Association between organophosphate flame retardant exposure and lipid metabolism: data from the 2013-2014 National Health and Nutrition Examination Survey.

Organophosphate flame retardants (OPFRs) are emerging environmental pollutants that can be detected in water, dust, and biological organisms. Certain OPFRs can disrupt lipid metabolism in animal models and cell lines. However, the effects of OPFRs on human lipid metabolism remain unclear. We included 1,580 participants (≥20 years) from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) to explore the relationship between OPFR exposure and lipid metabolism biomarkers. After adjusting for confounding factors, results showed that one-unit increases in the log levels of diphenyl phosphate (DPhP) (regression coefficient = -5.755; S.E. = 2.289; p = 0.023) and log bis-(1-chloro-2-propyl) phosphate (BCPP) (regression coefficient = -4.637; S.E. = 2.019; p = 0.036) were negatively associated with the levels of total cholesterol (TC) in all participants. One-unit increases in the levels of DPhP (regression coefficient = -2.292; S.E. = 0.802; p = 0.012), log bis (1,3-dichloro-2-propyl) phosphate (BDCPP) (regression coefficient = -2.046; S.E. = 0.825; p = 0.026), and log bis-2-chloroethyl phosphate (BCEP) (regression coefficient = -2.604; S.E. = 0.704; p = 0.002) were negatively associated with the levels of high-density lipoprotein cholesterol (HDL-C). With increasing quartiles of urine BDCPP levels, the mean TC levels significantly decreased in all participants (p value for trend = 0.028), and quartile increases in the levels of DPhP (p value for trend = 0.01), BDCPP (p value for trend = 0.001), and BCEP (p value for trend<0.001) were negatively corelated with HDL-C, with approximately 5.9, 9.9, and 12.5% differences between the upper and lower quartiles. In conclusion, DPhP, BDCPP, and BCEP were negatively related to HDL-C concentration, whereas DPhP and BCPP levels were negatively associated with TC level. Thus, exposure to OPFRs may interfere with lipid metabolism.

Effect of acute alcohol consumption on blunt bowel mesenteric injury: a retrospective analysis.

BACKGROUND: The effect of alcohol consumption on trauma remains controversial. The effects of alcohol on hemorrhage and peritonitis after blunt abdominal trauma have rarely been discussed. This study aimed to explore the effects of acute alcohol intoxication on the clinical characteristics, injury patterns, and outcomes in a surgical blunt bowel mesenteric injury (BBMI) cohort. METHODS: A retrospective data analysis was performed using trauma cases of patients who had been tested for alcohol and had surgically proven BBMI from a Trauma Registry System from 2009 to 2021. Patients were grouped according to their positive blood alcohol concentration (BAC; >0.5% vs. no BAC; less than 0.5% no BAC) upon arrival at the emergency department (ED). The injury characteristics, physiological parameters, and outcomes with respect to post-injury complications and mortality were assessed. RESULTS: In total, 142 patients with surgical BBMI were included. Of these, 116 and 26 patients were assigned to the BAC-negative and BAC-positive groups, respectively. The overall injury severity, injury pattern, and age were comparable between the groups. The patients in the BAC-positive group had a significantly lower systolic blood pressure (99 mmHg vs. 119 mmHg; p = 0.046), worse shock index (0.96 vs. 0.82; p = 0.048), and lower percentage and number of packed red blood cells transfused (34.6% vs. 57.8%; p = 0.032 and 0 U vs. 2 U; p = 0.031) than those in the BAC-negative group. Additionally, although not statistically significant, patients in the BAC-positive group had lower leukocyte counts (9,700 cells/mm3 vs. 11,600 cells/mm3; p = 0.165 ) at the ED. However, significantly reduced percentages of leukocytes ≥ 12,000 cells/mm3 (26.9% vs. 48.3%; p = 0.048) and ≥ 12,000 or ≤ 4,000 cells/mm3 (26.9% vs. 50.9%; p = 0.027) were observed in the BAC-positive group at the ED. Furthermore, the 30-day mortality rate did not show statistically significant differences, and there was a higher incidence of bowel-related mortality in the BAC-positive group (11.5% vs. 1.7%, p = 0.043). CONCLUSIONS: For patients with BBMI arriving alive to the hospital, acute alcohol consumption was associated with significantly worse hemodynamic parameters, interfered inflammation status, and higher bowel related mortality rate.

