioleaching could be feasible, but some upgrades and future work must be done in order to optimize experimental conditions, especially the control of soil pH in acidic values.

A-072 An All-Purpose Particle Enhanced Immunoturbidimetric Assay for the Comparable, Instrument-Independent Monitoring of Procalcitonin in the Management of Sepsis

Abstract Introduction Sepsis is a life-threatening organ dysfunction caused by a dysregulated host immune response to infection. It is a global health concern and a leading cause of death worldwide, affecting an estimate of 48.9 million people every year. Procalcitonin (PCT) revealed to be an indispensable parameter for the management of sepsis. However, recent analysis of EQA survey results suggested crucial deviations of PCT measurements in Germany and studies by the IFCC Working Group on standardization of PCT stated the need for a higher-order reference measurement procedure.Here we present the evaluation of the all-purpose particle enhanced immunoturbidimetric assay (PETIA) of DiaSys, which can be easily applied to every high-throughput clinical chemistry analyzer. The high diversity of applications and datasets match current diagnostic and regulative needs (IVDR). Procalcitonin FS enables the equivalent and instrument-independent monitoring of PCT in the management of sepsis. Methodology Evaluation of Procalcitonin FS was performed on seven clinical chemistry analyzer platforms (Jeol BioMajesty® JCA-BM6010/C, DiaSys respons®920 and respons®940, Roche cobas c501, Abbott Architect c8000 and Alinity c, Beckman Olympus AU680). Measurements were performed according to Clinical and Laboratory Standards Institute (CLSI) protocols. Results The onboard stability reaches 8 weeks (with chimney) on BioMajesty® JCA-BM6010/C, 20 days on respons®920 and respons®940, 21 weeks on cobas c501, 9 weeks on Architect, 12 weeks on Olympus AU680 and 13 weeks on Alinity c. The calibration stability is 4 weeks (with chimney) on BioMajesty® JCA-BM6010/C, 2 weeks (with chimney) on respons®920 and respons®940, 21 weeks on cobas c501, 3 weeks on Architect, 5 weeks on Olympus AU680 and 10 weeks on Alinity c. The intra-assay precision (CV%) ranges from ≤4.57% on respons®920 up to ≤7.19% on respons®940. The Total Precision (CV%) ranges from ≤3.99% on cobas c501 up to ≤9.62% on Olympus AU680. LOB ranges from 0.07 ng/mL on BioMajesty® JCA-BM6010/C up to 0.130 ng/mL on Olympus AU680. LOQ ranges from 0.20 ng/mL on Architect up to 0.277 ng/mL on Olympus AU680. The reagent displayed a linear recovery up to 50 ng/mL and no prozone effect was detected up to 1000 ng/mL on all seven analyzers. The Passing & Bablok regression vs the reference test showed an excellent comparability/alignment between the methods (slope ≤1.11, intercept ≤0.156 ng/mL, R ≥ 0.986). Conclusion Evaluation work proves that DiaSys PETIA reagent Procalcitonin FS shows excellent performance on all seven clinical chemistry analyzers. In addition, the high comparability between the seven analyzers enables the reliable and instrument-independent monitoring of PCT in the management of sepsis, and thus offering a solution to the current landscape of deviating PCT measurement results.

B-112 Routine Application of PR3- and MPO-ANCA Chemiluminescence Immunoassays Demonstrates Enhanced Detection Rates

