Exponential Decay Model Research Articles

Coal permeability considering mining-induced stresses subjected to fractional derivative

Aiming at characterization of coal permeability under conditions of non-Darcian flow, in the transient pulse test, a new fractional-order decay model is developed to describe the pressure difference decay of coal considering mining-induced stresses. Coal permeability under the condition of mining-induced stress is determined experimentally by the MTS815 Flex Test GT testing machine to validate the fractional-order decay model. The results indicate that the new fractional-order decay model can estimate the permeability of coal considering mining-induced stresses more accurately than the exponential decay model. A conceptual permeability model of coal considering mining-induced stresses is obtained by characterization analysis of coal permeability evolution. Furthermore, the meaning of the fractional order is discussed, showing that it can be used to characterize the influence of mining-induced stresses on the seepage characteristics of coal.

Prediction of physical parameters of Jatropha biodiesel-ethanol dual fuel based on topological indices

A new topological index method was used to construct a quantitative structure–property relationship (QSPR) prediction model for elucidating the performance indicators of the Jatropha biodiesel-ethanol (JB-E) dual fuel. This model effectively solves the problem of these physical parameters being difficult to measure. On the one hand, the QSPR prediction model has been established based on the topological indices, calorific value, density, kinematic viscosity, and solidifying point of JB-E, while the internal and external tests of the prediction model are analyzed. On the other hand, a correlation model is established between the topological indices and critical parameters of dual fuels. The results show that the exponential decay model is more effective in reflecting the relationship between the topological indices and kinematic viscosity, while the linear model is more suitable for elucidating the relationship between the topological indices, calorific value, and density. The correlation coefficients of the three models are all greater than 0.999. Moreover, the correlation model between the topological index and critical parameters Tcm, Pcm, Vcm, and Zcm is established to accurately predict the critical parameters of dual fuels. Overall, this study has laid a strong foundation for theoretical calculations and applications of dual fuels.

Linear pathway analysis of European botulism poisoning response guidelines

Abstract Background Botulism is a rare illness caused by Clostridium botulinum toxin with a naïve case fatality ratio of 40-50%. There is no coordinated collective worldwide reporting on cases and comparatively few recommendations on case management. This study examined 14 European botulism treatment guidelines. Methods A ten-language search was conducted to examine European botulism guidelines. The guidelines were classified by differential diagnosis advice; expert advice access; mention of causalities; contract tracing; biological sampling method; and treatment access rapidity. The guidelines were linearly represented on a probability pathway. Quantified probabilities were entered into the algorithm. Probabilities for algorithmic delay or deviance were estimated or mathematically modeled against Hamiltonian, Ford- Fulkerson and Kruskal pathways. Case recognition was deemed proportional to the availability of information at point of care and produced a hazard function related to a Bayes’ probability model. Results Two guidelines did not display all diagnostic information in one place, and six European nations had incomplete descriptions of the chain of causality linking botulism cases: factorially reducing the Borel algorithmic likelihood of diagnosis through contact tracing and decreasing the affectable survival chance. Another limitation was specialist advice and treatment availability in a 48-hour window. Survival probability models to the quoted naïve minimum constraint of a 60% survival factor were depicted, with pharmacokinetic tendential to an exponential decay model. This highlighted the importance of well-constructed case management and logistical stockpiling methods. Conclusions In botulism poisoning the 48-hour window is cited as crucial to patient survival chances, to this extent, the availability of clear diagnostic criteria including causation considerations, expert advice access and logistically considered therapeutic stockpiles could improve survival probability. Key messages • An international standard for botulism guidance may further improve botulism case identification and survival rates. • National botulism guidelines with direct contact method to an expert and with strategic positioning of therapeutic stockpiles may reduce time to treatment and improve survival chances.