Association between Air Pollution and Short-Term Outcome of ST-Segment Elevation Myocardial Infarction in a Tropical City, Kaohsiung, Taiwan.

ST-segment elevation myocardial infarction (STEMI), one of the primary factors leading to global mortality, has been shown through epidemiological studies to have a relationship with short-term exposure to air pollutants; however, the association between air pollutants and the outcome of STEMI has not been well studied. The aim of this study was to estimate the impact of air pollutants on the outcomes of STEMI. Data on particulate matter <2.5 µm (PM2.5), <10 µm (PM10), nitrogen dioxide (NO2), and ozone (O3) at each of the 11 air monitoring stations in Kaohsiung City were collected between 1 January 2012 and 31 December 2017. Medical records of non-trauma patients aged > 20 years who had presented to the Emergency Department (ED) with a principal diagnosis of STEMI were extracted. The primary outcome measure was in-hospital mortality. After adjusting for potential confounders and meteorological variables, we found that an increase in the interquartile range (IQR) in NO2 was associated with an elevated risk of in-hospital mortality in patients with STEMI. Moreover, there was an observed higher risk of in-hospital mortality associated with an increase in the IQR of NO2 during the warm season, specifically in lag 3 (3 days prior to the onset, OR = 3.266; 95%CI: 1.203-8.864, p = 0.02). Conversely, an IQR increase in PM10 was associated with an increased risk of in-hospital mortality in patients with STEMI in lag 3 (OR = 2.792; 95%CI: 1.115-6.993, p = 0.028) during the cold season. Our study suggests that exposure to NO2 (during the warm season) and PM10 (during the cold season) may contribute to a higher risk of poor prognosis in patients with STEMI.

Ambient Air Pollution and Risk for Stroke Hospitalization: Impact on Susceptible Groups.

Stroke is a leading cause of death, and air pollution is associated with stroke hospitalization. However, the susceptibility factors are unclear. Retrospective studies from 2014 to 2018 in Kaohsiung, Taiwan, were analyzed. Adult patients (>17 years) admitted to a medical center with stroke diagnosis were enrolled and patient characteristics and comorbidities were recorded. Air pollutant measurements, including those of particulate matter (PM) with aerodynamic diameters < 10 µm (PM10) and < 2.5 µm (PM2.5), nitrogen dioxide (NO2), and ozone (O3), were collected from air quality monitoring stations. During the study period, interquartile range (IQR) increments in PM2.5 on lag3 and lag4 were 12.3% (95% CI, 1.1−24.7%) and 11.5% (95% CI, 0.3−23.9%) concerning the risk of stroke hospitalization, respectively. Subgroup analysis revealed that the risk of stroke hospitalization after exposure to PM2.5 was greater for those with advanced age (≥80 years, interaction p = 0.045) and hypertension (interaction p = 0.034), after adjusting for temperature and humidity. A dose-dependent effect of PM2.5 on stroke hospitalization was evident. This is one of few studies focusing on the health effects of PM2.5 for patients with risk factors of stroke. We found that patients with risk factors, such as advanced age and hypertension, are more susceptible to PM2.5 impacts on stroke hospitalization.

Exposure to tris(2-butoxyethyl) phosphate induces abnormal sperm morphology and testicular histopathology in male rats.

