The dark side of mobile work during non-work hours: moderated mediation model of presenteeism through conservation of resources lens

Owing to the development of Information and Communication Technology (ICT) and the inevitability of telecommuting in the COVID-19 environment, the boundary between working and non-working hours has become blurred. mWork, that is, ICT-based off-hour work, which has increased through the pandemic, affects employees' work attitudes, such as presenteeism. Hence, we designed a study to investigate the antecedents and mechanisms of employee presenteeism from the perspective of the conservation of resources theory. We supported our hypothesis using a sample of 325 Korean office workers obtained through three rounds of time-delay surveys. The results show that presenteeism is higher among employees with high mWork. In addition, employees' mWork increases sleep deprivation and presenteeism, and the exchange ideology of employees reinforces the positive effect of sleep deprivation on presenteeism. Additionally, the higher the level of exchange ideology, the stronger the mediating effect of mWork on presenteeism through sleep deprivation. This study verified the conservation of resources theory by identifying the mechanism by which mWork affects an employee's life, which in turn affects their work, and provides practical implications for managing productivity loss due to presenteeism.

The influence of sleep on job satisfaction: examining a serial mediation model of psychological capital and burnout

Introduction

This study draws on the conservation of resources theory to investigate whether the loss of sleep can trigger the loss of additional resources that are necessary for work.

Methods

Using cross-sectional design of 322 call center employees working at a government-owned public bank in South Korea, we test the study hypotheses using regression and bootstrapping indirect effects analyses.

Results

The results of analyses show that insufficient sleep increases employee burnout and that psychological capital mediates this relationship. We also find that insufficient sleep decreases job satisfaction via a serial mediation model such that insufficient sleep reduces psychological capital, which in turn increases burnout, and ultimately results in lower job satisfaction.

Discussion

The findings reinforce the previous assessment that although sleep is a non-work factor, its impact spills over to the workplace. Theoretically, this study goes beyond direct effect to uncover the underlying or mediating mechanisms that account for the impact of the sleep-burnout relationship and the sleep-job satisfaction relationship. For managers, the results highlight the significance of sleep to employees' overall health and well-being and thus underscore the need to foster a work culture that recognizes and prioritizes employee sleep needs.

Coaching leadership and creative performance: A serial mediation model of psychological empowerment and constructive voice behavior

This study empirically analyzes the role of coaching leadership in enhancing an organization's creative performance, discussing and evaluating important mediating paths of coaching leadership regarding creative performance. As a result of an empirical analysis based on survey data collected from 332 employees of Korean companies, this study first confirms that coaching leadership has a positive effect on both employees' creative performance. We also found that psychological empowerment and constructive voice behavior positively mediated the relationship between coaching leadership and creative performance. Finally, the serial mediating effect of coaching leadership on creative performance was tested through psychological empowerment and constructive voice behavior and confirmed to have a positive effect. This study indicates the importance of leadership as a critical variable that promotes employees' creative performance. In addition, by confirming the serial mediating role of psychological empowerment and constructive voice behavior, this study improves understanding of key mechanism in which coaching leadership leads to creative performance.

Paradoxical Leadership and Involvement in Creative Task via Creative Self-Efficacy: A Moderated Mediation Role of Task Complexity

Modern organizational environments encounter serious competition and paradoxical situations. This study discusses the effect of paradoxical leadership on overcoming competitive and paradoxical situations happening in the Korean workplace. More specifically, it investigates the dynamic relationship between paradoxical leadership and involvement in creative tasks in a Korean context and examines whether creative self-efficacy positively mediates this relationship. Our research design addresses the moderating role and moderated mediating role of task complexity in the relationship between paradoxical leadership and the involvement in creative tasks via creative self-efficacy. The main hypotheses were tested by using a cross-sectional design and administering questionnaires to 268 employees working in Korean firms. Empirical analysis revealed that paradoxical leadership is positively related to involvement in creative tasks and creative self-efficacy and that creative self-efficacy positively mediated the relationship between paradoxical leadership and involvement in creative tasks. Importantly, as the relationship between paradoxical leadership and creative self-efficacy depends on task complexity, the mediated relationship was effective under high task complexity. Uncovering the relationship between paradoxical leadership and involvement in creative tasks with the mediating role of creative self-efficacy and the moderated mediating role of task complexity can provide useful theoretical and managerial implications.

What hinders team innovation performance? Three-way interaction of destructive leadership, intra-team conflict, and organizational diversity

This paper aims to clarify the impact of destructive leadership on team innovation performance. It also explores the relevant conditions that maximize the above relationship. Specifically we examine how intra-team conflict organizational diversity moderate the relationship between destructive leadership team innovation performance. Finally the three-way interaction between destructive leadership intra-team conflict organizational diversity is analyzed for the worst conditions to maximize the negative effect of destructive leadership on team innovation performance. This paper used a cross-sectional design with questionnaires administered to 87 teams with 479 team members working in Korean manufacturing service firms. It applied a hierarchical regression analysis to test the hypothesized relationships including three-way interaction effect among destructive leadership intra-team conflict organizational diversity on team innovation performance. This paper provided empirical insights about how destructive behaviors of team leader hindered team innovation performance. The three-way interaction effects also revealed that the higher the levels of both intra-team conflict organizational diversity the greater the negative effect of destructive leadership on team innovation performance. This paper demonstrates how team leaders’ behavior team organizational conditions result in discouraging overall innovation outcomes. This paper contributes to the innovation leadership literatures by identifying possible leadership type hindering innovation performance at team level the specific conditions their dynamic interaction strengthening the negative effect of destructive leadership on team innovation performance.