Abstract Background Sensitive and accurate PR3- and MPO-ANCA detection are crucial in the diagnosis and monitoring of patients with ANCA-associated vasculitides (AAV) and the specific diseases categorised thereof, including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA). Chemiluminescence immunoassays (ChLIA) and bead technology have emerged as promising tools for fast, sensitive and accurate autoantibody detection. Applied to PR3- and MPO-ANCA, they could improve limitations in sensitivity, narrow measuring range and level of quantification seen in other assay formats. Here, we examined the routine performance of ChLIAs using human native MPO as well as human recombinant PR3 antigens. Methods The Anti-PR3 ChLIA (IgG) and prototype Anti-Myeloperoxidase ChLIA (IgG) were processed on the RA Analyzer 10 (EUROIMMUN) and the EliA PR3S and EliA MPOS on the Phadia250 (Thermo-Fisher Scientific), both in accordance to the recommendations by the manufacturers. For a comparative analysis of the routine performance, 675 sera from 615 individuals requested for PR3-ANCA, MPO-ANCA or both at the Central Diagnostic Laboratory at Maastricht University Medical Center were measured with the respective assays from both automation systems. The results were compared in respect to the qualitative outcome and numerical correlation. Results Of the total 675 samples, 585 and 556 were subjected to PR3-ANCA and MPO-ANCA analysis, respectively. For both ANCA types, all samples found positive with EliAs were also positive in the corresponding ChLIAs. 24 and 26 samples resulted positive for PR3- and MPO-ANCA by ChLIA, respectively, but were below cut-off in the relevant EliA test. Of those, 50.0% (n = 12 for PR3) and 96.2% (n = 25 for MPO) were from individuals in follow-up after AAV diagnosis, in the remaining cases an ANCA involvement was suspected based on symptoms of the patients. The overall concordance between the two assay systems was 96.0% for PR3-ANCA and 95.4% for MPO-ANCA detection. Conclusion In a routine scenario, the ChLIAs fully covered the PR3- and MPO-ANCA detection by the compared reference test system. Moreover, further positive results in samples found negative by EliA demonstrated enhanced detection rates by both ChLIAs, predominantly in samples from individuals with a known history of AAV. The clinical relevance will be subject to further studies.

Standardization, validation, and comparative evaluation of a faster and high-performance test for quantification of yellow fever neutralizing antibodies

Although it is considered the reference for quantification of neutralizing antibodies, classical method of the plaque reduction neutralization test (PRNT) is labor intensive, requires specific equipment and inputs, besides a long time for its finalization, even in the micro-PRNT version (in 96-well plates). It has a higher sample throughput, however the smaller wells make the reading of plaques more difficult. With an immunoenzymatic revelation step and a semi-automated reading, the μFRN-HRP (micro Focus Reduction Neutralization - Horseradish Peroxidase) is a faster and more efficient test for the quantification of YF neutralizing antibodies. This study aimed to standardize, validate, and compare it with the reference method in 6-well plates (PRNT). Once the execution protocol was standardized, precision, accuracy, selectivity, and robustness were evaluated to validate the μFRN-HRP. In addition, 200 sera of vaccinees were processed by the μFRN-HRP and by the micro-PRNT to compare with the reference test, estimating agreement by Intraclass Correlation Coefficient (ICC). The standardization and validation of the μFRN-HRP was carried out successfully. Weak to moderate agreement was observed between μFRN-HRP and PRNT for titers in reciprocal dilution, while the same comparison between the classical tests resulted in a better ICC. However, titers in milli-international units obtained by μFRN-HRP showed a substantial agreement with PRNT, while the agreement between micro-PRNT and PRNT was inferior. Therefore, μFRN-HRP can be used in the confirmation of natural YF infection and immune response to vaccination, replacing the micro-PRNT, gaining agility, while preserving the specificity of the result.

The application of capability indices in the validation of ELISA methodology.

Aim: To investigate the impact of sample replication number (duplicate vs triplicate) on the validation of ELISA methodology. Materials & methods: The methodology was validated with reference sample and test sample as an 11-point triplicate dilution series. The data were reanalyzed post-validation as if conducted as a duplicate dilution series. Results: The triplicate methodology was validated with a precision of 5.3% and mean bias of -1.7%. The duplicate methodology generated a precision of 5.7% and mean bias of -2.2%. Conclusion: Both the triplicate (method capability index =1.37) and duplicate (method capability index=1.25) ELISA methodology can support an 80-125% relative potency specification with a 0.004% or 0.018% probability of out-of-specification results, respectively.