Tris(2-butoxyethyl) phosphate (TBEP) is one of the most abundant organophosphate flame retardants in the environment. This study aimed to evaluate the effect of TBEP exposure during adolescence on male reproductive function in adult rats. Male Sprague-Dawley rats were treated with 20 and 200 mg/kg body weight of TBEP or corn oil from postnatal day (PND) 42 to PND 105. A significant increase in the proportion of sperm with abnormal morphology (flattened head and bent tail) and superoxide anion (O2-.) production in the sperm of the 200 mg/kg treated group was observed (p < 0.05). Excessive production of sperm hydrogen peroxide (H2O2) was found in both the 20 and 200 mg/kg treatment groups (p < 0.05). Disruption of testicular structure was observed in the 20 and 200 mg/kg treated groups and seminiferous tubule degeneration was observed in the 200 mg/kg treated group. Our study demonstrated the adverse effects of TBEP on male reproductive function in rats.

Association between Ambient Air Pollution and Emergency Room Visits for Pediatric Respiratory Diseases: The Impact of COVID-19 Pandemic.

The level and composition of air pollution have changed during the coronavirus disease 2019 (COVID-19) pandemic. However, the association between air pollution and pediatric respiratory disease emergency department (ED) visits during the COVID-19 pandemic remains unclear. The study was retrospectively conducted between 2017 and 2020 in Kaohsiung, Taiwan, from 1 January 2020 to 1 May 2020, defined as the period of the COVID-19 pandemic, and 1 January 2017 to 31 May 2019, defined as the pre-COVID-19 pandemic period. We enrolled patients under 17 years old who visited the ED in a medical center and were diagnosed with respiratory diseases such as pneumonia, asthma, bronchitis, and acute pharyngitis. Measurements of particulate matter (PM) with aerodynamic diameters of <10 µm (PM10) and < 2.5 µm (PM2.5), nitrogen dioxide (NO2), and Ozone (O3) were collected. During the COVID-19 pandemic, an increase in the interquartile range of PM2.5, PM10, and NO2 levels was associated with increases of 72.5% (95% confidence interval [CI], 50.5−97.7%), 98.0% (95% CI, 70.7−129.6%), and 54.7% (95% CI, 38.7−72.6%), respectively, in the risk of pediatric respiratory disease ED visits on lag 1, which were greater than those in the pre-COVID-19 pandemic period. After adjusting for temperature and humidity, the risk of pediatric respiratory diseases after exposure to PM2.5 (inter p = 0.001) and PM10 (inter p < 0.001) was higher during the COVID-19 pandemic. PM2.5, PM10, and NO2 may play important roles in pediatric respiratory events in Kaohsiung, Taiwan. Compared with the pre-COVID-19 pandemic period, the levels of PM2.5 and PM10 were lower; however, the levels were related to a greater increase in ED during the COVID-19 pandemic.

Clinical Validation of Cardiac Arrest Hospital Prognosis (CAHP) Score and MIRACLE2 Score to Predict Neurologic Outcomes after Out-of-Hospital Cardiac Arrest.

