Left lobe living donor liver transplantation using the resection and partial liver segment 2-3 transplantation with delayed total hepatectomy (RAPID) procedure in cirrhotic patients: First case report in Korea

In liver transplantation, the primary concern is to ensure an adequate future liver remnant (FLR) volume for the donor, while selecting a graft of sufficient size for the recipient. The living donor-resection and partial liver segment 2-3 transplantation with delayed total hepatectomy (LD-RAPID) procedure offers a potential solution to expand the donor pool for living donor liver transplantation (LDLT). We report the first case involving a cirrhotic patient with autoimmune hepatitis and hepatocellular carcinoma, who underwent left lobe LDLT using the LD-RAPID procedure. The living liver donor (LLD) underwent a laparoscopic left hepatectomy, including middle hepatic vein. The resection on the recipient side was an extended left hepatectomy, including the middle hepatic vein orifice and caudate lobe. At postoperative day 7, a computed tomography scan showed hypertrophy of the left graft from 320 g to 465 mL (i.e., a 45.3% increase in graft volume body weight ratio from 0.60% to 0.77%). After a 7-day interval, the diseased right lobe was removed in the second stage surgery. The LD-RAPID procedure using left lobe graft allows for the use of a small liver graft or small FLR volume in LLD in LDLT, which expands the donor pool to minimize the risk to LLD by enabling the donation of a smaller liver portion.

An Examination of the Effects of Job Insecurity on Counterproductive Work Behavior Through Organizational Cynicism: Moderating Roles of Perceived Organizational Support and Quality of Leader-Member Exchange

Job insecurity can trigger cynical attitudes and ultimately lead to harmful behaviors in organizations under the current fast-changing business environment. Drawing on psychological contract theory, this study aimed to investigate the relationship between job insecurity and counterproductive work behavior (CWB) by focusing on the mediating role of organizational cynicism and moderating roles of perceived organizational support (POS) and leader-member exchange (LMX). The data used for the analysis came from a survey that targeted tourism-related industries in South Korea, and 296 responses were finally analyzed. We analyzed reliability, correlation, and mediation, and conducted confirmatory factor analysis, regression analysis, and moderation analysis using SPSS PROCESS macro v. 3.5, with AMOS v. 25.0. The key findings of this study are as follows. First, we found that job insecurity was positively related to CWB. Second, organizational cynicism mediated the relationship between job insecurity and CWB. Third, POS and LMX intensified the negative effects of job insecurity and organizational cynicism, affecting CWB. These results imply that employees with a high level of POS and LMX are likely to have opportunistic behaviors (e.g., abuse, absences, sabotage) by abusing the support and trust from their organizations. The implications for research and practice, limitations, and directions for future research are discussed.

Prediction of very early subclinical rejection with machine learning in kidney transplantation

Protocol biopsy is a reliable method for assessing allografts status after kidney transplantation (KT). However, due to the risk of complications, it is necessary to establish indications and selectively perform protocol biopsies by classifying the high-risk group for early subclinical rejection (SCR). Therefore, the purpose of this study is to analyze the incidence and risk factors of early SCR (within 2 weeks) and develop a prediction model using machine learning. Patients who underwent KT at Samsung Medical Center from January 2005 to December 2020 were investigated. The incidence of SCR was investigated and risk factors were analyzed. For the development of prediction model, machine learning methods (random forest, elastic net, extreme gradient boosting [XGB]) and logistic regression were used and the performance between the models was evaluated. The cohorts of 987 patients were reviewed and analyzed. The incidence of SCR was 14.6%. Borderline cellular rejection (BCR) was the most common type of rejection, accounting for 61.8% of cases. In the analysis of risk factors, recipient age (OR 0.98, p = 0.03), donor BMI (OR 1.07, p = 0.02), ABO incompatibility (OR 0.15, p < 0.001), HLA II mismatch (two [OR 6.44, p < 0.001]), and ATG induction (OR 0.41, p < 0.001) were associated with SCR in the multivariate analysis. The logistic regression prediction model (average AUC = 0.717) and the elastic net model (average AUC = 0.712) demonstrated good performance. HLA II mismatch and induction type were consistently identified as important variables in all models. The odds ratio analysis of the logistic prediction model revealed that HLA II mismatch (OR 6.77) was a risk factor for SCR, while ATG induction (OR 0.37) was a favorable factor. Early SCR was associated with HLA II mismatches and induction agent and prediction model using machine learning demonstrates the potential to predict SCR.

How job crafting behaviors influence the innovative behavior of knowledge workers in the gig economy: based on the organismic integration theory

Introduction

The gig economy is extolled for its potential to stimulate economic and social development. This study examines the mediating roles of controlled and autonomous motivation in the relationship between job crafting and innovative behavior in the context of knowledge workers in the gig economy.

