Actual Limits Research Articles

Time pressure in diagnosing written clinical cases: an experimental study on time constraints and perceived time pressure.

Time pressure and time constraints have been shown to affect diagnostic accuracy, but how they interact is not clear. The current study aims to investigate the effects of both perceived time pressure (sufficient vs. insufficient time) and actual time constraints (lenient vs. restricted time limit) with regard to diagnostic accuracy. Residents from two university-affiliated trainingprograms in the USA participated in this online within-subjects experiment. They diagnosed cases under two perceived time pressure conditions: one where they were told they had sufficient time to diagnose the cases and one where they were told they had insufficient time. The actual time limit was either restricted or lenient (± one standard deviation from the mean time to diagnose). Participants provided their most likely diagnosis and a differential diagnosis for each case, and rated their confidence in their most likely diagnosis. A restricted time limit was associated with lower accuracy scores (p=0.044) but no effects of perceived time pressure on diagnostic accuracy were found. However, participants self-reported feeling more time pressure when they thought they had insufficient time (p<0.001). In addition, there was an effect of the actual time limit (p=0.012) andperceived time pressure (p=0.048) on confidence. This study showed that a restricted time limit can negatively affect diagnostic accuracy. Although participants felt more time pressure and were less confident when they thought they had insufficient time, perceived time pressure did not affect diagnostic accuracy. More research is needed to further investigate the effects of time pressure and time limits on diagnostic accuracy.

Thermal stress in externally irradiated tubes of solar central receivers with a gas–particle fluidized dense suspension

One of the objectives of the new generation of concentrating solar power plants is to increase the actual temperature limit (565 °C) up to or near 1000 °C. An alternative heat transfer fluid that could help to reach this objective is the use of a fluidized dense gas–particle suspension ascending through a vertical tube. Since the predominant cause of rupture in solar receivers is the creep-fatigue damage process, which is mostly influenced by the maximum temperatures and stress experienced along the tube, the main objective of this work is to numerically study the thermomechanical behavior of a non-uniform externally irradiated tube where particles are fluidized and moves upwards. The heat transfer problem in the two media present (i.e. dense suspension of particles and tube wall) was solved separately: a Computational Particles Fluid Dynamic model solves the heat transfer in the particles, whereas a three dimensional Finite Volume model simulates the heat conduction through the tube wall to obtain the temperature profile, which serves as input to calculate the thermal stress of the tube with an analytical method. Higher thermal stresses were obtained for an absorbed power of 250 kW/m2 (σVM,max=219MPa) compared to that for an absorbed power of 500 kW/m2 (σVM,max=72MPa) due to the lower temperature difference between the front and rear sides of the tube caused by the more pronounced increase of the radiative losses in the front side of the tube compared to that at the rear side. The thermomechanical behavior of a particle receiver was compared to that of a molten salt receiver. For an incident solar flux of 500 kW/m2, the particle receiver reduced the maximum thermal stress by 73% compared to the molten salt receiver. However, the tube’s maximum temperature exceeded the working limit for stainless steel tubes. In order for the receiver to survive heat fluxes characteristic of solar power plants, research into technological solutions that allow to improve the effectiveness of the heat transfer rate from the tube to the particle flow is necessary.

Artificial intelligence as an electronic person

With the development of technology, artificial intelligence is becoming an important part of the creative process, which raises many questions about traditional ideas about the author and copyright owner within the framework of current legislation. The article examines aspects related to artificial intelligence as a potentially new subject of copyright, analyzes its individual legal aspects in which artificial intelligence can be considered as an independent subject, and provides examples of existing precedents. At the same time, the current legislative gaps in the use of artificial intelligence as an author are being investigated, and issues related to the possibility of recognizing copyrights to works created by artificial intelligence, including the use of the term "creativity" in relation to the results of its activities, are being considered. The methodological basis is the universal dialectical method of cognition. General scientific and specific scientific methods were used : formal-logical, structural-functional, formal-legal and others. As a result of the conducted research, it was concluded that it is possible to introduce into legislation, along with a legal entity and an individual, a new entity – an electronic person. The scientific work formulates the author's concept of "electronic person", which has gained special relevance in the conditions of digitalization of modern society. It is assumed that an electronic person will be able to act as a subject of legal relations in the field of copyright, able to create new original works, recognize ownership of the results of his creative activity. In addition, the legal consolidation of an electronic person will establish the possible actual limits of the legal liability of artificial intelligence in the Russian Federation and determine who invested in it erroneous or deliberately incorrect source data that could harm both the individual and society as a whole.

