Alterations of resting-state functional network connectivity in patients with noise-induced hearing loss: A study based on independent component analysis.

Functional reorganization is a response to auditory deficits or deprivation, and less is known about the overall brain network alterations involving resting-state networks (RSNs) and multiple functional networks in patients with occupational noise-induced hearing loss (NIHL). So this study evaluated resting-state functional network connectivity (FNC) alterations in occupational NIHL using an independent component analysis (ICA). In total, 79 mild NIHL patients (MP), 32 relatively severe NIHL patients (RSP), and 84 age- and education- matched healthy controls (HC) were recruited. All subjects were tested using the Mini-mental State Examination scale, the tinnitus Handicap Inventory scale, the Hamilton Anxiety scale (HAMA) and scanned by T1-3DFSPGR, resting-state functional magnetic resonance imaging sequence in 3.0 T and analysed by the ICA. Seven RSNs were identified, compared with the HC, the MP showed increased FNC within the executive control network (ECN) and enhanced FNC within the default mode network (DMN) and the visual network (VN); compared with the HC, the RSP showed decreased FNC within the ECN and auditory network (AUN), DMN and VN; no significant changes in FNC were found in the MP compared with the RSP. Furthermore, the correlation analysis between the noise exposure time and hearing loss level, HAMA were both negative, and there were no significant correlations between the abnormal RSNs and the hearing level, noise exposure time and HAMA. These findings indicate that different degrees of NIHL involve different alterations in RSNs connectivity and may reveal the neural mechanisms related to emotion-related features and functional abnormalities following long-term NIHL.

Cluster randomized trial designs for modeling time-varying intervention effects.

Stepped-wedge cluster randomized trials (SW-CRTs) are typically analyzed assuming a constant intervention effect. In practice, the intervention effect may vary as a function of exposure time, leading to biased results. The estimation of time-on-intervention (TOI) effects specifies separate discrete intervention effects for each elapsed period of exposure time since the intervention was first introduced. It has been demonstrated to produce results with minimum bias and nominal coverage probabilities in the analysis of SW-CRTs. Due to the design's staggered crossover, TOI effect variances are heteroskedastic in a SW-CRT. Accordingly, we hypothesize that alternative CRT designs will be more efficient at modeling certain TOI effects. We derive and compare the variance estimators of TOI effects between a SW-CRT, parallel CRT (P-CRT), parallel CRT with baseline (PB-CRT), and novel parallel CRT with baseline and an all-exposed period (PBAE-CRT). We also prove that the time-averaged TOI effect variance and point estimators are identical to that of the constant intervention effect in both P-CRTs and PB-CRTs. We then use data collected from a hospital disinvestment study to simulate and compare the differences in TOI effect estimates between the different CRT designs. Our results reveal that the SW-CRT has the most efficient estimator for the early TOI effect, whereas the PB-CRT typically has the most efficient estimator for the long-term and time-averaged TOI effects. Overall, the PB-CRT with TOI effects can be a more appropriate choice of CRT design for modeling intervention effects that vary by exposure time.

Influence of Oxygen Exposure on Lignin Preservation during Sediment Lateral Transport in the Ocean: Insights from Molecular Dynamics Simulations.

Understanding the fate of terrestrial organic carbon (terrOC) preservation in the marine environments is critical for deciphering the biogeochemical processes associated with the global carbon cycle and the Earth's climate change. The mechanisms controlling terrOC preservation are not completely understood, while lateral oxygen exposure time (OET) is considered as a critical controlling factor. Here, we first utilized molecular dynamics simulations to investigate the structural properties of lignin under anoxic, suboxic, and oxic conditions for understanding the mechanisms of terrOC preservation during sediment lateral transport in the ocean. Our finding suggested that oxygen exposure was indispensable for terrOC degradation through influencing the structural stability and reactivity of lignin. Our simulated results showed that in suboxic environments, prolonged OET may enhance terrOC preservation. Our organic geochemical results suggested that terrOC preferably preserved in coarse silts (20-63 µm) than fine silts (<20 µm) in suboxic environments, largely due to hydrodynamics-driven prolonged OET in coarse sediments, which may efficiently reduce CO2 emissions. Overall, our study sheds new light on the mechanisms of lateral OETs on terrOC preservation in suboxic conditions and, from a unique molecular structural perspective, provides insights into the impact of prolonged OETs on terrOC oxidative degradation in the marine environment.