Background. Out-of-hospital cardiac arrest (OHCA) remains a challenge for emergency physicians, given the poor prognosis. In 2020, MIRACLE2, a new and easier to apply score, was established to predict the neurological outcome of OHCA. Objective. The aim of this study is to compare the discrimination of MIRACLE2 score with cardiac arrest hospital prognosis (CAHP) score for OHCA neurologic outcomes. Methods. This retrospective cohort study was conducted between January 2015 and December 2019. Adult patients (>17 years) with cardiac arrest who were brought to the hospital by an emergency medical service crew were included. Deaths due to trauma, burn, drowning, resuscitation not initiated due to pre-ordered "do not resuscitate" orders, and patients who did not achieve return of spontaneous circulation were excluded. Receiver operating characteristic curve analysis with Youden Index was performed to calculate optimal cut-off values for both scores. Results. Overall, 200 adult OHCA cases were analyzed. The threshold of the MIRACLE2 score for favorable neurologic outcomes was 5.5, with an area under the curve (AUC) value of 0.70 (0.61−0.80, p < 0.001); the threshold of the CAHP score was 223.4, with an AUC of 0.77 (0.68−0.86, p < 0.001). On setting the MIRACLE2 score cut-off value, we documented 64.7% sensitivity (95% confidence interval [CI], 56.9−71.9%), 66.7.0% specificity (95% CI, 48.2−82.0%), 90.8% positive predictive value (PPV; 95% CI, 85.6−94.2%), and 27.2% negative predictive value (NPV; 95% CI, 21.4−33.9%). On establishing a CAHP cut-off value, we observed 68.2% sensitivity (95% CI, 60.2−75.5%), 80.6% specificity (95% CI, 62.5−92.6%), 94.6% PPV (95% CI, 88.6%−98.0%), and 33.8% NPV (95% CI, 23.2−45.7%) for unfavorable neurologic outcomes. Conclusions. The CAHP score demonstrated better discrimination than the MIRACLE2 score, affording superior sensitivity, specificity, PPV, and NPV; however, the CAHP score remains relatively difficult to apply. Further studies are warranted to establish scores with better discrimination and ease of application.

Corrigendum: Shock Index, Pediatric Age-Adjusted Predicts Morbidity and Mortality in Children Admitted to the Intensive Care Unit.

[This corrects the article DOI: 10.3389/fped.2021.727466.].

Shock Index, Pediatric Age-Adjusted Predicts Morbidity and Mortality in Children Admitted to the Intensive Care Unit.

Background: The shock index, pediatric age-adjusted (SIPA), defined as the maximum normal heart rate divided by the minimum normal systolic blood pressure by age, can help predict the risk of morbidity and mortality after pediatric trauma. This study investigated whether the SIPA can be used as an early index of prognosis for non-traumatic children visiting the pediatric emergency department (ED) and were directly admitted to the intensive care unit (ICU). We hypothesized that an increase in SIPA values in the first 24 h of ICU admission would correlate with mortality and adverse outcomes. Methods: This multicenter retrospective study enrolled non-traumatic patients aged 1-17 years who presented to the pediatric ED and were directly admitted to the ICU from January 1, 2016, to December 31, 2018, in Taiwan. The SIPA value was calculated at the time of arrival at the ED and 24 h after ICU admission. Cutoffs included SIPA values >1.2 (patient age: 1-6), >1.0 (patient age: 7-12), and >0.9 (patient age: 12-17). The utility of the SIPA and the trends in the SIPA during the first 24 h of ICU admission were analyzed to predict outcomes. Results: In total, 1,732 patients were included. Of these, 1,050 (60.6%) were under 6 years old, and the median Pediatric Risk of Mortality score was 7 (5-10). In total, 4.7% of the patients died, 12.9% received mechanical ventilator (MV) support, and 11.1% received inotropic support. The SIPA value at 24 h after admission was associated with increased mortality [odds ratio (OR): 4.366, 95% confidence interval (CI): 2.392-7.969, p < 0.001], MV support (OR: 1.826, 95% CI: 1.322-2.521, p < 0.001), inotropic support (OR: 2.306, 95% CI: 1.599-3.326, p < 0.001), and a long hospital length of stay (HLOS) (2.903 days, 95% CI: 1.734-4.271, p < 0.001). Persistent abnormal SIPA value was associated with increased mortality (OR: 2.799, 95% CI: 1.566-5.001, p = 0.001), MV support (OR: 1.457, 95% CI: 1.015-2.092, p = 0.041), inotropic support (OR: 1.875, 95% CI: 1.287-2.833, p = 0.001), and a long HLOS (3.2 days, 95% CI: 1.9-4.6, p < 0.001). Patients with abnormal to normal SIPA values were associated with decreased mortality (OR: 0.258, 95% CI: 0.106-0.627, p = 0.003), while patients with normal to abnormal SIPA values were associated with increased mortality (OR: 3.055, 95% CI: 1.472-5.930, p = 0.002). Conclusions: In non-traumatic children admitted to the ICU from the ED, increased SIPA values at 24 h after ICU admission predicted high mortality and bad outcomes. Monitoring the trends in the SIPA could help with prognostication and optimize early management.