Ultrasensitive on-site colorimetric detection of Campylobacter in oyster with a portable biosensing platform based on hydroxamate/Fe3+–violurate chromogenic reaction and smartphone

The contamination of Campylobacter in shellfish poses a health risk for its pathogenicity associated with campylobacteriosis. However, an efficient method to detect this risk is unavailable. Herein, we introduce a portable colorimetric biosensing platform that comprises three modules: an enrichment module 1, a binding and transduction module 2, and a smartphone-based module 3. Module 1 is an aptamer-modified 96-well plate for the specific capture of Campylobacter in a simple and high-throughput manner. Module 2 features a bifunctional biopolymer of L-glutamic acid γ-hydroxamate–alginate–Fe3+ coordinating fusarinine C, which can bind the captured Campylobacter cells and transduce them into amplified color signals upon reaction with Fe3+–violurate complexes. Module 1 achieves a capture efficiency of 97.24 %, and the subsequent addition of module 2 renders colorimetric indication of Campylobacter ranging from 101 to 106 CFU/mL, achieving an actual limit of detection of 8 CFU/mL validated by Campylobacter single-cells. Moreover, the generated colors can be recognized and converted into cell densities by module 3 with ultrasensitivity. Notably, this biosensor–smartphone platform accomplishe reliable high-throughput colorimetric detection of Campylobacter in real samples with an accuracy of 80 %. This work showcases a proof of principle for efficient on-site detection of Campylobacter contamination regarding shellfish farming.

A phase transition coordinated monoclinic Fe-based Prussian blue for high-performance sodium-ion battery cathode

Prussian blue analogs (PBAs) are ideal cathode materials for sodium-ion batteries (SIBs) owing to their cost-effectiveness, good low-temperature performance, and facile synthesis process. Nevertheless, their actual capacity and cycling stability limit practical application. Herein, a new chelating agent, sodium tartrate, is proposed to synthesize high-quality Fe-based Prussian blue (HQ-NFF) with enhanced Na content and a stable structure through chelation effect-assisted co-precipitation. The crystal structure of HQ-NFF undergoes a phase transition to a Na-rich monoclinic phase after full discharge, leading to improved capacity and cycling stability. The HQ-NFF cathode exhibits an ultra-high capacity of 160.8 mAh g−1 and a capacity of 146.1 mAh g−1 at 2 C, with a capacity retention of 75.3 % after 150 cycles. Moreover, a 3D-printed HQ-NFF cathode with an areal loading of 7.88 mg cm−2, delivers a high areal capacity of 0.969 mAh cm−2 and good rate capability.

An Interdisciplinary Assessment of the Impact of Emerging Contaminants on Groundwater from Wastewater Containing Disodium EDTA