Methods

To examine these relationships, we propose and test a conceptual framework using an online survey conducted among knowledge workers in China. The participants consisted of 302 knowledge workers who voluntarily participated in the study. We used structural equation modeling to test the proposed relationships among the variables.

Results

Controlled and autonomous motivation mediates the relationship between job crafting and innovative behavior.

Discussion

Our study shed light on the knowledge workers' motivation dilemma in the gig economy, with theoretical implications for research regarding job crafting, motivation, and practice implications about the job crafting and innovative behavior of knowledge workers.

Graft-recipient-weight ratio and lowered immunosuppression is important for the success of adult liver retransplantation

This study analyzed the risk of liver retransplantation and factors related to better outcome. Adult liver transplantations performed during 1996-2021 were included. Comparison between first transplantation and retransplantation were performed. Among retransplantation cases, comparison between whole liver and partial liver graft was performed. Multivariable Cox analyses for analyzing risk factors for primary graft and overall patient survival were performed for the entire cohort as well as the subgroup of patients with retransplantation. A total 2237 transplantations from 2135 adults were included and 103 cases were retransplantation. A total of 44 cases (42.7%) were related to acute graft dysfunction while 59 cases (57.3%) were related to subacute or chronic graft dysfunction. Retransplantation was related poor primary graft (HR 3.439, CI 2.230-5.304, P < 0.001) and overall patient survival. (HR 2.905, CI 2.089-4.040, P < 0.001) Among retransplantations, mean serum FK506 trough level ≥ 9 ng/mL was related to poor primary graft (HR 3.692, CI 1.288-10.587, P = 0.015) and overall patient survival. (HR 2.935, CI 1.195-7.211, P = 0.019) Graft-recipient-weight ratio under 1.0% was related to poor overall patient survival in retransplantations. (HR 3.668, CI 1.150-11.698, P = 0.028). Retransplantation can be complicated with poor graft and patient survival compared to first transplantation, especially when the graft size is relatively small. Lowering the FK506 trough level during the first month can be beneficial for outcome.

Improved recurrence-free survival in patients with HCC with post-transplant plasma exchange

Total plasma exchange (TPE) can play a role in cancer treatment by eliminating immune checkpoint inhibitors. This study investigated whether TPE improved oncological outcomes in patients with HCC who underwent ABO-incompatible living donor liver transplantation (LT). The study included 152 patients who underwent ABO-incompatible living donor LT for HCC between 2010 and 2021 at Samsung Medical Center. Overall survival was analyzed using the Kaplan-Meier curve, whereas HCC-specific recurrence-free survival (RFS) was analyzed using the cumulative incidence curve after propensity score matching. Cox regression and competing risks subdistribution hazard models were used to identify the risk factors associated with overall survival and HCC-specific RFS, respectively. The propensity score matching resulted in 54 matched pairs, grouped according to whether they underwent postoperative TPE [post-transplant TPE(+)] or not [post-transplant TPE(-)]. The 5-year HCC-specific RFS cumulative incidence was superior in the post-transplant TPE (+) group [12.5% (95% CI: 3.1%-21.9%)] compared with the post-transplant TPE(-) group [38.1% (95% CI: 24.4%-51.8%), p = 0.005]. In subgroup analysis for patients with microvascular invasion and those beyond the Milan criteria, the post-transplant TPE(+) group showed significantly superior HCC-specific survival. The multivariable analysis also showed that postoperative TPE had a protective effect on HCC-specific RFS (HR = 0.26, 95% CI: 0.10-0.64, p = 0.004) and that the more post-transplant TPE was performed, the better RFS was observed (HR = 0.71, 95% CI: 0.55-0.93, p = 0.012). Post-transplant TPE was found to improve RFS after ABO-incompatible living donor LT for HCC, particularly in advanced cases with microvascular invasion and beyond Milan criteria. These findings suggest that TPE may have a potential role in improving oncological outcomes in patients with HCC undergoing LT.

Effect of pre-operative radiation therapy on surgical outcome in retroperitoneal sarcoma

Background

A high rate of locoregional recurrence is one of the major difficulties in successful treatment of retroperitoneal sarcoma (RPS). Although pre-operative radiation therapy (RT) is considered a potential way to improve local recurrence, concerns about the associated treatment toxicity and risk of peri-operative complications need to be addressed. Hence, this study investigates the safety of pre-operative RT (preRTx) for RPS.

Methods

A cohort of 198 patients with RPS who had undergone both surgery and RT was analyzed for peri-operative complications. They were divided into three groups according to the RT scheme: (1) preRTx group, (2) post-operative RT without tissue expander, and (3) post-operative RT with tissue expander.