Lifetime measurement and aging mechanism analysis of OLED subpixels

The lifetime of organic light-emitting diodes (OLED) is of great importance for both display and lighting applications. In order to measure the brightness attenuation of each subpixel on the OLED screen at the same time, an experimental platform was built with a spectrometer and an automatic mechanical system. By testing the brightness decay rate of red, green, blue, and white light from the OLED screen under different initial brightness, combined with data fitting using the extended exponential decay model, the aging mechanism of each subpixel is compared and analyzed. The comparative analysis results show that the lifetime of the OLED obeys an exponential decay distribution, and which of the blue light has the fastest decay rate within a reasonable time range. These testing and analysis methods could provide reference and guidance for OLED manufacturers and users.

Cold Load Pickup Model Adequacy for Power System Restoration Studies

When a grid section is re-energized after an interruption, the load behaviour can be significantly different from normal operation. In this manuscript, the impact of the phenomenon—known as cold load pickup—is investigated by evaluating 31 time series measured after network outages in Austria and Germany. Its impact on power system restoration and the adequacy of the most common type of simplified model for such investigations is assessed by the time domain simulation of a restoration setting involving the parallel operation of conventional and renewable generation. Parameter distributions are provided for the exponential decay and the delayed exponential decay model with the aim of facilitating meaningful consideration of the phenomenon in time domain simulations of power system restoration. The benefits and limitations of these models are assessed by comparison of time domain simulation results using either the normalized raw data, an exponential decay model or a step-wise active power chance to reflect load behaviour. It is shown that using an exponential decay model leads to higher fidelity of simulation results with respect to the resulting steady-state active power sharing among generators than just applying a step-wise power change in the simulation.

Estimation of R0 for the Spread of the First ASF Epidemic in Italy from Fresh Carcasses.

After fifty years of spread in the European continent, the African swine fever (ASF) virus was detected for the first time in the north of Italy (Piedmont) in a wild boar carcass in December, 2021. During the first six months of the epidemic, the central role of wild boars in disease transmission was confirmed by more than 200 outbreaks, which occurred in two different areas declared as infected. The virus entered a domestic pig farm in the second temporal cluster identified in the center of the country (Lazio). Understanding ASF dynamics in wild boars is a prerequisite for preventing the spread, and for designing and applying effective surveillance and control plans. The aim of this work was to describe and evaluate the data collected during the first six months of the ASF epidemic in Italy, and to estimate the basic reproduction number (R0) in order to quantify the extent of disease spread. The R0 estimates were significantly different for the two spatio-temporal clusters of ASF in Italy, and they identified the two infected areas based on the time necessary for the number of cases to double (td) and on an exponential decay model. These results (R0 = 1.41 in Piedmont and 1.66 in Lazio) provide quantitative knowledge on the epidemiology of ASF in Italy. These parameters could represent a fundamental tool for modeling country-specific ASF transmission and for monitoring both the spread and sampling effort needed to detect the disease early.

Temperature May Play a More Important Role in Environmental DNA Decay than Ultraviolet Radiation

Environmental DNA (eDNA) preservation is crucial for biological monitoring using eDNA technology. The decay of eDNA over time in natural water bodies and the effects of temperature and ultraviolet (UV) radiation on the decay rate are largely unknown. In this study, the linear and exponential decay models were used to explore the relationship between residual eDNA content and decay time, respectively. It was found that the residual eDNA content treated with a higher temperature decreased by an average of 89.65% at the end of experiment, while those in the 4 °C treatment group remained stable. The higher decision coefficient (R2) of the exponential decay models indicated that they could better reflect the decay of eDNA over time than linear. The difference in the decay rates of the exponential modes was slight between the 20 °C (25.47%) and 20 °C + UV treatment groups (31.64%), but both were much higher than that of the 4 °C group (2.94%). The results suggest that water temperature significantly affected the decay rate of eDNA, while UV radiation had little effect.

