Evaluation of Salivary Gland Function Using Diffusion-Weighted Magnetic Resonance Imaging for Follow-Up of Radiation-Induced Xerostomia

Yunyan Zhang,Dan Ou,Yajia Gu,Xiayun He,Weijun Peng 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.4

Objective: To investigate the value of diffusion-weighted magnetic resonance imaging (DW-MRI) as a noninvasive tool to assess salivary gland function for follow-up of patients with radiation-induced xerostomia. Materials and Methods: This study included 23 patients with nasopharyngeal carcinoma who had been treated with parotidsparing radiotherapy (RT). Salivary function was assessed by DW-MRI pre-treatment and one week and one year post-RT, respectively. The maximum apparent diffusion coefficient (ADC) of parotid glands (pADCmax) and the time to peak ADC of parotid glands (pTmax) during stimulation were obtained. Multivariate analysis was used to analyze factors correlated with the severity of radiation-induced xerostomia. Results: The ADCs of parotid and submandibular glands (1.26 ± 0.10 x 10-3 mm2/s and 1.32 ± 0.07 x 10-3 mm2/s pre-RT, respectively) both showed an increase in all patients at one week post-RT (1.75 ± 0.16 x 10-3 mm2/s, p < 0.001 and 1.70 ± 0.16 x 10-3 mm2/s, p < 0.001, respectively), followed by a decrease in parotid glands at one year post-RT(1.57 ± 0.15 x 10-3 mm2/s, p < 0.001) but not in submandibular glands (1.69 ± 0.18 x 10-3 mm2/s, p = 0.581). An improvement in xerostomia was found in 13 patients at one year post-RT. Multivariate analysis revealed 4 significant predictors for the improvement of xerostomia, including dose to parotid glands (p = 0.009, odds ratio [OR] = 0.639), the ADC of submandibular glands (p = 0.013, OR = 3.295), pADCmax (p = 0.024, OR = 0.474), and pTmax (p = 0.017, OR = 0.729) at one week post-RT. Conclusion: The ADC value is a sensitive indicator for salivary gland dysfunction. DW-MRI is potentially useful for noninvasively predicting the severity of radiation-induced xerostomia.

Multi-Task Support Vector Machine for Data Classification

Yunyan Song,Wenxin Zhu 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.7

Multi-task Learning (MTL) algorithms aim to improve the performance of several learning methods through shared information among all tasks. One particularly successful instance of multi-task learning is its adaptation to support vector machine (SVM). Recently advances in large-margin learning have shown that their solutions may be misled by the spread of data and preferentially separate classes along large spread directions. In this paper, we propose a novel formulation for multi-task learning by extending the recently published relative margin machine algorithm to the multi-task learning paradigm. The new method is an extension of support vector machine for single task learning. The objective of our algorithm is to obtain a different predictor for each task while taking into account the fact that the tasks are related as well as the spread of the data. We test the proposed method experimentally using real data. The experiments show that the proposed method performs better than existing multi-task leaning with SVM and single-task leaning with SVM.

Voltammetric Studies of Diazocalix[4]crown-6 for Metal Ion Sensing

Yunyan Dong,김태현,Chang-Seuk Lee,Hyun Jung Kim,Jae Hong Lee,Joung Hae Lee,김하석,김종승 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.12

The complex formation between diazocalix[4]dipropyl (1) and diazocalix[4]crown-6 ether (2) with alkali, alkaline earth and transition metal ions was investigated by voltammetry. Electrochemical properties of compounds 1 and 2 and their selectivity toward metal ions were evaluated in CH3CN solution by comparison of voltammetric behaviors of two phenols in each compound. Compounds 1 and 2 showed almost same voltammetric behavior which is two irreversible oxidation peaks caused by intramolecular hydrogen bonding between two phenols in 1 and 2. While, however, upon interacting with various metal ions, 1 with two propyl ether groups showed no significant changes in voltammetry, 2 with crown ether group caused significant voltammetric changes upon the addition of Ba2+ to 2. Their behavior is closely related to the complex formation by entrapment of metal ion into crown ether cavity, and ion-dipole interaction between metal ion and two phenolic groups in calix[4]crown-6.

Reinforcement and Ductility Effect of Plant Fine Roots on the Soil

Yunyan Zhou,Kun Xu 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Genetic Diversity of Chinese Melon Cultivars (Cucumis melo L.) Based on Simple Sequence Repeat Markers

Yunyan Sheng,Feishi Luan,Kenong Chen 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Supramolecular photochirogenesis in sensitizing chiral nanopore: Enantiodifferentiating photoisomerization of (Z)-cyclooctene included and sensitized by POST-1

Gao, Yunyan,Wada, Takehiko,Yang, Kwangsuk,Kim, Kimoon,Inoue, Yoshihisa Wiley Subscription Services, Inc., A Wiley Company 2005 Chirality Vol.17 No.suppl1

<P>By using homochiral mesoporous POST-1 (Scheme 1) as an inherently chiral sensitizing host, supramolecular enantiodifferentiating photoisomerizations of (Z)-cyclooctene (1Z) were performed for the first time to examine the sensitizing ability of the chiral nanopores, walls of which are decorated with pyridine chromophore. The homochiral nanopores of POST-1 crystals were demonstrated to function as an effective chiral-sensitizing cavity to give the optically active (E)-isomer 1E in up to 5% enantiomeric excess (ee), thus expanding the scope of porous material-mediated chirogenesis to both ground and excited electronic states. Chirality 17:S19–S23, 2005. © 2005 Wiley-Liss, Inc.</P>

