Acceleration of benzo(a)pyrene-induced colon carcinogenesis by Western diet in a rat model of colon cancer.

Colorectal cancer (CRC) is the third leading cause of cancer-related mortalities in the USA and around 52,550 people were expected to die from this disease by December 2023. The objective of this study was to investigate the effect of diet type on benzo(a)pyrene [B(a)P]-induced colon cancer in an adult male rat model, the Polyposis In the Rat Colon (PIRC) kindred type. Groups of PIRC rats (n = 10) were fed with AIN-76A regular diet (RD) or Western diet (WD) and received 25, 50 and 100 µg B(a)P/kg body wt. via oral gavage for 60 days. Rats fed diets alone, but no B(a)P, served as controls. After exposure, rats were euthanized; colon and liver samples were analyzed for activation of drug metabolizing enzymes (DMEs) CYP1A1, CYP1B1, SULT and GST. Plasma and tissue samples were analyzed by reverse phase-HPLC for B(a)P metabolites. In addition to these studies, DNA isolated from colon and liver tissues was analyzed for B(a)P-induced DNA adducts by the 32P-postlabeling method using a thin-layer chromatography system. Western diet consumption resulted in a marked increase in DME expression and B(a)P metabolite concentrations in rats that were administered 100 µg/kg B(a)P + WD (p < 0.05) compared to other treatment groups. Our findings demonstrate that WD accelerates the development of colon tumors induced by B(a)P through enhanced biotransformation, and the products of this process (metabolites) were found to bind with DNA and form B(a)P-DNA adducts, which may have given rise to colon polyps characterized by gain in tumor number, sizes, and dysplasia.

Technology-enacted abusive supervision and its effect on work and family.

This study examines the effects of technology-enacted abusive supervision, defined as subordinate perceptions of supervisor's use of information and communication technologies (ICTs) to engage in hostile communications. This research was designed to examine if technology-enacted abusive supervision has an impact on both the work and family domains. Based on conservation of resources theory, we theorize that technology-enacted abusive supervision enhances subordinate engagement in emotional labor surface acting, which contributes to emotional exhaustion, which in turn impacts both the work and family domains. Results demonstrate significant paths in both domains. Subordinate perceptions of technology-enacted abusive supervision are positively related to the engagement in technology-enacted incivility through the serial mediation of emotional labor surface acting and emotional exhaustion. Additionally, subordinate perceptions of technology-enacted abusive supervision are positively related to family undermining at home for the subordinate through the serial mediation of emotional labor surface acting, emotional exhaustion, and stress transmission.

Pressurized liquid extraction followed by liquid chromatography coupled to a fluorescence detector and atmospheric pressure chemical ionization mass spectrometry for the determination of benzo(a)pyrene metabolites in liver tissue of an animal model of colon cancer.

Since metabolism is implicated in the carcinogenesis of toxicants, an efficient extraction method together with an analytical method is warranted to quantify tissue burdens of a carcinogen and/or its metabolites. Therefore, the aim of this study was to validate a pressurized liquid extraction (PLE) method for measuring metabolites of benzo(a)pyrene [B(a)P; a food-borne carcinogen] from tissue samples. The sample extraction was performed separately by PLE and liquid-liquid extraction (LLE). PLE followed by high-performance liquid chromatography coupled to online fluorescence detector (HPLC-FLD) was used to quantify separated analytes; and by ultra-high-performance liquid chromatography (UHPLC) coupled to atmospheric pressure chemical ionization tandem mass spectrometry (UHPLC-APCI-MS/MS) were used for confirmation purposes. The UHPLC-MS/MS was set-up in the atmospheric pressure chemical ionization (APCI) positive interface with selective reaction monitoring (SRM). The analytical performance characteristics of the PLE technique was assessed at different temperatures, pressure, number of cycles and solvent types. A methanol + chloroform + water mixture (30:15:10, v/v/v) yielded greater recoveries at an extraction temperature range of 60-80°C, pressure of 10 MPa and an extraction time of 10 min. The PLE method was validated by the analysis of spiked tissue samples and measuring recoveries and limits of quantitation for the analytes of interest using HPLC-FLD equipment. The optimized PLE-HPLC-FLD method was used to quantify the concentrations of B(a)P metabolites in liver samples obtained from a colon cancer animal model. Overall, PLE performed better in terms of extraction efficiency, recovery of B(a)P metabolites and shortened sample preparation time when compared with the classic LLE method.