Effects of water to binder ratio on the chloride binding behaviour of artificial seawater cement paste blended with metakaolin and silica fume

• Effects of water to binder (w/b) ratios (0.2 and 0.4) and SCMs (silica fume and metakaolin) on chloride binding behaviour of seawater cement paste (SCP) are investigated. • Influence of water to binder (w/b) ratios (0.2 and 0.4) and SCMs (silica fume and metakaolin) on the porosity and pore size distribution of SCP is revealed by the 1 H Nuclear magnetic resonance (NMR) measurement. • The risk of steel corrosion in SCP with different w/b ratios is evaluated by the [Cl − ]/[OH − ] ratio. • The relationship between chloride binding ratio, porosity and [Cl − ]/[OH − ] ratio has been explored. This work investigates the effects of water-to-binder (w/b) ratio and supplementary cementitious materials (SCMs) including silica fume (SF) and metakaolin (MK) on chloride binding of seawater cement paste (SCP) by using a water extraction method. The chloride binding capacity, contents of chloride bound in Friedel’s salt and chloride adsorbed by C S H gel are quantified. The resistance to steel corrosion is evaluated by [Cl − ]/[OH − ] ratio. The results show that the chloride binding ratio (content of bound to free chloride) gradually increases with the w/b ratio decreasing from 0.4 to 0.2. In addition, the chloride ions adsorbed by C S H gel in SCP with w/b ratio 0.2 contributes more largely to chloride binding capacity than SCP with w/b ratio 0.4. Moreover, the incorporation of MK improves the chloride binding capacity of SCP while the utilization of SF doesn’t make much difference. In addition, the [Cl − ]/[OH − ] ratio in SCP keeps at a very low level during the whole experimental process, and decreases with the reduction of w/b ratio, the increase of content of MK and curing ages. The correlation of chloride binding ratio with [Cl − ]/[OH − ] ratio can be described by an exponential decay model while a linear relationship is observed between chloride binding ratio and the volume of macropores larger than 200 nm in diameter.

A Physically Based Statistical Model With the Parameterized Topographic Effect for Predicting the Weakening of Tropical Cyclones After Landfall Over China

AbstractAccurate prediction of tropical cyclone (TC) intensity is important but challenging. In this study, a physically based algebraic decay model for predicting TC weakening after landfall over China is introduced, which assumes the TC weakening rate is proportional to the square of the TC maximum near‐surface wind speed. In this algebraic decay model, a decay parameter including the topographic effect by modifying the surface drag coefficient with the normalized terrain height is determined by minimizing the forecast errors for all landfalling TCs over mainland China during 1980–2020. Results show that the algebraic decay model with topographic effect considered performs better than the commonly used exponential decay model for TCs after landfall over mainland China, especially when TCs move further inland. This new model has a time‐dependent decay parameter along the TC track due to the topographic variation, which is different from the previous exponential decay model.

Evaluation of volatile organic compound (VOC) emissions from memory foam mattresses and potential implications for consumer health risk.

Chemical emissions from two new memory foam mattresses were evaluated in a simulated consumer use environment over the course of 32 days. Passive 12- and 24-h samples (n=62) were collected for various VOCs. Airborne concentrations of chemicals associated with the mattresses (2-propanol, acetone, chloromethane, toluene, and ΣVOC) peaked during the first day after installation and progressively decayed over the course of the following 31 days. Emission rates were derived using a two-phase, double exponential source decay model paired with a one-compartment generalized indoor air quality model; short- and long-term emission half-lives for individual chemicals were on the order of hours (approximately 4 or 12h) and days (approximately 24 days), respectively. Model-estimated average ΣVOC concentrations for the 32-day period of the study were approximately 20 and 33μg/m3 for Mattress 1 and 2, respectively, while the modeled one-year average concentrations were 2.7 and 4.2μg/m3, respectively. First-year trends for both mattresses were qualitatively similar, with the sum of 2-propanol, acetone, chloromethane, and toluene contributing to approximately 81% and 95% of the first-year ΣVOC concentration of Mattress 1 and 2, respectively. The airborne concentrations of individual chemicals and ΣVOC measured and modeled in this study were well below available health-based benchmarks for individual chemicals and within available indoor air quality recommendations for ΣVOC, suggesting that it is unlikely that the use of the models of mattresses evaluated in this study would pose a health risk to consumers.

