Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential

The negatively charged nitrogen vacancy (NV⁻) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV⁻ state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.United States. Army Research Office (W911NF-12-1-0594)United States. National Institutes of Health (1R01NS087950)United States. Defense Advanced Research Projects Agency (D14PC00121)United States. Defense Advanced Research Projects Agency (HR0011-14-C-0018)United States. National Institutes of Health (1R43MH102942-01)National Science Foundation (U.S.) (1122374

COX-2 expression and clinical outcome in early-stage breast cancer patients treated with adjuvant chemotherapy: A prospective study

e22165 Background: To evaluate the association of cox-2 expression with the outcome after adjuvant chemotherapy in patients with early breast cancer. Methods: This was planned as a prospective study recruiting consecutive patients receiving adjuvant anthracycline based chemotherapy and with available tissue blocks permitting all immunohistochemical analyses. Cox-2 expression, in addition to other classical biological factors, was evaluated with immunohistochemistry. Disease and patient related, and biological predictors of both overall survival (OAS) and relapse free survival (RFS) were analyzed by Cox regression analysis. Median and mean survival times were calculated according to the Kaplan Meier method. Results: A total of 88 patients were recruited over a period of 24 months. Median age was 45 (29 to 70), and 60% of subjects were premenapausal. Median tumour diameter and number of axillary lymph nodes involved were 2 cm (1 to 6 cm), and 2 (0 to 15), respectively. Median follow up is 74.2 months. Univariate analysis revealed menopausal status and estrogen receptor expression as predictors of OAS, and menopausal status as the correlate of RFS. Multivariate analysis confirmed the independent predictive value of both menopausal status and estrogen receptor expression for OAS (P=0.009, HR=4.18, and P=0.014, HR=0.20, respectively). No multivariate analysis could be performed for RFS. Cox-2 expression was not associated with OAS or RFS (P=0.208, HR=1.92, and P=0.132, HR=1.89, respectively). Interestingly, Cox-2 expression was correlated with Estrogen receptor (ER) and Progesteron receptor (PR) expression (P=0.006, R=-0.303, and P=0.004, R=-0.312, respectively). Conclusions: Cox-2 expression fails to predict clinical outcome of early breast cancer patients treated with adjuvant chemotherapy. However, Cox-2 expression seems to negatively correlate with ER and PR expression. It should be tested in this patient population whether Cox-2 may play a part in hormonal resistance. No significant financial relationships to disclose. </jats:p