Association between liberal oxygen therapy and mortality in patients with paraquat poisoning: A multi-center retrospective cohort study.

Paraquat (N, N'-dimethyl-4, 4'-bipyridinium dichloride, PQ) intoxication is a common cause of lethal poisoning. This study aimed to identify the risk of using liberal oxygen therapy in patients with PQ poisoning. This was a multi-center retrospective cohort study involving four medical institutions in Taiwan. Data were extracted from the Chang Gung Research Database (CGRD) from January 2004 to December 2016. Patients confirmed to have PQ intoxication with a urine PQ concentration ≥ 5 ppm were analyzed. Patients who received oxygen therapy before marked hypoxia (SpO2 ≥ 90%) were defined as receiving liberal oxygen therapy. The association between mortality and patient demographics, blood paraquat concentration (ppm), and liberal oxygen therapy were analyzed. A total of 416 patients were enrolled. The mortality rate was higher in the liberal oxygen therapy group (87.8% vs. 73.7%, P = 0.007), especially in 28-day mortality (adjusted odds ratio [aOR]: 4.71, 95% confidence interval [CI]: 1.533-14.471) and overall mortality (aOR: 5.97, 95% CI: 1.692-21.049) groups. Mortality in patients with PQ poisoning was also associated with age (aOR: 1.04, 95% CI: 1.015-1.073), blood creatinine level (aOR: 1.49, 95% CI: 1.124-1.978), and blood paraquat concentration (ppm) (aOR, 1.51; 95% CI: 1.298-1.766). Unless the evidence of hypoxia (SpO2 < 90%) is clear, oxygen therapy should be avoided because it is associated with increased mortality.

Corrigendum: Shock Index, Pediatric Age-Adjusted Predicts Morbidity and Mortality in Children Admitted to the Intensive Care Unit.

[This corrects the article DOI: 10.3389/fped.2021.727466.].

Benefits of Early In-Hospital Antivenom Administration to Patients with Protobothrops mucrosquamatus Envenomation.

Protobothrops mucrosquamatus is one of the common venomous snakes in Southeast Asia. This retrospective cohort study conducted in six medical institutions in Taiwan aimed to obtain information on the optimal management strategies for P. mucrosquamatus snakebite envenomation. Data were extracted from the Chang Gung Research Database from January 2006 to December 2016. The association between early antivenom administration and patient demographics, pain requiring treatment with analgesic injections, and hospital length of stay was analyzed. A total of 195 patients were enrolled; 130 were administered antivenom within 1 hour after emergency department arrival (early group), whereas 65 were treated later than 1 hour after arrival (late group). No in-hospital mortality was identified. The difference in surgical intervention rates between the early and late groups was statistically insignificant (P = 0.417). Compared with the early group, the late group showed a higher rate of antivenom skin test performance (46.9% versus 63.1%, respectively, P = 0.033), longer hospital stay (42 ± 62 hours versus 99 ± 70 hours, respectively, P = 0.016), and higher rate of incidences of pain requiring treatment with analgesic injections (29.2% versus 46.2%, respectively, P = 0.019). After adjusting for confounding factors, early antivenom administration was associated with decreased pain requiring treatment with analgesic injections (adjusted odds ratio: 0.51, 95% CI: 0.260-0.985). Antivenom administration within 1 hour of arrival was associated with a decreased likelihood of experiencing pain and hospital length of stay in patients with P. mucrosquamatus snakebites. Antivenom skin testing was associated with delays in antivenom administration.

Massive Pulmonary Embolism Concomitant With Cardiac Tamponade as Initial Presentation of Lung Adenocarcinoma: A Diagnostic and Therapeutic Dilemma.