Experimental Investigation on Particle Breakage Behavior of Marine Silica Sand under High-Stress Triaxial Shear

There is often obvious particle breakage for silica sand under high-stress, which will lead to the bearing capacity reduction and excessive settlement of the foundation. This paper focuses on the particle breakage characteristics of marine silica sand from the East China Sea under high-stress conditions. A series of conventional triaxial tests for silica sand, including consolidated drained (CD) and consolidated undrained (CU) shear tests, were conducted under the confining pressures in the range of 2–8 MPa to investigate the breakage rule during the shearing process. The developments of particle breakage index Br with axial strain ε1 and volumetric strain εv present hyperbolic and linear trends, respectively. A hyperbolic model was adopted to describe the relationship of Br and ε1 and the corresponding model parameters were obtained. The particle breakage index also has a good correlation with the input work per unit volume under various average stresses, regardless of the stress history. Furthermore, the relationship between the fractal dimension and the particle breakage was studied based on the particle size distribution curve. It is concluded that the fractal dimension increases in an up–convex hyperbolic trend with the increase of particle breakage index. The dividing radius for whether the silica sand particles exhibit the fractal features is determined as approximately 0.4 mm. This is anticipated to provide reference and supplementary test data for analyzing sand constitutive models/environments regarding particle crushing.

Reliability of tomographic 3D ultrasound in measuring internal carotid artery plaque volume.

Tomographic 3D ultrasound (t3DUS) is a promise imaging technique for quantifying carotid plaque through measuring the degree of stenosis and plaque volume. Carotid plaque volume (CPV) could add benefit in predicting the potential risk of stroke. To assess the reproducibility and accuracy of t3DUS for measuring CPV within the internal carotid artery in patients undergoing carotid endarterectomy. t3DUS was used to obtain CPV in vivo from 25 symptomatic patients prior to surgery. Ex vivo CPV from the carotid endarterectomy specimen was then measured using a validated saline displacement method as a reference standard. CPV for each patient was measured twice using both methods (total n = 50 per technique). Intraclass correlation coefficient (ICC) and Bland-Altman plot were used to establish bias and limit of agreement between CPV measurements. There was an excellent agreement between t3DUS and reference test with respect to measuring CPV with an ICC value of 0.98 (95% confidence interval=0.97-0.99, P < 0.001). Bias in measurements was 0.02 ± 0.11 cm3 (95% limit of agreement=-0.19 to 0.25). Intra-observer agreement of t3DUS CPV measurements was excellent with an ICC value of 0.95 (95% confidence interval=0.92-0.97, P < 0.001). Bias in measurements was 0.004 ± 0.07 cm3 (95% limit of agreement=-0.14 to 0.15). t3DUS is a reproducible imaging method and showed excellent agreement with the reference standard with respect to measuring CPV. These findings suggest that t3DUS has the potential to be a valuable non-invasive tool for assessing carotid plaque burden and predicting the risk of stroke.

Evaluation of the diagnostic accuracy of the serological test for paratuberculosis in cattle according to tuberculosis status.

Enzyme-linked immunosorbent assays (ELISAs) are the most widely used diagnostic tools in bovine paratuberculosis (bPTB) control. However, their diagnostic accuracy may be compromised by bovine tuberculosis (bTB) infection, as both diseases share diagnostic targets. The bPTB and bTB infection status of 228 animals was determined using microbiological tissue culture as a reference test. The diagnostic performance (sensitivity, specificity, likelihood ratios and predictive values) of the bPTB-ELISA on blood serum samples, taking into account the bPTB animal-level prevalence of the area and the bTB status of the animals, was evaluated. A sensitivity of 40.7% (95% confidence interval [CI]: 27.5%-53.9%) and a specificity of 94.7% (95% CI: 91.4%-98.0%) were obtained for bPTB-ELISA in all animals. A bPTB-ELISA-positive animal would have a post-test probability of 70% or more of being infected in areas with a bPTB prevalence of 23% or more. A negative bPTB-ELISA result, in areas with a bPTB prevalence of 41% or less, would rule out the disease with more than 70% certainty. In bTB-positive animals, sensitivity increased (94.4% [95% CI: 81.4%-100%] vs. 25.1% [95% CI: 11.8%-38.4%]) and specificity decreased (82.6% [95% CI: 71.8%-93.4%] vs. 99.4% [95% CI: 98.0%-99.9%]). The bPTB-ELISA is a good tool to rule out bPTB co-infection in bTB-positive animals, while in bTB-negative animals, it allows confirmation of disease with more than 70% probability if disease prevalence is 6% or more. The observed differences could be enhanced by the effect of frequent application of the intradermal tuberculin test, which was unknown in the animals studied. These results provide useful guidance for the application and interpretation of ELISA as a tool for bPTB disease control.

