Dielectric properties of high percentage Mg doped CaCu₃Ti₄O₁₂, CaCu_3-xMg_xTi₄O₁₂ (x=0.20 and 0.50) ceramics carried out. They were synthesized by the semi-wet route using a solution based citrate–nitrate method along with inexpensive solid TiO₂ powder. X-ray diffraction analysis reveals that the ceramics form single phase when sintered at 950 °C for 12h. SEM analyses show the smooth surfaces of grains with a spherical appearance. The grains of CCMTO2 and CCMTO5 ceramics were found to be in the size range of 1-5 μm and 1-3 μm, respectively. Dielectric studies show that the CCMTO2 ceramic has higher value of dielectric constant and lower dielectric loss in comparison to that of CCMTO5.

Wild mushroom had sinister reputation because of handful of poisonous species whose accidental ingestion can lead to slow and painful death. However, most of the wild mushrooms are either edible or harmless. Based on ignorance, the common myth and misconceptions about the mushroom were dispelled with understanding in mushroom biology and advent of mushroom biotechnology. Now mushrooms are considered as most delicious food and a potent weapon against malnutrition. Mushroom Biotechnology deals with discovery of new mushrooms, domestication of newly discovered as well as other wild mushrooms, enhancement in the production of fruit bodies, increase in nutritional and medicinal attributes and applications in mitigating the environmental pollution and providing low cost, viable, multipurpose technology to farmers to meet the growing demand of food, feed, fodder, fertilizer and energy. It is an important tool for restoration, replenishment and remediation of earth’s overburdened ecosphere.

Novel thermochromic and phase materials based detector will be presented for several applications

Superhydrophobic polymer films are a material of interest for aircraft deicing fluids to achieve the selfcleaning lotus effect. Hydrophobic polymer films were obtained by a solvent selective method composed of hydrophilic polymethylmethacrylate (PMMA) and hydrophobic polystyrene (PS) and hydrophilic titania nanoparticles. The addition of titania nanoparticles changed the surface of the thin films from an anisotropic morphology to a spherical isotropic surface due to hydrophobic and hydrophilic repulsion. Irradiation of UV responsive titania nanoparticles retained the same surface morphology. Water contact angle measurements will be completed to determine the hydrophobic nature of the polymer films.

Recent studies on multinary oxides for applications as laser hosts and high dielectric capacitors have shown that processing at high temperature provides glassy or crystalline materials based on thermal treatments and cooling rates. Since hydroxyapatites are now subject of great interests due to their bioactivity, interest in producing soft and hard materials with glassy and crystalline nature by processing parameters has become very important. Crystalline materials by using Bridgman, Czochralski and flux growth methods are costly and require huge investment. We have observed that even low temperature solidification in organic flux produced oriented fibers. This organic treated material has different characteristics than in situ oxide materials prepared by sintering and grain growth. Examples of phosphate and silicate-based systems will be presented to demonstrate soft and hard materials. Effect of TiO2 and other hardening elements will be also reported.

We present an analysis and demonstration of using laser-speckle contrast imaging (LSCI) as a sensing modality for presentation attack detection in biometric authentication systems. We provide the design of an experimental testbed for the quantitative characterization of LSCI and measurement results for optimization of the parameters of the active imaging testbed. LSCI has traditionally been used as a qualitative tool for identification of blood flow in dermal micro-vasculature for diagnosis of tissue health. We have built a laboratory phantom model, simulating blood flow beneath diffuse tissue to enable quantitative characterization of the performance of LSCI as a function of both target and imaging system parameters. Our first testbed configuration was an objective LSCI setup, detecting unfocused light on a focal plane array. In objective configuration, we characterized speckle size and speckle contrast as a function of the testbed parameters. In the second testbed configuration, we evaluated the performance of objective LSCI for complex fluid flow scenes. Finally, we report on the quantitative measurement of speckle contrast as a function of fluid flow rate, thereby demonstrating the use of optimized LSCI as an important sensing modality for the detection of presentation attacks in biometric authentication systems.