A prediction model of abnormal acid reflux in gastroesophageal reflux disease.

BACKGROUND AND AIM: The measurement of esophageal acid exposure time (AET) using combined multichannel intraluminal impedance-pH (MII-pH) tests is the gold standard for diagnosing gastroesophageal reflux disease (GERD). However, this catheter-based 24-h test can cause considerable patient discomfort. Our aim is to identify factors affecting AET and to develop a scoring model for predicting AET abnormalities before conducting the MII-pH test. METHODS: Of the 366 patients who underwent MII-pH test at two facilities in Japan and Vietnam, 255 patients who also had esophagogastroduodenoscopy and high-resolution manometry were included in this study. Logistic regression analysis was conducted using risk factors for AET > 6% identified from a derivation cohort (n = 109). A scoring system predicting AET > 6% was then constructed and externally validated with a separate cohort (n = 146). RESULTS: Three variables were derived from the prediction model: male gender, Hill grades III-IV, and weak mean distal contractile integrals. Based on these scores, patients were classified into low (0 point), intermediate (1-3 points), and high (4 points) risk groups. The probabilities of having an AET > 6% were 6%, 34%, and 100% for these groups, respectively. A score of < 1 excluded patients with abnormal AET, with a negative predictive value of 93.8% in the derivation cohort and 80.0% in the validation cohort. CONCLUSIONS: We derived and externally validated a prediction model for abnormal AET. This system could assist in guiding the appropriate treatment strategies for GERD.

Long-term disease-specific quality of life after laparoscopic Nissen fundoplication in patients with borderline GERD.

BACKGROUND: Historically, DeMeester score over 14.7 has been used to diagnose GERD. The 2022 American Gastroenterological Association clinical guidelines define GERD based on acid exposure time (AET) instead of DeMeester score. We aim to compare outcomes after laparoscopic Nissen fundoplication (LNF) in patients based on differing GERD diagnostic criteria. METHODS: Patients who underwent first-time LNF between 2009 and 2017 were identified. Demographics, objective GERD evaluation, and outcomes were maintained in an IRB-approved database. Disease-specific quality of life was assessed with a survey (GERD-HRQL) with higher values representing more symptomatic disease. Descriptive statistics, Fischer's exact test and logistic regression were used to analyze the data, p-value < 0.05. RESULTS: 225 patients were stratified into two groups: borderline GERD (AET 4-6%, n = 25.11%) and GERD (AET ≥ 6%, n = 200.89%). The mean age was 50.1 ± 13.4 years and 169 (75%) were female. Baseline GERD-HRQL was lower in the borderline group (24.3 vs 30.0, p = 0.031). Short-term (5 weeks [IQR 4, 8]), medium-term (14 months [IQR 7.25, 31]) and long-term (6.75 years [IQR 5.5, 8]) follow-up was performed. GERD-HRQL scores did not differ between borderline and GERD patients at short-(6.0 vs 7.1, p = 0.630), medium-(12.0 vs 12.1, p = 0.818), or long-term follow-up (10.0 vs 9.0, p = 0.757). The absolute long-term improvement in GERD-HRQL was -12.3 (p = 0.022) vs. -21.3 (p < 0.001). At long-term follow-up there was no difference in PPI use (50% vs 47%, p = 0.852), satisfaction (58% vs 76%, p = 0.187), willingness to repeat the procedure given the benefit of hindsight (75% vs 85%, p = 0.386), or need for reoperation (14% vs 13%, p = 0.910). CONCLUSION: Both patients with borderline GERD and GERD achieve GERD-HRQL improvements at 7 years following laparoscopic Nissen fundoplication and demonstrate similar long-term PPI usage and satisfaction with surgical results. Borderline GERD patients have lower GERD-HRQL at baseline, and thus have smaller improvements in their QOL scores. Anti-reflux surgery should be considered for patients with a diagnosis of borderline GERD refractory to medical therapy.

