Characterization and optimization of a positively charged poly (ethylene glycol)diacrylate hydrogel as an actuating muscle tissue engineering scaffold.

Hydrogels have been used for many applications in tissue engineering and regenerative medicine due to their versatile material properties and similarities to the native extracellular matrix. Poly (ethylene glycol) diacrylate (PEGDA) is an ionic electroactive polymer (EAP), a material that responds to an electric field with a change in size or shape while in an ionic solution, that may be used in the development of hydrogels. In this study, we have investigated a positively charged EAP that can bend without the need of external ions. PEGDA was modified with the positively charged molecule 2-(methacryloyloxy)ethyl-trimethylammonium chloride (MAETAC) to provide its own positive ions. This hydrogel was then characterized and optimized for bending and cellular biocompatibility with C2C12 mouse myoblast cells. Studies show that the polymer responds to an electric field and supports C2C12 viability.

Rapid Syphilis Testing for Men Who Have Sex With Men in Outreach Settings: Evaluation of Test Performance and Impact on Time to Treatment.

BACKGROUND: Rapid syphilis tests (RST) may shorten time to syphilis diagnosis and treatment while enhancing access to testing in outreach settings. There are limited data on the performance of RST in outreach settings in the US. METHODS: We offered RST (Syphilis Health Check) at 6 outreach sites to men who reported having sex with men and no prior history of syphilis. Clients accepting RST were also tested with laboratory-based rapid plasma reagin (RPR) and reflex Treponema pallidum particle agglutination (TPPA) assay when RPR or RST were positive. Clients with positive RST were immediately referred to a sexually transmitted infection clinic. Those declining RST were screened with RPR and reflex TPPA only. The validity of the RST-based algorithm was compared with the RPR-based algorithm among participants receiving both. Time to treatment for those accepting RST was compared with those declining RST and to a historical control group screened in outreach settings with RPR and reflex TPPA before the availability of RST. RESULTS: Rapid syphilis test was accepted by 690 (64%) of 1081 eligible clients. Compared with RPR-based algorithm, RST sensitivity was 90%; specificity, 98.5%; positive predictive value, 47.4%; and negative predictive value, 98.5. The single false-negative case by RST was determined to be a late latent case by RPR/TPPA. Median time to treatment was 1 day (range, 0-6 days) for 9 of 690 accepting RST, compared to 9 days (range, 7-13 days) for 3 of 391 declining RST, and 9 days (range, 6-21 days) for 25 of 1229 historical controls (P < 0.0001). CONCLUSION: Compared with an RPR-based algorithm, RST identified all early syphilis cases. Although RST had high specificity and negative predictive value, the low positive predictive value resulted in additional assessments in a sexually transmitted infection clinic for some patients. However, RST use in outreach settings significantly decreased time to treatment for new syphilis cases.

Biological invasions: a field synopsis, systematic review, and database of the literature.

Species introductions of anthropogenic origins are a major aspect of rapid ecological change globally. Research on biological invasions has generated a large literature on many different aspects of this phenomenon. Here, we describe and categorize some aspects of this literature, to better understand what has been studied and what we know, mapping well-studied areas and important gaps. To do so, we employ the techniques of systematic reviewing widely adopted in other scientific disciplines, to further the use of approaches in reviewing the literature that are as scientific, repeatable, and transparent as those employed in a primary study. We identified 2398 relevant studies in a field synopsis of the biological invasions literature. A majority of these studies (58%) were concerned with hypotheses for causes of biological invasions, while studies on impacts of invasions were the next most common (32% of the publications). We examined 1537 papers in greater detail in a systematic review. Superior competitive abilities of invaders, environmental disturbance, and invaded community species richness were the most common hypotheses examined. Most studies examined only a single hypothesis. Almost half of the papers were field observational studies. Studies of terrestrial invasions dominate the literature, with most of these concerning plant invasions. The focus of the literature overall is uneven, with important gaps in areas of theoretical and practical importance.