Results

The preRTx was overall well tolerated and did not affect the R2 resection rate, operative time, and severe post-operative complications. However, the preRTx group was associated with higher incidence of post-operative transfusion and admission to intensive care unit (p = 0.013 and p = 0.036, respectively), where preRTx was an independent risk factor only for the post-operative transfusion (p = 0.009) in multivariate analysis. The median radiation dose was the highest in preRTx group, although no significant difference was demonstrated in overall survival and local recurrence rate.

Conclusion

This study suggests that the preRTx does not add significant post-operative morbidity to the patients with RPS. In addition, radiation dose elevation is achievable with the pre-operative RT. However, a meticulous intra-operative bleeding control is recommended in those patients, and further high-quality trials are warranted to evaluate the long-term oncological outcomes.

Indications for open hepatectomy in the era of laparoscopic liver resection: a high volume single institutional study

Background/Aim

Since the introduction of laparoscopy for liver resection in the 1990s, the performance of laparoscopic liver resection (LLR) has been steadily increasing. However, there is currently no data on the extent to which laparoscopy is used for liver resection. Herein, we investigated the extent to which laparoscopy is performed in liver resection and sought to determine whether surgeons prefer laparoscopy or laparotomy in the posterosuperior (PS) segment.

Methods

For this retrospective observational study, we enrolled patients who had undergone liver resection at the Samsung Medical Center between January 2020 and December 2021. The proportion of LLR in liver resection was calculated, and the incidence and causes of open conversion were investigated.

Results

A total of 1,095 patients were included in this study. LLR accounted for 79% of the total liver resections. The percentage of previous hepatectomy (16.2% vs. 5.9%, P<0.001) and maximum tumor size (median 4.8 vs. 2.8, P<0.001) were higher in the open liver resection (OLR) group. Subgroup analysis revealed that tumor size (median 6.3 vs. 2.9, P<0.001) and surgical extent (P<0.001) in the OLR group were larger than those in the LLR group. The most common cause of open conversion (OC) was adhesion (57%), and all OC patients had tumors in the PS.

Conclusions

We investigated the recent preference of practical surgeons in liver resection, and found that surgeons preferred OLR to LLR when treating a large tumor located in the PS.

The Role of Preoperative 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Retroperitoneal Sarcoma

¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) was used to predict pathologic grades based on the maximum standardized uptake value (SUVmax) in soft tissue sarcoma and bone sarcoma. In retroperitoneal sarcoma (RPS), the effectiveness of PET was not well known. This study was designed to investigate the association of SUVmax with histopathologic grade and evaluate the usefulness of ¹⁸F-FDG PET/CT before operation. Patients at Samsung Medical Center undergoing primary surgery for retroperitoneal sarcoma with preoperative ¹⁸F-FDG PET/CT imaging between January 2001 and February 2020 were investigated. The relationship between SUVmax and histologic features was assessed. The association of SUVmax with overall survival (OS), local recurrence (LR), and distant metastasis (DM) were studied. Of the total 129 patients, the most common histologic subtypes were liposarcoma (LPS; 68.2%) and leiomyosarcoma (LMS; 15.5%). The median SUVmax was 4.5 (range, 1- 29). Moreover, SUVmax was correlated with tumor grade (p < 0.001, Spearman coefficient; 0.627) and mitosis (p < 0.001, Spearman coefficient; 0.564) and showed a higher value in LMS (12.04 ± 6.73) than in dedifferentiated liposarcoma (DDLPS; 6.32 ± 4.97, p = 0.0054). SUVmax was correlated with pathologic parameters (tumor grade and mitosis) in RPS and was higher in the LMS group than the DDLPS group. The optimal SUVmax threshold to distinguish high tumor grade was 4.8. Those with a SUVmax greater than the threshold showed poor prognosis regarding OS, LR, and DM (p < 0.001).

Postoperative Outcomes of Distal Pancreatectomy for Retroperitoneal Sarcoma Abutting the Pancreas in the Left Upper Quadrant

Background

En bloc resection of the tumor with adjacent organs is recommended for localized retroperitoneal sarcoma (RPS). However, resection of the pancreas is controversial because it may cause serious complications, such as pancreatic fistula or bleeding. Thus, we evaluated the outcomes of distal pancreatectomy (DP) in pancreas-abutting RPS of the left upper quadrant (LUQ).

Methods

We retrospectively reviewed all consecutive patients who underwent surgery for RPS between September 2001 and April 2020. We selected 150 patients with all or part of their tumor located in the LUQ on preoperative computed tomography. Eighty-six patients who had tumors abutting the pancreas were finally enrolled in our study.