A Multilevel Study of the Relationship between CSR Promotion Climate and Happiness at Work via Organizational Identification: Moderation Effect of Leader–Followers Value Congruence

The purpose of the present study is to examine the effects of team level Corporate Social Responsibility (CSR) promotion climate on work happiness of team members. Furthermore, we investigate the mediating role of organizational identification at individual level and the moderating role of leader–follower value congruence at the team level in the relationship between CSR promotion climate and work happiness, thus overcoming the limitations of previous studies which mainly focused on a unitary level of analysis. To this end, a multilevel analysis was used, dealing with team- and individual-level relationships; the sample comprises 70 teams and 336 employees from 23 Korean firms. Our empirical analysis revealed that a team CSR promotion climate positively influenced team members’ happiness at work and organization identification. Furthermore, organization identification partially mediated the relationship between team CSR promotion climate and happiness at the workplace. By interacting with team CSR promotion climate, leader–followers value congruence positively regulated the influence of team CSR promotion climate on happiness at work. In this process, for a group with high leader–follower value congruence, the team CSR promotion climate strengthens team members’ happiness at the workplace. The study utilizes a multilevel analysis method to simultaneously verify team- and individual-level elements positively affecting team members’ happiness at work. Through this method, it confirmed that CSR promotion climate and team organization identification positively influence happiness at work. The theoretical and practical implications are presented, and directions for future research with limitations of the study are discussed.

Abusive Supervision and Employee's Creative Performance: A Serial Mediation Model of Relational Conflict and Employee Silence

Many previous studies on creativity have focused on discovering positive factors to improve creativity and innovation performance from leader, individual, and organizational perspectives. However, research on factors that hinder creative performance was relatively insufficient. This study examines leaders' behavior that hinders employees' creative performance by focusing on abusive supervision. Based on the Korean employee context, our research model draws upon constructs of abusive supervision, relational conflict, employee silence, and creative performance to hypothesize serial mediation mechanisms connecting abusive supervision to creative performance. Using survey data of 555 Korean employees, we find that abusive supervision is negatively related to creative performance. We also find that both relational conflict and employee silence mediate the relationship between abusive supervision and employee creative performance. More importantly, our empirical analysis indicates that a serial mediation effect testing a dual coordination effect was identified in the process of the leader's abusive supervision leading to employee's creative performance. Although many previous studies were focused on a single medium effect in the relationship between leadership types and employee creativity, this study applied the serial mediation effects in the relationship to test a dual medium effect. We further addressed a more complex process to explain the path of reducing creative performance by supervisor abusive supervision. We conclude by discussing both theoretical and practical implications.

Leader's Perception of Corporate Social Responsibility and Team Members' Psychological Well-Being: Mediating Effects of Value Congruence Climate and Pro-Social Behavior

Previous research, that showed that corporate social responsibility (CSR) had positive effects on the corporate image and performance, has attracted much attention and resulted in an increasing number of follow-up studies. However, CSR-related activities are focused on their effect on external stakeholders, although they are social service activities geared towards internal and external stakeholders, thus showing a research gap regarding the effects of internal stakeholders on organizational effectiveness. Therefore, this study investigated the mediating effects of the value congruence climate and prosocial behavior among the team members in the relationship between leader’s CSR perception and team members’ psychological well-being, using a multilevel analysis of the relationship between the team and individual level factors. For the empirical analysis, 69 teams (334 employees) were sampled from 23 Korean small and medium-sized enterprises (SMEs). Analyses revealed a positive effect of a leader’s CSR perception on the team members’ psychological well-being. Furthermore, a leader’s CSR perception had a positive effect on his/her team’s value congruence environment and team members’ prosocial behavior. The team’s value congruence environment and team members’ prosocial behavior were found to mediate the relationship between the leader’s CSR perception and team members’ psychological well-being. The relationships among these variables were investigated using a multilevel analysis model capable of simultaneous validation of team- and individual-level factors associated with team members’ psychological well-being. Future research directions were then discussed based on the theoretical and practical implications and limitations of the study results.

Servant Leadership and Creativity: A Study of the Sequential Mediating Roles of Psychological Safety and Employee Well-Being

With today’s increasingly dynamic and competitive business environment, creativity is critical for enterprises to enhance their competitiveness. Companies today invest and seek new ways to enhance creativity of employees within the organization. Our study describes the effects of servant leadership, psychological safety, and employee well-being on creativity under the conservation of resources theory. We used a sample of 252 full-time employees in the United Kingdom who had been recruited online and collected their data for analysis. We conducted confirmatory factor analyses to test the validity of the measurement model and regression to evaluate the direct effects. Subsequently, we used bootstrapping to confirm mediation and serial mediation effects. The results showed that servant leadership was positively related to creativity and that psychological safety and employee well-being were serial mediators between them.

