NEUDOSE: NEUtron DOSimetry & Exploration - A CubeSat for Dosimetry of Charged and Neutral Particles

Radiation hazard is a major concern for astronauts, especially as we look beyond LEO. We require a method for real-time measurements of both charged and neutral radiation for personal dosimetry. Large uncertainties in current data mostly due to radiation quality and dose-rate effects

Passive Attitude Control to Decrease CubeSatellite Complexity

Attitude control is often a requirement for the optimal functionality of satellite payloads. The McMaster Neutron Dosimetry and Exploration (NEUDOSE) mission aims to measure charged and neutral radiation in Low Earth Orbit. NEUDOSE can detect particles effectively from any direction due to its spherical symmetry, meaning unlike most satellite missions, it does not require attitude control to function. The attitude is still crucial for the mission in order to achieve optimal communication. The NEUDOSE satellite utilizes Ultra High Frequency and Very High Frequency dipole antennas for communication. If the satellite’s attitude lines up in a specific orientation, communication will be hindered due to the nature of the antenna’s radiation pattern. With short access times to the ground station, and relatively small amounts of data being transferred, effective communication is important for the success of the mission. Initially the NEUDOSE mission had an active attitude control system, but with the lack of pointing requirements for the payload’s operation, and a stringent power budget, the active system was removed. A passive magnetic attitude control system was then explored as a solution to optimize communication, without adding much complexity or burden on the power budget

A Dose Threshold for a Medium Transfer Bystander Effect for a Human Skin Cell Line

The existence of radiation-induced bystander effects mediated by diffusible factors is now accepted but the mechanisms and precise behavior at low doses remain unclear. We exposed cells to gamma doses in the range 0.04 mGy – 5 Gy, harvested the culture medium and transferred it to unirradiated reporter cells. Calcium fluxes and clonogenic survival were measured in the recipients. We show evidence for a dose threshold around 2 mGy for the human skin cell line used with a suggestion of increased survival below that dose. Similar experiments using direct gamma irradiation showed no reduction in survival until the dose exceeded 7 mGy. Preliminary data for neutrons where the gamma dose was kept below the bystander threshold, does not show significant bystander effect in the dose range 1 – 33 mGy. A lack of a bystander response with neutrons occurred at high dose around 1 Gy where significant cell killing from direct irradiation was observed. The result may have implications for understanding the role of bystander effects at low doses

Pseudoinvasion in an Adenomatous Polyp of the Colon Mimicking Invasive Colon Cancer

Pseudoinvasion or pseudocarcinomatous invasion in an adenomatous polyp of the colon can be unfamiliar to an endoscopist. Pseudoinvasion in an adenomatous polyp represents prolapse of the adenomatous epithelium into its stalk. In most cases its morphology does not differ from of general adenomatous polyps, but in some cases it can morphologically mimic a malignant polyp with submucosal invasion due to mass-like lesioning of its stalk. This makes it difficult for endoscopists to differentiate pseudoinvasion in an adenoma from an invasive carcinoma by conventional endoscopy; instead, endoscopic ultrasonography can provide useful information for differentiating these conditions. We report on an 82-year-old man who presented with a large pedunculated polyp with a thick stalk in the sigmoid colon, which mimicked a submucosal invasive carcinoma. The patient was diagnosed with pseudoinvasion in an adenomatous polyp after segmental resection of the sigmoid colon

Occult bacteremia in children with simple febrile seizure in the post-pneumococcal conjugate vaccine era

Purpose The authors aimed to investigate the utility of blood culture (BC) for children with simple febrile seizure (SFS) in the emergency department (ED) in the post-10/13-valent pneumococcal conjugate vaccine (PCV) era. Methods This study was performed at the ED of a tertiary care university-affiliated women and children’s hospital, and involved 3,237 previously healthy children aged 6-60 months who visited the ED with SFS from January 2013 through December 2017. The SFS was defined according to the International Classification of Diseases, 11th Revision codes related to seizure. The children were divided into 2 groups according to the vaccination rates of the period of their visit: the 70-PCV (70%, 2013-2014) and 97-PCV (97%, 2015-2017) groups. The primary outcome was the yield, defined as a true positivity of BC. In addition, we collected information on baseline characteristics, ED length of stay, inflammatory biomarkers, and ED outcomes. Results Of the 1,578 children with SFS who underwent BC, 1,357 belonged to the 97-PCV group. The median age of the study population was 22 months (interquartile range, 16.0-30.0), and 935 children (59.3%) were boys. Of the 41 children (2.6%) with positive BC results, 3 had the yield (0.2%): Staphylococcus aureus in 2 children and Streptococcus pneumoniae in the other. All 3 children belonged to the 97-PCV group. There were 38 contaminated BCs (2.4%; 95% confidence interval, 1.6%-3.2%). The 97-PCV group showed a shorter median ED length of stay (166.0 minutes [108.0-279.5] vs. 143.0 [109.5-209.5]; P = 0.010) and a lower rate of hospitalization (39.4% vs. 12.8%; P < 0.001). No differences between the 2 groups were found in the baseline characteristics and biomarkers. Conclusion This study suggests a low utility of BC in previously healthy children with SFS in emergency settings in the post-10/13-valent PCV era

Crystal structure of hyperthermophilic esterase EstE1 and the relationship between its dimerization and thermostability properties