Results

Fifty-three patients (53/86; 61.6%) were included in the non-DP group, and 33 patients (33/86; 38.4%) were included in the DP group. Total postoperative complications and complication rates for those Clavien–Dindo grade 3 or higher were similar between the non-DP group and DP group (p = 0.290 and p = 0.550). In the DP group, grade B pancreatic fistulae occurred in 18.2% (6/33) of patients, but grade C pancreatic fistulae were absent, and microscopic pancreatic invasion was noted in 42.4% (14/33) of patients. During multivariate analysis, microscopic pancreatic invasion was deemed a risk factor for local recurrence (p = 0.029). However, there were no significant differences on preoperative computed tomography findings between the pancreatic invasion and non-invasion groups.

Conclusion

DP is a reasonable procedure for pancreas-abutting RPS located at the LUQ when both complications and complete resection are considered.

The relationships between perceived team psychological safety, transactive memory system, team learning behavior and team performance among individual team members

Purpose

This study aimed to investigate the relationships between individual team member's perception of team psychological safety (TPS), individual team member's perception of transactive memory system (TMS), individual team member's perception of team learning behavior (TLB) and individual team member's perception of team performance (TP).

Design/methodology/approach

This cross-sectional study used a paper-based questionnaire that was distributed to 500 employees in travel-related industries and responses were received from 467 employees. Finally, 394 surveys were used after excluding insincere responses. Using SPSS & AMOS version 25.0, factor analysis, correlation, path analysis and mediation analysis were performed.

Findings

The findings reveal that there is a significant association between TPS, TMS, TLB and TP, except for the specialization subdimension of TMS and reflective communication and knowledge codification subdimensions of TLB. There was no mediation role of TLB; however, credibility and task coordination subdimensions of TMS showed partial mediating effects between TPS and TP.

Originality/value

This study offers suggestions for management, emphasizing the importance of TPS. Recent and rapid organizational changes have dramatically increased employees' job insecurity, which can affect their psychological safety. Therefore, organizations should actively support employees to feel psychologically stable to improve performance by utilizing TMS and TLB among individual team members.

Association of COVID-19 with skin diseases and relevant biologics: a cross-sectional study using nationwide claim data in South Korea

Background

As the coronavirus disease 2019 (COVID‐19) pandemic has spread, information about COVID‐19 and skin disease or related biologics is still lacking.

Objectives

To identify the association between COVID‐19 and skin diseases or biologics.

Methods

A nationwide claim dataset relevant to COVID‐19 in South Korea was analysed. This dataset included insurance claim data before and during COVID‐19 treatment and clinical outcomes. Claim data related to skin diseases and relevant biologics were analysed to determine the association of COVID‐19 with skin diseases and relevant biologics.

Results

The dataset contained a total of 234 427 individuals (111 947 male and 122 480 female) who underwent COVID‐19 testing. Of them, 7590 (3·2%) were confirmed as having COVID‐19, and 227 (3·0%) confirmed patients died. Among various skin diseases and biologics, no significant increase in the presence of specific skin diseases or exposure to biologics was observed in the COVID‐19‐positive group, even after adjusting for or matching covariates. The presence of skin diseases and exposure to biologics also did not seem to affect clinical outcomes including mortality.

Conclusions

Underlying skin diseases did not appear to increase susceptibility to COVID‐19 or mortality from COVID‐19. Considering the risks and benefits, biologics for dermatological conditions might be continuously used during the COVID‐19 pandemic.

Effects of quorum quenching on temporal succession of activated sludge microbial community in a membrane bioreactor

AIMS

Quorum quenching (QQ) is an attractive strategy for mitigating biofouling in membrane bioreactors (MBRs). However, the effects of QQ on the activated sludge (AS) process have not been adequately evaluated. This study investigated the long-term effects of QQ on a laboratory-scale anoxic-oxic MBR, focusing on AS performance and microbial community.

METHODS AND RESULTS

Anoxic-oxic MBRs with and without QQ were operated for 91 days. QQ did not affect COD and TN removal efficiencies over the experimental period, during which its activity remained >90%. QQ reduced floc size by approximately 8% but had no effect on biomass concentration. AS microbial communities were regularly analysed using massively parallel sequencing. AS bacterial communities were temporally dynamic irrespective of QQ presence, for example, a temporal increase in bacterial diversity and a temporal decay of community similarity. QQ counteracted the temporal change in diversity and the temporal distance-community decay. Community comparison revealed that QQ changed the successional trajectory of the AS community at a late period, because it decelerated temporal changes of specific members, such as Thiothrix and Sphingomonadaceae*. Correlation networks revealed that QQ increased network clustering, complexity and density. The combined results suggest that the tighter microbial association by QQ increased the community resistance.

CONCLUSIONS

QQ can enhance the diversity and stability of the AS community in MBR by counteracting the innate temporal change in community structure.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our findings are useful for the further advancement of QQ-based strategies in engineered microbial environments.