Microplastics alter the equilibrium of plant-soil-microbial system: A meta-analysis.

Microplastics (MPs) are widely identified as emerging hazards causing considerable eco-toxicity in terrestrial ecosystems, but the impacts differ in different ecosystem functions among different chemical compositions, morphology, sizes, concentrations, and experiment duration. Given the close relationships and trade-offs between plant and soil systems, probing the "whole ecosystem" instead of individual functions must yield novel insights into MPs affecting terrestrial ecosystems. Here, a comprehensive meta-analysis was employed to reveal an unambiguous response of the plant-soil-microbial system to MPs. Results showed that in view of plant, soil, and microbial functions, the general response patterns of plant and soil functions to MPs were obviously opposite. For example, polyethylene (PE) and polyvinyl chloride (PVC) MPs highly increased plant functions, while posed negative effects on soil functions. Polystyrene (PS) and biodegradable (Bio) MPs decreased plant functions, while stimulating soil functions. Additionally, low-density polyethylene (LDPE), PE, PS, PVC, Bio, and granular MPs significantly decreased soil microbial functions. These results clearly revealed that MPs alter the equilibrium of the plant-soil-microbial system. More importantly, our results further revealed that MPs tended to increase ecosystem multifunctionality, e.g., LDPE and PVC MPs posed positive effects on ecosystem multifunctionality, PE, PS, and Bio MPs showed neutral effects on ecosystem multifunctionality. Linear regression analysis showed that under low MPs size (<100 µm), ecosystem multifunctionality was gradually reduced with the increased size of MPs. The response of ecosystem multifunctionality showed a concave shape pattern along the gradient of experimental duration which was lower than 70 days. More importantly, there was a threshold (i.e., 5% w/w) for the effects of MPs concentration on ecosystem multifunctionality, i.e., under low concentration (< 5% w/w), ecosystem multifunctionality was gradually increased with the increased concentration of MPs, while ecosystem multifunctionality was gradually decreased under high concentration (i.e., > 5% w/w). These findings emphasize the importance of studying the effects of MPs on plant-soil-microbial systems and help us identify ways to reduce the eco-toxicity of MPs and maintain environmental safety in view of an ecology perspective.

Associations between Serum 25-hydroxyvitamin D, Sun Exposure Time, Dietary Vitamin D Intake, and New-Onset Acute Kidney Injury among 413,169 UK Adults.

