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Purpose The purpose of this paper is to explore how social network fatigue affects continuance intention of social networking services (SNSs) from a more comprehensive perspective. Design/methodology/approach A research model was proposed by integrating uses and gratification theory (UGT), social network fatigue and continuance intention. The relationships between the three dimensions of UGT and continuance intention were examined, as well as the direct and moderating effects of social network fatigue. To collect data, an online survey was adopted, and 227 valid responses were analyzed by structural equation modeling. Findings The empirical findings demonstrate that utilitarian gratification (information seeking), social gratification (social interaction) and hedonic gratification (perceived enjoyment) are positively associated with SNS users’ continuance intention. Meanwhile, social network fatigue can directly and negatively affect continuance intention. Furthermore, the relationships between the two dimensions of UGT (information seeking, perceived enjoyment) and continuance intention are also negatively moderated by social network fatigue. Originality/value This study contributes to the understanding about the relationship between continuance intention and social network fatigue. The authors indicate that social network fatigue will not only directly weaken SNS users’ continuance intention, but also negatively influence the formation process of the continuance intention. Some other theoretical and practical implications are also provided.

Objective This study's goal was to compare elastin metabolism in the vagina of women with and without pelvic organ prolapse and to define the regulation of this process by hormone therapy (HT). Methods Eighty-seven histologically confirmed full-thickness vaginal biopsies were procured from study subjects at time of surgery. Premenopausal women with no prolapse served as controls. Women with prolapse were divided into 3 groups – premenopausal, postmenopausal not on HT and postmenopausal on HT. The epithelium was excised leaving the subepithelium, muscularis and adventitia for analyses. The elastin precursor, tropoelastin, was measured by immunoblotting and mature elastin protein via a desmosine crosslink radioimmunoassay. Matrix metalloproteinases (MMPs) -2, -9 were quantitated by gelatin zymography. Data were analyzed using Kruskal-Wallis test and post-hoc analysis using the Mann-Whitney U test. Results Tropoelastin (432%), mature elastin (55%), proMMP-9 (90%) and active MMP-9 (106%) were increased in women with prolapse relative to controls while active MMP-2 (41%) was decreased. Comparison of tropoelastin and mature elastin values obtained from the same women showed them to be independently regulated (r =0.19). Interestingly, the highest amount of both proteins occurred in postmenopausal patients not on HT. Conclusion Elastin metabolism is altered in the vagina of women with prolapse relative to controls suggesting that vaginal tissue is rapidly remodeling in response to mechanical stretch. The finding that elastin levels are highest in the absence of hormones warrants further investigation.

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Objective The impact of polypropylene mesh implantation on vaginal collagen and elastin metabolism was analyzed using a nonhuman primate model to further delineate the mechanism of mesh induced complications. Methods 49 middle aged parous rhesus macaques underwent surgical implantation of 3 synthetic meshes via sacrocolpopexy. Gynemesh PS (n=12) and two lower weight, higher porosity, lower stiffness meshes - UltraPro (n = 19) and Restorelle (n=8) were implanted, in which UltraPro was implanted with its blue orientation lines perpendicular (low stiffness direction, n=11) and parallel (high stiffness direction, n=8) to the longitudinal axis of vagina. Sham operated animals were used as controls (n=10). Twelve weeks after surgery, the meshtissue complex was excised and analyzed. Results Relative to Sham, Gynemesh PS had a negative impact on the metabolism of both collagen and elastin favoring catabolic reactions while UltraPro only induced an increase in elastin degradation. Restorelle had the least impact. As compared to Sham, the degradation of collagen and elastin in the vagina implanted with Gynemesh PS was increased with a simultaneous increase in active MMP-1, -8, -13 and total MMP-2, -9 (all P<0.05). The degradation of elastin (tropoelastin and mature elastin) was increased in the UltraPro implanted vagina with a concomitant increase of MMP-2, and -9 (all P<0.05). Collagen subtype ratio III/I was increased in both Gynemesh PS and UltraPro perpendicular groups (P<0.05). Conclusion Following implantation with the heavier, less porous and stiffer mesh, Gynemesh PS, the degradation of vaginal collagen and elastin exceeded synthesis, most likely as a result of increased activity of MMPs, resulting in a structurally compromised tissue.

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Residual dipolar couplings (RDC) emerged to be an important structural parameter for organic and biomolecules. Herein, a new helical polyisocyanopeptide (l,l-PIAF-OBn) that forms lyotropic liquid crystals (LLC) in CDCl is proposed as a novel weakly orienting medium for acquiring residual dipolar couplings (RDCs) of organic molecules. We demonstrate its application for the structural elucidation of strychnine and triptolide.

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