The influence of hierarchical organizational culture, supportive environment and sexual harassment on Korean women’s work-to-family enrichment

Purpose

The purpose of this study is to examine the relationships among hierarchical organizational culture, organizational support for women, sexual harassment and work-to-family enrichment of working women in South Korea.

Design/methodology/approach

A total of 196 responses from married female employees who had a child (or children) in for-profit organizations in South Korea were analyzed by using structural equation modeling and bootstrapping analysis.

Findings

The findings indicated that hierarchical organizational culture was negatively associated with organizational support and was positively associated with sexual harassment. In addition, an organizational atmosphere that is friendly and supportive to women had a positive effect on work-to-family enrichment. However, the more sexual harassment female workers experienced, the less positive the relationship between their work and family lives. Hierarchical organizational culture negatively affected work-to-family enrichment, but the effect was indirect through organizational support and sexual harassment.

Originality/value

These findings emphasize the importance of transforming the traditional culture in Korean organizations to reduce power distance to create a more female-friendly and supportive environment. With the dramatic recent increase in the number of female workers, building such an environment can enhance organizations’ competitiveness by creating a positive spillover effect between women’s work and family lives.

Maximum standardized uptake value on 18F-fluorodeoxyglucose positron emission tomography/computed tomography improves outcome prediction in retroperitoneal liposarcoma

While ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) has been investigated in extremity sarcomas, there is no evidence on its usefulness in retroperitoneal sarcoma. This study was designed to evaluate the usefulness of ¹⁸F-FDG PET/CT in predicting aggressiveness of retroperitoneal liposarcoma. Patients experienced surgery for retroperitoneal liposarcoma from November 2007 to February 2018 and underwent preoperative ¹⁸F-FDG PET/CT were included. Preoperative maximum standardized uptake value (SUV_max) was calculated. To evaluate the predictability of SUV_max for Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) grade 3, receiver operating characteristics (ROC) curve analysis was performed. To analyze whether SUV_max can be a risk factor for prognosis, multivariable Cox regression was performed including potential risk factors regarding operation and histopathology. A total of 133 patients were included. ROC curve showed area under the curve of 0.877 (P < 0.001), with a cut-off point of 4.5 SUV_max showing 85.7% sensitivity and 78.3% specificity. Cox analyses showed that SUV_max > 4.5 was a significant factor for recurrence-free survival (HR = 2.148, CI 1.301-3.546, P = 0.003) and overall survival (HR = 5.052, CI 1.854-13.766, P = 0.002). SUV_max is highly predictive of FNCLCC grade 3 and SUV_max > 4.5 can be used as a prognostic factor before obtaining the histopathology.

A multicentre, open, investigator-initiated phase IV clinical trial to evaluate the efficacy and safety of ingenol mebutate gel, 0·015% on the face and scalp, and 0·05% on the trunk and extremities, in Korean patients with actinic keratosis (PERFECT)

BACKGROUND

Ingenol mebutate gel is a novel, field-directed topical treatment for actinic keratosis (AK). Most pivotal studies have targeted Western populations. No clinical study has been conducted to investigate its efficacy and safety in Asian populations.

OBJECTIVES

To evaluate the efficacy and safety of ingenol mebutate gel for treating AK of face/scalp and trunk/extremities in a large Asian (Korean) population.

PATIENTS AND METHODS

In this multicentre, open-label, interventional, parallel-group, prospective phase IV study (PERFECT, trial registration no.: NCT02716714), the eligible patients were allocated into either the face/scalp or the trunk/extremities group, according to their selected treatment area location. After application of ingenol mebutate gel, the participants were followed up for 6 months. The primary efficacy endpoint was complete clearance (CC) of AK lesions in the selected treatment area at day 57. Quality of life was evaluated using Skindex-29. Safety endpoints included local skin responses, scar, pigmentation, pain and adverse events.

RESULTS

In total, 78·1% [95% confidence interval (CI) 66·86-86·92%] of subjects had CC at day 57, with 76·6% (95% CI 64·31-86·25%) in the face/scalp group and 88·9% (95% CI 51·75-99·72%) in the trunk/extremities group. Among them, CC was sustained in 88·9% (48 of 54, 95% CI 77·37-95·81%) at month 6. The local skin responses significantly increased 1 day after the treatment compared with baseline, and decreased afterwards. Among the total subjects, 7·8% (6 of 77) had hyperpigmentation on the application area. Scars were not reported.

CONCLUSIONS

Ingenol mebutate is effective for the treatment of AK in Asians, with tolerable safety profiles.

