ABSTRACT
Wide field-of-view magnetic field microscopy has been realised by probing shifts in optically detected magnetic resonance (ODMR) spectrum of Nitrogen Vacancy (NV) defect centers in diamond. However, these widefield diamond NV magnetometers require few to several minutes of acquisition to get a single magnetic field image, rendering the technique temporally static in it's current form. This limitation prevents application of diamond NV magnetometers to novel imaging of dynamically varying microscale magnetic field processes. Here, we show that the magnetic field imaging frame rate can be significantly enhanced by performing lock-in detection of NV photo-luminescence (PL), simultaneously over multiple pixels of a lock-in camera. A detailed protocol for synchronization of frequency modulated PL of NV centers with fast camera frame demodulation, at few kilohertz frequencies, has been experimentally demonstrated. This experimental technique allows magnetic field imaging of sub-second varying microscale currents in planar microcoils with imaging frame rates in the range of 50-200 frames per s (fps). Our work demonstrates that widefield per-pixel lock-in detection of frequency modulated NV ODMR enables dynamic magnetic field microscopy.
ABSTRACT
BACKGROUND: Gmelina arborea Roxb (Verbenaceae), also known as "Gambhari", is an important medicinal plant in the Ayurveda. There are no meticulous scientific reports on effect of the plant on inflammation and pain. OBJECTIVE: To study the anti-inflammatory and anti-nociceptive properties of aqueous extracts (AE) and methanol extracts (ME) of G. arborea. MATERIALS AND METHODS: The AE and ME of stembark of G. arborea was prepared by cold maceration and Soxhlet extraction technique respectively. Anti-inflammatory activity was determined in Wistar albino rats in a model of acute plantar inflammation induced by carrageenan. The anti-nociceptive activity was evaluated by using hot plate test and writhing test in Swiss albino mice. Significant differences between the experimental groups were assessed by analysis of variance. RESULTS: AE and ME at dose of 500 mg/kg showed maximum inhibition in carrageenan induced inflammation up to 30.15 and 31.21% respectively. In hot plate test, the AE and ME showed the maximum response of 8.8 ± 0.97 (P < 0.01) and 8.2 ± 1.24 (P < 0.01) respectively at dose of 500 mg/kg when compared with control. AE showed maximum inhibition of writhing response (84.3%) as compared to ME (77.9%) in writhing test at a dose of 500 mg/kg. CONCLUSION: The findings suggested that G. arborea possess significant anti-inflammatory and anti-nociceptive activities.