Advances in benchmarking and round robin testing for PEM water electrolysis: Reference protocol and hardware

While the number of publications in the PEM water electrolysis community increases each year, no common ground concerning reference hardware (test cells and test bench) and testing protocols has been yet established. This would, however, be necessary for the comparability of experimental results. First attempts for such reference hardware and procedures have been made in the framework of the Task 30 Electrolysis within the Technology Collaboration Programme on Advanced Fuel Cells (AFC TCP) of the International Energy Agency (IEA). Since then, improvements of both the test hardware (test cell and components) as well as the measurement protocol were identified, and a revised methodology and key results based on a comprehensive measurement series have been obtained. A detailed protocol for testing commercial reference components with a reference laboratory test cell developed in-house by Fraunhofer ISE is presented. For evaluation of the protocol and the hardware, it was tested at three different institutions at the same time. Impedance spectroscopic and polarization data was acquired and analyzed. The obtained differences in performance were calculated to give the community an expectation window to compare own data to. Finally, the importance of a thorough temperature control and the conditioning phase are demonstrated.

Prediction of Esophageal Varices in Viral Hepatitis C Cirrhosis: Performance of Combined Ultrasonography and Clinical Predictors.

This study is aimed at evaluating the diagnostic performance of clinical predictors and the Doppler ultrasonography in predicting esophageal varices (EV) in patients with hepatitis C-related cirrhosis and exploring the practical predictors of EV. We conducted a prospective study from July 2020 to January 2021, enrolling 65 patients with mild hepatitis C-related cirrhosis. We obtained clinical data and performed grayscale and the Doppler ultrasound to explore the predictors of EV. Esophagogastroduodenoscopy (EGD) was performed as the reference test by the gastroenterologist within a week. The prevalence of EV in the study was 41.5%. Multivariable regression analysis revealed that gender (female, OR = 4.04, p = 0.02), platelet count (<150000 per ml, OR = 3.13, p = 0.09), splenic length (>11 cm, OR = 3.64, p = 0.02), and absent right hepatic vein (RHV) triphasicity (OR = 3.15, p = 0.03) were significant predictors of EV. However, the diagnostic accuracy indices for isolated predictors were not good (AUROC = 0.63-0.66). A combination of these four predictors increases the diagnostic accuracy in predicting the presence of EV (AUROC = 0.80, 95% CI 0.69-0.91). Furthermore, the Doppler assessment of the right hepatic vein waveform showed good reproducibility (κ = 0.76). Combining clinical and Doppler ultrasound features can be used as a screening test for predicting the presence of EV in patients with hepatitis C-related cirrhosis. The practical predictors identified in this study could serve as an alternative to invasive EGD in EV diagnosis. Further studies are needed to explore the diagnostic accuracy of additional noninvasive predictors, such as elastography, to improve EV screening.

Thermal shock resistance of industrial foam filters-a comparative study

For ceramic foams, there is no thermal shock resistance testing standard available at the moment. This work aims to investigate the influence of the different test conditions. Among the descending thermal shock test conditions, heating mode, thermal shock temperature, and quench medium, the latter has the highest impact on the residual mechanical properties. Reference alumina (Al2O3) foams and commercially-available ceramic foam filters (ZrO2, Al2O3–ZrO2, Al2O3–P, and SiC) were subjected to thermal shock with water and air as quenching medium. Due to the low thermal expansion coefficients, SiC and ZrO2 possess the highest calculated thermal shock resistance Rfoam. SiC and ZrO2 foams also had the highest experimentally evaluated residual strength after being quenched in water. An immersion thermal shock procedure with molten metal was tested on Al2O3 reference test pieces. The residual elastic moduli and strengths decrease with increasing temperature which is a function of immersion duration and depends on the usage of an interlayer between the foams and the melt. In order to evaluate the temperature gradient and its development over time, temperature measurements were conducted using a thermocouple inserted and fixed in the midplane of the foams and bulk test pieces.