In recent years, there has been a surge in interest concerning emerging contaminants, also known as contaminants of emerging concern (CECs), due to their presence in environmental matrices. Despite lacking regulation, these chemicals pose potential health and environmental safety risks. Disodium EDTA, a widely utilized chelating agent, has raised concerns regarding its environmental impact. The present work aimed to verify the presence of Disodium EDTA at the exit of eight wastewater treatment plants discharging into some losing streams flowing within a large alluvial aquifer. Conducted in the Province of Parma (Northern Italy), the research employs a multidisciplinary approach, incorporating geological, hydrogeological, chemical, and microbial community analyses. Following a territorial analysis to assess industries in the region, through the use of ATECO codes (a classification system for economic activities), the study investigated the concentration of Disodium EDTA in effluents from eight diverse wastewater treatment plants, noting that all discharges originate from an activated sludge treatment plant, released into surface water courses feeding the alluvial aquifer. Results revealed detectable levels of Disodium EDTA in all samples, indicating its persistence post-treatment. Concentrations ranged from 80 to 980 µg/L, highlighting the need for further research on its environmental fate and potential mitigation strategies. Additionally, the microbial communities naturally occurring in shallow groundwater were analyzed from a hydrogeological perspective. The widespread presence of a bacterial community predominantly composed of aerobic bacteria further confirmed that the studied aquifer is diffusely unconfined or semi-confined and/or diffusely fed by surface water sources. Furthermore, the presence of fecal bacteria served as a marker of diffuse leakage from sewage networks, which contain pre-treated wastewater. Although concentrations of Disodium EDTA above the instrumental quantification limit have not been found in groundwater to date, this research highlights the significant vulnerability of aquifers to Disodium EDTA. It reveals the critical link between surface waters, which receive treated wastewaters impacted by Disodium EDTA, and groundwater, emphasizing how this connection can expose aquifers to potential contamination. At this stage of the research, dilution of wastewaters in surface- and groundwater, as well as hydrodynamic dispersion within the alluvial aquifer, seem to be the main factors influencing the decrease in Disodium EDTA concentration in the subsurface below the actual quantification limit. Consequently, there is a pressing need to enhance methodologies to lower the instrumental quantification limit within aqueous matrices. In a broader context, urgent measures are needed to address the risk of diffuse transport of CECs contaminants like Disodium EDTA and safeguard the integrity of surface and groundwater resources, which are essential for sustaining ecosystems and human health.

Pangoniometry is a modern method of physiological and hygienic assessment of the severity of work according to the indicator "Working posture"

Introduction. The development of occupational health is largely ensured by its comprehensive approach to the study of the "Man–machine–production environment" system, which includes an assessment of many factors characterizing the production system in the action shaping working conditions. However, in the concept of "Working conditions" they are "a set of factors in the working environment and the labor process that influence the performance and health of the employee", that is, they are interpreted statically (as a set...) and passively — without the participation of the employee in shaping the conditions of his work. This is probably why the working conditions are being investigated dose exposures of material factors that do not contribute to the identification of their primary connection with a working person — a connection that forms the result of the actual interaction of material factors with the animate at a certain time in a given workplace, the identification of which is available only to effective exposures of material factors — expositions of a higher level of quality, claiming to have the appropriate quality of rationing – comprehensive, universal, with an expanded scale of assessment of working conditions, and for the first time opens up the possibility of their identification, depending on the state and dynamics of the employee's health. In this study, scientists measured and evaluated the effective exposure of one of the most difficult to determine and evaluate the characteristics of the labor severity factor — the "Working posture". The experts gave an assessment in comparison with the traditionally defined basic exposures of the working position in the studied labor processes. The study aims to increase the accuracy of the hygienic assessment of the severity of work according to the indicator "Working posture" using a modern technique — pangoniometry. Materials and methods. In three groups of workers (2 car drivers, 10 doctors of clinical laboratory diagnostics and 30 electricians on duty), specialists applied three different methods of studying the working posture, two of which are widely represented in the normative and methodological and scientific literature, and the third was developed by the authors and was called pangoniometric. This technique consisted in drawing up diagrams of working poses, which are the material for measuring with the help of a protractor the limits of fluctuations in the degrees of motion of various parts of the locomotor system in joints. The researchers also measured the actual limits of fluctuations in angular degrees, determined that they exceeded the known optimal limits in areas of increased stress on the joint and the time of its operation in these areas. The authors have carried out statistical processing of the obtained material using the Student's t-test and the Pearson correlation coefficient. Results. It was found that the indicator of the effective effect of the forms of working poses obtained by the method of pangoniometry significantly, by 1–2 classes and degrees of harmfulness, clarifies the assessment of the severity of labor in comparison with the indicator of the dose exposure of working poses. Limitation. There were a small number of car drivers studied — two people. Conclusion. Pangoniometry is a method of physiological-hygienic and physiological-clinical comprehensive research and assessment of the impact of forms of working postures on health in the labor process. The method clarifies the hygienic assessment of the severity of work according to the indicator "Working posture" by identifying the primary relationship between the load on the joints and their working tension, materializing this important relationship in diagnostic and preventive terms in the indicator of the effective effect of the goniometric index of the working posture. In an indicator that has the property of being a guide to managing working conditions in the workplace by openly modeling elements of not only the material factor, but also the animate interacting with it, represented by the properties of the employee's body. Ethics. In preparing the article, the authors were guided by the Ethical principles of medical research set out in the Helsinki Declaration of the World Medical Association in the latest edition.