BACKGROUND: The prospective associations of serum 25(OH)D, sun exposure time, and dietary vitamin D with risk of acute kidney injury (AKI) are unclear. OBJECTIVES: We aimed to evaluate the relations of serum 25(OH)D, sun exposure time, and dietary vitamin D intake with new-onset AKI and examine whether genetic susceptibility modified such associations. METHODS: A total of 413,169 participants (mean age was 56.4 y, 47.2% were male) from UK Biobank without prior AKI were included. Sun exposure time was expressed as time spent outdoors. Genetic risk scores were calculated by 263 single nucleotide polymorphisms, which showed significant associations with the estimated glomerular filtration rate. The primary outcome was new-onset AKI. Cox proportional hazards models were used to estimate the HRs and (95% CIs). RESULTS: During a median follow-up duration of 12 y, 16,938 (4.1%) participates developed new-onset AKI. Compared with those with serum 25(OH)D <25 nmol/L, significantly lower risks of new-onset AKI were found between participants with 25(OH)D 25 to <50 nmol/L (adjusted HR: 0.76; 95% CI: 0.73, 0.80), and ≥50 nmol/L (adjusted HR: 0.69; 95% CI: 0.65, 0.72). Moreover, in summer, participants who spent ≥4 h outdoors per day (tertile 3) had a significantly lower risk of new-onset AKI (adjusted HR: 0.90; 95% CI: 0.86, 0.95) than those who spent <2 h outdoors per day (tertile 1). Similar results were found for time spent outdoors in winter. In addition, those in quintile 5 of dietary vitamin D intake showed a lower risk of new-onset AKI (≥4.2 µg/d, adjusted HR: 0.90; 95% CI: 0.82, 0.98) than those in quintile 1 (<1.0 µg/d). Genetic risks of kidney diseases did not significantly modify all the 3 above associations (all P-interactions >0.05). CONCLUSIONS: Serum 25(OH)D concentrations, time spent outdoors, and dietary vitamin D intake were all inversely associated with new-onset AKI, independent of genetic risks for kidney diseases.

Assessing exposure-time treatment effect heterogeneity in stepped-wedge cluster randomized trials.

A stepped-wedge cluster randomized trial (CRT) is a unidirectional crossover study in which timings of treatment initiation for clusters are randomized. Because the timing of treatment initiation is different for each cluster, an emerging question is whether the treatment effect depends on the exposure time, namely, the time duration since the initiation of treatment. Existing approaches for assessing exposure-time treatment effect heterogeneity either assume a parametric functional form of exposure time or model the exposure time as a categorical variable, in which case the number of parameters increases with the number of exposure-time periods, leading to a potential loss in efficiency. In this article, we propose a new model formulation for assessing treatment effect heterogeneity over exposure time. Rather than a categorical term for each level of exposure time, the proposed model includes a random effect to represent varying treatment effects by exposure time. This allows for pooling information across exposure-time periods and may result in more precise average and exposure-time-specific treatment effect estimates. In addition, we develop an accompanying permutation test for the variance component of the heterogeneous treatment effect parameters. We conduct simulation studies to compare the proposed model and permutation test to alternative methods to elucidate their finite-sample operating characteristics, and to generate practical guidance on model choices for assessing exposure-time treatment effect heterogeneity in stepped-wedge CRTs.

Estimation of the time of exposure based on interval and censored data using the ε-accelerated EM algorithm.

Accurately estimating the timing of pathogen exposure plays a crucial role in outbreak control for emerging infectious diseases, including the source identification, contact tracing, and vaccine research and development. However, since surveillance activities often collect data retrospectively after symptoms have appeared, obtaining accurate data on the timing of disease onset is difficult in practice and can involve "coarse" observations, such as interval or censored data. To address this challenge, we propose a novel likelihood function, tailored to coarsely observed data in rapid outbreak surveillance, along with an optimization method based on an ε $$ \varepsilon $$ -accelerated EM algorithm for faster convergence to find maximum likelihood estimates (MLEs). The covariance matrix of MLEs is also discussed using a nonparametric bootstrap approach. In terms of bias and mean-squared error, the performance of our proposed method is evaluated through extensive numerical experiments, as well as its application to a series of epidemiological surveillance focused on cases of mass food poisoning. The experiments show that our method exhibits less bias than conventional methods, providing greater efficiency across all scenarios.

Acid exposure time better predicts outcomes following anti-reflux surgery than DeMeester score.

