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Biological specimens suffer radiation damage when imaged in an electron microscope, ultimately limiting the attainable resolution. At a given resolution, an optimal exposure can be defined that maximizes the signal-to-noise ratio in the image. Using a 2.6 Å resolution single particle cryo-EM reconstruction of rotavirus VP6, determined from movies recorded with a total exposure of 100 electrons/Å2, we obtained accurate measurements of optimal exposure values over a wide range of resolutions. At low and intermediate resolutions, our measured values are considerably higher than obtained previously for crystalline specimens, indicating that both images and movies should be collected with higher exposures than are generally used. We demonstrate a method of using our optimal exposure values to filter movie frames, yielding images with improved contrast that lead to higher resolution reconstructions. This ‘high-exposure’ technique should benefit cryo-EM work on all types of samples, especially those of relatively low-molecular mass. Microscopes allow us to visualize objects that are invisible to the naked eye. One type of microscope—called the electron microscope—produces images using beams of particles known as electrons, which enables them to produce more detailed images than microscopes that use light. There are several ways to prepare samples for electron microscopy. For example, in ‘electron cryo-microscopy’—or cryo-EM for short—a sample is rapidly frozen to preserve its features before it is examined under the microscope. This technique generates images that can be analyzed by computers to produce three-dimensional models of individual viruses, proteins, and other tiny objects. Unfortunately, the samples need to be exposed to high-energy beams of electrons that will damage the sample while the images are gathered, which results in sample movement and blurry images that lack the finer details. The contrast between the sample and its background is one of the factors that determine the final quality of an image. The higher the contrast, the greater the level of structural information that can be obtained, but this requires the use of longer exposures to the electron beam. To overcome this issue, researchers found that instead of recording a single image, it is possible to record movies in which the movement of the sample under the electron beam can be tracked. After the movies are gathered, the movie frames are aligned using computer software to reduce the blurring caused by the sample moving and can then be used to make three-dimensional models. Grant and Grigorieff improved this method further by studying how quickly a large virus-like particle called ‘rotavirus double-layered particle’ is damaged under the electron beam. These experiments identified an optimum range of exposure to electrons that provides the highest image contrast at any given level of detail. These findings were used to design an exposure filter that can be applied to the movie frames, allowing Grant and Grigorieff to visualize features of the virus that had not previously been observed by cryo-EM. This method was also used to study an assembly of proteins known as the proteasome, which is responsible for destroying old proteins. Grant and Grigorieff's findings should be useful for cryo-EM studies on many kinds of samples.

Industrial metrology and inspection systems commonly rely on phase measurement profilometry (PMP) using sinusoidal fringe patterns projecting, yielding dense, and accurate 3D reconstruction regardless of the presence of texture. However, applying PMP method to industrial 3D inspection is still a big challenging problem due to rigorous industrial measurement conditions including large surface reflectivity variation range and vibration. Aiming to solve these problems, an enhanced phase measurement profilometry (EPMP) is proposed. In EPMP, an optimal exposure time (OET) calibration method is proposed to solve large surface reflectivity variation range problem, and it can avoid saturating the camera sensor in areas of specular reflection while keep the signal-to-noise ratio (SNR) of fringe image in areas of weak reflection at most. To resist the influence of vibration, an improved pose calibration method (IPC) is used to allow fast calibration of pose of cameras by acquiring only one image of planar target. Moreover, an automatic online 3D inspection system for evaluating 3D geometric dimension quality of railway truck adapter (RTA) is developed, and according to the experiments, the EPMP indicates a satisfactory result in accuracy and repeatability, which can meet the requirements of the 3D inspection task in industrial measurement conditions.

To solve the problem of low accuracy in automatic concrete crack image segmentation and the non-standardization of concrete crack image datasets, an exposure-based concrete crack image capture scene characterization method was proposed, and the optimal exposure interval for crack segmentation was presented by multiple scene image capture experiments. First, current public crack datasets were collected and analyzed, and it was shown that improper spatial resolution, mislabeling, overexposure, and defocus are frequent non-standardization problems in crack dataset production. Through the analysis of the photoelectric principle in concrete crack imaging, an equivalent exposure was set as a core indicator for scene characterization. Twenty-one indoor scenes were designed by varying the illumination intensity and exposure time, and the experimental results showed that an equivalent exposure can be a core control index for scene characterization. The grayscale distribution law of concrete crack images was analyzed with four specimens’ images captured indoors in 50 exposure scenes, and the segmentation accuracy of an image from each scene was calculated through comparison with corresponding manually labeled binary files. The experiment’s results revealed that 5~50 lx·s was the optimal equivalent exposure interval for concrete crack image segmentation, in which better segmentation accuracy was achieved with an F1 score of up to 96.3%.