<p>Abstract</p> <p>Background</p> <p>EstE1 is a hyperthermophilic esterase belonging to the hormone-sensitive lipase family and was originally isolated by functional screening of a metagenomic library constructed from a thermal environmental sample. Dimers and oligomers may have been evolutionally selected in thermophiles because intersubunit interactions can confer thermostability on the proteins. The molecular mechanisms of thermostabilization of this extremely thermostable esterase are not well understood due to the lack of structural information.</p> <p>Results</p> <p>Here we report for the first time the 2.1-Å resolution crystal structure of EstE1. The three-dimensional structure of EstE1 exhibits a classic α/β hydrolase fold with a central parallel-stranded beta sheet surrounded by alpha helices on both sides. The residues Ser154, Asp251, and His281 form the catalytic triad motif commonly found in other α/β hydrolases. EstE1 exists as a dimer that is formed by hydrophobic interactions and salt bridges. Circular dichroism spectroscopy and heat inactivation kinetic analysis of EstE1 mutants, which were generated by structure-based site-directed mutagenesis of amino acid residues participating in EstE1 dimerization, revealed that hydrophobic interactions through Val274 and Phe276 on the β8 strand of each monomer play a major role in the dimerization of EstE1. In contrast, the intermolecular salt bridges contribute less significantly to the dimerization and thermostability of EstE1.</p> <p>Conclusion</p> <p>Our results suggest that intermolecular hydrophobic interactions are essential for the hyperthermostability of EstE1. The molecular mechanism that allows EstE1 to endure high temperature will provide guideline for rational design of a thermostable esterase/lipase using the lipolytic enzymes showing structural similarity to EstE1.</p

Design of a Custom Secondary On-Board Computer for the NEUDOSE CubeSat Mission

The NEUtron DOSimetry & Exploration (NEUDOSE) CubeSat is the first small satellite mission from McMaster University. The mission includes two on-board computers (OBCs): a commercial off-the-shelf (COTS) board as the primary OBC, and a custom student-designed board, the secondary on-board computer (SOBC), as a secondary payload to the mission

Comparison of the Effectiveness of Interventional Endoscopy in Bleeding Peptic Ulcer Disease according to the Timing of Endoscopy

Background/Aims: The optimal timing for interventional endoscopy in bleeding peptic ulcer disease is controversial. This study compared the outcomes between early endoscopy and delayed endoscopy in patients with bleeding peptic ulcer disease. Methods: We conducted a prospective analysis of data from 90 patients with bleeding peptic ulcer disease who visited the emergency room between May 2006 and September 2007. Patients were categorized into two groups: the early-endoscopy group (admitted during the daytime or at night with prompt endoscopic management) and the delayed-endoscopy group (admitted at night or during weekends, with endoscopic management delayed until the next day). We compared the clinical outcomes of endoscopy between the two groups. Results: There were 49 patients in the early-endoscopy group and 41 patients in the delayed-endoscopy group. Patient demographics, clinical characteristics, bleeding control modality, and Rockall score did not differ between the two groups. There were also no significant differences between the early- and delayed-encloscopy groups 'in the re-bleeding rate (3/49 vs 5/41, p=0.313), the duration of hospital stay (10.7 vs 9.3 days, p=0.437), and the total amount of blood transfused (3.4 vs 2.7 units, p=0.240). Conclusions: The effectiveness of interventional endoscopy for patients with bleeding peptic ulcer disease is not significantly affected by the timing of endoscopy. (Gut and Liver 2009;3:266-270)This work was supported by the research fund of Hanyang University Industrial Digital Park (200700000005845)

Recent Changes in the Clinicopathologic Features of Korean Men with Prostate Cancer: A Comparison with Western Populations

Purpose : The aim of this study was to evaluate the recent changes in the clinicopathologic features of prostate cancer in Korea and to compare these features with those of Western populations. Materials and methods : We retrospectively reviewed the data of 1582 men undergoing radical prostatectomy for clinically localized prostate cancer between 1995 and 2007 at 10 institutions in Korea for comparison with Western studies. The patients were divided into two groups in order to evaluate the recent clinicopathological changes in prostate cancer: Group 1 had surgery between 1995 and 2003 (n=280) and Group 2 had surgery between 2004 and 2007 (n=1302). The mean follow-up period was 24 months. Results : Group 1 had a higher prostate-specific antigen level than Group 2 (10.0 ng/mL vs. 7.5 ng/mL, respectively; p<0.001) and a lower proportion of biopsy Gleason scores ≤6 (35.0% vs. 48.1%, respectively; p<0.001). The proportion of patients with clinical T1 stage was higher in Group 2 than in Group 1. Group 1 had a lower proportion of organ-confined disease (59.6% vs. 68.6%; p<0.001) and a lower proportion of Gleason scores ≤6 (21.3% vs. 33.0%; p<0.001), compared to Group 2. However, the relatively higher proportion of pathologic Gleason scores ≤6 in Group 2 was still lower than those of Western men, even though the proportion of organ-confined disease reached to that of Western series. Conclusion : Korean men with prostate cancer currently present better clinicopathologic parameters. However, in comparison, Korean men still show relatively worse pathologic Gleason scores than Western men.ope

High Grade Hemangioendothelioma of the Temporal Bone in a Child: A Case Report

Hemangioendothelioma is a rare vascular tumor characterized by endothelial tumor cells and variable malignant behavior, and it's not common for this lesion to involve the bone. Although there are a few reports of cranial involvement by hemangioendothelioma, only rare cases arising in temporal bone have been published. We present the radiologic findings of a 7-year-old boy who had a high grade hemangioendothelioma involving the temporal bone with intracranial extension. Evidence of flow voids on MR images suggested a tumor of vascular origin, and the ill-defined margins, cortical destruction and intracranial extension on the CT and MR images were correlated with the tumor's high histologic grade