BACKGROUND: Criteria to diagnose gastroesophageal reflux disease (GERD) vary. The American Gastroenterology Association (AGA) 2022 Expert Review on GERD focuses on acid exposure time (AET) rather than DeMeester score from ambulatory pH testing (BRAVO). We aim to review outcomes following anti-reflux surgery (ARS) at our institution, grouped by differing criteria for the diagnosis of GERD. METHODS: A retrospective review of a prospective gastroesophageal quality database was performed for all patients undergoing evaluation for ARS with preoperative BRAVO ≥ 48 h. Group comparisons were made using two-tailed Wilcoxon rank-sum and Fisher's exact tests and two-tailed statistical significance of p < 0.05. RESULTS: Between 2010 and 2022, 253 patients underwent an evaluation for ARS with BRAVO testing. Most patients (86.9%) met our institution's historical criteria: LA C/D esophagitis, Barrett's, or DeMeester ≥ 14.72 on 1+ days. Fewer patients (67.2%) met new AGA criteria: LA B/C/D esophagitis, Barrett's, or AET ≥ 6% on 2+ days. Sixty-one patients (24%) met historical criteria only, with significantly lower BMI, ASA, less hiatal hernias, and less DeMeester and AET-positive days, a less severe GERD phenotype. There were no differences between groups in perioperative outcomes or % symptom resolution. Objective GERD outcomes (need for dilation, esophagitis, and postop BRAVO) were equivalent between groups. Patient-reported quality of life scores, including GERD-HRQL, RSI, and Dysphagia Score did not differ between groups from preop through 1 year postop. Those who met our historical criteria only reported significantly worse RSI scores (p = 0.03) and worse GERD-HRQL scores at 2 years postop, though not statistically significant (p = 0.07). CONCLUSION: Updated AGA GERD guidelines exclude a portion of patients who historically would have been diagnosed with and surgically treated for GERD. This cohort appears to have a less severe GERD phenotype but equivalent outcomes up to 1 year, with more atypical GERD symptoms at 2 years postop. AET may better define who should be offered ARS than DeMeester score.

Sample Size Calculations for Stepped Wedge Designs with Treatment Effects that May Change with the Duration of Time under Intervention.

The stepped wedge design is often used to evaluate interventions as they are rolled out across schools, health clinics, communities, or other clusters. Most models used in the design and analysis of stepped wedge trials assume that the intervention effect is immediate and constant over time following implementation of the intervention (the "exposure time"). This is known as the IT (immediate treatment effect) assumption. However, recent research has shown that using methods based on the IT assumption when the treatment effect varies over exposure time can give extremely misleading results. In this manuscript, we discuss the need to carefully specify an appropriate measure of the treatment effect when the IT assumption is violated and we show how a stepped wedge trial can be powered when it is anticipated that the treatment effect will vary as a function of the exposure time. Specifically, we describe how to power a trial when the exposure time indicator (ETI) model of Kenny et al. (Statistics in Medicine, 41, 4311-4339, 2022) is used and the estimand of interest is a weighted average of the time-varying treatment effects. We apply these methods to the ADDRESS-BP trial, a type 3 hybrid implementation study designed to address racial disparities in health care by evaluating a practice-based implementation strategy to reduce hypertension in African American communities.

Value of pH Impedance Monitoring While on Twice-Daily Proton Pump Inhibitor Therapy to Identify Need for Escalation of Reflux Management.