Comparison and interobserver reliability between a visual analog scale and the Wisconsin Calf Health Scoring Chart for detection of respiratory disease in dairy calves

Respiratory disease is an ongoing challenge for calves in the dairy sector with a relatively high prevalence and impact on welfare and economics. Applying scoring protocols for detecting respiratory disease requires that they are easily implemented, consistent between observers and fast to use in daily management. This study was conducted in one Danish dairy farm from September 2020 through January 2021. The study included 126 heifer calves enrolled in the age of 17 to 24 d. All calves were observed every second day for a period of 46 d. At each visit all calves were scored with a new Visual Analog Scale (VAS) and the Wisconsin Calf Health Scoring Chart (WCHSC). We calculated agreement between the 2 scoring systems based on conditional probability to score higher or lower than a cut-off in the VAS compared with a specified cut-off in WCHSC used as reference test. A generalized mixed effects regression model was performed to develop a model that could estimate the prevalence of respiratory disease and the overall agreement between the 2 scoring systems. The overall agreement between the VAS and WCHSC was 89.6%. The second part of the study assessed inter-observer reliability between 2 experienced observers and between an experienced observer and veterinary students. The inter-observer reliability was calculated by intra-class correlation coefficient and was 0.58 between experienced observers and was 0.34 between an experienced observer and veterinary students indicating a moderate to poor reliability between the observers. It was possible to use VAS as an alternative clinical scoring method, which primarily focuses on the general condition of the individual calf rather than specific categories of clinical signs. Our study set up lacked a comparison to other diagnostic tools i.e., thoracic ultrasound to confirm the findings which should be considered in future studies when exploring VAS as a screening tool for detection of respiratory disease in dairy calves.

Estimating IgG concentration directly by radial immunodiffusion or indirectly by refractometry measure of serum total protein lack precision.

To establish and compare the precision of serum total protein (STP) measured by an optical refractometer to the precision of IgG concentrations measured using radial immunodiffusion (RID), the reference test for quantifying IgG in neonatal calves. 6 sera with previously measured IgG concentration using RID from neonatal beef calves were selected from 3 stratum: low-serum IgG stratum between >5.0 and <15.0g/L(n = 4); moderate-serum IgG stratum between 35.0-45.0g/L(n = 1); high-serum IgG stratum between 60.0-70.0g/L(n = 1). STP was measured 13 times with an optical refractometer. IgG concentrations were measured 28 times with a commercial bovine IgG RID for each sera. The homogeneity of variance within the tests was evaluated with the Levene test (α = 0.10). Unrestricted random sampling bootstrapping (5,000 repetitions) was used to calculate the coefficient of variation (CV) for each serum and test. The homogeneity of variance between simulated test CVs by serum was evaluated (α = 0.10). Differences between simulated test CV by serum were assessed with the Kruskal-Wallis test (α = 0.05). No difference was observed in the variance for STP between sera (P = .39). The average CV for STP was 4.2%, 10.1% for the low IgG stratum, and 15.5% for the moderate/high IgG stratum. Variance differed in serum IgG concentration (P < .0001). Serum with higher IgG concentrations had more variance. Simulated CV for STP and IgG had homogeneity of variance for only 1 sera (P = .31). STP had a smaller CV compared to IgG for every serum (P < .0001). Estimating IgG concentration directly by RID or indirectly by STP lacks the precision that might affect diagnostic interpretation regarding a calf's absorption of maternal antibodies.

Fecal Calprotectin and Organic Gastrointestinal Disease: A Systematic Review.

