An integrated multi-wavelength SCATTIRSTORM microscope combining TIRFM and IRM modalities for imaging cellulases and other processive enzymes

We describe a multimodal SCATTIRSTORM microscope for visualizing processive enzymes moving on immobilized substrates. The instrument combines Interference Reflection Microscopy (IRM) with multi-wavelength Total Internal Reflectance Fluorescence Microscopy (TIRFM). The microscope can localize quantum dots with a precision of 2.8 nm at 100 frames/s, and was used to image the dynamics of the cellulase, Cel7a interacting surface-immobilized cellulose. The instrument, which was built with off-the-shelf components and controlled by custom software, is suitable for tracking other degradative enzymes such as collagenases, as well as motor proteins moving along immobilized tracks.

Circular Gabor wavelet algorithm for fingerprint liveness detection

Biometrics usage is growing daily and fingerprint-based recognition system is among the most effective and popular methods of personality identification. The conventional fingerprint sensor functions on total internal reflectance (TIR), which is a method that captures the external features of the finger that is presented to it. Hence, this opens it up to spoof attacks. Liveness detection is an anti-spoofing approach that has the potentials to identify physiological features in fingerprints. It has been demonstrated that spoof fingerprint made of gelatin, gummy and play-doh can easily deceive sensor. Therefore, the security of such sensor is not guaranteed. Here, we established a secure and robust fake-spoof fingerprint identification algorithm using Circular Gabor Wavelet for texture segmentation of the captured images. The samples were exposed to feature extraction processing using circular Gabor wavelet algorithm developed for texture segmentations. The result was evaluated using FAR which measures if a user presented is accepted under a false claimed identity. The FAR result was 0.03125 with an accuracy of 99.968% which showed distinct difference between live and spoof fingerprint.

HYGIENIC ASPECTS OF ENDO- AND EXOGENIC METHODS OF PREVENTION OF CARIES AND THEIR EFFICIENCY IN THE REMINERALIZATION OF TEETH ENAMEL

According to the dental survey, the prevalence of caries in 33-45 years aged adults amounts to 98%. Studies of the effectiveness of prevention of tooth decay have shown the effectiveness of this direction. But the exogenous methods do not guarantee the restoration of the balance between the processes of demineralization and remineralization of the enamel. Demineralizing factors will prevail if the concentration of essential minerals in the mixed saliva is reduced. Therefore, it is necessary to develop endogenous techniques that will promote the process of remineralization of enamel and normalization of the ion-molecular balance. The aim of the study was to compare endogenous or exogenous methods in order to saturate mixed saliva with mineral complexes in preventing the development of primary demineralization of hard tooth tissue. Material and methods. The chemical composition of the mixed saliva sediment in 27 patients was analyzed by IR spectroscopy. To record the measurement of IR spectra, a Vertex-70 spectrometer (Bruker, Germany) and a PLATINUMATR full internal reflectance attachment with a diamond prism were used, as well as a clinical determination of the enamel remineralization rate (COSRE test) was performed. Results and Discussion. The relationship between the use of endogenous and exogenous methods of saturation of mixed saliva with mineral complexes and changes occurring in its molecular composition has been revealed, in favor of the effectiveness of endogenous methods.