Creativity in the South Korean Workplace: Procedural Justice, Abusive Supervision, and Competence

Innovation is now a feature of daily life. In a rapidly changing market environment and amid fierce competition, organizations pursue survival and growth through innovation, and the key driver of innovation is the creativity of employees. Because the value of creativity has been emphasized, many organizations are looking for effective ways to encourage employees to be creative at work. From a resource perspective, creativity at work can be viewed as a high-intensity job demand, and organizations should encourage it by providing and managing employee resources. This study is an attempt to empirically investigate how competence and abusive supervision affect the relationship between procedural justice and creativity from the conservation of resources perspective. Findings from two-wave time-lagged survey data from 377 South Korean employees indicate that procedural justice increases creativity through the mediation of competence. Furthermore, abusive supervision has a negative moderating effect on the relationship between procedural justice and competence. The findings show that competence moderates the relationship between procedural justice and creativity and that the lower the level of abusive supervision, the greater the effect of procedural justice on competence and creativity.

Innovative Behavior in the Workplace: An Empirical Study of Moderated Mediation Model of Self-Efficacy, Perceived Organizational Support, and Leader-Member Exchange

Recently, most organizations, from for-profit organizations to nonprofit organizations, are facing a rapidly changing environment and increased uncertainty. Organizational performance now depends on quickly responding and overcoming change through employees’ innovative behavior. As the importance of innovative behavior has been highlighted, many organizations are looking for effective ways to encourage employees to adopt innovative behavior. From the resource perspective, innovative behavior can be regarded as high-intensity job demand, and organizations should support innovative behavior by providing and managing employees’ resources. Based on the conservation of resource perspective, this study attempted to empirically explore how self-efficacy and perceived organizational support affect the relationship between leader–member exchange (LMX) and innovative behavior. Using two-wave, time-lagged survey data from 337 employees in South Korea, we found that leader–member exchange enhances innovative behavior via the mediation of self-efficacy. Additionally, perceived organizational support positively moderates the relationship between leader–member exchange and self-efficacy. Our findings demonstrate that self-efficacy is a mediating mechanism in the relationship between leader–member exchange and innovative behavior. Furthermore, this study suggests that the higher the level of perceived organizational support, the greater the effect of leader–member exchange on innovative behavior affected by self-efficacy.

Work Engagement Among Public Employees: Antecedents and Consequences

This study is an investigation of the relationships among job meaningfulness, work engagement, and performance, including testing for a possible mediation effect of work engagement on the relationship between job meaningfulness and performance. We examine task interdependence as a boundary condition that facilitates employee engagement using two-stage multiple-source respondent data drawn from a sample of 183 Uzbek employees from public organizations and their 47 supervisors to test the hypotheses. The research findings confirm a positive association between job meaningfulness and engagement and the relationship between work engagement and performance. Mediation analysis using bootstrapping indicated that work engagement explained the influence of meaningfulness on performance. Furthermore, task interdependence negatively moderated the relationship between meaningfulness and engagement. This study responds to calls for researchers to identify the key and situational drivers of work engagement as well as examine the importance of meaningfulness in the public sector. It also increases the external validity of the findings by examining the relationship between engagement and performance in a non-Western context, namely, Islamic Uzbekistan. Despite the limitations of this research, the empirical findings contribute to the growing body of research on work engagement and meaningfulness in public organizations.

Effects of Employee Well-Being and Self-Efficacy on the Relationship between Coaching Leadership and Knowledge Sharing Intention: A Study of UK and US Employees

Knowledge acquisition practices are important to enterprises, particularly since market competition is intensifying. In recent years, organizations have begun to pay more attention to knowledge sharing practices. Many organizations are looking for methods to motivate their employees to actively share knowledge with other employees. This study uses the conservation of resources theory to examine coaching leadership as an antecedent-and employee well-being as a mediator-in facilitating knowledge sharing intention; it finds that self-efficacy is the boundary condition in these relations. We collected data in two waves and recruited participants online-full-time employees in the UK and US. Using a sample of 322 employees, we conducted a confirmatory factor analysis to test the validity of the results and used hierarchical multiple regression to examine the direct and interaction effects. Then, we used the bootstrapping method to test the indirect and moderated mediation effects. Our results show that coaching leadership is positively related to knowledge sharing intention, and employee well-being mediates the relationship. Moreover, self-efficacy positively moderates the direct and indirect effects. Our findings demonstrate that employee well-being is a mediating mechanism in the relationship between coaching leadership and knowledge sharing intention, with self-efficacy acting as a boundary condition.

The Effect of Perceived Supervisor-Subordinate Congruence in Honesty on Emotional Exhaustion: A Polynomial Regression Analysis

Do subordinates unequivocally prefer honest superv =isors? This study investigates whether congruence in supervisor–subordinate honesty has a positive effect on lowering the emotional exhaustion experienced by subordinates. For the research data, a two-part survey with a one-month time interval was conducted among office workers, and 409 responses were collected. These were empirically analyzed using polynomial regression analysis and response surface analysis, instead of the common methodology based on difference values used in past studies on the fit between a person and their environment. The analysis results confirmed that supervisor–subordinate congruence in honesty has a negative relationship with subordinates’ emotional exhaustion and supervisor–subordinate congruence at higher levels of honesty will have stronger negative relationships with emotional exhaustion. This study expands the intrapersonal context of the existing research on supervisors’ honesty to the interpersonal context and empirically demonstrates the effect of honesty congruence. It also discusses its theoretical and practical implications as well as limitations, and it provides suggestions for future studies.

