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Perceptions Of Corporate Social Responsibility In The Capital Market
Choi, Hyunjung,Moon, Doocheol Clute Institute 2016 The Journal of Applied Business Research Vol.32 No.5
<P>This study investigates how capital market participants such as investors and financial analysts perceive corporate social responsibility (CSR) as improving earnings quality. Managers use CSR as a signal of future financial improvement, which causes companies to invest in CSR in the current period. An expectation of future financial improvement leads to increase in the quality of earnings because it curtails the incentive to engage in earnings management. In addition, CSR is a signal to increase the reputation of the firm. If a firm values its reputation, managers of a CSR firm would refrain from earnings management to avoid damage to its reputation. We use a sample of Korean listed companies for the period 2002-2011 and a proxy for CSR involvement based on the Korea Economic Justice Institute index. When we use earnings response coefficients (ERCs) to measure investors’ perceptions of earnings quality, we find that ERCs are higher for firms with engagement in CSR activity. Further, when we use the predictive ability of past earnings in forecasting future earnings to measure analysts’ perceptions of earnings quality, we find that the predictive ability of past earnings is higher when firms engage in CSR. Our results provide evidence that capital market participants perceive CSR as a signal of improved earnings quality.</P>
Comparison of Machine Learning Models According to Data Trends for Predicting Tomato Growth
Hyunjung Hwang,Hyuntae Lee,Seungwoo Cha,Jihyeon Choi,Hwanyong Choi,Sangjun Chung,Seoheui Lee,Junhyuck Jang,Christopher RETITI DIOP EMANE,Yuna Kim,Jongtae Lim,Kyoungsoo Bok,Jaesoo Yoo 한국콘텐츠학회 2022 한국콘텐츠학회 ICCC 논문집 Vol.2022 No.12
Choi, Hyunjung,Ahn, Soomi,Chang, Huikyoung,Cho, Nam Suk,Joo, Kyungmi,Lee, Byeong Gon,Chang, Ihseop,Hwang, Jae Sung Munksgaard 2007 Experimental dermatology Vol.16 No.2
<P>Abstract: </P><P>Tyrosinase, a type I membrane glycoprotein, is synthesized and glycosylated in the endoplasmic reticulum (ER) and Golgi. The enzyme is subsequently transported to melanosomes where it participates in melanogenesis. Previous studies showed that the disruption of early ER N-glycan processing by deoxynojirimycin (DNJ), an inhibitor of <I>&agr;</I>-glucosidase, suppresses tyrosinase enzymatic activity and melanogenesis. However, the disruption of late glycan processing, mainly performed by ER and Golgi <I>&agr;</I>-1,2-mannosidases, on tyrosinase enzymatic activity and melanogenesis remains to be investigated. Following treatment of HM3KO human melanoma cells with deoxymannojirimycin (DMJ), an inhibitor of <I>&agr;</I>-1,2-mannosidase, transport of tyrosinase to the melanosome, enzymatic activity, and melanogenesis were reduced in a dose-dependent manner. However, DMJ did not directly inhibit tyrosinase enzymatic activity and expression. Interestingly, an extract of <I>Streptomyces subrutilus</I> culture medium (ESSCM) containing DMJ and DNJ as the main components inhibited glycosylation and transport of tyrosinase to the melanosome as well as melanin synthesis, but with no negative effects on cell viability. These inhibitory effects of ESSCM were stronger than those of DMJ or DNJ alone. Tyrosinase glycosylation and melanogenesis in HM3KO melanoma cells were more effectively inhibited by DMJ and DNJ combined than DMJ or DNJ alone. Accordingly, we propose that ESSCM is a potential candidate for treating undesirable hyperpigmentation conditions, such as melasma, postinflammatory melanoderma, and solar lentigo.</P>
Hyunjung Lee,Cheolhun Choi,Cheolhun Choi,Hyejin Jeong,Seongheon Lee,Seongwook Jeong 대한마취통증의학회 2013 Korean Journal of Anesthesiology Vol.64 No.1
Background: Although cisatracurium has many advantages in anesthetic practices, the best choice of a nondepolarizing neuromuscular blocking agent that can replace succinylcholine is rocuronium. However, it is reported that remifentanil with propofol might provide reliable intubating condition, even without a neuromuscular blocking agent; therefore, it might improve the intubating condition with cisatracurium. This study examined intubating conditions after administering rocuronium or cisatracurium in a rapid sequence induction with remifentanil-propofol. Methods: Fifty two ASA physical status 1 or 2 adult patients scheduled for an elective surgery were enrolled in a randomized double-blinded trial. Anesthesia was induced in all patients with propofol 2.0 mg/kg and remifentanil 0.5 μg/kg, administered over 60 seconds. Rocuronium 0.9 mg/kg (3 × ED95, R group, n = 23) or cisatracurium 0.15 mg/kg (3 × ED95, C group, n = 29) was administered after the induction sequence. Laryngoscopy was attempted when the anesthesiologist thought it was 90 seconds after drug administration and appropriate time for intubation. The examiner, another anesthesiologist, recorded the exact time to intubation and suppression of maximal T1 on TOF. The intubating condition was assessed by the first anesthesiologist, as excellent, good, poor or not possible. Results: The best time to laryngoscopy was predicted by measuring TOF and was found to be significantly longer in the C group (197 ± 53 s) than in the R group (102 ± 49 s) (P value < 0.05). However, time to larygoscopy, intubating condition during the laryngoscopy, and hemodynamic changes after intubation was similar in both groups. Conclusions: Despite fundamentally slower onset time, cisatracurium can provide quite good intubating conditions, which were comparable to those achieved with equipotent doses of rocuronium, which is more expensive in anesthesia inducted with remifentanil and propofol.