The ability to precisely control and manipulate acoustic waves can be highly limiting in applications and environments where placement of physical barriers for acoustic steering cannot be employed (e.g. tissues, air, etc.) In this work, we describe the ability to generate acoustic waveguides via thermally-induced optical reflection of sound (THORS) for the manipulation of acoustic waves in free space (i.e., air). Abrupt, density barriers are formed by photothermally depleting the sample in a laser beam’s path via photothermal processes, resulting in sharp differences in compressibility and significant acoustic reflection (greater than 30%). Optical waveguiding of sound can be achieved by generating THORS channels with a cylindrical (ring shaped) laser beam. By containing the acoustic waves inside a THORS cylindrical channel, a dramatically reduced acoustic decay profile of 1/r^0.6 with distance is achieved. Additionally, we describe the effects that optical modulation frequency of the THORS channel has on the efficiency of acoustic waveguiding. We also show how external acoustic waves, incident to a THORS channel are suppressed, increasing the signal-to-background ratio of the internally waveguided acoustic signals. Optical waveguiding of acoustic waves offers a new paradigm in the manipulation of sound over extended distances, providing potentially significant improvements to photoacoustic sensing, secure communications, and many other applications.

Leader-follower controllability in brain networks which are affected neurodegenerative diseases can provide important biomarkers relevant for disease evolution. The brain network is viewed as a dynamic system where the nodes interact via neighbor-based Laplacian feedback rules. The network has cooperative connections between the nodes described by positive weights along with competitive connections which are described by negative connection weights. The nodes take the role of either leaders or followers, thus forming a leader-follower signed dynamic graph network. The results of this analysis can be easily generalized on unsigned brain networks. We apply the leader-follower concept to structural and functional brain networks with neurodegenerative diseases (dementia) and show that the found leaders represent important biomarkers for disease evolution. In other words, the leader nodes drive the network towards deteriorating cognitive states.

Diffuse optical tomography is an emerging biomedical imaging technique, due to its numerous advantages, such as low cost and non-ionizing radiation. In this work, we have developed a very simple setup, which included a single source – photodiode (SP) pair for scanning a sample of water with diluted Intralipid, simulating a biological tissue. LEDs emitting at 470, 525 and 624 nm, as well as a 650 nm Fabry Perot laser, were used as light sources. Scattered light from the sample was detected by the photodiode placed next to the LED. The SP distance could vary and the phantom could be scanned by moving the SP pair in precise, small and automated steps without any intervention during the measurements. Therefore, we obtained measurements from multiple locations on the sample, with just one SP pair. The presented experimental system verified the feasibility of deploying extremely low cost devices for detection and imaging absorbing objects of 1 cm height, placed inside a scattering medium. Maximum depth detection was 2.5 cm. As expected, the quality of the obtained images was degrading, as the object’s depth or the scanning step was increasing. Additionally, we developed Monte Carlo simulations of the setup, which achieved good agreement with the experimental results. We also conducted another set of simulations, studying the depth sensitivity of a single static SP pair considering a scattering medium similar to the experimental phantom with and without object. We observed that the depth sensitivity increases as the source wavelength increases from 450 nm to 650 nm.

The Air Force is interested in real-time, wearable, and minimally invasive monitoring of physiological and psychological traits to improve the readiness and performance of the warfighter. Reducing or removing false alarms from such wearables significantly enhance the chance for a successful mission accomplishment. Highly accurate human performance monitoring and health protection requires precise monitoring of chemical and biochemical biomarkers. However, the biomarker detection in physiologically relevant media, such as sweat, saliva, and exhaled breath faces significant challenges ranging from chemical interference to environmental extremity. In this presentation, we address the lessons learned from building minimally invasive sampling technologies that are needed for acquiring data about the concentrations of relevant biomarkers as the physiological and psychological indicators. We discuss the opportunities and limitations in the sampling mechanisms of the biomarkers that can occur in multiple phases, including the gas phase (breath) and/or liquid phase (sweat, blood, ISF). In addition, we provide insight on the limit of current state of the art technologies for deployable real-time biomarker monitoring, including but not limited to the number/property/concentration of the molecular biomarkers and their corresponding sensor selectivity/sensitivity. Finally, we show our ongoing in-house and collaboration research works on integrating these sensors to real-world platforms using unaltered samples to ultimately enable both real-time physiologic monitoring, as well as total exposure health protection.