Psychological Safety in Ghana: Empirical Analyses of Antecedents and Consequences

This study examines psychological safety as a mediator in the relationship between Leader–Member Exchange (LMX) and voice behavior. Based on the conservation of resources theory, a moderated mediation framework was used to examine human capital investments, specifically employee education and tenure, as boundary conditions of this relationship. The research hypotheses were tested with a sample of 207 employee-supervisor dyads working in a time-lagged design. The study found that psychological safety is an intermediary mechanism through which LMX affects voice behavior. Employees’ level of education negatively moderates the relationship between LMX and psychological safety. Furthermore, the results suggest that organizational tenure accentuates the relationship between LMX and psychological safety, and strengthens the indirect effect of LMX on voice behavior. The theoretical contributions and managerial implications are discussed in addition to directions for future research.

Consumer purchase intention of a cosmetic product after the Fukushima nuclear incident

We examined the factors affecting consumer purchase intention of a cosmetic product after the Fukushima nuclear incident and the role of distinctiveness in postcrisis recovery. Through a 2-group experiment and structural equation modeling, we found that the incident did not affect the firm's reputation and brand image but it was perceived as a significant threat to health and product safety that consequently negatively affected purchasing intentions. Findings also showed that high distinctiveness is a valid factor in diminishing the impact of crisis. In particular, a firm's reputation and indirect effects on revenue are least affected by, or even positively related to distinctiveness. We have included discussion of the critical implications for firms around the importance of maintaining desirable relationships with the public as preparation for a crisis and for rapid postcrisis recovery.

Effects of transformational and shared leadership styles on employees' perception of team effectiveness

Using 3 sets of multiple regression models, we examined the effectiveness of transformational and shared leadership styles in relation to team effectiveness, based on the perceptions of 424 employees of Korean financial and insurance firms. Transformational leadership is a vertical leadership style emanating from the formal leader of a team, whereas shared leadership is a distributed leadership style that emanates from the team members. We found that transformational leadership contributed to team output effectiveness, whereas shared leadership improved the team's organizing and planning effectiveness. These findings imply that different styles of leadership contribute to different aspects of team effectiveness. We suggest that managers should collaborate more with team members and should pay attention to the fit between the leader's behavior and the characteristics of the team output in order to promote overall team effectiveness.

Women scientists' workplace and parenting role identities: A polynomial analysis of congruence

We empirically examined the congruence effect of work- and parenting-role identities on women scientists' perception of organizational support. With the assistance of the staff of the Center for Women in Science, Engineering, and Technology in South Korea, we obtained data from 215 women employed as scientists by responses to a survey. The results of polynomial regressions showed a positive congruence effect of their employment and parenting role identities on perceived organizational support (POS); the more closely aligned the two identities were, that is, the higher the level of congruence of the role identities, the stronger was the POS. These findings highlight the pivotal role played by the balance between workand parenting-role identities in promoting a positive attitude in the workplace among women scientists. The theoretical and practical implications and limitations are also discussed.

Aerothermoelastic-Acoustics Simulation of Flight Vehicles

This paper describes a novel computational-fluid-dynamics-based numerical solution procedure for effective simulation of aerothermoacoustics problems with application to aerospace vehicles. A finite element idealization is employed for both fluid and structure domains, which fully accounts for thermal effects. The accuracies of both the fluid and structure capabilities are verified with flight- and ground-test data. A time integration of the structural equations of motion, with the governing flow equations, is conducted for the computation of the unsteady aerodynamic forces, which uses a transpiration boundary condition at the surface nodal points in lieu of the updating of the fluid mesh. Two example problems are presented herein to that effect. The first one relates to a cantilever wing with a NACA 0012 airfoil. The solution results demonstrate the effect of temperature loading that causes a significant increase in acoustic response. A second example, the hypersonic X-43 vehicle, is also analyzed; and relevant results are presented. The common finite element-based aerothermoelastic-acoustics simulation process, its applicability to the efficient and routine solution of complex practical problems, the employment of the effective transpiration boundary condition in the computational fluid dynamics solution, and the development and public domain distribution of an associated code are unique features of this paper.

The Impact of Career Management on Organizational Commitment and the Mediating Role of Subjective Career Success

To determine the importance of career management behavior (CMB) for organizational outcomes, this study investigated the impact of CMB and organizational support for career development (OSCD) on subjective career success (SCS) and eventually on organizational commitment. Based on survey data from 355 employees of large Korean manufacturing firms, we found that both CMB and OSCD were positively associated with SCS. The results show that SCS positively affects organizational commitment and positively mediates both the relationship between CMB and organizational commitment and the relationship between OSCD and organizational commitment. Our findings imply that employee career success, which is affected by individual and organizational efforts, contributes to the outcomes of the organization in which employees are embedded.

