There has been significant recent interest in the development of technologies for enumeration of rare circulating cells directly in the bloodstream in many areas of research, for example, in small animal models of circulating tumor cell dissemination during cancer metastasis. We describe a fiber-based optical probe that allows fluorescence detection of labeled circulating cells in vivo in a diffuse reflectance configuration. We validated this probe in a tissue-mimicking flow phantom model in vitro and in nude mice injected with fluorescently labeled multiple myeloma cells in vivo. Compared to our previous work, this design yields an improvement in detection signal-to-noise ratio of 10 dB, virtually eliminates problematic motion artifacts due to mouse breathing, and potentially allows operation in larger animals and limbs.
This paper provides a comparative analysis of right handed people and left handed people when they write with both their hands. Two left handed and one right handed subject were asked to write their respective names on a paper using both, their left and right handed, and their brain signals were measured using EEG. Similarly, they were asked to perform simple mathematical calculations using both their hand. The data collected from the EEG from writing with both hands is compared. It is observed that though it is expected that the right brain only would contribute to left handed writing and vice versa, it is not so. When a right handed person writes with his/her left hand, the initial instinct is to go for writing with the right hand. Hence, both parts of the brain are active when a subject writes with the other hand. However, when the activity is repeated, the brain learns to expect to write with the other hand as the activity is repeated and then only the expected part of the brain is active.
Fluorescent proteins are often used as reporters of protein concentration in biology and biomedicine applications. They can be detected using a fluorimeter equipped with fiber optics for ease of access. However, small changes in the path length due to change in the position, or immersion depth of the optical fiber results in large changes in readings. To alleviate the situation, the fiber is equipped with a fixed-length-extension that provides constant path length. The operation of the fiber equipped fluorimeter is theoretically modelled and practically verified in this paper.
The main bioprocess variables that are continuously measured are pH, dissolved oxygen (DO), and dissolved car- bon dioxide (DCO<sub>2</sub>). Less common variables are redox, concentrations of substrate and product concentrations, product activity, etc. Recently, pH and DO have been measured using optical chemical sensors due to their small form factor and convenience in use. These sensors are typically interrogated using a lab grade spectrometer, or with the help of a low-cost, tailor-made optoelectronic transducer that is designed around the optical sensor. Recently, we proposed a new class of optoelectronic transducers that are capable of monitoring several different optical sensors without the need to switch the optics or hardware when changing the type of sensor. This allows flexibility closer to the lab-grade devices at a price point of a dedicated sensor. <p> </p>In this work, we have demonstrated a universal optical platform capable of monitoring pH or DO sensors. It uses the principle of ratio-metric fluorescence measurements for pH and fluorescence lifetime measurements for DO. The platform is capable of seamlessly switching between these two modes. It is also capable of auto recognition of the sensor type. The platform can operate both with patch-type or fiber optic type of sensors. The platform has measurement accuracy of about 0.08 pH units and approximately 5 % air saturation with oxygen. Additionally, an approach to obtain identical calibrations between several devices is presented. <p> </p>The described platform has been tested in actual bioprocesses and has been found adequate for continuous bioprocess monitoring.
The tympanic membrane (ear drum) is a thin tissue film that is stretched between the outer and middle ear. Sound waves travel from outside the ear, and strike the tympanic membrane resulting in its vibration. These vibrations amplify the sound waves and transmit them to the ossicles (auditory bones). The magnitude of amplification is directly proportional to vibrating area of tympanic membrane. Hence a perforation in this membrane would result in hearing loss.
Pure-tone audiometry is the traditional procedure used to detect the amount of hearing loss in a patient. However, it is lengthy and less efficient, as it largely depends on the response of the patient to sound intensity and frequency of pure-tones.
We present a relatively more efficient approach to determine hearing loss due to perforated tympanic membrane using image processing techniques. We describe an algorithm that uses unsharp masking to sharpen images of the perforations as well as the tympanic membrane. Then, it converts the image into a binary image using thresholding. A median filter is applied to get rid of the noise component in the image. The ratio of the area of perforation and total area of tympanic membrane will define the percentage of hearing loss. Our approach will eliminate the error introduced due to patient dependency as in the traditional method.