This review aimed to assess the diagnostic utility of fecal calprotectin (FCP) for identifying organic gastrointestinal disease (OGID) in patients undergoing colonoscopy for gastrointestinal discomfort or active progression of inflammatory bowel disease (IBD). Studies published between January 2013 and December 2022 evaluating the clinical efficacy of FCP for differentiating OGID against functional gastrointestinal disease (FGID) were identified using PubMed, Cochrane, and Scopus databases. Clinical diagnostic studies involving individuals with lower gastrointestinal symptoms; using FCP as a diagnostic biomarker either in primary, secondary, or tertiary healthcare centers conducted either prospectively or retrospectively using stool samples (index test), contrasting FCP with a reference test, such as colonoscopy, or endoscopy, and assessed using enzyme-linked immunosorbent assay were reviewed. The included studies were subjected to the revised Quality Assessment of Diagnostic Accuracy Studies for assessing the methodological quality by two independent authors.An initial literature search yielded 545 articles rendering 417 records after removing the duplicate records. After reading the abstracts and titles, 89 articles were eligible for full-text screening. The qualitative synthesis resulted in 20 articles. The efficient use of FCP for differentiating IBD from irritable bowel syndrome was investigated in 15 studies.Two of the included studies assessed the diagnostic ability of FCP to distinguish OGID from FGID, two studies utilized patients with ulcerative colitis, and one study involved patients with Crohn's disease. Overall study quality was high for 65% of studies,moderate for 25% of studies, and low for 10% of studies. The review outlined the diagnostic accuracy of non-invasive FCP assessment for OGID in various clinical scenarios and in individuals of various ages. FCP is used as a tool for screening and monitoring in clinical practice for determining the need of further comprehensive investigations, thereby reducing the redundant use of invasive techniques.

High-pressure fermentation of CO2 and H2 by a modified Acetobacterium woodii

Global warming due to the increased atmospheric carbon dioxide concentration is the driving force for developing strategies that exploit CO2 as raw material to produce interesting compounds for industry. According to this approach, Acetobacterium woodii was modified to convert CO2 and H2 into acetone. Gas fermentation was performed at high pressure to debottleneck the issue of the low availability of gaseous substrates in the liquid medium. This work aimed to investigate the catalytic performance of a modified A. woodii strain for acetone synthesis at 10 bar providing an H2-CO2 blend. First, tests were performed to assess the ability of the biocatalyst to survive heterotrophically at high pressure. Moreover, a reference test was set up in autotrophy at atmospheric pressure to confirm that it produced both acetate and acetone. Feeding the strain at 10 bar with the H2-CO2 mix resulted in growth inhibition and formic acid production. This outcome suggested a metabolism impairment due to bicarbonate build-up in the reactor at high CO2 partial pressure. Thus, bacteria were grown at atmospheric pressure in a medium with an augmented exogenous salt concentration. Results confirmed that formic acid production and growth inhibition could be due to HCO3–. Furthermore, the modified A. woodii grown at atmospheric pressure in a sterile medium pressurized before inoculation showed the same outcomes. Finally, tests at 10 bar lowering the CO2 partial pressure indicated that this gas was responsible for formic acid production but was not the only inhibitory factor for autotrophic cell growth at high pressure.

Effect of thermal cycles on volumetric and shear behavior of sand–concrete interface

Energy piles are dual-purpose foundation elements that transfer the building loads to the supporting soil and act as heat exchangers for heating and cooling. Energy piles are subjected to heating and cooling cycles over days and seasons, resulting in cyclic expansion and contraction. The cyclic expansion and contraction bring about the modification of vertical stress and the increase of vertical displacements on the piles, in other words, the thermo-mechanical behavior of the pile, the soil, and the soil–pile interface is changed by the cyclic thermal cycles. Investigation to know the effect of temperature cycles on soil–pile interface characteristics has high academic and significant engineering values. This paper intends to investigate the thermo-mechanical response of soil–pile interface under different types of cyclic thermal loadings, to better understand the behavior of energy piles and their surrounding soils after the buildings are constructed and the geothermal activation. Direct shear tests are performed by using a new interface direct shear test machine composed of a temperature controlling device to assess the influence of different cyclic thermal loadings on the shear behavior of Fontainebleau sand–concrete interface. Direct shear tests are carried out after three different thermal loadings, i.e., a constant temperature of 13 °C, and two different kinds of cyclic cooling–heating​ (8–18 °C) loadings with 10 cycles (namely CT-1 and CT-2). The horizontal stress and horizontal displacement are evaluated after the 10 thermal cycles in CT-1 and CT-2 programs, and the shear results are then compared. The results reveal that the cyclic thermal cycles increase the peak shear strength of CT-2, however they do not significantly affect the residual shear strength of both CT-1 and CT-2. The peak/residual interface friction angle of the reference test is 29.5∘/28.4°, after the 10 cyclic thermal cycles, it becomes to 28.9∘/27.9° for CT-1, and 31.7∘/28.5° for CT-2.