Afterslip From the 2020 M 6.5 Monte Cristo Range, Nevada Earthquake

AbstractWe investigate postseismic deformation following the 15 May 2020, Mw 6.5 Monte Cristo Range, Nevada earthquake using geodetic and aftershock data. Seven months of Sentinel 1‐A/B SAR images were used to model deformation as afterslip on two subparallel fault planes outlined by aftershocks. Postseismic deformation fits exponential and logarithmic decay models equally well. For exponential decay, the average decay time is ∼38 days. On the western plane, where most coseismic slip was observed, afterslip was minor, occurred at shallower depths than coseismic slip, and is anticorrelated with aftershock distribution. On the eastern plane, afterslip is significant, exceeds coseismic moment release, occurred at and below coseismic slip, and is correlated with aftershock distribution. On both segments, geodetic moment exceeds seismic moment, suggesting most afterslip occurred aseismically. Aseismic creep does not make up for observed coseismic shallow slip deficit, perhaps related to fault immaturity.

Intra-subject stability of different expressions of spatial QRS-T angle and their relationship to heart rate.

Three-dimensional angle between the QRS complex and T wave vectors is a known powerful cardiovascular risk predictor. Nevertheless, several physiological properties of the angle are unknown or poorly understood. These include, among others, intra-subject profiles and stability of the angle relationship to heart rate, characteristics of angle/heart-rate hysteresis, and the changes of these characteristics with different modes of QRS-T angle calculation. These characteristics were investigated in long-term 12-lead Holter recordings of 523 healthy volunteers (259 females). Three different algorithmic methods for the angle computation were based on maximal vector magnitude of QRS and T wave loops, areas under the QRS complex and T wave curvatures in orthogonal leads, and weighted integration of all QRS and T wave vectors moving around the respective 3-dimensional loops. These methods were applied to orthogonal leads derived either by a uniform conversion matrix or by singular value decomposition (SVD) of the original 12-lead ECG, giving 6 possible ways of expressing the angle. Heart rate hysteresis was assessed using the exponential decay models. All these methods were used to measure the angle in 659,313 representative waveforms of individual 10-s ECG samples and in 7,350,733 individual beats contained in the same 10-s samples. With all measurement methods, the measured angles fitted second-degree polynomial regressions to the underlying heart rate. Independent of the measurement method, the angles were found significantly narrower in females (p < 0.00001) with the differences to males between 10o and 20o, suggesting that in future risk-assessment studies, different angle dichotomies are needed for both sexes. The integrative method combined with SVD leads showed the highest intra-subject reproducibility (p < 0.00001). No reproducible delay between heart rate changes and QRS-T angle changes was found. This was interpreted as a suggestion that the measurement of QRS-T angle might offer direct assessment of cardiac autonomic responsiveness at the ventricular level.

Neutralizing-antibody response to SARS-CoV-2 for 12 months after the COVID-19 workplace outbreaks in Japan.

This study aimed to elucidate the 12-month durability of neutralizing antibodies (NAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients infected during the 2020 workplace outbreaks of coronavirus disease 2019 (COVID-19) in Japan. We followed 33 Japanese patients infected with SARS-CoV-2 in April 2020 for 12 months (12M). Patients were tested for NAbs and for antibodies against the SARS-CoV-2 nucleocapsid (anti-NC-Ab) and antibodies against the spike receptor-binding domain (anti-RBD-Ab). Tests were performed at 2M, 6M, and 12M after the primary infection (api) with commercially available test kits. In 90.9% (30/33) of patients, NAbs persisted for 12M api, though the median titers significantly declined from 78.7% (interquartile range [IQR]: 73.0-85.0%) at 2M, to 59.8% (IQR: 51.2-77.9) at 6M (P = 0.008), and to 56.2% (IQR: 39.6-74.4) at 12M (P<0.001). An exponential decay model showed that the NAb level reached undetectable concentrations at 35.5 months api (95% confidence interval: 26.5-48.0 months). Additionally, NAb titers were significantly related to anti-RBD-Ab titers (rho = 0.736, P<0.001), but not to anti-NC-Ab titers. In most patients convalescing from COVID-19, NAbs persisted for 12M api. This result suggested that patients need a booster vaccination within one year api, even though NAbs could be detected for over two years api. Anti-RBD-Ab titers could be used as a surrogate marker for predicting residual NAb levels.

