The main objective of this research is to measure the Doppler signal by the ultrasonic patch. Blood flow measurement is critical for vasospasm, stroke, and embolism monitoring on patients in the ICU or understanding the neurovascular coupling on different subjects. Currently, A conventional transcranial Doppler (TCD) probe is widely used for these applications. A headset design must be applied and fixed on the participants to obtain stable blood flow spectra. However, the TCD headset is operator dependent. The operator needs to be a trained expert and hold the ultrasound probe to get accurate blood flow velocity information. The stretchable and wearable non-invasive ultrasonic patch can not only free the operator's hands but can also provide long-term continuous monitoring, which is not possible by using the current operator-dependent ultrasound machine. The device can be conformal to the skin and attached to the skin surface.

Inclusion Criteria:

• Able to provide informed consent.
• In relatively good health with no serious medical conditions.

Exclusion Criteria:

• Inability to sign the informed consent.
• History of the following conditions: Heart attack, low blood pressure, aortic stenosis/carotid artery stenosis (also known as heart valve disease), glaucoma (a group of eye conditions that damage the optic nerve) or retinopathy (a disease of the eye retina).

Participants without any serious medical conditions.

The study protocol, statistical analysis plan, and clinical study report will be shared and discussed in the research articles.

1.5 years

Anyone can access it through research articles.