Examining the factor structure of the Connor-Davidson Resilience Scale (CD-RISC) in a post-9/11 U.S. military veteran sample.

The present study examined the structural validity of the 25-item Connor-Davidson Resilience Scale (CD-RISC) in a large sample of U.S. veterans with military service since September 11, 2001. Participants (N = 1,981) completed the 25-item CD-RISC, a structured clinical interview and a self-report questionnaire assessing psychiatric symptoms. The study sample was randomly divided into two subsamples: an initial sample (Sample 1: n = 990) and a replication sample (Sample 2: n = 991). Findings derived from exploratory factor analysis (EFA) did not support the five-factor analytic structure as initially suggested in Connor and Davidson's instrument validation study. Although parallel analyses indicated a two-factor structural model, we tested one to six factor solutions for best model fit using confirmatory factor analysis. Results supported a two-factor model of resilience, composed of adaptability- (8 items) and self-efficacy-themed (6 items) items; however, only the adaptability-themed factor was found to be consistent with our view of resilience-a factor of protection against the development of psychopathology following trauma exposure. The adaptability-themed factor may be a useful measure of resilience for post-9/11 U.S. military veterans.

Ex vivo DNA Assembly.

Even with decreasing DNA synthesis costs there remains a need for inexpensive, rapid, and reliable methods for assembling synthetic DNA into larger constructs or combinatorial libraries. Advances in cloning techniques have resulted in powerful in vitro and in vivo assembly of DNA. However, monetary and time costs have limited these approaches. Here, we report an ex vivo DNA assembly method that uses cellular lysates derived from a commonly used laboratory strain of Escherichia coli for joining double-stranded DNA with short end homologies embedded within inexpensive primers. This method concurrently shortens the time and decreases costs associated with current DNA assembly methods.