Synthesis of Highly Active Doped Graphitic Carbon Nitride using Acid‐Functionalized Precursors for Efficient Adsorption and Photodegradation of Endocrine‐Disrupting Compounds

AbstractA highly active non‐metallic doped bulk graphitic carbon nitride (g‐C3N4) was synthesized via acid‐functionalized melamine decomposition. Specifically, melamine was treated with acetic acid, sulfuric acid, and phosphoric acid to obtain oxygen, sulfur, and phosphorus‐doped g‐C3N4 derivatives. Sulfur‐doped g‐C3N4 exhibited remarkable photocatalytic activity to degrade two environmentally harmful hormones, 17β‐estradiol, and 17α‐ethinylestradiol, due to its narrow energy bandgap and high surface area. The hormones were removed entirely in 30–45 min by adsorption in the dark, followed by photodegradation under visible light (430 nm). Furthermore, the pseudo‐second‐order kinetic model fitted the adsorption kinetics well, and photocatalytic degradation followed the exponential decay model. LC–MS identified the intermediate products for the photodegradation of 17β‐estradiol (E2). This study provides a simple one‐step method to synthesize highly reactive metal‐free doped bulk g‐C3N4 photocatalysts to remove harmful water pollutants.

30. Influence of toggling on pullout force and screw diameter increase in spine fixation

<h3>BACKGROUND CONTEXT</h3> Pedicle screw fixation provides spinal stabilization and maintains normal vertebral motions in degenerative spondylolisthesis and scoliosis. Pedicle screw fixation requires several parameters to be optimized at the screw-bone interface to minimize clinical and biomechanical failure, including screw trajectory, bone density and screw sizing. Although prior studies have demonstrated screw loosening as an effect of toggling, they ultimately focus on the magnitude of the pullout force after cyclic loading rather than screw-bone interface throughout cycling. <h3>PURPOSE</h3> A stiffness decay model may help to better predict stability and investigate the effects of pedicle screw diameter to pedicle width ratio on overall screw stability following cyclic loading in the thoracolumbar spine. <h3>OUTCOME MEASURES</h3> Pullout force, toggling forces, decay functions. <h3>METHODS</h3> Thoracolumbar vertebrae (T1-L5) were harvested from two cadaveric spines. Pedicle screws were placed using a standard surgical technique. Five-hundred cycles toggle testing was conducted with a uniaxial load frame followed by axial pullout tests. Exponential decay models with a stiffness coefficient were computed to examine toggling force over the number of toggle cycles for each screw. Linear regression modeling and Pearson's correlation tests were used to compare the decay coefficient with the ratio of the screw diameter to the pedicle diameter, the pullout strength, and pedicle loosening. Subgroup analysis was performed between under-sized (70% pedicle diameter) screws. <h3>RESULTS</h3> Sixty-eight pedicles were harvested. Of the 44 viable pedicles, 33 (75%) were from the thoracic spine and 11 (25%) were from the lumbar spine. There were 23 pedicle screws in the undersized group and 21 pedicle screws in the normal-sized group. The average screw diameter was 53% (SD 5%) of the pedicle diameter in the undersized group and 77% (SD 8%) of the pedicle diameter in the normal-sized group (p < 0.001). A significant association was found between the screw to pedicle diameter ratio and the natural log of the stiffness decay coefficient (p = 0.035). The average pullout force was 170 N (SD 75) in the under-sized pedicle group and 194 N (SD 109) in the normal-sized group (p=0.40). Higher pullout force was associated with a lower stiffness decay coefficient (p = 0.005). Both pullout force and the natural log of the stiffness decay coefficients were associated with the drop in maximum toggling force after 500 cycles (p = 0.026 and p < 0.001, respectively). Utilizing the stiffness decay coefficient provided a better fit model for the predicted drop in maximum toggling force with a lower Akaike information criterion. <h3>CONCLUSIONS</h3> Pedicle screws with a high stiffness decay coefficient during toggle testing had lower pullout strengths. While higher pedicle screw to bone diameter ratios were associated with increased stiffness decay coefficient, there was no relationship between pedicle screw size and pullout strength. In subgroup analysis, however, increasing pedicle screw to bone diameter ratios were associated with lower pullout strength in the normal-sized group. Clinically, selecting a screw size that maximizes the pedicle diameter-screw ratio may not always lead to better fixation in all spine levels or regions. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Dynamic Behaviors of Newly Deposited Atmospheric Heavy Metals in the Soil-Pak Choi System.

