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Attitude of the Korean dentists towards radiation safety and selection criteria
Lee, Byung-Do,Ludlow, John B. Korean Academy of Oral and Maxillofacial Radiology 2013 Imaging Science in Dentistry Vol.43 No.3
Purpose: X-ray exposure should be clinically justified and each exposure should be expected to give patients benefits. Since dental radiographic examination is one of the most frequent radiological procedures, radiation hazard becomes an important public health concern. The purpose of this study was to investigate the attitude of Korean dentists about radiation safety and use of criteria for selecting the frequency and type of radiographic examinations. Materials and Methods: The study included 267 Korean dentists. Five questions related to radiation safety were asked of each of them. These questions were about factors associated with radiation protection of patients and operators including the use of radiographic selection criteria for intraoral radiographic procedures. Results: The frequency of prescription of routine radiographic examination (an example is a panoramic radiograph for screening process for occult disease) was 34.1%, while that of selective radiography was 64.0%. Dentists' discussion of radiation risk and benefit with patients was infrequent. More than half of the operators held the image receptor by themselves during intraoral radiographic examinations. Lead apron/thyroid collars for patient protection were used by fewer than 22% of dental offices. Rectangular collimation was utilized by fewer than 15% of dental offices. Conclusion: The majority of Korean dentists in the study did not practice radiation protection procedures which would be required to minimize exposure to unnecessary radiation for patients and dental professionals. Mandatory continuing professional education in radiation safety and development of Korean radiographic selection criteria is recommended.
Attitude of the Korean dentists towards radiation safety and selection criteria
이병도,John B. Ludlow 대한영상치의학회 2013 Imaging Science in Dentistry Vol.43 No.3
Purpose: X-ray exposure should be clinically justified and each exposure should be expected to give patients benefits. Since dental radiographic examination is one of the most frequent radiological procedures, radiation hazard becomes an important public health concern. The purpose of this study was to investigate the attitude of Korean dentists about radiation safety and use of criteria for selecting the frequency and type of radiographic examinations. Materials and Methods: The study included 267 Korean dentists. Five questions related to radiation safety were asked of each of them. These questions were about factors associated with radiation protection of patients and operators including the use of radiographic selection criteria for intraoral radiographic procedures. Results: The frequency of prescription of routine radiographic examination (an example is a panoramic radiograph for screening process for occult disease) was 34.1%, while that of selective radiography was 64.0%. Dentists’ discussion of radiation risk and benefit with patients was infrequent. More than half of the operators held the image receptor by themselves during intraoral radiographic examinations. Lead apron/thyroid collars for patient protection were used by fewer than 22% of dental offices. Rectangular collimation was utilized by fewer than 15% of dental offices. Conclusion: The majority of Korean dentists in the study did not practice radiation protection procedures which would be required to minimize exposure to unnecessary radiation for patients and dental professionals. Mandatory continuing professional education in radiation safety and development of Korean radiographic selection criteria is recommended.
Xiaoying Zhang,Min Lu,Richard A. Ludlow,Wentao Ma,Huaming An 한국원예학회 2021 Horticulture, Environment, and Biotechnology Vol.62 No.5
The fruit of the perennial rosebush Rosa roxburghii were valued for their high levels of ascorbic acid, superoxide dismutaseactivity, and cancer preventing eff ects. The high cellulose and low pectin content of Rosa roxburghii fruit results in an undesirablefi brous texture and hence needs to be addressed. However, little is known about the molecular mechanisms underlyingdietary fi ber metabolism in this fruit. Here, we report that the contents of cellulose, pectin, and lignin were increased byshading treatments at the maturation stage of fruit development. Under 50% shading, the soluble pectin content increased by16.39%, which may improve the fruit palatability. However, deeper shading of 100% caused the lignin content to increase by28.86%, which conversely may lower fruit quality. Based on transcriptome analysis, we identifi ed candidate genes involvedin dietary fi ber metabolism, including cellulose synthase (CesA) 1, 2, 3, and 5 , â-1,4-xylosyltransferase (IRX) , arabinosyltransferase(ARAD) 1 and 2 , galacturonosyltransferase (GAUT) , cellulolytic enzyme (Cx) , and pectin methylesterase , inwhich CesA1, CesA2, CesA3, IRX, ARAD2 , and GAUT3 signifi cantly responded to shading and positively correlated withthe content of their corresponding component. Furthermore, cinnamyl alcohol dehydrogenase was signifi cantly regulatedby shading treatment and positively correlated with increasing lignin concentration. These results may facilitate a betterunderstanding of the molecular mechanisms of dietary fi ber metabolism in R. roxburghii fruit under low light conditionsand provide a framework for future crop improvement.
Faraday-Shielded dc Stark-Shift-Free Optical Lattice Clock
Beloy, K.,Zhang, X.,McGrew, W. F.,Hinkley, N.,Yoon, T. H.,Nicolodi, D.,Fasano, R. J.,Schä,ffer, S. A.,Brown, R. C.,Ludlow, A. D. American Physical Society 2018 Physical Review Letters Vol.120 No.18
<P>We demonstrate the absence of a dc Stark shift in an ytterbium optical lattice clock. Stray electric fields are suppressed through the introduction of an in-vacuum Faraday shield. Still, the effectiveness of the shielding must be experimentally assessed. Such diagnostics are accomplished by applying high voltage to six electrodes, which are grounded in normal operation to form part of the Faraday shield. Our measurements place a constraint on the dc Stark shift at the 10(-20) level, in units of the clock frequency. Moreover, we discuss a potential source of error in strategies to precisely measure or cancel nonzero dc Stark shifts, attributed to field gradients coupled with the finite spatial extent of the lattice-trapped atoms. With this consideration, we find that Faraday shielding, complemented with experimental validation, provides both a practically appealing and effective solution to the problem of dc Stark shifts in optical lattice clocks.</P>