Role Overload and Work Performance: The Role of Psychological Strain and Leader-Member Exchange.

The relation between role overload and work performance remains insufficiently understood. Drawing upon conservation of resources theory, we expected role overload to negatively relate to performance through psychological strain and this relation to be buffered by leader-member exchange (LMX). Study 1 (N = 212) examined depression as a severe type of strain that mediates between role overload and in-role performance, job dedication, and voice behavior. Study 2 (N = 191) used generic, perceived strain as a mediator between role overload and in-role performance and reward recommendations. Both studies tested LMX's buffering effect, controlling for role ambiguity and conflict. A supplementary panel study (N = 99) assessed the temporal relationship between role overload and strain. Role overload triggered psychological strain, which undermined performance, and LMX acted as a buffer on role overload, but not on role ambiguity or role conflict. We discuss the implications of these findings for theory and practice.

Peritoneal dialysis catheter insertion using a very-low-site approach: a 5-year experience.

PURPOSE: Peritoneal dialysis (PD) catheter tip migration accounts for the majority of cases of PD catheter malfunction. In this case series, we described our experiences of using a modified PD catheter implantation approach through a site that is lower than the site that is conventionally used, to reduce catheter malfunction. METHODS: We retrospectively identified 76 patients who received PD catheter implantation at the Affiliated Wujin Hospital of Jiangsu University, among whom 39 received the traditional approach of low-site insertion and 37 received a modified approach of very-low-site insertion. All participants were followed up for at least 2 years after PD catheter implantation, and the development of catheter dysfunction or death during this period was monitored. RESULTS: We found that the survival rate of the initially inserted catheter was 75.68% among the very-low-site group. This survival rate was significantly better than that observed among the low-site group (48.72%; p = 0.029). Kaplan-Meier curves of the initial catheter survival also showed that the catheter survival was significantly higher in the patients in the very-low-site group than those in the low-site group (log rank p = 0.012). Complications, such as catheter tip migration, were not observed in the very-low-site group, while tip migration occurred in 15.38% of the patients in the low-site group (very-low-site group vs low-site group: p = 0.039). CONCLUSIONS: A safe and simple PD catheter implantation can be performed either through the low-site approach or the very-low-site approach.

Phages Displaying Peptides with beta Turn Conformation.

Peptide CX(2)GPX(4)C, which was supposed to adopt a typical beta turn conformation, was displayed on the surface of filamentous phages by fusing to the N-terminus of minor coat protein g3p. The diversity of this library was 1.04x10(8). Sequences from 19 randomly selected phage clones indicated that the distribution of nucleotides and amino acids paralleled the expected frequency. The combined index of hydropathy and isoelectric point of these 19 peptides were randomly distributed over wide ranges. The enrichment was obtained after 3 rounds of screening with monoclonal antibody 12CA5. And the results of phage ELISA and competitive ELISA showed that the 15 individual phage clones randomly selected from the third round elution specifically bound to the antigen-binding site of the antibody. This binding was abolished after destroying of the conformation.

Potential GM-CSF Antagonists Selected from a Peptide Phage Display Library.

Peptide phage display libraries have been successfully applied in areas of mapping antibody epitope, finding ligands for enzymes, receptors, and many other molecules. But it has been demonstrated to be very difficult to select cytokine-binders from peptide phage display libraries probably because cytokine is not so sticky as antibody that there are rare chances of capturing peptide phages during biopanning. A pVIII-based peptide phage display library was panned with the cytokine GM-CSF and some GM-CSF binding clones were selected based on high throughput screening (HTS) method and confirmed by ELISA and micropanning assays. These cytokine-binders may be utilized in affinity chromatography in cytokine downstream processing and even act as potential antagonists of GM-CSF if their affinity are further improved through secondary library strategy.