Inclusive Leadership and Work Engagement: Mediating Roles of Affective Organizational Commitment and Creativity

We examined the mediating roles of affective organizational commitment and employee creativity in the relationship between inclusive leadership and employee work engagement. Participants were 246 employees of 6 companies in the services industry in Vietnam, and they completed the Employee Work Engagement Scale, Inclusive Leadership Scale, Affective Organizational Commitment Scale, and Employee Creativity Scale. We found that inclusive leadership was positively related to employee work engagement, and that both affective organizational commitment and employee creativity mediated this relationship. Our findings represent a theoretical contribution to social exchange theory and provide useful managerial implications for organizations to improve work engagement among employees.

Ethical Leadership and Followers' Attitudes Toward Corporate Social Responsibility: The Role of Perceived Ethical Work Climate

Increasing attention is being paid to how leaders influence followers' perceptions of the importance of ethics and corporate social responsibility (CSR) for organizational effectiveness. However, few researchers have conducted empirical investigations into the impact of leadership style on followers' attitudes toward CSR. In this study, participants comprised 313 employees of 5 large financial and banking service firms in Korea. Results indicated that ethical leadership was strongly associated with followers' rating of CSR. In addition, we examined how employees' perception of ethical work climate mediates and moderates the relationship between ethical leadership and followers' attitudes toward CSR. Our findings supported a positive link between ethical leadership and followers' attitudes toward CSR, with perception of an ethical work climate acting as a significant mediator and moderator in this relationship. Implications for leadership practice and CSR, and recommendations for future research directions are discussed.

Incidental renal cell carcinoma originating from a native kidney after en-bloc resection for adrenal carcinoma in a kidney transplant recipient

BACKGROUND

Renal transplantation is the best treatment for patients with end-stage renal disease. Although there is significantly increased risk of malignancy after renal transplantation, carcinoma of the native kidney is very rare, and moreover, the risk of endocrinologic malignancy after renal transplantation is lower than in the general population and adrenal cortical carcinoma extremely rare. We report a case of incidental renal cell carcinoma originating from a native kidney after en-bloc resection for adrenal carcinoma in a kidney transplant recipient.

CASE REPORT

A 57 year-old male patient had undergone living-donor kidney transplantation for chronic renal failure from hypertension 15 years earlier and had a right adrenal tumor diagnosed on surveillance abdomen-pelvis computerized tomography. Based on 24-hour catecholamine laboratory findings, nonfunctioning tumor was suspected. The planned en-bloc resection of right adrenal gland and right native kidney combining the perirenal tissue and Gerota fascia was performed, because the tumor was suspicious for malignancy and could possibly invade the perirenal tissue or right kidney. On the final pathology, combined adrenal cortical carcinoma and incidental renal cell carcinoma was confirmed. Renal cell carcinoma was papillary, type I, and stage T1N0M0. Adrenal cortical carcinoma was 7.6 × 6.5 cm in size, had marked nuclear atypia, and was grade IV/IV. Mitotic counts were >10 per high-power field, but it had no capsular invasion or vascular invasion, and free resection margin was confirmed. In the preoperative period, he had taken immunosuppressants FK506 and mycophenolate sodium, but after combined carcinomas were confirmed, the regimen of combination of immunosuppressants was changed to sirolimus with low-dose FK506 and half-dose mycophenolate sodium.

Prenylated xanthones from mangosteen as promising cholinesterase inhibitors and their molecular docking studies

Garcinia mangostana is a well-known tropical plant found mostly in South East Asia. The present study investigated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of G. mangostana extract and its chemical constituents using Ellman's colorimetric method. Cholinesterase inhibitory-guided approach led to identification of six bioactive prenylated xanthones showing moderate to potent cholinesterases inhibition with IC50 values of lower than 20.5 μM. The most potent inhibitor of AChE was garcinone C while γ-mangostin was the most potent inhibitor of BChE with IC50 values of 1.24 and 1.78 μM, respectively. Among the xanthones, mangostanol, 3-isomangostin, garcinone C and α-mangostin are AChE selective inhibitors, 8-deoxygartanin is a BChE selective inhibitor while γ-mangostin is a dual inhibitor. Preliminary structure-activity relationship suggests the importance of the C-8 prenyl and C-7 hydroxy groups for good AChE and BChE inhibitory activities. The enzyme kinetic studies indicate that both α-mangostin and garcinone C are mixed-mode inhibitors, while γ-mangostin is a non-competitive inhibitor of AChE. In contrast, both γ-mangostin and garcinone C are uncompetitive inhibitors, while α-mangostin is a mixed-mode inhibitor of BChE. Molecular docking studies revealed that α-mangostin, γ-mangostin and garcinone C interacts differently with the five important regions of AChE and BChE. The nature of protein-ligand interactions is mainly hydrophobic and hydrogen bonding. These bioactive prenylated xanthones are worthy for further investigations.

Does procurement technique affect posttransplant graft function in deceased donor liver transplantation?

INTRODUCTION

Various techniques have been described deceased donor liver transplantation (DDLT) procurement. One is a technique whereby almost total dissection is done in the porta hepatis and perihepatic detachment is carried out before cross-clamping the donor aorta. In another approach, after the donor aorta is cross-clamped, rapid and minimal en bloc dissection is performed with minimal manipulation. We evaluated early posttransplant graft function among liver procurement techniques.