Porphyrin complex-based reversible fluorescent film sensor for differentiating and detecting sarin mimics vapor

This study presents a TAPP-based fluorescent sensor for diethylchlorophosphate (DCP), a surrogate for sarin, addressing the critical challenge of detecting nerve agents. The sensor can form a reversible weak bond interaction with the PO group in sarin by using the reversible weak bond complexation mechanism in the porphyrin cavity, which is the key to realize the reversible function of the sensor. In this study, we constructed a fluorescence probe that combines the advantages of physical process and chemical reaction process sensing, which not only ensures selectivity, but also realizes continuous and reversible real-time detection of DCP. The sensor demonstrates excellent photochemical stability and sensitivity, with an actual detection limit of 10 ppt and a theoretical detection limit of 1 ppt. In addition, it can differentiate challenging interferents like HCl through response kinetics, offering a practical, cost-effective, and environmentally sustainable solution for nerve agent detection in high-risk environments.

Parallel optofluidic detection of multiple cardiac biomarkers for point-of-care testing applications

Point-of-care testing (POCT), which enables personalized, accurate, affordable, and accessible medical services, is indispensable in the diagnostics, screening, and treatment of disease, especially for emergency and severe cases. Considering the complexity of disease, multiplexed point-of-care (MPOC) testing is very important for the simultaneous detection of several biomarkers to improve accuracy and increase analysis throughput. In this work, a microfiber interferometer based multiplexed optofluidic (MIMO) chip sensor is proposed for multiplexed, quantitative detection of cardiac biomarkers. Four microfiber interferometers are suspended and fixed in four separate microscale sample channels of an imprinted polydimethylsiloxane (PDMS) chip. A drop of the sample is distributed into the four parallel channels automatically and reacts with the probe on the microfiber sensor surface specifically, which leads to the wavelength shift of the spectrum resulting from evanescent wave interactions with biomolecules. There microfiber interferometers are functionalized with myoglobin (Myo) antibody, cardiac troponin I (cTnI) antibody, and creatine kinase–myocardial band isoenzymes (CK–MB) antibody respectively and the rest microfiber interferometer is with no functionalization, which acts as the control channel to reduce noise. By using compact dedicated commercial optical modules, miniaturized and low cost experimental setup is organized and achieve four channel simultaneous measurement through time division multiplexing. Three cardiac biomarkers, Myo, cTnI, and CK–MB, are synchronously detected on the proposed MIMO chip sensor. In a standard buffer sample, the log-linear sensing range of CK–MB is 0.2 ∼ 200 ng/mL with detection limit of 3.7 pg/mL, the log-linear sensing range of Myo is 2 ∼ 2000 ng/mL with detection limit of 0.5 ng/mL, and the log-linear sensing range of cTnI 0.02 ∼ 20 ng/mL with detection limit of 2.6 pg/mL, which all perfectly cover the actual diagnostic limit of myocardial infarction. Furthermore, the MIMO chip sensor maintains excellent performance of both specificity and detection capabilities in more complex serum samples. In double-blind trials of multiple biomarker detection, the MIMO chip sensor exhibits comparable detection ability with a commercial kit and good resistance to environmental disturbance. The proposed MIMO chip sensor sensing system offers a low-cost, portable, self-driven, and miniaturized scheme for a multiplexed point-of-care testing device, promoting the feasibility and accessibility of personalized medical services and paving the way for clinical application and industrialization.

Label-Free and DNAzyme-Mediated Biosensor with a High Signal-to-Noise Ratio for a Lumpy Skin Disease Virus Assay.