Wearable biosensors have emerged as an advancement in the field of performance and threat monitoring in part due to the potential to overcome the limits of conventional soldier health monitoring and environmental sensing technologies. However, to transition these devices to universal use, several challenges like selectivity, sensitivity, stability, level of invasivity, and efficient sample handling must be overcome. Additionally, discovery of novel biomarker and correlation to performance for current and emerging threats should continue. We introduce the integration of a synthetic and biomimetic xerogel layer onto a photonic chip, for the stable and selective monitoring of targeted soldier performance biomarkers. The molecularly imprinted polymer (MIP) material has been optimized for selection and capture of the human stress hormone cortisol, and a proof-of-principle experiments will be discussed. This sensor can be integrated onto a wearable diagnostics platform, thus potentially providing real-time monitoring of stress, and other biomarkers, in commonly accessed fluids like sweat.

A Neuropeptide Y-binding aptamer (NPY-BA) and 15 nm gold nanoparticles (AuNPs) were used to create plasmonic aptasensors for the selective detection of Neuropeptide Y in a rapid colorimetric assay. In this report, we describe different parameters that can be varied to optimize the sensitivity and selectivity of these assay and demonstrate initial NPY detection in sweat.

Cancer, obesity, and opioid abuse pose a combined threat to the well-being of the people in the United States, affecting over 70% and costing more than $250 billion per year in medical expenses. The unavailability of sensing technologies addressing the fundamental molecular changes related to disease initiation, progression, and therapeutic interventions is a critical roadblock for successfully combating these diseases/disorders. Recent clinical studies have shown that microRNA (miRNA) in circulating blood could use as a potential biomarker for combating these diseases/disorders because miRNA expression take place first in the biochemical cascade and therefore, miRNA could provide reliable and clinically important information that is superior and appear earlier than other biomarkers. Despite this progress, miRNAs have not yet been translated or utilized in the clinical diagnosis of any disease. This lack of progress is partially due to the differences among and limitations of various detection technologies, which produce inconsistent and inaccurate results. To address this issue, we have developed a low-cost and disposable device that can detect and quantify target miRNA levels. MiRNA detection is an integrated two-step process that used external electric fields to selectively concentrate fluorophore-labeled target miRNAs in nanoscale metallic hotspots within the device and enhance the fluorescence intensity via multiple metal-fluorophore interactions. This paper demonstrates how external electric fields could modulate the radiative decay rate of fluorophore molecules and subsequently enhance the fluorescence intensity.

The guided-mode resonance (GMR) sensor operates with resonant leaky Bloch modes induced in periodic films. The resonance occurs in 1D or 2D nanopatterns that are fabricated by nanoimprint technology. Optical sensors are needed in many fields including medical diagnostics and environmental monitoring. Inducing resonance in multiple modes enables extraction of complete bioreaction information including biolayer thickness, biolayer refractive index, and any change in the refractive index in the background buffer solution. We refer to this version of the GMR sensor as the complete biosensor. We summarize the principles, technology, and applications of this basic sensing methodology. As an example application, we use commercial GMR sensors to quantify the detection of peptides. Using a sandwich neuropeptide-Y (NPY) assay, we measure sub-nM NPY concentrations.