Dynamic behaviors of the newly deposited atmospheric heavy metals in the soil-pak choi (Brassica chinensis L.) system are investigated by a fully factorial atmospheric exposure experiment using soils exposed to 0.5-year and 1.5-year atmospheric depositions. The results showed approximately 17-87%, 19-64%, and 43-84% of the Cu, Cd, and Pb in pak choi edible parts were contributed from the new depositions, respectively. For the newly deposited metals, foliar uptake was the key pathway of shoot bioaccumulation rather than from root uptake of the deposited metals in soils, resulting in no significant soil contribution differences between pak chois growing in 0.5-year and 1.5-year exposed soils. Indeed, highly bioavailable metals in atmospheric deposition significantly increased the soil plant-bioavailable Cu, Cd, and Pb fractions; however, soil aging resulted in similar percentages of the plant-bioavailable fractions in 0.5-year and 1.5-year exposed soils, which indicated the bioavailability of metals deposited into soils rapidly decreased with aging. The soil aging process of the deposited metals was well fitted with the first-order exponential decay model, and soil organic matter and clay were the major driving factors. Our findings highlight high plant bioaccumulation rates and the rapid soil aging process of newly deposited metals during the plant growth period.

Microbial cultivation using mathematical representations accounting for the reaction kinetics in two-stage nitritation/ANAMMOX process

Mathematical representations accounting for the reaction kinetics were used to improve the cultivation rate of ANAMMOX microorganisms in the pilot-scale partial nitritation (PN)/anaerobic ammonium oxidation (ANAMMOX) reactor. In line with the fluctuations in the properties of raw reject water, control strategies of the hydraulic retention time (HRT) and the mixed liquid suspended solid (MLSS) concentration calculated by the mass balance-based model were proposed to improve PN performance. As a result, control of the MLSS concentration to cope with the fluctuation of C/N ratio resulted in a higher nitrite production rate (NPR) that was suitable for enhancing the cultivation rate of the ANAMMOX microorganisms. Based on the performance in the optimized PN, the observed yield of ANAMMOX microorganisms was calculated to be 0.091 gVSS/gNH4+−N. The biomass as volatile suspended solids (VSS) wasted was 309.8–554.3 gVSS/d. Based on the reaction kinetics of ANAMMOX, the quantity of stored microorganisms over time was simulated using a modified first-order exponential decay model; the calculated value was 6.3–11.2 kg/m3/year. These results can be used for the scale-up or design of the ANAMMOX process.

RSEDM: A New Rotational-Scan Exponential Decay Model for Extracting the Surface Urban Heat Island Footprint

Surface urban heat islands are widely focused on due to their close relationship with a series of environmental issues. Obtaining a precise footprint is an important prerequisite for heat island research. However, the land surface temperature curves used for calculating footprint are affected by factors such as the complexity of land-use types, thereby affecting the accuracy of footprint. Therefore, the rotational-scan exponential decay model is developed in this paper, which first takes the gravity center of an urban area as the origin of polar coordinates, specifies due north as the starting direction, and rotationally scans the suburbs that are within 20 km outside urban areas in a clockwise direction at an angle of 1°. The eligible suburbs are screened out according to the built-up area rate, water body rate, and merge tolerance. Then, exponential decay fitting of the temperature curve is performed to obtain the extension distance of the heat island and the background temperature, which are used to determine the final footprint. Based on the method, the footprints of 15 cities were calculated and compared with those of the traditional method. The results show that: (1) this method could effectively eliminate the influence of a large number of contiguous built-up areas and water bodies in the suburbs on the footprint calculation, thus greatly improving the accuracy of the temperature curve and footprint. (2) Three of four cities had the largest footprint boundary in spring. All four cities had the strongest heat island intensity in summer and the smallest footprint boundary and intensity in winter. (3) Coupling effect would aggravate the negative impact of heat islands in the suburbs and threaten the suburban environment. As a state-of-the-art method, it can enhance the calculation accuracy and precisely reflect the spatial pattern of footprint, which is of great significance for the sustainable development of cities.

