Cavity ring-up spectroscopy for dissipative and dispersive sensing in a whispering gallery mode resonator

In whispering gallery mode resonator sensing applications, the conventional way to detect a change in the parameter to be measured is by observing the steady state transmission spectrum through the coupling waveguide. Alternatively, cavity ring-up spectroscopy (CRUS) sensing can be achieved transiently. In this work, we investigate CRUS using coupled mode equations and find analytical solutions with a large spectral broadening approximation of the input pulse. The relationships between the frequency detuning, coupling gap and ring-up peak height are determined and experimentally verified using an ultrahigh \textit{Q}-factor silica microsphere. This work shows that distinctive dispersive and dissipative transient sensing can be realised by simply measuring the peak height of the CRUS signal, which might improve the data collection rate

Optomechanical Transduction and Characterization of a Silica Microsphere Pendulum via Evanescent Light

Dissipative optomechanics has some advantages in cooling compared to the conventional dispersion dominated systems. Here, we study the optical response of a cantilever-like, silica, microsphere pendulum, evanescently coupled to a fiber taper. In a whispering gallery mode resonator the cavity mode and motion of the pendulum result in both dispersive and dissipative optomechanical interactions. This unique mechanism leads to an experimentally observable, asymmetric response function of the transduction spectrum which can be explained using coupled-mode theory. The optomechanical transduction, and its relationship to the external coupling gap, are investigated and we show that the experimental behavior is in good agreement with the theoretical predictions. A deep understanding of this mechanism is necessary to explore trapping and cooling in dissipative optomechanical systems.Comment: 5 page

Some hematological and biochemical parameters in smokeless tobacco (Jharda) chewers

The effect of Jharda powder (smokeless tobacco) on some hematological and biochemical parameters in consumers was investigated. Hematological parameters including hemoglobin content and white blood cell and leukocyte counts were higher in jharda powder consumers, while monocytes and basophiles counts were lower. Higher biochemical parameters like serum cholesterol, glucose and protein were observed in blood samples of Jharda consumers

In vitro antimicrobial and antioxidant activities of bark extracts of Bauhinia purpurea

Bark extracts of Bauhinia purpurea were phytochemically analyzed and evaluated for antimicrobial and antioxidant activities. The phytochemical analysis of the bark extracts revealed the presence of alkaloids, flavonoids, steroids, saponins, triterpenes and carbohydrates. While most of them were present in methanolic and aqueous extracts, one or a few of them were present in other solvent extracts. Among different solvent extracts, aqueous extract exhibited a broad spectrum of antimicrobial activity. It showed strong antibacterial activity against Gram positive bacterial strains like Bacillus subtilis, Staphylococcus aureus and Gram negative strains like Escherichia coli and Klebsiella pneumonia and antifungal activity against Candida albicans. While methanolic extract showed moderate to strong antibacterial activity against B. subtilis, E. coli and K. pneumonia, the extracts of hexane, chloroform and ethyl acetate did not show any anti bacterial or antifungal activity against the tested fungal and bacterial strains. Antioxidant activity of the bark extracts were evaluated in terms of inhibition of free radicals by 2, 2’-diphenly-1-picrylhydrazyl (DPPH). Aqueous extract followed by methanolic extract exhibited strong to moderate antioxidant activity. The antioxidant property and antimicrobial activity of the extracts of B. purpurea against the tested microbial strains therefore, supports that there is scientific basis for their utilization in traditional medicine for wound healing and also in treatment of some infectious diseases.Key words: Bauhinia purpurea, phytochemical analysis, antimicrobial activity, antioxidant property

TeraHz tuning of whispering gallery modes in a PDMS, stand-alone, stretchable microsphere

We report on tuning the optical whispering gallery modes in a poly dimethyl siloxane-based (PDMS) microsphere resonator by more than a THz. The PDMS microsphere system consists of a solid spherical resonator directly formed with double stems on either side. The stems act like tie-rods for simple mechanical stretching of the microresonator over tens of microns, resulting in tuning of the whispering gallery modes by one free spectral range. Further investigations demonstrate that the whispering gallery mode shift has a higher sensitivity (0.13 nm/{\mu}N) to an applied force when the resonator is in its maximally stretched state compared to its relaxed state.Comment: 3 pages, 4 figures, submitted to Optics Letter

Seizure Detection, Seizure Prediction, and Closed-Loop Warning Systems in Epilepsy

Nearly one-third of patients with epilepsy continue to have seizures despite optimal medication management. Systems employed to detect seizures may have the potential to improve outcomes in these patients by allowing more tailored therapies and might, additionally, have a role in accident and SUDEP prevention. Automated seizure detection and prediction require algorithms which employ feature computation and subsequent classification. Over the last few decades, methods have been developed to detect seizures utilizing scalp and intracranial EEG, electrocardiography, accelerometry and motion sensors, electrodermal activity, and audio/video captures. To date, it is unclear which combination of detection technologies yields the best results, and approaches may ultimately need to be individualized. This review presents an overview of seizure detection and related prediction methods and discusses their potential uses in closed-loop warning systems in epilepsy