Listeria monocytogenes and Salmonella spp. are among the most common cause of foodborne illnesses that negatively affect consumers’ health and food producers’ finances and credibility. Techniques used to detect pathogens (e.g., total viable counts, polymerase chain reaction, and enzyme-linked immunosorbent assays) are time consuming and costly as they require laboratory conditions with trained personnel. To meet this demand without compromising public health concerns, highly sensitive and rapid sensors are needed in food processing facilities for pathogen detection to reduce cost and holding time for food products. Ideally, these sensors should be small, label-free, low cost, portable, and highly sensitive/selective. This study describes some recent approaches for creating biomimetic sensors by optimizing the bacteria capture efficiency without the need for pre-concentration and pre-labeling steps. Two in-field biosensors were developed for measuring pathogenic bacteria in food matrices. The first example consists of pH-responsive polymer nanobrushes embedded with platinum nanoparticles platform with enhanced limit of detection and sensitivity for quantification of Listeria monocytogenes in fresh vegetables. A new approach using a one-step metal and polymer simultaneous deposition was tested using two pH-sensitive polymers and a thiol-terminated DNA aptamer selective to surface protein internalin A of Listeria monocytogenes. The second example demonstrates development of pathogenic biosensors for chicken broth using antibodies and DNA aptamers selective to Salmonella Typhimurium adsorbed to aerosolized graphene interdigitated electrodes (IDEs). Devices were printed in polyimide tape and aerosolized graphene was thermally annealed. The integrity of the substrate was analyzed and the nano-biosensors were characterized for topography, pH-actuation, graphene content, and electroactivity using electron microscopy, cyclic voltammetry, and multiple spectroscopy techniques (Raman, Fourier-transform infrared, and electrochemical impedance). Electrochemical impedance spectroscopy was used to evaluate the signal and determine the limit of detection by evaluating the change in charge transfer resistance. The nano-biosensors have a detection limit of approximately 5 CFU.mL-1, and a response time of approximately 17 minutes (15 minutes incubation period). The pH-sensitive nanobrushes and graphene-based biosensors have a selectivity for the target pathogen of approximately 95% in vegetable and chicken broth, respectively. The designed biosensor platform showed great potential to replace current standard methods used by the food industry for rapid foodborne pathogenic bacteria detection.

Reducing a graph model is extremely important for the dynamical analysis of large-scale networks. In order to approximate the behavior of such a system it is helpful to be able to simplify the model. In this paper, the graph reduction model is introduced. This method is based on removing edges that close independent cycles in the graph. We apply this novel model reduction paradigm to brain networks, and show the differences between the model approximation error for various brain network graphs ranging from those of healthy controls to those of Alzheimer's patients. The graph simplification for Alzheimer's brain networks yields the smallest approximation error, since the number of independent cycles is smaller than in either the healthy controls or mild cognitive impairment patients.

As the Army moves towards equipping the soldier with more advanced wearable sensing devices for real-time environmental, health, and performance monitoring, there is a significant need for the biological receptors integrated into such devices capable of consistent performance in multifaceted operational environments. The instability, long development times, and inconsistencies in production of monoclonal antibodies, the gold standard receptors for biological detection, has resulted in the advent of alternative antibody technologies to fill these technological gaps. Protein Catalyzed Capture (PCC) agent technology is capable of the bottom-up development of highly stable and tailorable receptors through iterative in situ ‘click’ chemistry cycles with one-bead-one-compound (OBOC) peptide libraries. Aside from the inherent thermal stability and binding performance comparable to, and oftentimes exceeding, monoclonal antibodies, the modularity of PCCs allows for easy integration into various detection platforms and assays. Capable of full receptor development in ~2 weeks, as highlighted in this proceeding, PCCs can fulfill the need for alternative antibodies by addressing critical gaps in adaptability, manufacturability, and stability.

Human performance monitoring (HPM) devices for sweat sensing in both civilian and military uses necessitate chemical sensors with low limits of detection, rapid read out times, and ultra-low volumes. Electronic and electrochemical sensing mechanisms for biomarker identification and quantification are attractive for overall ease of use, including robust, portable, fast readout, and simple operation. Transistors have the high signal gain required to sense low concentrations (μM to pM) at low volumes (μL to nL) in real-time (<1 minute), metrics not achievable by benchtop analytical techniques. Two main challenges currently prohibit the realization of transistor-based biosensors: i) the need for printed devices for low-cost, disposable sensors; and ii) the need to overcome diminished sensitivity in high ionic strength solutions. In this proof-of-concept work, we demonstrate organic electrochemical transistors (OECT) as a promising low cost, printable device platform for electrochemical detection of biomarkers in high ionic strength environments. This work focuses on how the materials choice and functionality impacts the electrochemical and sensor and transducer performance and determining the feasibility of reducing the size of the sensor to nanoliter volume detection. Initial studies target dopamine. Detection limits for simple electrochemical approaches using platinum or glassy carbon electrodes remain relatively high (~ 1-10 ng/mL or 50 nM). Using an OECT, we demonstrate an initial detection level of dopamine at ~ 10 pg/mL achieved without any selective binding modifications to the gate electrode at gate voltages below 1 V.