Two problems appear to be most topical in conjunction with mortgage valuation practices during an economic crisis: the assessment of sustainable long-term mortgage values and the assessment of liquidation discounts to prevailing market values which would provide for the most advantageous liquidation/quick sale strategy. This paper addresses the latter issue, which has traditionally proven intractable to analytical modeling. Apart from reviewing some research devoted to the subject of liquidation value modeling, predominantly from the Eastern European perspective, where this issue has, for years, commanded a particular economic interest, this paper synthesizes the best features of this research and builds on it to propose its own model, which lays equal emphasis on both the sellerside and demand-side perspectives. The first perspective accounts for the financial interests of a lender in forced sale disposals, while the latter perspective engages economic analysis on the side of market feasibility of identified efficient lender disposal strategies. By negotiating both perspectives, an optimal analytic solution to the issue of liquidation value discounts can be obtained. This is achieved by what we call a SI-MI framework which is developed throughout the paper.We also adapt this framework specifically to the mortgage banking context where we use it to bring to light some rarely discussed linkages between the LTV policies of a bank and its mortgage liquidation strategies. This also allows us to propose a model and an LTV formula which can help organize thinking about optimal LTV policies in credit issuing processes.We hope that, with the re-appearance of liquidation value basis/premise of valuation as a recognized international basis of valuation in the new edition of the International Valuation Standards (IVS 2017), the findings of this paper will become topical.

The purpose of this study was to determine the optimal electrocardiographic (ECG) pulsing windows and evaluate the effect on reduced dose and accuracy using 320-detector rows dynamic volume computed tomography (DVCT). A total of 170 patients were prospectively studied. The optimal reconstruction windows were analyzed in 76 patients scanned using retrospective ECG gating. Forty-seven patients were scanned by the predicted triggering windows. The optimal positions of exposure intervals according to different heart rates were evaluated. Optimal image quality, radiation dose, and diagnostic accuracy were then investigated by applying optimal triggering windows. The optimal ECG pulsing windows were determined as follows: when heart rate was <70 beats per minute, the exposure windows should be preset at 60%–80%; for a heart rate 70–90 beats per minute at 70%–90%; and for a heart rate ≥90 beats per minute at 30%–50%. The radiation dose for patients scanned with prospective ECG gating was significantly lower (5.9 versus 12.9 mSv, P < 0.001). However, because two or three heart beats were needed when heart rate was >70 beats per minute, the radiation dose increased with increasing heart rate for both retrospective and prospective ECG gating (r = 0.64, P < 0.001 and r = 0.59, P < 0.001, respectively). On the basis of a per segment analysis, overall sensitivity was 98.0% (49/50), specificity was 99.2% (602/607), the positive predictive value was 90.7% (49/54), and the negative predictive value was 99.8% (602/603). In conclusion, DVCT has the potential to provide high image quality across a wide range of heart rates using an optimized ECG pulsing window. However, it is recommended to control heart rate below 70 beats per minute, if possible, to decrease the radiation dose.

This chapter examines the risk limit policy proposed by ALCO for A/L managers. This policy ensures that the gross economic capital does not go beyond a certain amount; the interest rate gap has to be in a specified tunnel; and the interest rate income sensitivities have to be in a specified tunnel. Some companies compute their economic capital limits using a model. The idea is to set a confidence interval around the risk taking optimal strategy. The economic capital benchmark represents the optimal strategy risk exposure. Nevertheless, this optimum is known with incertitude. Nowadays, this indicator is criticized because it is possible to build arbitrage strategy with it. Income smoothing strategies may affect the sensitivity computations! Income sensitivities limits should take into account the smoothing strategies' possible impact on the indicator.

Air pollution may be associated with elevated dementia risk. Prior research has limitations that may affect reliability, and no studies have evaluated this question in a population-based cohort of men and women in the United States. We evaluated the association between time-varying, 10-y average fine particulate matter ( ) exposure and hazard of all-cause dementia. An additional goal was to understand how to adequately control for age and calendar-time-related confounding through choice of the time axis and covariate adjustment. Using the Adult Changes in Thought (ACT) population-based prospective cohort study in Seattle, we linked spatiotemporal model-based exposures to participant addresses from 1978 to 2018. Dementia diagnoses were made using high-quality, standardized, consensus-based protocols at biennial follow-ups. We conducted multivariable Cox proportional hazards regression to evaluate the association between time-varying, 10-y average exposure and time to event in a model with age as the time axis, stratified by apolipoprotein E (APOE) genotype, and adjusted for sex, education, race, neighborhood median household income, and calendar time. Alternative models used calendar time as the time axis. We report 1,136 cases of incident dementia among 4,166 individuals with nonmissing APOE status. Mean [mean ± standard deviation (SD)] 10-y average was . Each increase in the moving average of 10-y was associated with a 16% greater hazard of all-cause dementia [1.16 (95% confidence interval: 1.03, 1.31)]. Results using calendar time as the time axis were similar. In this prospective cohort study with extensive exposure data and consensus-based outcome ascertainment, elevated long-term exposure to was associated with increased hazard of all-cause dementia. We found that optimal control of age and time confounding could be achieved through use of either age or calendar time as the time axis in our study. Our results strengthen evidence on the neurodegenerative effects of . https://doi.org/10.1289/EHP9018.