The impact of proactivity, leader-member exchange, and climate for innovation on innovative behavior in the Korean government sector

Purpose

In the current business environment, no organization is assured of survival without continuous innovation. Employees’ innovative behavior is critical to enhance the innovation of an organization. While most literature on innovative behavior has focused on employees in the private sector, the purpose of this paper is to explore the factors that affect innovative behaviors in the government sector. In particular, it examines how proactivity, leader-member exchange (LMX), and climate for innovation affect employees’ innovative behavior in the Korean government sector, which is generally characterized as highly hierarchical, structured, and formalized.

Design/methodology/approach

The authors selected a sample of government employees in the Ministry of Education in Korea. Through the researchers’ contacts, ten government agencies agreed to recruit their employees to participate in the study. Data from 1,011 respondents were analyzed in two steps using structural equation modeling. First, to examine the construct validity of the measures, the authors examined the measurement model using the confirmatory factor analysis. Second, the interrelationships among the four variables were assessed. The hypothesized structural model was examined and compared to several alternative models to explore the best model fit to the data. The authors then examined the regression coefficients to determine the hypothesized relationships in the final structured model.

Findings

The results revealed the following: proactivity and climate for innovation had positive relationships with innovative behavior; LMX had a positive relationship with proactivity although it did not have a direct relationship with innovative behavior; and organizational climate for innovation did not ensure proactivity of employees.

Originality/value

The antecedents included in this research have been studied in relation to innovative behavior in several studies, but studies have called for further study. Few studies have examined innovative behavior in the public sector and they have examined innovation in the public sector which has mostly been focused on environmental factors surrounding government organizations or policy choices of government leaders while ignoring the individual traits of public workers, relational dynamics among people, and the cultural aspects of the organizations. This study investigated the interrelationships among the antecedents in the process of impacting innovative behavior in the public sector in Korea. In addition, little research has examined the antecedents of innovative behavior together. This study expands our knowledge of the roles and interrelationships of proactivity, LMX, and organizational climate for innovation as they relate to innovative behavior.

The effects of perceived authentic leadership and core self-evaluations on organizational citizenship behavior

Purpose

The purpose of this paper is to investigate the effect of the perceived authentic leadership of supervisors and employees’ core self-evaluations on their organizational citizenship behavior (OCB) and to examine the role of psychological empowerment as a partial mediator of those relationships.

Design/methodology/approach

A cross-sectional survey was used to obtain individual perceptions from employees working in one of the biggest companies in Korea. Data from 374 samples was analyzed. Construct validity of each measurement model is examined using confirmatory factor analysis and the hypothesized structural model is tested by structural equation modeling.

Findings

The authors found that perceived authentic leadership, core self-evaluation, and employees’ psychological empowerment had significant impact on employees’ OCB, accounting for 58 percent of the variance in OCB. In addition, 54 percent of the variance in psychological empowerment was explained by authentic leadership and core self-evaluations, partially mediating the relationship between authentic leadership and OCB and the relationship between core self-evaluations and OCB.

Originality/value

Positivity is instrumental in driving intrinsic motivation for work and voluntary devotion to colleagues and organizations. This study contributed to the emerging research branch of management and organizational psychology such as positive organization scholarship and positive organizational behavior by exploring the relationship among the relevant constructs. More specifically, the authors found that positive contextual factor (i.e. authentic leadership), positive personality factor (i.e. core self-evaluations), and positive work experience (i.e. psychological empowerment) do have positive influence on employees’ extra-role performance (i.e. OCB).

Capsanthin Inhibits both Adipogenesis in 3T3-L1 Preadipocytes and Weight Gain in High-Fat Diet-Induced Obese Mice

Adipogenesis in murine preadipocyte 3T3L-1 has been used as a model system to study anti-obese bioactive molecules. During adipogenesis in 3T3-L1 preadipocytes, we found that capsanthin inhibited adipogenesis (IC₅₀; 2.5 μM) and also showed lipolytic activity in differentiated adipocytes from the preadipocytes (ED₅₀; 872 nM). We identified that the pharmacological activity of capsanthin on adipogenesis in 3T3-L1 was mainly due to its adrenoceptor-β₂-agonistic activity. In high-fat diet animal model study, capsanthin significantly enhanced spontaneous locomotive activities together with progressive weight-loss. The capsanthin-induced activation of kinetic behavior in mice was associated with the excessive production of ATP initiated by both the enhanced lipolytic activity together with accelerated oxidation of fatty acids due to the adrenoceptor β₂-agonistic activity of capsanthin. Capsanthin also dose-dependently increased adiponectin and p-AMPK activity in high fat diet animals, suggesting that capsanthin has both anti-obesity and insulin sensitizing activities.