Sweat-based human performance monitoring devices offer the possibility of real-time emotional and cognitive awareness in both civilian and military applications. Broad applicability and point of use necessitate non-invasive, printable, flexible, wearable chemical sensors with low power consumption. Sweat fluidics must enable movement of sweat across the sensor compartment within 1 minute to assure only fresh sweat is at the chemical sensor. The sensor material should have reaction kinetics to capture a sufficient number of target molecules for quantification in real-time (< 1minute). Chemical selectivity is critical in complex biofluids such as sweat, which may be comprised of 800+ biomarkers. Given these constraints, there continues to be significant technological barriers for translation from laboratory-based proof-of-concept demonstrations and scalable manufacturing of devices. Using finite element simulations, we focus on determining which sweat flow geometry and chemical capture dynamics are best suited to meet temporal performance requirements. Two common sensing approaches are compared and contrasted: bio-recognition chemical adsorption events and electrochemical detection. Responsivity of both mechanisms is shown to be highly dependent on fluid dynamics, analyte capture efficiency, analyte concentration, and reaction kinetics. Key metrics of temporal response and capture efficiency will be discussed for a number of state of the art electronic sensor materials, with a focus on the validity of printable platforms.

Wearable electronics are finding emerging applications in mobile health, rehabilitation, prosthetics/exoskeletons, athletic training, human-machine interaction, etc. However, our skin is soft, curvilinear and dynamic whereas wafer-based electronics are hard, planar, and rigid. As a result, state-of-the-art wearables can only be strapped or clipped on human body. The development of flexible and stretchable electronics offers a remedy for such challenge. E-tattoos represent a class of stretchable circuits, sensors, and actuators that are ultrathin, ultrasoft, skin-conformable and deformable just like a temporary tattoo. We introduce a low-cost, dry and freeform “cut-and-paste” and “cut-solder-paste” method invented by my lab to fabricate e-tattoos. This method has been proved to work for thin film metals, polymers, ceramics, as well as 2D materials. Using these method, we created the first truly imperceptible e-tattoos based on graphene, and modular and reconfigurable Bluetooth and NFC enabled wireless e-tattoos.

This study investigates the response of flexible piezoelectric materials exposed to blast wave pressure impulses from inair and underwater explosions. A shock tube was used to produce reproducible shock waves from explosions with average peak pressures in excess of 1,000 kPa for underwater experiments and 100 kPa for in-air experiments. Flexible piezoelectric polyvinylidene fluoride (PVDF) and lead zirconate titanate Pb(Zr,Ti)O3 (PZT) materials were tested for sensing the pressure impulse generated from an explosion. The rise time, peak amplitude, and duration of the blast wave pressure impulse were measured for each piezoelectric material and compared to an OEM blast wave sensor. This study uniquely identifies flexible piezoelectric materials that can accurately measure the blast wave pressure impulse from both in-air and underwater explosions. The accurate response and flexibility of the selected piezoelectric materials demonstrate the potential to be integrated into several forms of sensors, including wearable. Military and industrial applications can potentially benefit from a wearable blast wave sensor to improve medical diagnosis and treatment of blast exposure.

This paper presents a microcontroller-based solution to classify blood glucose levels using acetone and ethanol breath volatile organic compounds. Two metal oxide semiconductor-based chemical sensors able to detect acetone and ethanol at parts per million concentrations were used. The sensors were tested in a controlled setup with humidified air spiked with acetone and ethanol, mimicking human breath corresponding to low and high blood glucose groups. A support vector machine algorithm was trained and implemented in a microcontroller. In a real time-time test, the trained algorithm classified low and high blood glucose groups with 97% accuracy. Subsequently, a smart wristband prototype that integrates the two sensors was developed. An Arduino-based wearable microcontroller platform was used for its small formfactor and a low-power operation. The wristband is enclosed in a 3D printed housing and powered by an onboard 3.7 V 500 mAh rechargeable Li-ion battery. A smartphone app communicates with the wristband through Bluetooth, allows data visualization, and saves data in the cloud. The presented work makes a significant contribution towards the development of a wearable device for detecting blood glucose levels from a patient’s breath.