Lumpy skin disease virus (LSDV) is a severe and highly contagious form of cowpox. As LSDV continues to mutate and there is no vaccine and treatment in nonendemic countries, early detection of LSDV becomes an important basis for epidemic prevention and control, especially for detection of conserved sequences. A new label-free and sensitive fluorescence method was developed based on a light-up RNA aptamer for detecting LSDV. The method integrated recombinase polymerase amplification (RPA), CRISPR/Cas12a, 10-23 DNAzyme, and Baby Spinach RNA aptamer for triple cascade signal amplification. Based on highly sensitive and specific RPA and CRISPR/Cas12a, DNAzyme achieved a third signal amplification. Additionally, the Baby Spinach RNA aptamer had stronger fluorescence signals and higher quantum yields. The label-free method had ultrahigh sensitivity with the actual detection limit as 1.29 copies·μL-1. The method was 100-fold more sensitive compared to RPA with Cas12a. Moreover, it had no cross-reactivity with viruses belonging to the Capripoxvirus, such as sheep pox virus and goat pox virus with genetic homology as 97%. Furthermore, the method displayed 100% accuracy in 50 actual samples. Therefore, the method based on RPA, Cas12a, and 10-23 DNAzyme had advantages in LSDV detection and provided a new solution for LSD prevention and control.

On the Origin of the Light Yield Enhancement in Polymeric Composite Scintillators Loaded with Dense Nanoparticles.

Fast emitting polymeric scintillators are requested in advanced applications where high speed detectors with a large signal-to-noise ratio are needed. However, their low density implies a weak stopping power of high energy radiation and thus a limited light output and sensitivity. To enhance their performance, polymeric scintillators can be loaded with dense nanoparticles (NPs). We investigate the properties of a series of polymeric scintillators by means of photoluminescence and scintillation spectroscopy, comparing standard scintillators with a composite system loaded with dense hafnium dioxide (HfO2) NPs. The nanocomposite shows a scintillation yield enhancement of +100% with an unchanged time response. We provide for the first time an interpretation of this effect, pointing out the local effect of NPs in the generation of emissive states upon interaction with ionizing radiation. The obtained results indicate that coupling fast conjugated emitters with optically inert dense NPs could lead to surpassing the actual limits of pure polymeric scintillators.

GINS1 as a Novel Biomarker of Survival in Colon Adenocarcinoma Patients — A Secondary Publication

The study focused on elaborating the role of GINS1 expression and its regulatory mechanisms in colon adenocarcinoma (COAD). Using the UALCAN informational index, GINS1 expression assessment unveiled a critical up-regulation in malignant cells that stood out from normal controls, suggesting its contribution to COAD expansion. Further dismantling GINS1 expression across various boundaries revealed unsurprising up-regulation in different malignant development stages, racial groups, genders, and age classes in COAD patients, characteristics for its imperative role in cancer progression. Moreover, this study investigated the promoter methylation status of GINS1, uncovering a critical uniqueness between COAD samples and normal controls. Analyzing promoter methylation across various clinical boundaries uncovered powerful variations, with particular methylation patterns seen across cancer stages, race groups, genders, and age groups. Survival analysis using the Kaplan-Meier (KM) plotter tool showed a colossal connection between GINS1 expression levels and overall survival (OS) in COAD patients, with low GINS1 expression interfacing with higher OS. Additionally, mutational examination using the cBioPortal stage revealed that no critical change was found in COAD. Overall, these findings revealed the complex contribution of GINS1 in COAD pathogenesis, underlining its actual limit as a prognostic biomarker and supportive therapeutic agent in COAD management.