Comparison of microbial communities of activated sludge and membrane biofilm in 10 full-scale membrane bioreactors

Operation of membrane bioreactors (MBRs) for wastewater treatment is hampered by the membrane biofouling resulting from microbial activities. However, the knowledge of the microbial ecology of both biofilm and activated sludge in MBRs has not been sufficient. In this study, we scrutinized microbial communities of biofilm and activated sludge from 10 full-scale MBR plants. Overall, Flavobacterium, Dechloromonas and Nitrospira were abundant in order of abundance in biofilm, whereas Dechloromonas, Flavobacterium and Haliscomenobacter in activated sludge. Community structure was analyzed in either biofilm or activated sludge. Among MBRs, as expected, not only diversity of microbial community but also its composition was different from one another (p < 0.05). Between the biofilm and activated sludge, community composition made significant difference, but its diversity measures (i.e., alpha diversity, e.g., richness, diversity and evenness) did not (p > 0.05). Effects of ten environmental factors on community change were investigated using Spearman correlation. MLSS, HRT, F/M ratio and SADm explained the variation of microbial composition in the biofilm, whereas only MLSS did in the activated sludge. Microbial networks were constructed with the 10 environmental factors. The network results revealed that there were different topological characteristics between the biofilm and activated sludge networks, in which each of the 4 factors had different associations with microbial nodes. These results indicated that the different microbial associations were responsible for the variation of community composition between the biofilm and activated sludge.

Paid educational leave and self-directed learning

Purpose

– The purposes of this study are to explore paid educational leave (PEL), self-directed learning (SDL) and the relationship between them; and to identify the implications for legislation on the learning leave scheme in South Korea.

Design/methodology/approach

– The research method of the study is a literature review. Articles were identified through a keyword search from major academic databases. The literature search covers the time period of 1960-2012.

Findings

– This paper shows that enacting PEL is a social policy that benefits to both employers and workers because it reduces training costs, eliminates educational barriers for employees and enhances opportunities to develop skills and competencies.

Research limitations/implications

– This study contributes to research by exploring the crucial role of PEL based on the Person-Process-Context model for SDL. It also examines the relationship between SDL and PEL in the workplace learning.

Practical implications

– This study provides a rationale to legislate PEL as a right of workers. Through an appropriate revision of the Lifelong Education Act, the right of workers to receive the PEL benefit should be legally adopted to promote workers’ SDL in South Korea.

Originality/value

– This paper provides theoretical and practical evidence for institutionalizing PEL in South Korea. It suggests the passage of PEL legislation because it is beneficial to all stakeholders.

Crossing the Border between Laboratory and Field: Bacterial Quorum Quenching for Anti-Biofouling Strategy in an MBR

Quorum quenching (QQ) has recently been acknowledged to be a sustainable antifouling strategy and has been investigated widely using lab-scale membrane bioreactor (MBR) systems. This study attempted to bring this QQ-MBR closer to potential practical application. Two types of pilot-scale QQ-MBRs with QQ bacteria entrapping beads (QQ-beads) were installed and run at a wastewater treatment plant, feeding real municipal wastewater to test the systems' effectiveness for membrane fouling control and thus the amount of energy savings, even under harsh environmental conditions. The rate of transmembrane pressure (TMP) build-up was significantly mitigated in QQ-MBR compared to that in a conventional-MBR. Consequently, QQ-MBR can substantially reduce energy consumption by reducing coarse bubble aeration without compromising the effluent water quality. The addition of QQ-beads to a conventional MBR substantially affected the EPS concentrations, as well as microbial floc size in the mixed liquor. Furthermore, the QQ activity and mechanical stability of QQ-beads were well maintained for at least four months, indicating QQ-MBR has good potential for practical applications.

Protein Profile in Corpus Luteum during Pregnancy in Korean Native Cows

Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism, but the profile of proteins associated with progesterone synthesis in cyclic and pregnant corpus luteum (CL) is not well-known in cattle. In Experiment 1, plasma progesterone level was monitored in cyclic cows (n = 5) and pregnant cows (n = 6; until d-90). A significant decline in the plasma progesterone level occurred at d-19 of cyclic cows. Progesterone level in abbatoir-derived luteal tissues was also determined at d 1 to 5, 6 to 13 and 14 to 20 of cyclic cows, and d-60 and -90 of pregnant cows (n = 5 each). Progesterone level in d-60 CL was not different from those in d 6 to 13 CL and d-90 CL, although the difference between d 6 to 13 and d-90 was significant. In Experiment 2, protein expression pattern in CL at d-90 (n = 4) was compared with that in CL of cyclic cows at d 6 to 13 (n = 5). Significant changes in the level of protein expression were detected in 32 protein spots by two-dimensional polyacrylamide gel electrophoresis (2-DE), and 23 of them were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Six proteins were found only in pregnant CL, while the other 17 proteins were found only in cyclic CL. Among the above 6 proteins, vimentin which is involved in the regulation of post-implantation development was included. Thus, the protein expression pattern in CL was disorientated from cyclic luteal phase to mid pregnancy, and alterations in specific CL protein expression may contribute to the maintenance of pregnancy in Korean native cows.