METHOD

Between January 2008 and August 2012, we performed 45 consecutive adult DDLTs. One patient was excluded from this analysis due to early death from sepsis after transplantation. The 44 included patients were divided into two cohorts according to the procurement technique: A warm dissection (n = 23; 52%) and a cold dissection group (n = 21; 48%). We compared early posttransplant graft function using the aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (T-bil), and prothrombin time (PT) values of the two groups from the first to seventh postoperative day.

RESULT

The AST values in the warm group were significantly greater than those in the cold group on postoperative days 3 and 5. In addition, the ALT values in the warm group were greater than those in the cold group on postoperative days 4, 5, and 6. Moreover, the T-bil values in the warm group were greater than those in the cold group on postoperative days 2, 3, 4, 5, 6, and 7. However, there were no differences in PT values.

CONCLUSION

During liver procurement for DDLT, rapid en bloc procurement with minimal manipulation after clamping the donor aorta achieved better early graft function posttransplantation.

Surgical outcomes and prognostic factors for ampulla of Vater cancer

BACKGROUND AND AIMS

The prognosis for patients with ampulla of Vater cancer is better than other periampullary cancers. The aim of the present study is to determine the clinicopathologic factors predictive of survival and recurrence in patients with ampulla of Vater cancer.

MATERIAL AND METHODS

From 1991 to 2008, we identified and reviewed 78 patients with ampulla of Vater cancer retrospectively. Clinicopathologic factors possibly influencing survival and recurrence were statistically analyzed.

RESULTS

Pancreaticoduodenectomy was performed in 68 patients and 2 patients underwent transduodenal ampullectomy. Hospital mortality was 2.6%. The 5-year survival rates following resection were 59.9%. Univariate analysis for overall survival revealed that total bilirubin greater than 5 mg/dl, ulcerative tumors, differentiation, and pancreatic invasion were significant prognostic factors. Recurrence occurred in 31 patients. Univariate analysis for disease-free survival revealed that total bilirubin greater than 5mg/dl, preoperative biliary drainage, tumor differentiation, and stage were statistically significant. Multivariate analysis revealed that tumor differentiation was an independent prognostic factor for recurrence. The presence of lymph node metastasis did not affect overall survival significantly in this study. However, two or more metastatic lymph nodes significantly affect disease-free survival.

CONCLUSIONS

Pancreaticoduodenectomy is a safe surgical procedure with acceptable long-term survival for ampulla of Vater cancer. Pancreaticoduodenectomy with lymph node dissection might control lymph node spread and enhance survival outcome.

Electric field-induced coherent control in GaAs: polarization dependence and electrical measurement [Invited]

A static electric field enables coherent control of the photoexcited carrier density in a semiconductor through the interference of one- and two-photon absorption. An experiment using optical detection is described. The polarization dependence of the signal is consistent with a calculation using a 14-band k · p model for GaAs. We also describe an electrical measurement. A strong enhancement of the phase-dependent photocurrent through a metal-semiconductor-metal structure is observed when a bias of a few volts is applied. The dependence of the signal on bias and laser spot position is studied. The field-induced enhancement of the signal could increase the sensitivity of semiconductor-based carrier-envelope phase detectors, useful in stabilizing mode-locked lasers for use in frequency combs.

Optical coherent control induced by an electric field in a semiconductor: a new manifestation of the Franz-Keldysh effect

In (100)-oriented GaAs illuminated at normal incidence by a laser and its second harmonic, interference between one- and two-photon absorption results in ballistic current injection, but not modulation of the overall carrier injection rate. Results from a pump-probe experiment on a transversely biased sample show that a constant electric field enables coherent control of the carrier injection rate. We ascribe this to the nonlinear optical Franz-Keldysh effect and calculate it for a two-band parabolic model. The mechanism is relevant to centrosymmetric semiconductors as well.

Contactless photoconductive terahertz generation

We describe a pulsed terahertz (THz) emitter that uses a rapidly oscillating, high-voltage bias across electrodes insulated from a photoconductor. Because no carriers are injected from the electrodes, trap-enhanced electric fields do not form. The resulting uniform field allows excitation with a large laser spot, lowering the carrier density for a given pulse energy and increasing the efficiency of THz generation. Compared to a dc bias, less susceptibility to damage is observed.

Terahertz near-field enhancement in narrow rectangular apertures on metal film

We report huge field accumulations in rectangular aperture arrays on thin metal film by using shape resonance in THz frequency region. A huge far-field transmission enhancement is observed in samples of various widths ranging from 10 mum to 1.8 mum which correspond to only an order of lambda/100. Theoretical calculations based on vector diffraction theory indicates 230 times near-field enhancement in case of the 1.8 mum wide rectangular aperture. Transmission measurement through the single rectangular aperture shows that the shape resonance, not the periodicity, is mainly responsible for the transmission enhancement and the corresponding field enhancement.

Central bisectionectomy for centrally located hepatocellular carcinoma

BACKGROUND

Central bisectionectomy, which involves the removal of the central hepatic segments (IVA, IVB, V, VIII) for hepatocellular carcinoma (HCC), is performed to reduce the volume of resected liver and to overcome the problem of insufficient future residual volume.

METHODS

Twenty-seven patients with HCC underwent central bisectionectomy from January 1998 to April 2007 in one hospital. The surgical techniques, clinicopathological characteristics and outcomes were reviewed.