Prediction of brake pad wear and remaining useful life considering varying vehicle mass and an experimental holistic approach

Estimation of passenger car brake pad wear is considered, including real-time mass estimation to account for variations in vehicle mass. A longitudinal dynamics model is used to estimate mass, the application of the brakes, and a longitudinal braking force. Wear is modelled from brake work based on the product of the braking force and distance travelled during braking. Data is provided by standard vehicle on-board diagnostics data and a sensor fusion based on an inertial measurement unit and satellite position data, sampled from a single car with 10,200 km of on-road driving, including 31 brake pad wear measurement samples, and driving with up to 23% increased vehicle mass. The mass is accurately estimated within ±5% of the actual. Braking states determined from comparisons of measured and modelled deceleration provide accuracies of ≈91%, precisions of ≈96%, and recall rates of ≈86%, with inclusion of varying mass only resulting in minor differences. Brake work is estimated with (a) constant mass, (b) estimated mass, (c) actual mass, and (d) actual mass and braking states. Compared to (a), (b) and (c) provide 9% and 11% increased work, while (d) provides an increase of about 5% compared to (c). Wear coefficients are fitted on the initial half of the wear data considering (a), (b), and (d). Here (a) and (b) provide similar wear rates of k≈−1.22 mm/GJ, while (d) is about 5% lower. Validating on the second half of the data, (b) and (d) provide very similar wear estimates, with overall lower errors than (a). At the final sample, however, (a) provides a slightly lower absolute error, overestimating the wear by about 2%, while (b) and (d) underestimate it by about 3%. RUL, in terms of distance, is estimated across about 9,500 km of data by estimating a running ratio between cumulated work and distance. Here only (a) and (b) are considered, with (a) overestimating the RUL by 600 km at the actual wear limit, while (b) underestimates it by 190 km. A distance-based model is also considered, resulting in a constant RUL error of about 2,000 km.

Extracellular volume measured by whole body CT scans predicts chronic cardiotoxicity in breast cancer patients treated with neoadjuvant therapies based on anthracyclines: A retrospective study

IntroductionNeoadjuvant chemotherapies for breast cancer (BC) are effective but potentially cardiotoxic, and expose long survivors at risk of chemotherapy-related cardiac dysfunction (CTRCD). Unfortunately, early screening for CTRCD has actual diagnostic limits. Myocardial extracellular volume (mECV) is a radiological marker used in cardiac CT scans and cardiac magnetic resonance for diagnosis and follow-up of CTRCD. It can be measured in whole-body CT (WB-CT) scan, routinely performed in patients at high risk of relapse, to evaluate CTRCD occurrence during oncological follow-up. Methods82 WB-CT scans were examined at baseline (T0) and during oncological follow-up at first year (T1) and fifth year (T5) after the end of neoadjuvant treatment. mECV was measured at 1 min (PP) and 5 min (DP) after contrast injection. 31 echocardiograms were retrieved in T1 to perform a linear correlation between mECV and left ventricular ejection fraction (LVEF). ResultsmECV values in T0 were similar between the two groups both in PP and in DP. Significant results were found for PP values in T1 (37.0 % vs 32 %, p = 0.0005) and in T5 (27.2 % vs 31.2 %, p = 0.025). A cut-off value of 35 % in PP proved significant in T1 (OR = 12.4, p = 0.004), while mECV was inversely correlated with LVEF both in PP (adj-S = −3.54, adj-p = 0.002) and in DP (adj-S = −2.51, adj-p = 0.0002), suggesting a synergistic action with the age at diagnosis (p < 0.0001, respectively). ConclusionsWB-CT scans performed during oncological reassessment in patients at high-risk of recurrence could be used for CTRCD screening in cardiovascular low-risk patients, especially in aging patients with mECV values above 35 %.

Development of microbial desalination cells for the treatment of reverse osmosis reject water: A new benchtop approach

To address the growing global demand for usable water, there is an immediate necessity to enhance wastewater treatment systems. A continuous mode adaption of the conventional three-chamber microbial desalination cell (MDC) configuration was used, with gravity facilitating the flow of residential reject water for desalination. Initially, operating in batch mode with a 100 mL treatment volume, the single microbial desalination machine was expanded to 300 mL in continuous mode, capable of treating 5 L of home refuse water over 36 days. The batch mode MDC had a maximum current and power density of 3.81 µA/cm2 and 0.337 µW/cm2, resulting in 76 % desalination and 83.9 % COD eradication rates. Scaling up increased the MDC's performance, reaching a maximum of 0.45 µW/cm2 and 5.31 µA/cm2, which was 1.3 times greater than batch mode operation. The current work demonstrates the feasibility of microbial desalination cells and their novel approach for treating much higher quantities of reverse osmosis (R.O.) saline water in a comparable period of roughly 36 days. It emphasizes the actual limits when dealing with real-world wastewater samples, presenting a unique path for biotechnology by simultaneously generating bio-electricity and tackling future contaminants. Furthermore, incorporating desalination chambers with microbial fuel cells increases efficiency and opens up new options for enhanced wastewater treatment, resource recovery, and bioenergy generation. This pioneering strategy uses innovative membrane technologies and microbial optimization approaches to push the limits of desalination.

