Comparison of neutron and secondary gamma dose assessment using polygon mesh and voxel computational phantoms

The newly developed mesh-type reference computational phantoms (MRCPs) represent the evolution of the previous reference phantoms and a more detailed description of the human body, addressing the voxel reference phantom limitations. These allow for a more accurate dose calculation in the human body, which in some cases results in a significant difference of the calculated quantities. In this work, the absorbed dose calculation due to neutrons and gammas was calculated using a voxel and a mesh-type computational phantom. The goal was to understand how a more accurate description of the human body affects the estimated neutron dose. The phantoms were tested in a real-case scenario: they were placed in front of a neutron Howitzer container model using PHITS. This model corresponds to the neutron Howitzer container at the Neutron Measurements Laboratory of the Energy Engineering Department of the Polytechnic University of Madrid (UPM), and at the time of measurement it was equipped with a ²⁴¹Am-Be neutron source of 74 GBq in its center. The container allows the source to be in either the irradiation or the storage position. Results show that when dealing with neutrons, the dose deviation when using GOLEM or the MRCP leads to a general 20%-30% deviation that goes up to above 400% in small thin structures such as the eye.

1105 A Randomized Controlled Trial of a Psychological Intervention for Decreasing Bedtime Procrastination: The BED-PRO Study

Introduction

Bedtime Procrastination (BP) is defined as the behavior of going to bed later than intended, without having external reasons for doing so. Previous studies have shown that BP has a negative effect on sleep and health, and there is a need to develop interventions to decrease BP. This study (BED-PRO) is an ongoing study evaluating a behavioral intervention to reduce BP.

Methods

Fifteen participants who scored higher than 33 on the Bedtime Procrastination Scale were randomized to either the treatment (TRT, n=6) or control group (CTRL, n=9). Treatment consisted of four face-to-face individual sessions. All participants completed self-report questionnaires on Bedtime Procrastination Scale (BPS), Epworth Sleepiness Scale (ESS), Positive Affect and Negative Affect Schedule (K-PANAS-R) and completed the 7-day sleep diary. Data was analyzed using two-way mixed Measures Analysis of Variance (ANOVA).

Results

Mean age of the participants was 21.78 (±1.8) years and 80% (n=12) were females. Group by time interactions from repeated measures analyses revealed significant post intervention improvements in the TRT group compared to the CTRL group on all bedtime procrastination duration and scores, sleep efficiency, refreshment after waking, daytime sleepiness and negative affect of K-PANAS-R. Specifically, bedtime procrastination duration in the TRT group measured by sleep diaries decreased significantly from 75.30 (±58.57) min to 14.83 (±7.83) min, while the CTRL group did not change from 57.60 (±32.01) to 54.36 (±40.82) min (p=0.019). In addition, the TRT group reported significant improvements in bedtime procrastination scores from 36.00 (±4.05) to 22.50 (±6.72).

Conclusion

Based on results, the behavioral intervention used in this study looks promising in improving bedtime procrastination and sleep.

Support

This work was supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea(NRF-2018S1A5A8026807)