RESULTS

The median operating time was 330 min. Twelve patients developed postoperative complications and two died. The most common complication, occurring in five patients, was bile duct injury leading to biloma or bile leakage. Median follow-up was 19.1 (range 1.4-102.2) months and eight patients developed a recurrence. Twenty-four patients were alive at the time of writing.

CONCLUSION

Although biliary complications occur somewhat frequently, central bisectionectomy in centrally located HCC can be performed safely to preserve liver volume.

Effects of ultraviolet intensity and wavelength on the photolysis of triclosan

The effects of ultraviolet (UV) intensity and wavelength on triclosan (TCS) photodegradation kinetic, efficiency, mechanisms and pathway were studied. The TCS photodegradation followed the pseudo-first order kinetic model at all UV intensities examined at the wavelengths of 254 and 365 nm and the photodegradation rate increased with increasing UV intensity. TCS photodegradation efficiencies of 90 to 98% and 79 to 90% were obtained at the wavelengths of 254 and 365 nm, respectively. TCS was degraded mainly by photon induced hydroxyl radicals while the direct photon reaction with TCS played a subordinate role. Chlorophenol, dichlorophenol and phenol were the intermediates detected in all experiments conducted. Dibenzodichloro-p-dioxin and dibenzo-p-dioxin were observed as the intermediates only at lower UV intensities investigated at the wavelength of 365 nm. Based on these intermediates, a complete TCS photolysis pathway was proposed for the first time.

Lead biosorption by waste biomass of Corynebacterium glutamicum generated from lysine fermentation process

Biomass waste, mainly Corynebacterium glutamicum, is generated from large-scale lysine fermentation process. In this study, protonated C. glutamicum biomass was evaluated as a biosorbent for the removal of lead from synthetic wastewater. As Pb2+ were bound to the biomass, the solution pH deceased, indicating that protons in the biomass were exchanged with lead ions. The Corynebacterium biomass bound Pb2+ at up to 2.74 mmol g(-1) at pH 5, where lead does not precipitate. Compared with other biosorbents and conventional sorbents, such as natural zeolite, activated carbon and synthetic ion exchange resin, the protonated C. glutamicum biomass was considered to be a useful biomaterial for lead biosorption.

Increasing rice productivity and yield by manipulation of starch synthesis

Plant productivity and yield are dependent on source-sink relationships, i.e. the capacity of source leaves to fix CO2 and the capacity of developing sink tissues and organs to assimilate and convert this fixed carbon into dry matter. Studies from our laboratories as well as others have demonstrated that rice productivity and yield are mainly sink-limited during its development because of limited capacity to utilize the initial photosynthetic product (triose phosphate). This limitation in triose phosphate utilization, evident at both the vegetative and reproductive stages of rice development, may be associated with limited capacity for carbohydrate synthesis in rice leaves (which are poor accumulators of starch) or feedback due to limited sink strength of developing seeds. Strategies in improving triose phosphate utilization by enhancing starch production in leaves and developing seeds by the expression of engineered genes for ADP glucose pyrophosphorylase, a key regulatory enzyme of starch biosynthesis, are discussed.

Identification of a cytoskeleton-associated 120 kDa RNA-binding protein in developing rice seeds

During rice seed development, prolamine RNAs are localized to the surface of the prolamine storage protein bodies (PBs), organelles bounded by the endoplasmic reticulum (ER). The exact mechanism by which prolamine RNAs are enriched on this ER subdomain is not known but recent evidence indicates the directed transport and targeting of prolamine RNAs to the prolamine PBs. As such a process involves RNA signal determinants and cytoskeleton-interacting proteins that recognize these signals, we obtained an enriched cytoskeleton-PB fraction and identified a prominent RNA-binding activity, Rp120, by RNA-binding UV-cross-linking assay. Recombinant cDNA clones of Rp120 revealed that the primary sequence shared considerable structural homology to the human transcriptional coactivator p100 and possessed a modular organization, four nucleic acid-binding SN domains, a tudor domain and a coil-coil domain. Consistent with the presence of SN domains, Rp120 binds a variety of RNAs including prolamine RNA. Interaction with the latter RNA, however, was specific as binding activity was evident only to the prolamine 3' UTR and not to the 5' UTR or coding sequences. Rp120 is also able to interact with other proteins as its sedimentation behavior in sucrose density gradient suggests an association with the cytoskeleton. The presence of a tudor domain, suggested to have a role in RNA processing or transport, together with the SN and coiled-coil domains are consistent with the view that Rp120 may be involved in RNA sorting in rice endosperm.

Investigation of subunit function in ADP-glucose pyrophosphorylase

ADP-glucose pyrophosphorylase (AGPase), a key regulatory enzyme in higher plant starch biosynthesis, is composed of a pair of large and small subunits (alpha(2)beta(2)). Current evidence suggests that the large subunit has primarily a regulatory function, while the small subunit has both regulatory and catalytic roles. To define the structure-function relationship of the large subunit (LS), the LS of potato AGPase was subjected to chemical mutagenesis and coexpressed with the wild-type (WT) small subunit (SS) cDNA in an AGPase defective Escherichia coli strain. An LS mutant (M143) was isolated, which accumulated very low levels of glycogen compared to the WT recombinant AGPase, but maintained normal catalytic activity when assayed under saturating conditions. Sequence analysis revealed that M143 has a single amino acid change, V463I, which lies adjacent to the C-terminus. This single mutation had no effect on the Km for ATP and Mg(2+), which were similar to the WT enzyme. The K(m) for glucose 1-P, however, was sixfold higher than the WT enzyme. These results suggest that the LS plays a role in binding glucose 1-P through its interaction with the SS.