Pulmonary embolism and cardiac tamponade are potentially fatal acute conditions that rarely present concomitantly in the emergency department (ED). Both require early diagnosis and urgent intervention, and are usually observed as separate easily identifiable diseases. However, in a patient exhibiting a concomitant presentation of pulmonary embolism with cardiac tamponade, diagnosis and therapeutic intervention are extremely challenging. A 48-year-old woman presented with cardiac tamponade as an initial symptom of an underlying lung adenocarcinoma and masked massive pulmonary embolism (MPE), which led to the development of sudden cardiac arrest after successful pericardiocentesis. She presented with a high index of suspicion for a diagnosis of MPE using echocardiography after successful pericardiocentesis, and this diagnosis was confirmed using computed tomography. Extracorporeal membrane oxygenation and adjusted-dose unfractionated intravenous heparin administration were performed; unfortunately, they were unsuccessful. This report would help ED physicians because this case demonstrates that lung cancer can initially present as pulmonary embolism with cardiac tamponade and pulmonary embolism can be misdiagnosed in the presence of concomitant cardiac tamponade. Bedside echocardiography may fail to diagnose life-threatening MPE with coexisting cardiac tamponade. MPE can also lead to the development of sudden cardiac arrest after successful pericardiocentesis. Thrombolytic and anticoagulant use in MPE with coexisting hemorrhagic cardiac tamponade is a controversial issue. The risk-benefit ratio of both therapies needs to be considered on a case-by-case basis for improved clinical outcomes.

Comparison of Clinical Practice in the Emergency Department: Female Versus Male Emergency Physicians.

BACKGROUND: There are fewer female emergency physicians (EPs) than male ones. This study attempted to analyze the differences in clinical practice between female and male EPs in the emergency department (ED). MATERIALS AND METHODS: A retrospective, 1-year cohort study was conducted across 4 EDs in the largest healthcare system in Taiwan. A total of 199,757 adult patients without trauma treated by 76 EPs (9 females and 67 males) were included in the study. The clinical practice of female and male EPs was compared. The door-to-order and door-to-disposition times were used to evaluate EP efficiency. Indicators of diagnostic tool use included laboratory examinations and computed tomography scans. Patient dispositions included discharge, ED observation, general ward and intensive care unit admissions and ED mortality rate. Disposition accuracy was evaluated by determining the 72-hour ED revisit rate. RESULTS: The clinical practice of female and male EPs was similar. After adjusting for the potential confounding factors through a regression model, female EPs showed slight increase in laboratory examination use (adjusted odds ratio = 1.05; 95% CI: 1.01-1.09) compared with male EPs, but no difference in computed tomography use was observed between sexes. Additionally, no differences among patient dispositions and 72-hour ED revisit rates (adjusted odds ratio = 1.0; 95% CI: 0.93-1.06) were observed between female and male EPs. CONCLUSIONS: Female and male EPs had similar clinical efficiency on patient evaluation, and they had no difference in diagnostic tool use. Furthermore, they showed similar patient disposition with the same accuracy.

Effects of Background Lighting Color and Movement Distance on Reaching Times Among Participants With Low Vision, Myopia, and Normal Vision.

This study investigated the effects of target distance (30, 35, and 40 cm) and the color of background lighting (red, green, blue, and yellow) on the duration of movements made by participants with low vision, myopia, and normal vision while performing a reaching task; 48 students (21 women, 27 men; M age = 21.8 year, SD = 2.4) participated in the study. Participants reached for a target (a white LED light) whose vertical position varied randomly across trials, ranging in distance from 30 to 40 cm. Movement time was analyzed using a 3 (participant group) × [4 (color of background lighting) × 3 (movement distance)] mixed-design ANOVA model. Results indicated longer times for completing a reaching movement when: participants belonged to the low vision group; the target distance between the starting position and the target position was longer (40 cm); and the reaching movement occurred in the red-background lighting condition. These results are particularly relevant for situations in which a user is required to respond to a signal by reaching toward a button or an icon.