ADHD (Attention Deficit Hyperactivity Disorder) affects 7% of the population. ADHD causes behavioral problems, learning limitations and social exclusion. Current ADHD Treatment has limitations in terms of cost, drug-base medication, and labor-intensive educational treatments. Focus Locus aims to provide an alternative treatment based on gamification through VR, AR and Mixed Reality modalities, telemetry and remote monitoring. In this paper we present the REEFocus game system that has been developed in the context of the Focus Locus project and present the first analysis results of a two-month clinical trial in a companion paper. The paper is meant to give an overview of the REEFocus game system design and implementation, the pilot description and some preliminary validation results. A detailed analysis and results of the data collected during the pilot is still an ongoing process and the quantitative analysis results keep on being published as they become available.

Electroencephalogram (EEG) recording is a widely used method to measure electrical activity in the brain. Rodent EEG brain recording not only is noninvasive but also has the advantages to accomplish full brain monitoring, compared with that of the invasive techniques like micro-electrode-arrays. In comparison to other noninvasive recording techniques, EEG is the only technique that can achieve sub-ms scale time resolution, which is essential to obtain causal relationship. In this work, we demonstrated a simple microfabrication process for developing a high-density polyimide-based rodent EEG recording cap. A 34-channel rodent electrode array with a total size of 11mmx8mm, individual electrode diameter 240μm and interconnect wire linewidth 35μm was designed and fabricated. For the fabrication process, we first deposit 350nm SiO2 on a silicon substrate. We then fabricate 6-7μm thick first layer polyimide caps with fingers and contact holes. Gold deposition and then lithography etching of 34 channel contact-electrodes and their interconnects were fabricated in the second step. The third step was to cover metal interconnects with a 10μm thick second layer polyimide, which was fabricated with photolithography before the final film released by HF undercutting etching of SiO2 layer. Then the fabricated EEG cap is interfaced with a commercial 34-channel female connector, which is soldered with 34-line wires. These wires are then connected to an ADC to record the EEG data in computer for post-processing. With polyimide, the EEG cap is biocompatible, and flexible which makes it suitable for good contact with rodent skulls.

This paper documents on EEG dynamics findings of the testing of the REEFOCUS game developed in the context of the FocusLocus project. REEFOCUS aims at providing an innovative game-based intervention programme for assisting children to manage and overcome ADHD (Attention Deficit and Hyperactivity Disorder) symptoms. ADHD affects 7% of the population and causes behavioral problems, learning limitations and social exclusion. Backed up by cognitive science research, REEFOCUS game incorporates multisensory training methods for behavioral change and mental and motor skill acquisition. REEFOCUS is designed to be personalized and adaptive to each child’s individual condition. REEFOCUS actively involves parents, attending clinicians and special needs educators, allowing them to remotely monitor the progress of children and adjust the intervention programme according to their preferences. The REEFOCUS solution aspires to be an efficient and cost-effective alternative in ADHD treatment without the undesirable side-effects of currently established approaches (e.g. medication). The REEFOCUS game has been deployed and tested in operational conditions and with intended end-users. The findings from this study indicate that REEFOCUS is an effective game-based intervention for altering EEG characteristics associated with ADHD. In this study, the EEG metrics, namely Attention and Theta-to-Beta Ratio (TBR), as provided by the device’s Brain Computer Interface (BCI), were analyzed in order to detect statistical changes form the first to the last Gaming Sessions.