Transcriptional expression characteristics and subcellular localization of ADP-glucose pyrophosphorylase in the oil plant Perilla frutescens

Three ADP-glucose pyrophosphorylase clones were isolated from the cotyledon cDNA library of the oil plant, Perilla frutescens, and their intracellular localization investigated. Two of three cDNAs (PfagpS1 and PfagpS2) were homologous to the catalytic small subunit of AGPases found in other plants, while the third clone (PfagpL) was highly similar to the large subunit type. Transcripts for PfagpS1 and PfagpS2 were observed in both photosynthetic and non-photosynthetic tissue, showing the highest expression in the stem, while PfagpL transcripts were abundantly expressed in stem and cotyledon. To evaluate the subcellular localization of PfagpS2 and PfagpL as well as the maize BT2, N-terminus-GFP DNA fusion were constructed and transformed into tobacco plants. Immunoblot analysis showed that the expressed PfagpS2- and PfagpL-GFP fusions were targeted to the plastid in the heterologous tobacco system whereas the BT2-GFP remained intact, suggesting a cytoplasmic location. These intracellular assignments were confirmed by direct confocal microscopic examination. GFP signals were localized to the cytoplasm as well as in the nucleus in BT2-GFP plants, and to the plastids in PfagpS2- and PfagpL-GFP plants. Our results indicate that Perilla cotyledons contain multiple AGPase subunits, of which at least two isoforms and very likely the third, are plastidial in nature.

Messenger RNA targeting of rice seed storage proteins to specific ER subdomains

Rice seeds, a rich reserve of starch and protein, are a major food source in many countries. Unlike the seeds of other plants, which typically accumulate one major type of storage protein, rice seeds use two major classes, prolamines and globulin-like glutelins. Both storage proteins are synthesized on the endoplasmic reticulum (ER) and translocated to the ER lumen, but are then sorted into separate intracellular compartments. Prolamines are retained in the ER lumen as protein bodies whereas glutelins are transported and stored in protein storage vacuoles. Mechanisms responsible for the retention of prolamines within the ER lumen and their assembly into intracisternal inclusion granules are unknown, but the involvement of RNA localization has been suggested. Here we show that the storage protein RNAs are localized to distinct ER membranes and that prolamine RNAs are targeted to the prolamine protein bodies by a mechanism based on RNA signal(s), a process that also requires a translation initiation codon. Our results indicate that the ER may be composed of subdomains that specialize in the synthesis of proteins directed to different compartments of the plant endomembrane system.

Parameter estimates for direct and maternal genetic effects on yearling, eighteen-month, and slaughter weights of Korean native cattle

Data collected by the National Livestock Research Institute of the Rural Development Administration of Korea were used to estimate genetic parameters for yearling (YWT, n = 5,848), 18-mo (W18, n = 4,585), and slaughter (SWT, n = 2,279) weights for Korean Native cattle. Nine animal models were used to obtain REML estimates of genetic parameters: DP-2 included genetic, uncorrelated dam, and residual random effects; DQ-2 included genetic, sire x region x year-season interaction, and residual random effects; DPQ-2 was based on DQ-2 but included both interaction and dam effects; DMP-2 was based on DP-2 but with dam effect partitioned to include maternal genetic and permanent environmental effects; and DMPQ-2 was based on DMP-2 but also included sire interaction effects. Those five models included two fixed factors: region x year-season and age of dam x sex effects. Models DP-3, DQ-3, DPQ-3, and DMPQ-3 were based on DP-2, DQ-2, DPQ-2, and DMPQ-2 but included as a third fixed factor whether or not identification of the sire was known. Estimates of heritability with DMPQ-3 for YWT, with DPQ-3 for W18 and SWT when analyzed with single-trait analyses were .14, .11, and .17, respectively, and were nearly the same with bivariate analyses. Estimate of maternal heritability for YWT from single-trait analysis was .04, with estimates for other traits near zero. For bivariate analyses, the estimate for YWT was .01. With single trait analysis, estimate of the direct-maternal genetic correlation for YWT was negative (-.81). Estimates of direct genetic correlations between YWT and W18, YWT and SWT, and W18 and SWT were .99, 1.00, and .97, respectively. Estimates of environmental correlations varied from .60 to .81; the largest was between W18 and SWT. Including a fixed factor for whether sire identification was missing or not missing reduced the estimate of heritability for slaughter weight. The results suggest that the sire x region x year-season interaction is important for yearling weight and may be needed in a model for slaughter weight. Maternal effects may be of slight importance for yearling weight but of no importance for W18 and SWT. Models for national cattle evaluations for Korean Native cattle for YWT should be considered that include maternal genetic and permanent environmental as well as sire x region x year-season interaction effects, but those effects seem not to be needed for models for W18 and SWT. Not much reranking of sires occurred when ranked was based on the different models for W18 and SWT.