BACKGROUND AND AIMS: Acid exposure time (AET) and reflux episode thresholds from the Lyon Consensus may not apply for pH impedance studies performed while on proton pump inhibitor (PPI) therapy. We aimed to determine metrics from "on PPI" pH impedance studies predicting need for escalation of therapy. METHODS: De-identified pH impedance studies performed while on twice-daily PPI (Diversatek, Boulder, CO) in healthy volunteers (n = 66, median age 37.5 years, 43.9% female), and patients with proven gastroesophageal reflux disease (GERD) (European heartburn-predominant cohort: n = 43, median age 57.0 years, 55.8% female; North American regurgitation-predominant cohort: n = 42, median age 41.6 years, 42.9% female) were analyzed. Median values and interquartile ranges for pH impedance metrics in healthy volunteers were compared with proven GERD patients with and without 50% symptom improvement on validated measures. Receiver operating characteristic (ROC) analyses identified optimal thresholds predicting symptom response. RESULTS: Both conventional and novel reflux metrics were similar between PPI responders and nonresponders (P ≥ .1 for each) despite differences from healthy volunteers. Combinations of metrics associated with conclusively abnormal reflux burden (AET >4%, >80 reflux episodes) were seen in 32.6% and 40.5% of heartburn and regurgitation-predominant patients, respectively, 57.1% and 82.4% of whom reported nonresponse; and 85% with these metrics improved with invasive GERD management. On ROC analysis, AET threshold of 0.5% modestly predicted nonresponse (sensitivity, 0.62; specificity, 0.51; P = .22), and 40 reflux episodes had better performance characteristics (sensitivity, 0.80; specificity, 0.51; P = .002); 79% with these metrics improved with invasive GERD management. CONCLUSION: Combinations of abnormal "on PPI" pH impedance metrics are associated with PPI nonresponse in proven GERD patients, and can be targeted for treatment escalation, including surgery, particularly in regurgitation-predominant GERD.

Phenotyping patients with borderline elevated esophageal acid exposure.

Acid exposure time (AET) <4% on ambulatory reflux monitoring definitively rules out pathologic gastroesophageal acid reflux, while AET >6% indicates pathologic reflux per the Lyon Consensus, leaving AET of 4-6% as borderline. We aimed to elucidate the borderline AET population and identify metrics that could help differentiate this group. A total of 50 subjects in each group, AET <4, 4-6, and >6% on pH-impedance monitoring between 2015 and 2019, were retrospectively reviewed. In addition to demographic and clinical information, the extracted data included mean nocturnal baseline impedance (MNBI) on reflux study and high-resolution manometry (HRM) parameters and diagnosis. After excluding patients with prior foregut surgery, major esophageal motility disorder, or unreliable impedance testing, a total of 89 subjects were included in the analysis (25 with normal AET < 4%, 38 with borderline 4-6%, 26 with abnormal >6%). MNBI in borderline AET patients was significantly lower compared to normal AET (1607.7 vs. 2524.0 ohms, P < 0.01), and higher than abnormal AET (951.5 ohms, P < 0.01). Borderline subjects had a greater frequency of ineffective esophageal motility (IEM) diagnosis per Chicago classification v3.0 (42.1 vs. 8.0%, P = 0.01), but did not demonstrate any differences compared to abnormal subjects (34.6%, P = 0.56). Patients with borderline AET had an average MNBI that was in between normal AET and abnormal AET. Borderline AET patients also commonly demonstrate IEM on HRM, similar to those with abnormal AET. Our findings can be potentially useful in assigning higher clinical significance for patients found to have borderline AET with concomitant low MNBI and IEM on manometry.

The online learning experience and reported headaches associated with screen exposure time among Saudi health sciences students during the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic has become a global health issue and has significantly impacted university education. As a result, learning methods have been shifted to be delivered through online learning. Online learning has increased reliance on computer screens, which can cause visual discomfort and may cause or exacerbate headaches due to prolonged screen exposure. However, time spent using electronic devices has not yet been examined in relation to the online learning experience. PURPOSE: This study assessed the online learning experiences and reported headaches associated with screen exposure time among health sciences university students. METHODS: A cross-sectional study was conducted among a convenience sample of 353 students at Saudi University. Online learning experiences, screen time exposure, and reported headache questionnaires were used to collect the data. RESULTS: Students were moderately satisfied with the online learning experience. Nevertheless, they faced many challenges with online learning that affected their communication efficacy, and they preferred that blended learning be continued. In addition, this study found a high prevalence of headache (65.72%) and a high screen exposure time among the studied students (52.69%). Increased screen time exposure is linked with increased headache and migraine reporting among students (p < 0.05). CONCLUSION: Headache is a common health issue among health professional students, and it can harm their academic performance and quality of life, especially related to online learning. Greater awareness of headaches, stress reduction and prevention programs, and ergonomic practices to deal with headaches are essential. Blended learning approaches can improve student learning and performance in health science courses.

