Wireless Dynamic Light Scattering Sensors Detect Microvascular Changes Associated With Ageing and Diabetes.

This article presents clinical results of wireless portable dynamic light scattering sensors that implement laser Doppler flowmetry signal processing. It has been verified that the technology can detect microvascular changes associated with diabetes and ageing in volunteers. Studies were conducted primarily on wrist skin. Wavelet continuous spectrum calculation was used to analyse the obtained time series of blood perfusion recordings with respect to the main physiological frequency ranges of vasomotions. In patients with type 2 diabetes, the area under the continuous wavelet spectrum in the endothelial, neurogenic, myogenic, and cardio frequency ranges showed significant diagnostic value for the identification of microvascular changes. Aside from spectral analysis, autocorrelation parameters were also calculated for microcirculatory blood flow oscillations. The groups of elderly volunteers and patients with type 2 diabetes, in comparison with the control group of younger healthy volunteers, showed a statistically significant decrease of the normalised autocorrelation function in time scales up to 10 s. A set of identified parameters was used to test machine learning algorithms to classify the studied groups of young controls, elderly controls, and diabetic patients. Our conclusion describes and discusses the classification metrics that were found to be most effective.

Alignment tolerant, low voltage, 0.23†V.cm, push-pull silicon photonic switches based on a vertical pn junction.

In this paper, we present the design, fabrication and characterization of a carrier depletion silicon-photonic switch based on a highly doped vertical pn junction. The vertical nature of the pn junction enables the device to exhibit a modulation efficiency as high as 0.23 V.cm. Fast switching times of 60ps are achieved in a lumped configuration. Moreover, the process flow is highly tolerant to fabrication deviations allowing a seamless transfer to the 350 nm process node of a commercial complementary-metal-oxide semiconductor (CMOS) foundry. Overall, this work showcases the possibility of fabricating highly efficient carrier depletion-based silicon photonic switches using medium resolution lithography.

Multimodal optical measurement for study of lower limb tissue viability in patients with diabetes mellitus.

According to the International Diabetes Federation, the challenge of early stage diagnosis and treatment effectiveness monitoring in diabetes is currently one of the highest priorities in modern healthcare. The potential of combined measurements of skin fluorescence and blood perfusion by the laser Doppler flowmetry method in diagnostics of low limb diabetes complications was evaluated. Using Monte Carlo probabilistic modeling, the diagnostic volume and depth of the diagnosis were evaluated. The experimental study involved 76 patients with type 2 diabetes mellitus. These patients were divided into two groups depending on the degree of complications. The control group consisted of 48 healthy volunteers. The local thermal stimulation was selected as a stimulus on the blood microcirculation system. The experimental studies have shown that diabetic patients have elevated values of normalized fluorescence amplitudes, as well as a lower perfusion response to local heating. In the group of people with diabetes with trophic ulcers, these parameters also significantly differ from the control and diabetes only groups. Thus, the intensity of skin fluorescence and level of tissue blood perfusion can act as markers for various degrees of complications from the beginning of diabetes to the formation of trophic ulcers.

Self-assembled electrical circuits and their electronic properties.

A straightforward method for the self assembly of single walled carbon nanotubes (SWNTs) between gold electrodes was developed. The technique utilizes the hybridization between short complementary DNA sequences located on metal contacts and SWNTs. new technique enables simple production of hundreds of devices with high yields. The electrical characteristics are shown to depend strongly on the existence of the chemical binding groups at the contacts as well as along the tubes. This technique was used to drive the self assembly of SWNT-based field effect transistors (CNTFETs). In principle, the devices made by this method behave like those made using direct metal-carbon nanotube contacts. The inverse subthreshold slope of the CNTFETs depends on the source-drain voltage applied to the device, confirming that the conductance of CNTFETs is determined by the Schottky barriers at the interfaces between the CNTs and the gold electrodes.