Social media addiction and social media reactions: The implications for job performance.

We investigate the intersection of social media and the workplace, focusing on job performance impacts of employees' social media addictions and social media reactions through work-family balance and burnout. The research model is grounded in conservation of resources theory, which suggests social media compulsions and emotional reactions to co-worker's social media posts will deplete employees' energetic and constructive resources, making it difficult to achieve work-family balance and increasing the likelihood of job burnout, and will ultimately degrade job performance. A sample of 326 full-time employees revealed a negative relationship between social media addiction and work-family balance and a positive relationship between social media reactions and job burnout. Balance and burnout mediated the relationship between social media and job performance such that social media addiction was negatively related to job performance through work-family balance, and social media reactions were negatively related to performance through burnout and work-family conflict.

OXIDATIVE STRESS IN REPRODUCTIVE TOXICOLOGY.

Oxidative stress (OS) has been implicated in the causation of environmentally-induced diseases. However, the role of toxicants in the pathophysiology of disorders and diseases affecting the reproductive system are less understood. This review focuses on some of the mechanisms that underlie OS-induced reproductive toxicity at the cellular- and organ levels (germ cell damage and perturbed organ responses to endocrine stimuli). While most of the reproductive and developmental studies conducted in adult animals and transgenerational adult animals point to the involvement of genotoxicity, the part played by epigenetic alterations is accorded a recent recognition, thus warranting more studies in this area. Additionally, metabolomic, proteomic and transcriptomic approaches need to be employed to advance our understanding of key metabolites formed and the expression of anti-OS genes at the molecular level that are necessary for combating reactive oxygen species formation. The resulting data could be analyzed using bioinformatics tools to identify the pathways linked to disease causation and as a consequence, the adoption of therapeutic strategies, including but not limited to administering phytochemicals (many of which possess antioxidant properties) to improve disease outcomes.

Is more always better? An examination of the nonlinear effects of perceived organizational support on individual outcomes.

A wide range of research has accumulated detailing the positive associations of perceived organizational support (POS) with desirable workplace outcomes (e.g., high performance, high commitment, low deviance). In the process, there has been an implicit assumption that these relationships are linear, with ever-increasing POS resulting in ever-increasing positive outcomes. However, there are theoretical and practical reasons to question whether these relationships may be nonlinear rather than linear. Our results offer support for the notion that the relationships between POS and key individual outcomes rated by the supervisor may best be represented as nonlinear. We conclude by highlighting the implications for both theory and practice.

Interactive effect of leaders' influence tactics and ethical leadership on work effort and helping behavior.

The purpose of this study was to explore the interactive influence of a) leaders' exemplification and supplication efforts and b) followers' perceptions of the leaders' ethicality on followers' work efforts and helping behaviors. We surveyed 58 leaders and 175 followers who worked for a governmental agency in the United States. Results indicated that the expected positive (negative) relationship between leaders' usage of exemplification and work effort was evident when ethical leadership was high (low). The expected positive relationship between leaders' engagement in supplication and helping behaviors was not present when ethical leadership was high, but the predicted negative relationship was found between supplication and helping when perceptions of leaders' ethicality were low.

An investigation of abusive supervision, vicarious abusive supervision, and their joint impacts.

