Main-chain benzoxazine has great potential for a number of fields, particularly fiber chemistry, due to its flexibility in molecular design and viscosity. It is expected that its thermal properties ...can be improved by blending with a low molecular weight benzoxazine possessing a functional group with excellent thermal properties. In this study, two types of bisphenol-A-based main-chain benzoxazine were synthesized, using aliphatic and aromatic diamine and o-aminobenzonitrile benzoxazine, then blended. Their thermal properties were investigated through FT-IR, DSC, and TGA. The copolybenzoxazine that comprised main-chain benzoxazine with aromatic diamine and o-aminobenzonitrile benzoxazine showed improved thermal stability over a low-temperature range and demonstrated a synergistic effect on char yield.
The importance of fast neutron detection for nuclear safeguards purposes has increased due to its potential advantages such as reasonable cost and higher precision for larger sample masses of nuclear ...materials. Pulse-shape discrimination (PSD) is inevitably used to discriminate neutron- and gamma-ray- induced signals from organic scintillators of very high gamma sensitivity. The light output (LO) threshold corresponding to several MeV of recoiled proton energy could be necessary to achieve fine PSD performance. However, this leads to neutron count losses and possible distortion of results obtained by neutron multiplicity counting (NMC)-based nuclear material accountancy (NMA). Moreover, conventional PSD techniques are not effective for counting of neutrons in a high-gamma-ray environment, even under a sufficiently high LO threshold. In the present work, PSD performance (figure-of-merit, FOM) according to LO bands was confirmed using a conventional charge comparison method (CCM) and compared with results obtained by convolution neural network (CNN)-based PSD algorithms. Also, it was attempted, for the first time ever, to reject fake neutron signals from distorted PSD regions where neutron-induced signals are normally detected. The overall results indicated that higher neutron detection efficiency with better accuracy could be achieved via CNN-based PSD algorithms.
A 54-year-old man was transferred from another hospital due to a hematoma in the third portion of the duodenum on abdomen CT. He had been admitted for 2 weeks due to vomiting at another hospital. He ...had abdominal discomfort and nausea without abdominal pain when he visited the Gwangyang Sarang Hospital. Other than a distended abdomen and mild general abdominal tenderness, the results of physical examination were unremarkable. Abdominal CT revealed an approximately 9 cm thick walled hematoma at the anteroinferior site of the duodenal third portion. Upper endoscopy revealed stenosis of the third portion of the duodenum without mucosal lesions. The endoscope was not advanced through the narrowed duodenal lumen. A retroperitoneal hematoma was diagnosed, and his state was classified as subacute rather than acute based on the duration. The surgeon did not recommend surgical treatment. Urgent treatment was unnecessary; he was managed conservatively. The size of the hematoma decreased from 9.0 cm to 5.8 cm on the following CT. He could begin to eat food on the 26th admission day, and he was discharged on the 31st admission day. The hematoma disappeared entirely on the following CT. This paper describes a rare case of idiopathic retroperitoneal hematoma with a spontaneous resolution.
The surface of conventional carbon nanotube (CNTs) were modified into 4-aminobenzoyl functionalized CNTs (ABCNT) and benzoxazine functionalized CNTs (BZCNT) to improve their surface interaction with ...bisphenol A based benzoxazine resins (BA-a). Polybenzoxazine (PBZ) composites using these materials were prepared to investigate the effect of different functional groups on the thermal and electrical properties of the composites. The surface modification of CNTs was characterized by Fourier Transform Infrared spectroscopy and thermogravimetric analysis. The PBZ composite with BZCNT showed the better conductivity and thermal properties than the composite with ABCNT due to the chemical bond between BZCNT/BA-a during the curing process which does not exist in the ABCNT/BA-a composite.
자발적으로 소실된 특발성 후복막 혈종 1예 황유정; Yu Jeong Hwang; 진석재 ...
The Korean journal of gastroenterology,
11/2021, Letnik:
78, Številka:
5
Journal Article
Recenzirano
A 54-year-old man was transferred from another hospital due to a hematoma in the third portion of the duodenum on abdomen CT. He had been admitted for 2 weeks due to vomiting at another hospital. He ...had abdominal discomfort and nausea without abdominal pain when he visited the Gwangyang Sarang Hospital. Other than a distended abdomen and mild general abdominal tenderness, the results of physical examination were unremarkable. Abdominal CT revealed an approximately 9 cm thick walled hematoma at the anteroinferior site of the duodenal third portion. Upper endoscopy revealed stenosis of the third portion of the duodenum without mucosal lesions. The endoscope was not advanced through the narrowed duodenal lumen. A retroperitoneal hematoma was diagnosed, and his state was classified as subacute rather than acute based on the duration. The surgeon did not recommend surgical treatment. Urgent treatment was unnecessary; he was managed conservatively. The size of the hematoma decreased from 9.0 cm to 5.8 cm on the following CT. He could begin to eat food on the 26th admission day, and he was discharged on the 31st admission day. The hematoma disappeared entirely on the following CT. This paper describes a rare case of idiopathic retroperitoneal hematoma with a spontaneous resolution. (Korean J Gastroenterol 2021;78:295-299)
Hepatitis B virus (HBV) infection leads to hepatic and extrahepatic manifestations including chronic kidney disease (CKD). However, the association between HBV and CKD is not clear. This study ...investigated the association between chronic HBV infection and CKD in a nationwide multicenter study.
A total of 265,086 subjects who underwent health-check examinations in 33 hospitals from January 2015 to December 2015 were enrolled. HBV surface antigen (HBsAg) positive cases (n = 10,048), and age- and gender-matched HBsAg negative controls (n = 40,192) were identified. CKD was defined as a glomerular filtration rate (GFR) < 60 mL/min/1.73 m
or proteinuria as at least grade 2+ of urine protein.
HBsAg positive cases showed a significantly higher prevalence of GFR < 60 mL/min/1.73 m
(3.3%), and proteinuria (18.9%) than that of the controls (2.6%,
< 0.001, and 14.1%,
< 0.001, respectively). In the multivariate analysis, HBsAg positivity was an independent factor associated with GFR < 60 mL/min/1.73 m
along with age, blood levels of albumin, bilirubin, anemia, and hemoglobin A1c (HbA1c). Likewise, HBsAg positivity was an independent factor for proteinuria along with age, male, blood levels of bilirubin, protein, albumin, and HbA1c. A subgroup analysis showed that HBsAg positive men but not women had a significantly increased risk for GFR < 60 mL/min/1.73 m
.
Chronic HBV infection was significantly associated with a GFR < 60 mL/min/1.73 m
and proteinuria (≥ 2+). Therefore, clinical concern about CKD in chronic HBV infected patients, especially in male, is warranted.
Polybenzoxazine is a novel class of thermosetting resins that supplements several shortcomings of conventional materials and has a wide range of advantages. Molecular flexibility of benzoxazines is a ...desirable characteristic. Two kinds of monomer, 2,2-bis(3,4-dihydro-3-phenyl-2H-1,3-benzoxazine)propane (abbreviated as BA-a) and polyetheramine based benzoxazine monomer (abbreviated as JA-c), were used to control the brittleness of thermoset resins. JA-c was introduced to modify the flexibility by long alkyl ether chains and to reduce the cross-linking density of the BA-a and JA-c copolymers. The structures of the synthesized monomers and the physical properties of cured polymeric resin are characterized by spectroscopic and thermal analysis.
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