Biomedical optical Engineering

TECHNICAL FIELD - This application relates to the field of coatings that prevent fogging on solid surfaces without altering the characteristics of the covered surface. The coatings may be used on devices and equipment for sports and recreation, the medical field, military and industrial safety
applications. Such devices and equipment include windows and mirrors of automobiles, motorcycles, boats, airplanes, and trains. In industrial and instrumentation application: protective windows, domes, and lenses of gauges, dials, meters. In medical applications: intraocular lenses, endoscopic/laparoscopic lenses, protective eyewear, contact lenses for visual correction, medical implants, surfaces, and medical and surgical tools.
BACKGROUND
The problem of condensation with fogging: Hydrophobic versus hydrophilic surfaces. Protective eyewear, glasses, sunglasses, swimming goggles, diving goggles, helmet visors, windshields, intraocular lenses, medical scopes, and high-precision instrumentation are just several applications where visual distortion due to fogging with condensation poses a problem.
Control of fogging due to condensation on polymer and glass surfaces has seen development, testing and patenting of solutions for a broad spectrum of optical, vision, visor, goggle and lens materials, including optical glasses, borosilicate glass, polycarbonates, tinted thin film coatings, and other polymers for athletic visor and vision-wear. These can require optimization of the robustness and resiliency to create permanent anti-fog coatings, and optimization of adhesion on polycarbonates and surfaces with difficult geometries such as very high curvature. Therefore, anti-fog technologies and their applications have to be conceived and optimized by
adapting to a broad range of specifications for use, use duration, etc., and require working directly with a variety of end users to create such adaptability. End users for anti-fog technology include, but were not limited to: surgeons, professional athletes, recreational users, professional safety users, fire-workers, emergency personnel, biohazard handlers, medical and surgical personnel, and instrumentation dials and domes manufacturers.
Control of fogging should be tested using the specific conditions of condensation experienced by each group end users, such as body or outdoor temperatures, and water vapor pressures and various fluids present during use, such as bodily fluids, sweat, blood, skin oils and human tears or fluids produced from machinery. U.S. patent application Ser. No. No. 13/674,307 (hereinafter '307 application) describes an emulsion that physically changes the surface topography so that condensation behavior can be controlled. The result in the '307 application is a hydrophilic surface that manipulates water droplets so that the water droplets form a thin translucent film on the hydrophilic surface. The'307 application describes a  wet anti-fog technology, where the emulsion is applied when the
surface requires an antifogging coating and should not be dried on the surface. When the emulsion of the '307 application is dried, the polymers come out of the solution and precipitate so that the coated surface is no longer optically transparent and fails to maintain optical quality.
Specifically, the emulsion described in the '307 application is optimized for temporary application and for ease of application. The emulsion described in the '307 application was designed for medical applications, including but not limited to vitro-retinal surgery as well as endoscopic and laparoscopic procedures and surgeries. Thus the emulsion described in the '307
application does not permanently coat the surfaces with anti-fog technology. Accordingly, there is need for a dry permanent anti-fog technology that manipulates water so the water droplets form a thin translucent film on a surface rather than produce fogging on the surface while maintaining optical quality. First, the invention consists of permanent anti-fog coatings, including but not limited to their materials components, composition, adaptive formulation and several methods of fabrication.
The permanent anti-fog is referred to as “FogKnox™”. It includes but is not limited to very high quality optical transmission films that are distortion-free, and exhibit a very high degree of transparency. FogKnox™ includes but is not limited to dry, permanent and very highly uniform optical anti-fog coatings, which can be delivered in wet (fluid) or solid from. Both wet and solid form preserve and improve instantaneously visualization on edges of lenses, dials and surfaces and wide-angle lens. Only after drying is the anti-fog a permanent, non-removable solid film. In a separate embodiment, the anti-fog coatings can be made removable for applications where
lenses and devices on which they are applied need to be resurfaced, called KnoxFog™. The antifoam coatings can also be made semi-permanent, so it can be scrubbed, thus removable by scrubbing, detergent washing and/or sonication, for medical applications, and are then called
VitreOx™. Second, the invention includes, for all above mentioned anti-fog coatings, their method of application in large scale, medium scale or small scale manufacturing, via several possible coating processes, adaptive compositions, adjustments of physical properties and surface
preparation procedures, which are disclosed as the second part of the invention. Third, all the above coatings can also be applied on existing, already manufactured optical devices, tools, dials, goggles, vials, bottles and scopes, via the third element of the invention, specific delivery device and its cartridge of anti-fog coatings materials. The delivery device
includes a coating delivery and element to allow for quick drying element attachment to the metered delivery automated mechanism to apply the coating in a few seconds, and let it dry within minutes.