Effects of spacing between items and view direction on errors in the perceived height of a rotated 3-D figure.

This study investigated the errors in the perceived height of virtual cones presented on the screen. 80 students (50 women, 30 men; M age = 18.8 yr., SD = 1.2 using a duodecimal system) participated in the study. They judged the height of virtual cones in several conditions: (a) different spaces between the items in the array (2, 4, and 6 cm); (b) different viewing directions - bottom-up or top-down; (c) cones presented in different forward-rotated angles (15, 30, and 45°). Results indicate that fewer errors in the perceived heights of virtual cones were made when: the space between items was 2 cm, judgment was made in a bottom-up view and at a 15° angle. These results may have implications for graphics-based interface design such as interior design, driver navigation systems, geological models, and flight-simulation systems.

Effects of light, rotation, and texture on errors in the estimated length of a three-dimensional object in a two-dimensional display.

This study investigated the effects of light type (spot, directional, and point), forward-rotated stimulus angle (20 degrees, 45 degrees, and 70 degrees), and surface texture (wood, metal, transparent glass, dark brown leather, and translucent plastic) on errors in the estimated vertical diameter of a three-dimensional object. Twenty female and 12 male Taiwanese college students, ages 18-22 years, participated in the current study. Participants were asked to judge the vertical diameter of an elliptical hole within a square plate that was displayed on an LCD monitor. Analysis indicated that the errors in estimated vertical diameter for rotated angles of 20 degrees and 45 degrees were greater than were those for 70 degrees. Additionally, the error of estimated vertical diameter for a rotated angle of 45 degrees was less than was that for 20 degrees. The surface texture also affected errors in estimated vertical diameter: transparent glass was associated with more errors than were wood and metal textures. However, light type had no effect on errors in estimated vertical diameter. These results have implications for the graphics-based design of interfaces.

Effects of peptide concentration on remineralization of eroded enamel.

Promoting remineralization to repair eroded enamel is a promising therapy in clinics. In this study, biocompatible asparagine-serine-serine (NSS) peptide chelates free ions from artificial saliva through charged functional groups, and subsequently form nano-hydroxyapatite crystals to partially repair erosive lesions. The nanomechanical properties, cross-sectional microstructure, types of deposited minerals, and subsurface microstructure of enamel at various treatment stages were characterized by nanoindentation, scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM), respectively. The results revealed that the nanohardness and elastic modulus of eroded enamel increase with peptide concentration, particularly for the 3NSS peptide system. In contrast, the structure of the 5NSS peptide is larger and longer, leading to increasing difficulty in penetrating to the deep acid-eroded regions; therefore, the remineralization effect was restricted to the top enamel surface. The 3NSS peptide with high concentration promoted the formation of smaller, finer, and staggered nanohydroxyapatite crystals. The enamel remineralized with a 100µM 3NSS exhibited the highest degree of nanohardness recovery (34%), resulting from subsurface crystalline regrowth.

Color of light-source and background luminance on perceived convexity and concavity of a blurred 3-D hemisphere.

In the present study, the effect of light-source color, size, background luminance, and blur on the perceived convexity and concavity of a 3-D hemisphere was investigated. The sample consisted of 84 undergraduates divided into Experience and No-experience groups based on experience working with 3D software. Participants were asked to adjust the angle of light in a clockwise direction until a convex hemisphere appeared concave. Analysis indicated that the color of light had a statistically significant effect on the angle of adjusted light, and the Experience group adjusted the angle of light less than did the No-experience group. The angle of the adjusted light was significantly smaller under the high background luminance condition compared with the medium and low luminance conditions. The angle of adjusted light under the low blur condition was greater than that under the high and medium blur conditions. These results have implications for graphics-based interface design.