The potent protective effect of wild ginseng (Panax ginseng C.A. Meyer) against benzo[alpha]pyrene-induced toxicity through metabolic regulation of CYP1A1 and GSTs

Wild Panax ginseng C.A. Meyer (WG) is a well-known medicinal herb. In this study, the protective effects of a water extract from the root of WG on benzo[alpha]pyrene (BP)-induced hepatotoxicity and the mechanism of these effects were investigated for the first time. The effects of WG on liver toxicities induced by BP were assessed by blood biochemical and histopathological analyses. BP caused severe liver injury in rats, as indicated by elevated plasma ALT, AST and LPO levels. Pretreatment with WG for 4 weeks completely abrogated increases in the ALT, AST and LPO levels when challenged with BP. Reductions in GSH content and GST activity by BP were reversed by WG. These protective effects of WG against BP-induced toxicity were consistent with the results of histopathological examinations. We next examined the effects of WG on the gene expression of the enzymes that metabolize BP in H4IIE cells. CYP1A1 mRNA and protein expression were increased by BP. WG moderately inhibited BP-induced CYP1A1 gene expression. Moreover, GSTA2, GSTA3 and GSTM2 gene expressions were significantly increased by WG through the Nrf2/antioxidant responsive element pathway for enzyme induction. In summary, WG is efficacious in protecting against BP-induced hepatotoxicity as results of metabolic regulations through both the inhibition of metabolic enzyme activation and the enhancement of electrophilic detoxification, implying that WG should be considered a potential chemopreventive agent.

The difference between the constitutive and facultative skin color does not reflect skin phototype in Asian skin

BACKGROUND/PURPOSE

The assessment of the sensitivity of human skin to ultraviolet (UV) radiation is important in the area of phototherapy, photodermatoses, photo-aging, photo-carcinogenesis, and photo-protection. Some reports have shown that quantitatively measured skin color is a good indicator for predicting UV sensitivity to human skin in Caucasians. In this study, our aim was to define the correlation between skin color and the skin phototype assessed by the Fitzpatrick method in Asian brown skin.

METHODS

A total of 180 medical students with similar life styles were included in this study. Their skin phototype was classified according to the system introduced by Fitzpatrick. Then, using a Minolta Spectrophotometer CM-2002, their skin color was determined on the buttocks and forehead. The buttock color was taken as the constitutive skin color, and the forehead color as the facultative skin color. Using these measured values, we compared the skin color with the skin phototype to find their correlation. Also, we investigated whether the difference between the constitutive and facultative skin colors of each individual had a relationship with his or her skin phototype.

RESULTS

The constitutive skin color became darker with increasing skin phototype, and this change was statistically significant. As for the facultative skin color, it also became darker with increasing skin phototype, but was less well correlated with the skin phototype than the constitutive skin color. However, the difference between the constitutive and facultative skin colors did not show consistent results in predicting the skin phototype.

CONCLUSION

In this study, we found that the constitutive skin color can be a good indicator of the skin phototype. However, the difference between the constitutive and facultative skin colors of each individual does not give any meaningful information for the assessment of his or her skin phototype in Asian skin.

Electrical measurement of moisturizing effect on skin hydration and barrier function in psoriasis patients

Transepidermal water loss (TEWL) in psoriatic skin lesions seems to be related to the severity of the psoriasis, and the electrical capacitance and conductance of the skin are indicators of the hydration level of the stratum corneum. We compared the characteristics of these electrical measurements, in assessing the persistent effect of a moisturizing cream on skin hydration and barrier function in psoriasis patients. Seventeen Korean psoriasis patients were recruited. Their right leg was treated with the moisturizer twice daily for 6 weeks, while their left leg was used as the control site. For each patient, one psoriatic plaque on each leg was selected as the involved psoriatic lesion. Uninvolved psoriatic skin was regarded as the apparently healthy looking skin 4-5 cm away from the periphery of the psoriatic lesion. The TEWL, electrical capacitance and conductance were measured, in order to evaluate the barrier function and hydration level of the stratum corneum. The clinical and biophysical data for each patient were recorded at the start of the study and after 2, 4 and 6 weeks. The degree of skin dryness at the applied area improved progressively. The electrical capacitance at the treated psoriatic lesion increased significantly after 2 weeks, and this improvement was maintained during the entire study period. However, no noticeable change was observed in the electrical conductance. The TEWL showed an inverse pattern to that of the skin capacitance, decreasing during the study period. The skin capacitance and TEWL exhibited good correlation with the visual assessment of skin dryness, but the skin conductance did not. Our data suggest that electrical capacitance and TEWL may be useful in the evaluation of the effect of a moisturizer on the hydration status and barrier function of psoriatic skin.