Mind reading, or imagined speech recognition, has many real-world applications including silent communication between soldiers in a combat zone, lie-detectors, and even communication with stroke victims who are fully coherent but unable to produce verbal speech. However, while previous research has shown that using electroen- cephalography (EEG) to read imagined speech is certainly possible, it is currently impractical because each EEG device can be calibrated for only one person. No calibration test has been developed to allow the same EEG device to accurately read the imagined speech of different people. A calibration test is necessary because different people have different neurons firing even when thinking of the same letter, word, syllable, etc. For example, the neurons that fire when person A thinks of the letter ’a’ is different than those fired when person B thinks of the same letter. In this paper, and as a first step we demonstrate the possibility of reading a brain using noninvasive (EEG) technology. Further an algorithm is developed to calibrate the same device for different subjects. This is accomplished first by gathering raw EEG data, performing pre-processing on that data, performing feature extraction, and finally using speech classification to match the EEG data. Further, two different calibration methods are tested: additional mini-training sets for each person, and a group of normalized training sets, and the results are presented.

Diabetes has been a serious problem that poses threat to people's health all around the world. It is still a challenge for us to detect blood glucose concentration continuously and non-invasively. In this research, we developed a free-space spectrum domain optical coherence tomography (SD-OCT) system for non-invasive blood glucose detection which possessed advantages of easy construction, analyzation and control. In this system, a laser with center wavelength of 980nm was applied because of its low absorption in both glucose and water, which was suitable for OCT imaging. However, the laser with wavelength of 980nm was not used in the OCT with optic fiber type which was commercially designed for wavelengths of 830nm, 1310nm and 1550nm. By applying a dispersing prism, we could obtain higher resolution spectrum to acquire better OCT images and more accurate glucose concentration. The tomography function of this free-space SD-OCT system was proved to work by scanning onion sample. Pristella maxillaris is a kind of fish with transparent body structure and suitable size, thus we consider it to be an ideal animal for blood glucose measurement by optical methods. We cultivated pristella maxillaris, an ideal fish for this experiment, in glucose solutions with five different concentrations as samples to study glucose monitoring. The OCT signals of the five groups correlated respectively to the glucose concentrations. Therefore, our method provided the potential for measuring blood glucose concentration non-invasively.

People with diabetes are at high risk of diabetic eye disease such as diabetic retinopathy (DR) which is the most common cause of vision loss. It is caused by damage to the small blood vessels in the retina. If untreated, it may result in varying degrees of vision loss and even blindness. Since DR may cause no symptoms or only mild problems in its early stages, a diabetic person must have regular annual eye exams. During eye exams, doctors often image the retina using fundus cameras for diagnosis. However, fundus cameras are too large and heavy to be transported easily and too costly to be purchased by every health clinic. Therefore, there is a growing demand for small, portable, and inexpensive retinal imaging systems to perform fast DR screening. Recent technological developments have enabled the use of smartphones as biomedical imaging devices. The smartphonebased portable retinal imaging systems available on the market are used only to capture and save retinal images; they do not analyze them using any image processing techniques. In this paper, we investigated the smartphone-based portable ophthalmoscope systems available on the market and compared their field of view to determine if they are suitable for DR screening during a general health screening. Based on the results, iNview retinal imaging system has the largest field of view and better image quality compared with iExaminer, D-Eye, Peek Retina retinal imaging systems.

In recent years, there is an increasing interest in noninvasive treatments for neurological disorders like Alzheimer and Depression. Transcranial magnetic stimulation (TMS) is one of the most effective methods used for this purpose. The performance of TMS highly depends on the coils used for the generation of magnetic field and induced electric field particularly their designs affecting depth and focality tradeoff characteristics. Among a variety of proposed and used TMS coil designs, circular coils are commonly used both in research and medical and clinical applications. In current study, we focus on changing the outer and inner sizes (diameter) and winding turns of ring coils and try to reach deeper brain regions without significant field strength decay. The induced electric field and the decay rate of the generated field with depth were studied with finite element method calculations. The results of the performed simulations indicate that larger diameter coils have a larger equivalent field emission aperture and produce larger footprint of induced electric field initially. However, their emission solid angles are smaller and, as a result, the field divergence or the decay rates of the generated field with depth are smaller as well, which give them a good potential to perform better for deep brain stimulation compared with that of smaller coil.