Springer Science and Business Media LLC

This paper describes a potential method to detect changes in cerebral blood flow (CBF) using electrocardiography (ECG) signals, measured across scalp electrodes with reference to the same signal across the chest—a metric we term the Electrocardiography Brain Perfusion index (EBPi). We investigated the feasibility of EBPi to monitor CBF changes in response to specific tasks. Twenty healthy volunteers wore a head-mounted device to monitor EBPi and electroencephalography (EEG) during tasks known to alter CBF. Transcranial Doppler (TCD) ultrasound measurements provided ground-truth estimates of CBF. Statistical analyses were applied to EBPi, TCD right middle cerebral artery blood flow velocity (rMCAv) and EEG relative Alpha (rAlpha) data to detect significant task-induced changes and correlations. Breath-holding and aerobic exercise induced highly significant increases in EBPi and TCD rMCAv (p < 0.01). Verbal fluency also increased both measures, however the increase was only significant for EBPi (p < 0.05). Hyperventilation induced a highly significant decrease in TCD rMCAv (p < 0.01) but EBPi was unchanged. Combining all tasks, EBPi exhibited a highly significant, weak positive correlation with TCD rMCAv (r = 0.27, p < 0.01) and the Pearson coefficient between EBPi and rAlpha was r = − 0.09 (p = 0.05). EBPi appears to be responsive to dynamic changes in CBF and, can enable practical, continuous monitoring. CBF is a key parameter of brain health and function but is not easily measured in a practical, continuous, non-invasive fashion. EBPi may have important clinical implications in this context for stroke monitoring and management. Additional studies are required to support this claim.

In the color Doppler mode of ultrasonography, a rapidly changing mixture of red and blue colors referred to as ‘twinkling artifact’ (TA) may appear for a stationary hyperechogenic target. This introduces ambiguity in diagnosis as well as provides conclusive information. We reviewed the possible mechanisms, and also illustrated the clinical potential in the detection of pathological sites associated with calculi, calcifications, cacinoses and fibroses and foreign bodies such as surgical clips, catheters, and guiding needles which were inconclusive in conventional grayscale sonograms. In order to increase the clinical utility of TA, a practical means to enhance TA was suggested which leads to a ‘TA mode’ to be implemented in a clinical scanner.

Transdermal drug delivery has emerged as an alternative to conventional drug delivery systems as it enables painless and convenient drug administration. However, next-generation healthcare systems need to facilitate “on-demand” delivery operations and should be highly efficient to penetrate the physiological barriers in the skin. Here, we report an ultrathin dye-loaded epidermal tattoo (UDET) that allows wirelessly stimulated drug delivery with high efficiency. The UDET consists of an electrospun dye-loaded silk nanofiber mat and a covered carbon nanotube (CNT) layer. UDETs are conformally tattooed on pigskins and show stable operation under mechanical deformation. Biological fluorescence dyes such as vitamin B12, riboflavin, rhodamine B, and sodium fluorescein are applied as model drugs. Illuminating the UDET by a low-power light-emitting diode (< 34.5 mW/cm2) triggers transdermal drug delivery due to heat generation. The CNTs convert the absorbed light into heat, and then the dyes loaded on silk can be diffused through the epidermis. The CNT layer is electrically conductive and can detect the temperature by reading the resistance change (0.1917 Ω/°C). This indicates that the UDET can be used simultaneously to read temperature and deliver the loaded dye molecules, making it a promising on-demand drug delivery strategy for future medicine technology.

Photoacoustic microscopy (PAM) has become an increasingly popular technology for biomedical applications, providing anatomical, functional, and molecular information. In this concise review, we first introduce the basic principles and typical system designs of PAM, including optical-resolution PAM and acoustic-resolution PAM. The major imaging characteristics of PAM, i.e. spatial resolutions, penetration depth, and scanning approach are discussed in detail. Then, we introduce the major biomedical applications of PAM, including anatomical imaging across scales from cellular level to organismal level, label-free functional imaging using endogenous biomolecules, and molecular imaging using exogenous contrast agents. Lastly, we discuss the technical and engineering challenges of PAM in the translation to potential clinical impacts.

Manual analysis of EEG signals by an expert is very much time consuming due to the long length of EEG recordings. The suitable computerized analysis is essentially required to differentiate among the normal, interictal and ictal (epileptic) EEGs. In the present work the EEG signals are decomposed into different sub-bands using discrete wavelet transform (DWT) to obtain the detail and the approximation wavelet coefficients. The coefficients are used to calculate the quantitative values of relative wavelet energy and wavelet entropy from different data sets to select the features of EEG signals. The support vector machine (SVM), feed forward back-propagation neural network (FFBPNN), k-Nearest Neighbor Classifier (k-NN) and Decision tree classifier (DT) are used to classify the EEG signals. It is revealed that the accuracy between normal subjects with eyes open condition (data set A) epileptic data set E using SVM is obtained as 96.25%. Classification accuracy between the normal subjects with eye closed condition and epileptic data set E is obtained as 83.75% using k-NN classifier. Similar accuracies while discriminating the interictal data set C versus ictal data set E, and interictal data set D versus ictal data set E are obtained as 97.5% and 97.5% respectively, using a FFBPNN. These accuracies are quite higher than the earlier results published. The results are discussed quite in detail towards the last sections of the present paper. Our experimental results demonstrate that the proposed method gives quite high statistical parameters for EEG classifications especially to classify the interictal data(C, D) and ictal data (E). These experiments indicate that the present method can be useful in analyzing and detecting the EEG signal associated with epilepsy.

Here we report the fabrication of a noncontact pulse oximeter system based on a dual-wavelength imaging system and its oxygen saturation monitoring performance during wound healing. The dual-wavelength imaging system consists of 660 nm and 940 nm light-emitting diodes and a multi-spectral camera that simultaneously accepts visible and near-infrared images. Using the proposed system, images were acquired at 30 fps at both wavelengths, and photoplethysmography signals were extracted by specifying a specific region in the images. We removed the signals caused by small movements and smoothed them using the discrete wavelet transform and moving average filter. To confirm the feasibility of the proposed noncontact oxygen saturation system, a wound model was created using a hairless mouse and oxygen saturation was measured during wound healing. The measured values were compared and analyzed using a reflective animal pulse oximeter. Through a comparative analysis of these two devices, the error of the proposed system was evaluated and the possibility of its clinical application and wound healing monitoring through oxygen saturation measurement confirmed.

Many important biological functions involve the recognition of helical domains of natural proteins. A number of strategies have been developed to mimic natural helices in proteins. Unnatural peptides are constructed with incorporation of artificial building blocks other than α-amino acid residues, and could adopt stable helical conformations. These nontraditional helical oligomers have been explored to mimic biological functions involved with helical domains of natural proteins. This review provides representative examples of the mimicry of natural peptide helices with unnatural ones and related biological applications.