IL-4 Inhibits the Melanogenesis of Normal Human Melanocytes through the JAK2–STAT6 Signaling Pathway
Choi, Hyun,Choi, Hyunjung,Han, Jiyeon,Jin, Sun Hee,Park, Ju-Yearl,Shin, Dong Wook,Lee, Tae Ryong,Kim, Kwangmi,Lee, Ai-Young,Noh, Minsoo The Society for Investigative Dermatology, Inc 2013 The Journal of investigative dermatology Vol.133 No.2
Skin diseases can be characterized by their predominant CD4-positive T-helper (Th) cell profiles. Chronic dermatological conditions often give rise to abnormal skin pigmentation. To understand the role of Th cells in pigmentation, the effects of the major Th cell cytokines, IFNγ, IL-4, and IL-17A, on melanogenesis were evaluated using cultured normal human melanocytes (NHMs) instead of relying on transformed melanoma cell lines. IL-4 directly inhibited melanogenesis in NHMs and downregulated both transcription and translation of melanogenesis-associated genes, such as microphthalmia-associated transcription factor (MITF) and dopachrome tautomerase. Despite the lack of a direct inhibition of melanin pigment synthesis, IFNγ and IL-17A increased the synthesis of an antimelanogenic cytokine IL-6 in NHMs. IFNγ activated signal transducers and activators of transcription 1 (STAT1) and STAT3 phosphorylation in NHMs, and IL-4 increased the STAT3 and STAT6 phosphorylation. The differential phosphorylation profile of STAT proteins between IFNγ and IL-4 may explain the difference in their effect on melanogenesis in NHMs. The IL-4-induced downregulation of melanogenesis was inhibited by treating NHMs with a JAK2 inhibitor AG490 or STAT6 siRNA. In conclusion, the involvement of the IL-4-induced JAK2–STAT6 signaling and the IFNγ- or IL-17A-dependent antimelanogenic IL-6 production should be considered as one of the mechanisms explaining the association with hypopigmention in skin diseases.
Choi, Hyunjung,Ahn, Soomi,Lee, Byeong G.,Chang, Ihseop,Hwang, Jae S. Munksgaard International Publishers 2005 Pigment cell research Vol.18 No.6
<P>Summary</P><P>The development of effective skin-lightening agents is an increasingly important area of research aimed at the treatment of hyperpigmentation induced by UV irradiation or by medical conditions such as melasma, postinflammatory melanoderma and solar lentigo. Although some inhibit tyrosinase, identifying and understanding the mechanisms of action of other agents is an important goal if more effective pigmentation inhibitors are to be developed. We present here that an extract of <I>Lepidium apetalum</I> (ELA) decreased UV-induced skin pigmentation in brown guinea pigs and melanogenesis of HM3KO human melanoma cells. Interestingly, ELA did not reduce melanogenesis in HM3KO cells unless they were co-cultivated in keratinocyte-conditioned medium prepared by culturing keratinocytes with ELA. Under these conditions, ELA decreased tyrosinase mRNA and protein expression as well as melanin content via an ELA-mediated increase in keratinocyte IL-6 production which in turn was shown to decrease in the expression Mitf, a transcription factor implicated in tyrosinase gene expression and melanocyte differentiation. The results reveal that ELA may be an effective inhibitor of hyperpigmentation caused by UV irradiation or by pigmented skin disorders through a mechanism involving IL-6-mediated downregulation of Mitf rather than a direct inhibition of tyrosinase activity.</P>
Outbreak of Rice Panicle Blast in Jeonbuk Province of Korea in 2021
Hyunjung Chung,Woo-Il Lee,Soo Yeon Choi,Nak-Jung Choi,Sang-Min Kim,윤주연,Bong Choon Lee 한국식물병리학회 2023 Plant Pathology Journal Vol.39 No.1
Rice panicle blast is one of the most serious diseases threatening stable rice production by causing severe damage to rice yields and quality. The disease is easy to occur under low air temperature and frequent heavy rainfall during the heading season of rice. In 2021, a rice panicle blast severely occurred in the Jeonbuk province of Korea. The incidence area of panicle blast accounted for 27.7% of the rice cultivation area of Jeonbuk province in 2021, which was 13.7-times higher than in 2019 and 2.6-times higher than in 2020. This study evaluated the incidence areas of rice panicle blast in each region of Jeonbuk province in 2021. The weather conditions during the heading season of rice, mainly cultivated rice cultivars, and the race diversity of the Jeonbuk isolates were also investigated. It will provide important information for the effective control of the rice panicle blast.