Evaluation of Product Quality of Low-Salt Pork Sausage Using Prerigor Pork Ham

ObjectivesThe objective of this study was to develop pork sausages with reduced salt content using the pre-rigor pork ham to have similar product quality to regular-salt (1.5%) sausages.Materials and MethodsPork ham with pre-rigor (< 1 h after slaughter) and post-rigor (> 1 d after slaughter) were purchased at the local market. Sausages containing pre-rigor pork hams with various salt contents (0– ∼1.5%) were manufactured and compared to the post-rigor sausages with regular salt (1.5%). To confirm the states of pre-rigor and post-rigor, pH and temperature of pork hams were measured. The pH, color, cooking loss (CL, %), expressible moisture (EM, %), textural properties, lipid oxidation (TBAR), protein oxidation (VBN) of the sausages were measured, while the protein solubility and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of meat batter were measured. The experiment design was one-way analysis of variance at a significant level of 0.05.ResultsThe pre-rigor ham had higher pH and temperature than the post-rigor ham, as expected. Protein solubility of pre-rigor sausages was higher than those with reduced salt concentrations (< 1.0%). However, no differences in CIE color values (L*, a*, b*), CL, TBARS, and VBN were observed among treatments. The EM (%) of pre-rigor sausages with 0.5 and 1.0% salt were similar to those with pre-rigor sausages with 1.5% salt. Textural properties of sausages were not different between pre-rigor with various salt levels (0.5∼1.5%) and post-rigor sausages with 1.5% salt. High intensity of myosin heavy chain band was shown in pre-rigor meat batters as compared to the post-rigor ones.ConclusionPre-rigor sausages containing 1.0% salt had similar characteristics to those with post-rigor with 1.5% salt. This result indicated that the amount of salt on sausages could be reduced by approximately one-third of regular-salt (1.5%) level without detrimental effects.

P1740Clinical impact of symptom onset-to-balloon time and door-to-balloon time on 1-year adverse event in patients with ST-segment elevation myocardial infarction

Background and objectives

The impact of treatment delays to reperfusion on patient mortality after primary percutaneous coronary intervention (PCI) for ST elevation myocardial infarction (STEMI) is controversial. we evaluated the relation between the delay in the time to reperfusion during primary PCI and the 1-year clinical outcome of patients with STEMI treated by primary angioplasty.

Methods

The study enrolled 6,676 patients (age, 62.5±12.6 years; 26.5% female) with STEMI who underwent primary angioplasty onset between November 2005 and March 2012 from the KAMIR and KorMI Registry. The patients were divided into three groups according to the symptom onset-to-balloon (STB) time: group I, II, III (≤180 minutes, >180 ∼ ≤360 minutes, >360 minutes), and divided into three groups according to the door-to-balloon (DTB) time: group A, B, C (≤90 minutes, >90 ∼ ≤120 minutes, >120 minutes). The 1-year cardiac death and major adverse cardiac event (MACE) rates were compared among the three groups of time variables

Results

The cardiac death rate was 7.9% and MACE rate was 16.9% at one year follow-up. The 1-year cardiac death rate among STB time groups were significantly higher in group II (95% CI=1.05–2.60:p=0.030) and group III (95% CI=1.14–2.74:p=0.011), while that among DTB time groups were not significantly different based on a multivariate Cox proportional analysis, which was adjusted by age, sex, diabetes mellitus, hypertension, systolic blood pressure, left ventricular ejection fraction, peak level of CK-MB, anterior myocardial infarction. The 1-year MACE rate were not significantly different among STB time groups and DTB time group A, B, but was significantly higher in group C (95% CI=1.08–1.58:p=0.006).

Conclusions

These results suggest that, in patient with STEMI treated by primary angioplasty, STB time rather than DTB time was related 1-year clinical outcome especially cardiac death after adjustment for baseline characteristics. Therefore, all efforts should be made to shorten the total ischemic time in patients with acute myocardial infarction

Eruption guidance of horizontally angulated, distally displaced mandibular second premolars: Three case reports

AIM

An improperly positioned tooth germ can lead to tooth impaction, damage to adjacent teeth, and loss of arch integrity. This report describes three cases of eruption guidance of developing mandibular second premolars (MnP2) that were horizontally angulated and displaced to the distal side of the roots of the second primary molars.

CASE REPORT

The primary second molars were extracted when root formation of the succeeding premolar began. Surgical exposure was performed to accelerate eruption. These two procedures led to spontaneous eruption of all premolars. In the last case, however, a displaced second premolar disturbed the eruption of the first molar into the occlusal plane.

CONCLUSIONS

Several factors should be considered for an optimal treatment approach, including the clinical eruption status, development of the root MnP2, and effect on the mandibular first molar.