Long-range intramolecular photoredox reaction via coupled charge and proton transfer of triplet excited anthraquinones mediated by water

Hou, Yunyan,Huck, Lawrence A.,Wan, Peter Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.10

The formal intramolecular photoredox reaction initially discovered for the parent 2-(hydroxymethyl)-anthraquinone (1) has been extended to include analogs 3-6 in which the oxidizable benzyl alcohol group is significantly further away from the anthraquinone moiety. All of 3-6 undergo a clean and efficient formal intramolecular photoredox reaction in water catalyzed by acid ($\Phi$ = 0.1-0.6), in which the alcohol is oxidized to aldehyde and the anthraquinone is reduced to dihydroxyanthracene. The need for water, observation of acid catalysis, unimolecularity of reaction in anthraquinone, AM1 calculations and LFP studies support a mechanism involving a highly polarized triplet excited state in which the electron density of the distal phenyl moieties is transferred to the central anthraquinone ring, which is subsequently trapped adiabatically by protonation at the anthraquinone carbonyl oxygen and deprotonation at the benzyl C-H.

이중모음의 정의에 대하여

나운연 ( Luo Yunyan ) 인하대학교 한국학연구소 2017 한국학연구 Vol.0 No.47

한국어의 이중모음에 관한 연구는 일찍부터 시작했지만, 여전히 명확하지 않은 지점이 있다. 특히 이중모음을 어떻게 정의하느냐에 대한 문제는 연구자 간 이견이 더욱 많아 일관성을 찾아보기 힘들다. 이중모음의 정의를 정확히 기술하자는 목적으로 본고는 일반언어학의 관점에서 한국어 이중모음의 정의에 대해 검토하고, 논의 상 혼란이 있는 점을 밝혀 바람직한 논의 방향을 제시해보았다. 최근 음운론 개론서 및 학술지 논문을 검토한 결과, 두 가지 논의 사항을 발견하였다. 첫째, 이중모음의 구성을 무엇으로 볼 것인가 둘째, 현재 혼재되어 쓰이고 있는 부음에 해당하는 용어를 무엇으로 통일할 것인가. 그리고 논란 중인 견해들의 합리성을 자세히 분석하여 본고의 견해를 제시하였다. 결과적으로 본고는 반모음이 독립된 음소로 인정된 이상, 이중모음의 구성을 반모음과 단모음의 결합으로 보는 것이 합리적이고, 부음의 용어로는 반모음이 가장 타당하다고 보았다. 그리고 이에 따라 한국어의 이중모음을 반모음과 단모음으로 이루어진 하나의 음절로 정의하는 방안을 제안하였다. Although the study of diphthongs in Korean began early, there still remains some problems that have not yet been solved. In particular, consistent views are difficult to see in studies concerning the definition of diphthongs. In order to describe the definition of the diphthong more correctly, this paper examines the definition of the Korean diphthong in terms of general linguistics, clarifies the confusion in the precedent studies, and try to present a desirable research direction. By examining the viewpoints from recent researchs on the diphthong, two problems concerning composition of the diphthong and mixture of terms corresponding to syllable subsidiary of the diphthong have been found. At same time this paper analyzes the rationality of the controversial views and presented some viewpoints of this study. As a result, it is reasonable to regard the composition of the diphthong as a semivowel and a monophthong when the semivowel is recognized as an independent phoneme. Therefore, this paper proposes a method to define the Korean diphthong as a syllable consisting of a semivowel and a monophthong.

Probing the effect of thickener microstructure on rheological and tribological properties of grease

Changjiang Zhou,Guanlin Ren,Xiaoqiang Fan,Yunyan Lv 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.111 No.-

The thickener microstructure strongly determines the properties of lubricating grease. Here, four types ofgrease were synthesized through different thickeners (lithium complex soap, polyurea, calcium sulfonatecomplex soap, bentonite), thickening polyalphaolefin. The influence of the thickener microstructure onthe physicochemical, rheological, and tribological properties was evaluated. Results show that thelithium complex soap with a spiral fiber structure shows the best physicochemical properties and thehighest yield stress. The four greases show the shear-thinning behavior because of the deformation ofthe thickener structures. The calcium sulfonate complex soap with a dense porous structure presentsoptimal tribological properties because of the synergy effect of the thickener deposited film and thetribo-chemical reaction film.

Damage of scarf-repaired composite laminates subjected to low-velocity impacts

Xiaoquan Cheng,Wenyi Zhao,Shufeng Liu,Yunyan Xu,Jianwen Bao 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.2

The damage characters of scarf repaired composite laminates subjected to low-velocity impact with various energy levels at different locations are studied experimentally. The results are compared with those of the original laminates which have no initial damage and don’t need repair. The impact load-time history of the specimens, the velocity-time curves of the impactor, the post impact compressive strength of the specimens and the C-scan photographs of the damaged regions are obtained. The delamination threshold load and damage character of the specimen section at impact point are also studied. The results have shown that the impact response of a repaired composite laminate is sensitive to the location of the impact. The impact load and the delamination threshold load have shown different characters for specimens with different impact locations. The debonding characters of the adhesive and compressive strength after impact of the specimens are also influenced by impact locations.