Diagnostic accuracy of bimanual palpation in bladder cancer patients undergoing cystectomy: A prospective study.

To prospectively assess the concordance of examination under anesthesia (EUA)-based clinical T stage with pathological T stage and diagnostic accuracy of EUA in patients with bladder cancer undergoing cystectomy. Consecutive patients with bladder cancer undergoing cystectomy between June 2017 and October 2020 in a single academic center were included in a prospective study. Two urologists performed EUA (one blinded to imaging) before patients underwent cystectomy. We assessed the concordance between clinical T stage in bimanual palpation (index test) and pathological T stage in cystectomy specimens (reference test). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated with 95% confidence intervals (CIs) to detect or exclude locally advanced bladder cancer (pT3b-T4b) in EUA. The data of 134 patients were analyzed. Given that stage pT3a cannot be palpated, for the nonblinded examiner, T staging in EUA was concordant with pT in 107 (79.9%) patients, 20 (14.9%) cases being understaged in EUA and 7 (5.2%) overstaged. For the blinded examiner, staging was correct in 106 (79.1%) patients, 20 (14.9%) cases being understaged and 8 (6%) overstaged. For the nonblinded examiner, sensitivity, specificity, PPV, and NPV of EUA were 55.9% (95% CI 39.2%-72.6%), 93% (88%-98%), 73.1% (56%-90.1%), and 86.1% (79.6%-92.6%), respectively; for the blinded examiner, they were 52.9% (36.2%-69.7%), 93% (88%-98%), 72% (54.4%-89.6%) and 85.3% (78.7%-92%), respectively. Awareness of imaging results did not have a major impact on EUA results. Bimanual palpation should still be used for clinical staging, given its specificity, NPV, and that it could correctly determine bladder cancer T stage in 80% of cases.

Shear transfer at the steel‐concrete interface using different mechanical connectors

AbstractThe present article is dealing with an assessment of the longitudinal shear at the steel‐concrete interface using several types of mechanical connections. Experimental and numerical tests have been performed to understand better the short and long‐term effects of the influence of the newly defined connectors.Experimental tests consisted of 12‐column push‐out tests (CoPOT). In the test campaign, four types of surface finishing have been tested: i) reference tests (0v2) without any mechanical shear connectors, (ii) angled, V‐shaped, variant of the novel flat shear connector (Av2), (iii) transversal variant of the novel flat shear connector (Bv2) and (iv) multiple ribs on the flanges having a height of 0.7mm (Cv2). Three specimens for each configuration were tested in short‐term loading. The loading procedure defined in EN1994‐1‐1:2004 Annex B was applied for all the tests. Also, one of each specimen was tested in long‐term loading to observe the effect of concrete shrinkage on the quality of bond performance. No significant differences in behavior were observed between both load sequences and the test results after shrinkage is within the short‐term tests’ margin of variation. Numerical simulations performed using FE software Abaqus®, while applying a simplified definition of the bond, supported the results of the previous investigation.