Research on the minimum detection limit for measuring high-purity gases by gas chromatography

Abstract At present, the application fields of high-purity gases (purity reached 99.999% and above) include the semiconductor manufacturing industry, chemical analysis, fuel cells, aerospace, medicine, etc., and the quality and purity requirements of high-purity gases are also getting higher and higher. As the only detector that can detect ppb-level trace impurities, the pulsed discharge helium ionization detector (PDHID) is the most used detector in the field of high-purity gases. The minimum detection limit of existing PDHID-related analysis methods is usually calculated theoretically. In order to verify the actual minimum detection limit of PDHID, a multi-group gas distribution system was used in this paper to dilute the permanent gas components in the high-purity gas, and the gas chromatograph with pulsed discharge helium ionization detector (GC-PDHID) was used to detect the obtained different concentrations of standard gases. The experimental results showed that PDHID possessed high sensitivity, good linearity, and a wide linear range. The actual minimum detection limit for the permanent gas components in the high-purity gas could reach the ng/g (ppb) level, which could realize the detection of ultra-low concentration samples, and further verify the actual minimum detection limit of PDHID. This experiment provides a reference basis for the analysis of trace gases in the gas industry, especially in industries such as high-purity and ultra-high-purity gases and gas for the electronics industry, and is of great significance in actual production work.

Влияние режима пожара на огнестойкость несущих строительных конструкций машинных залов ГРЭС

Machine rooms of a state district power plant (GRES) are sizeable. Heat impact on the structures of the building in the case of a real fire can significantly differ from the impact in the case of a standard fire. Therefore, the calculation of fire resistance of building structures should be conducted not only in conditions of a standard fire but of a real fire as well. The objective of the study is the theoretical evaluation of the actual limits of fire resistance of load-bearing building structures of the machine room of the main building of the Nizhneturinskaya GRES in conditions of standard and real fire regimes. Numerical experiments to calculate the heating of load-bearing building structures in the case of a standard fire and the case of the most hazardous scenario of the real fire development have been conducted in the framework of the study. A field 3-dimensional model to calculate fire hazardous factors and a non-stationary thermal conductivity equation have been applied. The obtained results have been analyzed. The field model adapted to the space-planning solutions of the machine room has been described. The most hazardous scenario of the development of real fire in case of combustion of the turbine oil spill in the sector of the machine room with the lowest height of ceiling has been chosen. The temperature fields in the gaseous environment of the machine room at different moments are presented. It has been detected that the heating of reinforced concrete structures of the machine room ceiling is significantly uneven due to the 3-dimensional gas dynamic pattern of fire. Dependencies of temperatures of the frame of reinforced concrete load-bearing structures of the ceiling on the time of standard and real fires in the most heated section of the ceiling have been obtained. It has been determined that the maximum temperature of the frame in the case of the standard fire is lower than in the case of real fire. Due to the features of the 3-dimensional thermal gas dynamic pattern of fire in machine rooms of the GRES, the fire resistance of load-bearing building structures in these premises must be determined in both conditions of standard fire and real fire, considering the most hazardous scenario of its development.