The invention consists of three parts made to work together to ensure safe, fast and effective deployment to the end users, which include but are not limited to surgeons and doctors in emergency and operating rooms, occupational hazards equipment goggles, visors and shields, defensive protective armors and high impact vision wear, high performance athletic equipment, and avionics surfaces. The three parts are the anti-fog coating materials composition, their methods of preparation and processing in large, medium or small scale manufacturing, and a single unit delivery device with the coating materials to apply on any existing surface, lens, scope, tools or dials, as a wet or quickly drying coating.

Two-photon excitation fluorescence is a powerful technique commonly used for biological imaging. However, the low absorption cross section of this non-linear process is a critical issue for performing biomolecular spectroscopy at the single molecule level. Enhancing the two-photon fluorescence signal would greatly improve the effectiveness of this technique, yet current methods struggle with medium enhancement factors and/or high background noise. Here, we show that the two-photon fluorescence signal from single Alexa Fluor 488 molecules can be enhanced up to 10 times by using a 3 μm diameter latex sphere while adding almost no photoluminescence background. We report a full characterization of the two-photon fluorescence enhancement by a single microsphere using fluorescence correlation spectroscopy. This opens new routes to enhance non-linear optical signals and extend biophotonic applications.

We have explored the real-time response of the forearm vasculature to rhythmic contraction of antagonistic striated muscle groups. Dual-wavelength measurements were collected at 2 Hz, and the resulting image series (30 images per wavelength) was analyzed using appropriate time-series analysis methods. This revealed absorption coefficient fluctuations that were spatially coincident with the relevant muscle groups, occurring at the expected frequency and with the expected phase relation between the involved flexors and extensors.

The purpose of this study is to  not only apply threshold methods  and in particular Otsu’s method, but also give a detailed in depth  but simple understanding on the probability distribution , probability theory  and expected value,(mean). The differences between the respective mean intensity for each segment and global mean intensity is used to compute the variance between the classes. We then use Bayes’ formula of conditional probability  to compute the mean intensity and with this the Global average intensity, the intensity mean of image pixels, and subsequently the effective threshold. Furthermore we present the histogram and uniform  probability distribution in using the properties of a random variable. From the results we highlight the importance of reducing noise but also in  pre processing the images by segmentation for better results

https://www.ijert.org/effect-of-inter-speaker-hypernasality-variation-in-cleft-palate-on-acoustic-vowel-space

https://www.ijert.org/research/effect-of-inter-speaker-hypernasality-variation-in-cleft-palate-on-acoustic-vowel-space-IJERTV10IS040006.pdf

Vocal tract transfer function of voiced hypernasal speech of cleft palate (CP) speakers contains information related to hypernasality (HP). The acoustic sign of HP is profoundly variable making HP detection more challenging for human trained professionals. Vowels /i/, /a/ and /u/ uttered by adults (male, female) and children with increasingly HP in read speech sentences are used in this study. In the first half part, variability in acoustic parameters among and across vowel class are made. Test results show significant fluctuation in acoustic parameters among CP speakers. Variability of spectral parameters came out to be maximum from the experimental result for /u/ showing that it is the most affected vowel for HP. For children it is least variable and for females it shows most variable value. Variability of /i/, /a/ are seen to be greatest for children. Among the vowels, /a/ which is mid low vowel, shows minimum variation for females and high front vowel /i/ shows least variation for males. In the later part of our study, a threshold-based parameter is used for HP detection. Vowel space area (VSA) of healthy speech and hypernasal speech is used as a measure to detect HP. It is observed from the result that VSA traversed by CP children is reduced by 4.15 times and CP males is shrunken by 3.7 times with respect to VSA of CP females. VSA of CP females are observed to have the greatest area indicating that speech of CP female has better intelligibility than male or children. VSA of CP children producing HP are observed to have the lowest value indicating that speech clarity of CP children decreases more than the male and female group.

Dynamics of fluorescent diamond nanoparticles in HeLa cells has been studied with two-photon fluorescence correlation spectroscopy (FCS). Fluorescent nanodiamond (FND) is an excellent fluorescent probe for bioimaging application, but they are often trapped in endosomes after cellular uptake. The entrapment prohibits FCS from being performed in a time frame of 60 s. Herein, we show that the encapsulation of FNDs within a lipid layer enhances the diffusion of the particles in the cytoplasm by more than one order of magnitude, and particles as small as 40 nm can be probed individually with high image contrast by two-photon excited luminescence. The development of the technique together with single particle tracking through one-photon excitation allows probing of both short-term and longterm dynamics of single FNDs in living cells.