Lateral‐torsional buckling experiments of built‐up section CFS beams

AbstractThis paper investigates the lateral‐torsional buckling of built‐up cold‐formed steel beams featuring two or three component C‐ or sigma‐sections arranged to have a closed loop. Several thicknesses of each cross‐section with nominal yield stress values of 450 MPa and 550 MPa were tested to obtain lateral buckling strength data for a range of cross‐section slenderness values. Complementary reference tests were conducted on the same built‐up sections braced laterally to obtain the in‐plane section capacities, precluding the effect of lateral‐torsional buckling. Coupon tests were also conducted to determine the mechanical properties of the steel material. The test rig featured a dual‐actuator set‐up, with one actuator (applying vertical load) mounted on a trolley that was moved horizontally by the second actuator in response to the signal from a transducer measuring the lateral buckling displacement at the mid‐length of the beam, thus ensuring vertical loading throughout the experiments. The rig also featured specialized end bearings allowing free flexural rotations and warping, while restraining lateral displacements and twist rotations. The paper describes the test rig and the results of the in‐plane and lateral‐torsional buckling experiments. Particular attention is paid to the use of closed parts to enhance the torsional rigidity of the built‐up sections and thereby their lateral‐torsional buckling capacity.

Chemical composition and antimicrobial activity of Rosa Damascena mill. (variety rainbow) from clonal micropropagation

Damask rose of the Veselka variety is an important industrial rose variety used to obtain essential oil. It is widely used in modern cosmetology, perfumery, and aromatherapy. In addition, the essential oil of Damask rose has a whole spectrum of pharmacological properties.&#x0D; The scientific innovation of this research lies in its foundation on cultivating and acquiring planting materials of the Damask rose in vitro. This approach guarantees controlled conditions for plant growth, the production of robust seedlings, and an enhancement in the precision and credibility of the research outcomes.&#x0D; Moreover, the study has scientific novelty in that it explores to assess both the quantitative and qualitative constituents of the essential oil in the acquired plant material of the Damask rose. This assessment takes place within the context of cultivating regenerative plants in an outdoor environment. Such an approach acknowledges the potential distinctions in the oil's component composition acquired from plants propagated through this method in comparison to traditional vegetative reproduction. Lastly, the research has scientific novelty in investigating the potential antimicrobial properties of Damask rose essential oil, which could have significant practical implications in the development of new drugs and combatting infectious diseases.&#x0D; The purpose of the study was to establish the component composition of the essential oil of Rosa damascena Mill., which was grown in vitro, and to determine its antimicrobial effect.&#x0D; Methods. The object of the study was the essential oil of Damask rose of the Veselka variety, which was grown by the method of clonal micropropagation in vitro. The essential oil was extracted from fresh petals collected during dry weather conditions prior to sunrise by hydrodistillation. Determination of the qualitative composition and quantitative content of volatile substances was carried out by the GC-MS method using an Agilent 7890B chromatograph. Antimicrobial activity was studied in vitro using the disk diffusion method with reference test strains of microorganisms Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Candida albicans ATCC 885-653.&#x0D; Results. According to the results of the chromato-mass spectrometric study, 41 compounds (6 of which were in the isomeric state) were identified, which was belong to 13 different classes of chemicals. Dominant compounds among terpenoid substances were shown: geraniol – 30.96 %, citronellol – 27.08 %, alkanes: nonadecane – 17.29 %, and heneicosene – 5.46 %.&#x0D; It was established that the essential oil of Damask rose had a significant antimicrobial effect against strains of C. albicans and E. coli, the diameters of which growth retardation zones ranged from 32-35 mm and 20-23 mm, respectively. In studies with P. aeruginosa and S. aureus, the essential oil showed moderate antibacterial activity: the diameters of the growth retardation zone of these microorganisms ranged from 13 to 15 mm and 11 to 12 mm, respectively.&#x0D; Conclusion. For the first time, the qualitative composition and quantitative content of volatile substances in the essential oil extracted from the petals of Rosa damascena Mill., Veselka variety, cultivated through the clonal micropropagation in vitro, were explored by chromatography-mass spectrometry techniques. The results of the study of antimicrobial activity showed that the studied essential oil exhibits significant fungicidal effects against Candida microorganisms, along with moderate bactericidal effects on gram-negative (E. coli, P. aeruginosa) and gram-positive (S. Aureus) bacteria. These results highlight the potential of this essential oil for further investigation in the realm of developing novel medicines and herbal preparations. Further clinical studies are needed to assess this potential.