The influence of postscreening follow-up time and participant characteristics on estimates of overdiagnosis from lung cancer screening trials.

We aimed to explore the underlying reasons that estimates of overdiagnosis vary across and within low-dose computed tomography (LDCT) lung cancer screening trials. We conducted a systematic review to identify estimates of overdiagnosis from randomised controlled trials of LDCT screening. We then analysed the association of Ps (the excess incidence of lung cancer as a proportion of screen-detected cases) with postscreening follow-up time using a linear random effects meta-regression model. Separately, we analysed annual Ps estimates from the US National Lung Screening Trial (NLST) and German Lung Cancer Screening Intervention Trial (LUSI) using exponential decay models with asymptotes. We conducted stratified analyses to investigate participant characteristics associated with Ps using the extended follow-up data from NLST. Among 12 overdiagnosis estimates from 8 trials, the postscreening follow-up ranged from 3.8 to 9.3 years, and Ps ranged from -27.0% (ITALUNG, 8.3 years follow-up) to 67.2% (DLCST, 5.0 years follow-up). Across trials, 39.1% of the variation in Ps was explained by postscreening follow-up time. The annual changes in Ps were -3.5% and -3.9% in the NLST and LUSI trials, respectively. Ps was predicted to plateau at 2.2% for NLST and 9.2% for LUSI with hypothetical infinite follow-up. In NLST, Ps increased with age from -14.9% (55-59 years) to 21.7% (70-74 years), and time trends in Ps varied by histological type. The findings suggest that differences in postscreening follow-up time partially explain variation in overdiagnosis estimates across lung cancer screening trials. Estimates of overdiagnosis should be interpreted in the context of postscreening follow-up and population characteristics.

Enhanced orange persistence in Sr3Al2O5Cl2:Eu2+, Dy3+ phosphor by Mg2+ substitution in Sr2+lattice site

The initial intensity and afterglow duration of existing long-wavelength persistent phosphors are insufficient for practical applications. Herein, the afterglow of orange-emitting Sr 3 Al 2 O 5 Cl 2 :Eu 2+ , Dy 3+ phosphors are enhanced by co-doping with Mg 2+ using the conventional solid-state reaction. Rietveld refinement for the prepared phosphor revealed that all Eu 2+ cations were placed on the Sr 2+ sites, whereas Dy 3+ occupancy in the lattice was improved by incorporating Mg 2+ . All phosphor samples with different Mg 2+ concentrations emit 609-nm-centred orange luminescence caused by the 5d→4f transition of Eu 2+ . The photoluminescence was significantly enhanced with the increase in the Mg 2+ doping due to the increased amount of divalent Eu 2+ in the samples, as confirmed by the X-ray photoelectron spectroscopy investigation. Incorporating Mg 2+ also enhanced the afterglow performance by creating suitable electron traps in the phosphor. The afterglow profiles were simulated by a double exponential decay model, and the results revealed that significant improvement in the afterglow lifetime was achieved for the 0.3 Mg 2+ -doped phosphors. Also, Mg 2+ introduction resulted in a deeper trap level (∼0.72 eV) and an increased trap concentration. Consequently, the Mg 2+ -doped exhibits brighter initial photoluminescence and longer afterglow. • Sr 3−x Mg x O 5 Cl 2 :Eu 2+ , Dy 3+ phosphor exhibits orange emission at 609 nm. • The photoluminescence is improved due to the increased Eu 2+ content after Mg 2+ doping. • Enhanced afterglow is observed after the incorporation of Mg 2+ cations. • The improved afterglow is caused by the increased trap concentration and modified trap depth.