Development of FPGA-based multi-sensor excitation low voltage (MSELV) chassis at Jefferson Lab

The design and development of the sensor excitation and read back chassis was driven by the requirements for the monitoring and control of two conduction-cooled superconducting magnets in Hall B for the 12 GeV accelerator upgrade. The torus and solenoid superconducting magnets require extensive instrumentation. Sensor selection was accomplished by applying Jefferson Lab's (JLab) risk mitigation process, which employed a failure modes and effects analysis approach. The goal was to accommodate all sensor types for monitoring and control and to develop a generic multisensor excitation low voltage chassis that would be used across both magnet systems with a reduced set of functions. The chassis has been deployed in experimental Hall B at JLab and has been performing successfully since July 2016.

Identification of Neisseria gonorrhoeae in synovial fluid using the polymerase chain reaction

OBJECTIVE

To analyze synovial fluid (SF) for the presence of Neisseria gonorrhoeae DNA using the polymerase chain reaction (PCR).

METHODS

We used a modified, nested PCR to detect the presence of N gonorrhoeae DNA in 41 samples of SF obtained from 10 patients with clinical gonococcal arthritis whose SF samples were sterile by culture and from 27 controls, including 11 patients with Reiter's syndrome. Results obtained using this method were compared with those obtained using the GEN-PROBE system, an RNA-DNA hybridization technique.

RESULTS

With nested PCR, N gonorrhoeae DNA was detected in 11 of 14 SF samples obtained from patients with culture-negative clinical gonococcal arthritis but in none of the 11 SF samples from Reiter's syndrome patients. The specificity of this technique was 96.4%, with a sensitivity of 78.6%. The rate of false-positive results was 3.6%. The GEN-PROBE technique was unable to detect N gonorrhoeae ribosomal RNA in any of the samples.

CONCLUSION

These findings demonstrate the potential utility of the PCR in confirming the clinical diagnosis of gonococcal arthritis as well as providing insight into the pathogenesis of this disorder in patients whose SF are sterile by standard culture techniques. PCR may also prove helpful in differentiating N gonorrhoeae arthritis from acute Reiter's syndrome.