Recent work has begun to look at the impact of abusive supervision, a dysfunctional workplace behavior, on employee outcomes. This study extends this line of research by examining vicarious abusive supervision (abuse not directly experienced, but rumors about it or hearing about it, that is "experienced vicariously"). In particular, this research effort investigates whether vicarious abuse has effects above and beyond those accounted for by personally experienced abusive supervision on the outcomes of job frustration, coworker abuse, and perceived organizational support. Our sample is composed of 233 workers from a large variety of organizations. Results reveal that both personally experienced and vicarious abuse have negative impacts and these effects are heightened when both forms of abusive supervision are present. Practical and theoretical implications, as well as directions for future research, are offered.

Water adsorption on clay minerals as a function of relative humidity: application of BET and Freundlich adsorption models.

Water adsorption on kaolinite, illite, and montmorillonite clays was studied as a function of relative humidity (RH) at room temperature (298 K) using horizontal attenuated total reflectance (HATR) Fourier transform infrared (FTIR) spectroscopy equipped with a flow cell. The water content as a function of RH was modeled using the Brunauer, Emmett, and Teller (BET) and Freundlich adsorption isotherm models to provide complementary multilayer adsorption analysis of water uptake on the clays. A detailed analysis of model fit integrity is reported. From the BET fit to the experimental data, the water content on each of the three clays at monolayer (ML) water coverage was determined and found to agree with previously reported gravimetric data. However, BET analysis failed to adequately describe adsorption phenomena at RH values greater than 80%, 50%, and 70% RH for kaolinite, illite, and montmorillonite clays, respectively. The Freundlich adsorption model was found to fit the data well over the entire range of RH values studied and revealed two distinct water adsorption regimes. Data obtained from the Freundlich model showed that montmorillonite has the highest water adsorption strength and highest adsorption capacity at RH values greater than 19% (i.e., above ML water adsorption) relative to the kaolinite and illite clays. The difference in the observed water adsorption behavior between the three clays was attributed to different water uptake mechanisms based on a distribution of available adsorption sites. It is suggested that different properties drive water adsorption under different adsorption regimes resulting in the broad variability of water uptake mechanisms.

Fostering good citizenship through ethical leadership: exploring the moderating role of gender and organizational politics.

Considering the implications of social exchange theory as a context for social role behavior, we tested relations between ethical leadership and both person- and task-focused organizational citizenship behavior and examined the roles played by employee gender and politics perceptions. Although social exchange theory predicts that ethical leadership is positively associated with citizenship, social role theory predicts that the nature of this relationship may vary on the basis of gender and politics perceptions. Results from data collected from 288 supervisor-subordinate dyads indicate that the pattern of male versus female employees' citizenship associated with ethical leadership depends significantly on their perceptions of politics. Implications for theory and practice are discussed.

Who abuses their coworkers? An examination of personality and situational variables.

This study examines predictors of abusive employee behavior toward coworkers. We examined two personality variables, negative affectivity and political skill, and two situational relationship variables-team member exchange and coworker relationship conflict. We tested our hypotheses with data obtained from a sample of 232 working employees. We found that political skill and team member exchange were negatively related to coworker abuse, whereas negative affectivity and relationship conflict were positively related. Additionally, we found statistical support for the negative affectivity-relationship conflict, political skill-team member exchange, and political skill-relationship conflict interactions. Practical implications and directions for future research are provided.

Got political skill? The impact of justice on the importance of political skill for job performance.

The present study examined the moderating effects of procedural and distributive justice on the relationships between political skill and task performance and organizational citizenship behavior (OCB) among 175 supervisor-subordinate dyads of a government organization. Using Mischel's (1968) situationist perspective, high justice conditions were considered "strong situations," whereas low justice conditions were construed as "weak situations." We found that when both procedural and distributive justice were low, political skill was positively related to performance. Under conditions of both high procedural and high distributive justice, political skill was negatively related to performance. Finally, under conditions of low distributive justice, political skill was positively related to OCB, whereas under conditions of high distributive justice, political skill had little effect on OCB. These results highlight the importance of possessing political skill in weak but not strong situations.

