Biometric sensing has critical challenges in both mechanical design as well as sensor selection. The main issues however lie in the signal acquisition (accuracy and reproducibility) and signal processing to find the derived physiological value and at what ultimate accuracy. The association with biological parameters of clinical interest are under the influence of external factors. The external factors include electromagnetic impacts which can modify the outcome of the signal processing or may reset the operational processes of the device to a state of disorder. It is imperative to consider all factors contributing to the accuracy and validity of the output.

Catheterization is a common medical operation to diagnose and treat cardiovascular diseases. The blood vessel lumen is coated with endothelial glycocalyx layer (EGL), which is important for the permeability and diffusion through the blood vessels wall, blood hemodynamics and mechanotransduction. However EGL’s role in catheter-blood vessel friction is not explored. We use a porcine aorta to mimic the blood vessel and a catheter loop was made to rub in reciprocating sliding mode against it to understand the role of catheter loop curvature, stiffness, normal load, sliding speed and EGL on the friction properties. Trypsin treatment was used to cause a degradation of the EGL. Decrease in catheter loop stiffness and EGL degradation were the strongest factors which dramatically increased the coefficient of friction (COF) and frictional energy dissipation at the aorta-catheter interface. Increasing sliding speed caused an increase but increase in normal load first caused a decrease and then an increase in the COF and frictional energy. These results provide the basic data for safety of operation and damage control during catheterization in patients with degraded EGL.

This article discusses laser-induced laboratory-air plasma measurements and analysis of hydroxyl (OH) ultraviolet spectra. The computations of the OH spectra utilize line strength data that were developed previously and that are now communicated for the first time. The line strengths have been utilized extensively in interpretation of recorded molecular emission spectra and have been well-tested in laser-induced fluorescence applications for the purpose of temperature inferences from recorded data. Moreover, new experiments with Q-switched laser pulses illustrate occurrence of molecular recombination spectra for time delays of the order of several dozen of microseconds after plasma initiation. The OH signals occur due to the natural humidity in laboratory air. Centrifugal stretching of the Franck-Condon factors and r-centroids are included in the process of determining the line strengths that are communicated as a Supplementary File. Laser spectroscopy applications of detailed OH computations include laser-induced plasma and combustion analyses, to name but two applications. This work also includes literature references that address various diagnosis applications.

This article reports new measurements of laser-induced plasma hypersonic expansion measurements of diatomic molecular cyanide (CN). Focused, high-peak-power 1064 nm Q-switched radiation of the order of 1 TW/cm 2 generated optical breakdown plasma in a cell containing a 1:1 molar gas mixture of N 2 and CO 2 at a fixed pressure of 1.1 × 10 5 Pascal and in a 100 mL/min flow of the mixture. Line-of-sight (LOS) analysis of recorded molecular spectra indicated the outgoing shockwave at expansion speeds well in excess of Mach 5. Spectra of atomic carbon confirmed increased electron density near the shockwave, and, equally, molecular CN spectra revealed higher excitation temperature near the shockwave. Results were consistent with corresponding high-speed shadowgraphs obtained by visualization with an effective shutter speed of 5 nanoseconds. In addition, LOS analysis and the application of integral inversion techniques allow inferences about the spatiotemporal plasma distribution.

Abstract This work discusses laboratory experiments using atomic and molecular spectroscopy for diagnosis of laser-induced phenomena of interest in the field of medicine, and in astronomy for the understanding of recorded spectra from selected stars. Photo-acoustic spectroscopy utilizes femtosecond laser-pulse trains for diagnostic and therapeutic applications. Optical emission spectroscopy explores nominal nanosecond laser-induced, nano-particle plasma and its detection sensitivity. The study of laboratory plasma generated in selected gas-mixtures reveals insights for the interpretation of white dwarf spectra.

Biological sensing forms an innate part of animal and vegetable physiology. Developing the exact and appropriate sensing mechanism to support diagnostic investigation of physiological functions often proves difficult and complex. Sensing mechanisms that can be applied can roughly be filed in the following categories: chemical, electronically, mechanical, Nuclear Magnetic Resonance, optical, Tagging with sensor molecules or, respectively, nanoparticles, and finally thermal, or energetic. Biosensors can be used to detect the difference between healthy and pathological conditions in biological media, one particular and highly sought after application is the detection of cancer. For instance, a microscopic needle inserted in suspected cancer region can provide the information related to the activity of the cancer: growth, dormant, reviving, or fully active, and at phases of the life with respect to a group of cancer cell structure (locally) the cancer operates. Biosensors are used on a daily basis for the monitoring of vital signs such as heart-rate, oxygen saturation in tissues, and the production of waste products that may affect tissue performance, such as lactic acid formed during anaerobic metabolism activity. The smaller the sensing device, the more closely events and conditions can be investigated in-situ. More specifically, this could be performed with minimal discomfort to the patient. Additionally, multiple locations may be examined with additional focus on the explicit and unique local metabolic activity. The minimally invasive nature of the biological sensing is also important because the invasive nature at which the most significant details are available also may create a physical and hormonal response that could potentially affect the outcome of the monitoring process of the chemical or mechanical data.