What Is the Duration of Irrigation? An In Vitro Study of the Minimum Exposure Time to Eradicate Bacteria With Irrigation Solutions.

BACKGROUND: Antiseptic irrigation solutions are commonly used by arthroplasty surgeons to reduce intraoperative bacterial colonization with the goal of reducing postoperative infections in the setting of primary total joint arthroplasty. Currently, the minimum irrigation time to eliminate common microbes implicated in periprosthetic joint infection is unknown. We sought to determine the minimum effective exposure time required to prevent growth of Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes with common antiseptic solutions. METHODS: S aureus, S epidermidis, and C acnes cultures were treated with povidone-iodine (0.35%), chlorhexidine (0.05%), sodium hypochlorite (0.5%), polyhexamethylene biguanide, and an acetic acid-based solution for 15, 30, 60, 90, and 120 seconds in triplicate. Bacterial growth was quantified using the drop plate method. Failure to eliminate all bacteria was considered "not effective" at that time point. RESULTS: Povidone-iodine 0.35% (Betadine), sodium hypochlorite 0.5% (HySept), and acetic acid (Bactisure) eradicated all bacterial growth after 90 seconds of treatment, and as low as 15 seconds in S aureus and C acnes (Betadine) or S epidermidis (Bactisure). Polyhexamethylene biguanide (Prontosan) required 90 seconds for elimination of S aureus and S epidermidis, and 120 seconds for C acnes. Chlorhexidine 0.05% (Irrisept) did eliminate S epidermidis at 120 seconds but did not effectively eradicate S aureus or C acnes. CONCLUSION: All tested antiseptic solutions demonstrated successful eradication of all bacterial growth in under 2 minutes of treatment time except chlorhexidine. Povidone-iodine may require the shortest duration of treatment time to successfully eradicate common bacteria.

Least-Square-Method-Based Optimal Laser Spots Acquisition and Position in Cooperative Target Measurement.

The relative positioning precisions of coordinate points is an important indicator that affects the final accuracy in the visual measurement system of space cooperative targets. Many factors, such as measurement methods, environmental conditions, data processing principles and equipment parameters, are supposed to influence the cooperative target's acquisition and determine the precision of the cooperative target's position in a ground simulation experiment with laser projected spots on parallel screens. To overcome the precision insufficiencies of cooperative target measurement, the factors of the laser diode supply current and charge couple device (CCD) camera exposure time are studied in this article. On the hypothesis of the optimal experimental conditions, the state equations under the image coordinates' system that describe the laser spot position's variation are established. The novel optimizing method is proposed by taking laser spot position as state variables, diode supply current and exposure time as controllable variables, calculating the optimal controllable variables through intersecting the focal spot centroid line and the 3-D surface, and avoiding the inconvenience of solving nonlinear equations. The experiment based on the new algorithm shows that the optimal solution can guarantee the focal spot's variation range in 5-10 pixels under image coordinates' system equivalent to the space with a 3 m distance and 0.6-1.2 mm positioning accuracy.

The Way to Modern Shutter Speed Measurement Methods: A Historical Overview.

Exposure time is a fundamental parameter for the photographer when the photo is composed, and the exact length of the exposure may be an essential determinant of performance in certain camera-based applications, e.g., optical camera communication (OCC) systems. There can be several reasons to measure the shutter speed of a camera: shutter speed may be checked at the time of manufacturing; it may be necessary to recheck in case of an elder camera model; it may be necessary to be measured if its exact value is not provided by the manufacturer; or a precise measurement may be necessary for a demanding application. In this paper various methods for shutter speed measurement are reviewed, presenting and analyzing methods that are still relevant today either for manufacturers, service personnel, amateur photographers, or the developers of camera-based systems. Each presented method is illustrated by real measurement results and the performance properties of the methods are also presented.