Core self-evaluations and job performance: the role of the perceived work environment.

Using trait activation theory as a framework, the authors examined the moderating role of two situational variables-perceptions of organizational politics and perceptions of leader effectiveness-on the relationship between core self-evaluations and job performance. Results from two samples (N = 137 and N = 226) indicate that employee perceptions of their work environment moderated the relationship between their core self-evaluations and supervisor ratings of their performance. In particular, those with higher core self-evaluations received higher performance ratings in environments perceived as favorable than in environments perceived as unfavorable.

Career success implications of political skill.

The authors investigated the individual characteristic of political skill and its relation to 5 different career-related outcomes (total compensation, promotions, career satisfaction, life satisfaction, and perceived external job mobility). They examined data obtained from a sample of 191 employees working a wide range of occupations. The results reveal that political skill is associated with 4 of the 5 outcomes. In addition, they examined the 4 dimensions of political skill and found that the networking ability dimension dominates the relations with the examined outcomes. The authors discuss practical implications, limitations, and directions for future research.

Attenuating the effects of social stress: the impact of political skill.

This study investigates the impact of perceived social stressors on job and career satisfaction. Additionally, the authors investigate whether individuals' reported levels of political skill could attenuate the negative effects of social stressors on these outcome variables. The authors test these hypotheses with a sample of 246 alumni from a private, Midwestern university. The authors' results provide support for the hypothesized negative influence of social stressors on job and career satisfaction and indicate that political skill can moderate these relationships. Practical implications and directions for future research are offered.

The impact of political skill on impression management effectiveness.

In this study, the authors investigated the effect of an individual's political skill on the relationships between 5 different impression management tactics (intimidation, exemplification, ingratiation, self-promotion, and supplication) and supervisor evaluations of performance. To test these relationships, the authors used a matched sample of 173 supervisor-subordinate dyads who worked full time in a state agency. Findings showed that individuals who used high levels of any of the tactics and who were politically skilled achieved more desirable supervisor ratings than did those who used the tactics but were not politically skilled. Opposite results were found when impression management usage was low. That is, individuals who were not politically skilled created a more desirable image in their supervisors' eyes than did their politically skilled counterparts when they did not use these tactics. Practical and research implications for the findings as well as directions for future research are offered.

A test of competing models of the relationships among perceptions of organizational politics, perceived organizational support, and individual outcomes.

The authors aimed to distinguish between perceptions of organizational politics (POPs) and perceived organizational support (POS). Previous research has shown that these two constructs are related, and whereas some researchers have suggested that POS mediates the relationships between POPs and outcomes (e.g., M. C. Andrews & K. M. Kacmar, 2001; R. Cropanzano, J. C. Howes, A. A. Grandey, & P. Toth, 1997), others have claimed that POPs mediate the relationships between POS and outcomes (e.g., G. R. Ferris, G. S. Russ, & P. M. Fandt, 1989). The authors investigated these competing models in an organizational sample of 418 employees from a water-management-district office. Results showed that POPs and POS were related to each other and to 5 outcomes: (a) job satisfaction, (b) pay satisfaction, (c) job strains, (d) role conflicts, and (e) turnover intentions. Results also indicated that POS fully mediated 3 of the 5 relationships between POPs and outcomes and partially mediated the other 2.

Too much of a good thing: the curvilinear effect of leader-member exchange on stress.

Organizational researchers have given considerable attention to the construct of leader-member exchange (LMX). Numerous studies have empirically supported the negative correlations between LMX relationships and unwanted individual outcomes, including stress. However, in the present study, the authors investigated whether the relationship is best represented as linear or curvilinear. The authors tested their research hypothesis in two organizational samples of 120 and 402 employees, respectively, and found support for the nonlinear relationship in both samples. The authors described strengths, limitations, practical implications, and directions for future research.