Silicon Tetrachloride as innovative working fluid for high temperature Rankine cycles: Thermal Stability, material compatibility, and energy analysis

Silicon Tetrachloride (SiCl4) is proposed as a new potential working fluid for high-temperature Rankine Cycles. The capability to overcome the actual thermal stability limit of fluids commercially employed in the state-of-the-art Organic Rankine Cycles (ORC) is demonstrated by static thermal stability and material compatibility tests. Experimental static test proves its thermo-chemical stability with a conventional stainless-steel alloy (AISI 316L) up to 650 °C. A preliminary material compatibility analysis performed with optical microscope on the AISI 316L cylinder, after exposure of 300 h to SiCl4 at temperature higher than 550 °C, confirms the potentiality of this fluid when coupled with high-grade heat sources. A thermodynamic analysis has been carried out accounting for the effect of operating conditions on the axial turbine efficiency. A comparison with fluids adopted in medium–high temperature ORCs is performed, evidencing that the proposed fluid could achieve more than + 10 % points as thermal efficiency gain compared to any commercial solutions when coupled with high-temperature sources such as solar, biomass, waste heat from industrial processes and prime movers. A 2 MW SiCl4 cycle operating full-electric at 550 °C reaches a thermal efficiency of 38 %, exceeding values attainable by any other working fluid under similar conditions and power size.

Nature-inspired fungal fusarinine C-powered dual-mode fluorometric/colorimetric biosensing of fecal Helicobacter pylori with high-reliability

Conventional diagnostic approaches for Helicobacter pylori lack sufficient sensitivity, accuracy, and flexibility, especially for low-density H. pylori infection. To overcome this limitation, we developed a highly reliable fluorometric/colorimetric dual-mode biosensing technique to detect minute quantities of H. pylori in human stool samples. Inspired by natural porphyrins, we discovered that the water-soluble fungal siderophore fusarinine C (FsC) emitted intense green fluorescence owing to intramolecular through-bond and intermolecular through-space conjugation, and turned reddish upon coordination with Fe3+. With FsC as an intrinsic fluorometric/colorimetric probe, a dual-mode biosensor was developed. It included an enrichment module of truncated H. pylori-specific-aptamer-modified superparamagnetic nanoparticles to capture H. pylori from samples, and a transduction module of alginate conjugated with FsC[Fe3+] and an optimized amount of FsC without Fe3+ to amplify the captured H. pylori to fluorescent and/or color signals. Remarkably, significantly increased sensitivity was achieved for this biosensor, with an actual limit of detection of 5 CFU/mL and single-cell-level detection resolution, as validated using laser-tweezer-sorted single H. pylori cells. Moreover, highly reliable dual-mode detection of low-density H. pylori (between 5 and 10 CFU/mL) was demonstrated. Using the colorimetric mode, a smartphone-biosensor platform for sensitive point-of-care testing of fecal H. pylori within 20 min was demonstrated, outperforming the clinical fecal antigen test strips; meanwhile, the fluorometric mode of the biosensor, owing to its greater sensitivity, can verify the colorimetric detection of minute H. pylori. This study first showcased a FsC-powered dual-mode biosensor for ultra-sensitive and accurate point-of-care detection of H. pylori with high reliability.

Students' Creative Thinking Ability Through the Project Based Learning (PjBL) Model Assisted by Talking Sticks

Having the ability to think creatively is preparation for facing the 4.0 era. The application of the Project Based Learning model assisted by Talking Stick in science subjects can create an active learning atmosphere, create new ideas, be cheerful and enthusiastic so that it can improve students' creative thinking abilities. This research is a type of quantitative experimental research with a pre-experimental design. The research was conducted in class V at SDN 01 Kaleo, SDN 02 Kaleo, and SD Inpres Kaleo, totaling 69 students. The research instrument uses multiple choice tests and descriptions. Data analysis uses the Actual Completion Limit (BTA). The mastery of students' creative thinking abilities increased by 11.6% from the pre-test of 66.7% to the post-test of 78.3%. After implementing the PjBL model assisted by Talking Stick, the classification of creative thinking abilities increased in the high category. There were no students in the pre-test while there were 14 students in the post-test. The creative thinking abilities of fifth grade students in the science subject water cycle material can increase after implementing the PjBL model with the help of Talking Stick. The development of a PjBL-based textbook with the help of Talking Stick for students' creative and critical thinking abilities is the idea for the development of this research.