Investigating the cause of hemolysis in patients supported by a pulsatile ventricular assist device.

A survey conducted by Abiomed, Inc. revealed that 10 of 60 patients who received ventricular assistance via the AB5000 ventricular assist device (VAD) experienced hemolysis. The present study was conducted to investigate which factors influence hemolysis under pulsatile-flow VADs such as the AB5000. We compared the specificity of the AB5000 and its driving console with those of the NIPRO-VAD and VCT50χ under severe heart failure conditions using a mock circulatory system with a glycerol water solution. We used the mock circuit with bovine blood to confirm which pump conditions were most likely to cause hemolysis. In addition, we measured the shear velocity using particle image velocimetry by analyzing the seeding particle motion for both the AB5000 and NIPRO-VAD under the same conditions as those indicated in the initial experiment. Finally, we analyzed the correlation between negative pressure, exposure time, and hemolysis by continuously exposing fixed vacuum pressures for fixed times in a sealed device injected with bovine blood. Applying higher vacuum pressure to the AB5000 pump yielded a larger minimum inlet pressure and a longer exposure time when the negative pressure was under - 10 mmHg. The plasma-free hemoglobin increased as more negative pressure was driven into the AB5000 pump. Moreover, the negative pressure interacted with the exposure time, inducing hemolysis. This study revealed that negative pressure and exposure time were both associated with hemolysis.

Length of exposure to long working hours and night work and risk of sickness absence: a register-based cohort study.

BACKGROUND: There is inconsistent evidence that long working hours and night work are risk factors for sickness absence, but few studies have considered variation in the length of exposure time window as a potential source of mixed findings. We examined whether the association of long working hours and night work with sickness absence is dependent on the length of exposure to the working hour characteristics. METHODS: We analysed records of working hours, night work and sickness absence for a cohort of 9226 employees in one hospital district in Finland between 2008 and 2019. The exposure time windows ranged from 10 to 180 days, and we used Cox's proportional hazards models with time-dependent exposures to analyse the associations between working-hour characteristics and subsequent sickness absence. RESULTS: Longer working hours for a period of 10 to 30 days was not associated with the risk of sickness absence whereas longer working hours for a period of 40 to 180 days was associated with a lower risk of sickness absence. Irrespective of exposure time window, night work was not associated with sickness absence. CONCLUSIONS: It is important to consider the length of exposure time window when examining associations between long working hours and sickness absence, whereas the association between night work and sickness absence is not similarly sensitive to exposure times.

An Automatic Exposure Method of Plane Array Remote Sensing Image Based on Two-Dimensional Entropy.

The improper setting of exposure time for the space camera will cause serious image quality degradation (overexposure or underexposure) in the imaging process. In order to solve the problem of insufficient utilization of the camera's dynamic range to obtain high-quality original images, an automatic exposure method for plane array remote sensing images based on two-dimensional entropy is proposed. First, a two-dimensional entropy-based image exposure quality evaluation model is proposed. The two-dimensional entropy matrix of the image is partitioned to distinguish the saturated areas (region of overexposure and underexposure) and the unsaturated areas (region of propitious exposure) from the original image. The ratio of the saturated area is used as an evaluating indicator of image exposure quality, which is more sensitive to the brightness, edges, information volume, and signal-to-noise ratio of the image. Then, the cubic spline interpolation method is applied to fit the exposure quality curve to efficiently improve the camera's exposure accuracy. A series of experiments have been carried out for different targets in different environments using the existing imaging system to verify the superiority and robustness of the proposed method. Compared with the conventional automatic exposure method, the signal-to-noise ratio of the image obtained by the proposed algorithm is increased by at least 1.6730 dB, and the number of saturated pixels is reduced to at least 2.568%. The method is significant to improve the on-orbit autonomous operating capability and on-orbit application efficiency of space camera.