Understanding the transmission dynamics of rabies among dogs is crucial for designing effective control strategies in endemic regions. In this study, we developed and analyzed two deterministic compartmental models. The SEI model captures the natural progression of rabies in the absence of intervention, while the SEIV model incorporates vaccination through pre‐exposure prophylaxis (PrEP) for susceptible dogs and post‐exposure prophylaxis (PEP) for exposed dogs. Analytical derivation of the basic reproduction number and stability analysis of disease‐free and endemic equilibria (EE) were performed. Numerical simulations demonstrated that vaccination substantially reduces infection levels, with PrEP emerging as the dominant factor in controlling transmission. Vaccination thresholds indicate that coverage above 56% for combined PrEP and PEP at equal rates, or above 62% coverage of PrEP together with 30% or more coverage of PEP, or PrEP alone exceeding 70%, is sufficient to eliminate rabies in the dog population of Dhaka City, Bangladesh. Extending the SEIV model into an optimal control framework further revealed that time‐dependent PrEP strategies effectively minimize infection, whereas PEP alone with feasible coverage is insufficient to eradicate the disease. Moreover, the cost‐effectiveness analysis reveals that the only PrEP implementation is the most cost‐effective strategy for vaccination‐dependent (PrEP and PEP) suppression of dog rabies transmission. These findings highlight the critical role of vaccination, particularly PrEP, in achieving rabies elimination and support national and global efforts to end dog‐mediated human rabies deaths by 2030.

Objectives Most studies on SpO 2 exposure patterns focus solely on SpO 2 intensity and neglect exposure duration. We systematically investigated the associations between SpO 2 exposure patterns and clinical outcomes from both intensity and temporal dimensions in critically ill patients. Methods In this retrospective cohort study, 121,758 critically ill patients were analyzed. The patient data were obtained from three databases: SICdb ( n  = 11,324) for continuous exposure analysis using heatmaps, MIMIC-IV ( n  = 50,110) for cumulative exposure analysis, and eICU ( n  = 60,324) for validation. We examined the relationships between SpO 2 exposure and 28-day mortality using Cox regression and logistic regression models. Restricted cubic spline analysis was performed using time-weighted SpO 2 as a continuous variable to examine the continuous association between SpO 2 values and mortality risk. Results Both analytical approaches revealed a U-shaped relationship between SpO 2 and mortality. Heatmap analysis revealed a SpO 2 of 93.5–97% as optimal, whereas Cox regression showed that a SpO 2 of 96–97% conferred the strongest protection (HR 0.714, 95% CI 0.694–0.733; P  < 0.001). Prolonged exposure to SpO 2  > 98% had a diminishing effect, whereas SpO 2  < 93.5% increased mortality risk (HR 1.236, P  < 0.001). External validation confirmed these findings (AUC 0.813). Conclusions Our study confirms a U-shaped relationship between SpO 2 and outcomes, emphasizing that oxygenation assessments should consider both intensity and duration. A prolonged SpO 2 above 98% or below 94% should be avoided in critically ill patients.

Objectives This prospective birth cohort study evaluated the effect of occupational exposure to endocrine disrupting chemicals (EDC) during pregnancy on inadequate fetal growth as measured by small-for-gestational age (SGA) and inadequate fetal growth measured by percentage of optimal birth weight (POBW). The study also identified the maternal characteristics associated with an increased risk of exposure to EDC. Methods We studied 4142 pregnant women who were in paid employment during pregnancy and participated in a population-based, prospective 2007-2011 birth cohort study, the Born in Bradford Study, with an estimated participation of 80%. Job titles were coded at 26-28 weeks` gestation at a 4-digit level according to 353 unit groups in the 2000 UK Standard Occupational Classification. They were then linked to expert judgment on exposure to each of ten EDC groups as assessed through a job exposure matrix (JEM). We performed generalized estimation equation modelling by a modified Poisson regression to assess the risk of POBW and SGA associated with an increased risk of chemical exposures. Results The frequency of POBW<85 significantly increased for mothers exposed to pesticides [adjusted risk ratio (RRadj) 3.72, 95% confidence interval (CI) 1.40-9.91] and phthalates (RRadj 3.71, 95% CI 1.62-8.51). There was a 5-fold increase risk of SGA for mothers exposed to pesticides (RRadj 5.45, 95% CI 1.59-18.62). Veterinary nurses and horticultural trades were most frequently associated with exposure to pesticides while hairdressers, beauticians, and printing machine minders were associated with phthalates. Conclusion Maternal occupational exposure to estimated concentrations of pesticides and phthalates is associated with impaired fetal growth.