Wearable Photoelectric Fingertip Force Sensing System Based on Blood Volume Changes without Sensory Interference.

Monitoring the force of fingertip manipulation without disturbing the natural sense of touch is crucial for digitizing the skills of experienced craftsmen. However, conventional force sensors need to be put between the skin and the objects, which affects the natural sense of the skin. Here, we proposed a fingertip force sensing method based on changes of blood volume and designed a wearable photoelectric fingertip force sensing system (PFFS) for digitalization of traditional Chinese medicine (TCM) pulse diagnosis. The PFFS does not interfere with the fingertips' tactile sense while detecting fingertip force. This PFFS detects the change of blood volume in fingertip by photoelectric plethysmography and can obtain the change of output current under different fingertip forces. We also studied the effect of various factors on PFFS output signals, including emission lights of different wavelengths, ambient temperature, and the user's heartbeat artifact. We further established the relationship between the change of blood volume and fingertip force by combining experimental and theoretical methods. Moreover, we demonstrated the feasibility of the PFFS to detect fingertip forces under commonly used conditions in TCM pulse diagnosis without sensory interference. This PFFS also shows promise for perceiving the viscosity of objects and recognizing gestures in human-computer interaction. This work paves the way for the digitalization of fingertip forces during TCM pulse diagnosis and other fingertip forces under natural conditions.

Instability of nocturnal parasympathetic nerve function in patients with chronic lung disease with or without nocturnal desaturation.

Objective/background: This study was performed to evaluate the association of nocturnal autonomic nerve (AN) dysfunction, especially parasympathetic nerve (PN) function instability, and nocturnal oxygen desaturation (NOD) in patients with chronic lung diseases (CLD). Patients and methods: Twenty-nine stable CLD patients with irreversible pulmonary dysfunction and mild-to-moderate daytime hypoxemia, 13 CLD patients receiving long-term oxygen therapy (LTOT) with maintained SpO2 >90%, and 17 senior healthy volunteers underwent two-night examinations of nocturnal AN function by pulse rate variability (PRV) instead of heart rate variation using a photoelectrical plethysmograph simultaneously monitoring SpO2 and the presence of sleep disordered breathing at home. AN function was examined by instantaneous time-frequency analysis of PRV using a complex demodulation method. Results: There were no significant differences in mean low frequency/high frequency (HF) ratio (index of sympathetic nerve activity) or mean HF amplitude (index of PN activity) among controls and CLD patients with and without NOD (defined as SpO2 <90% for at least 3% of total recording time at night). However, the relative times over which the same main HF peak was sustained for at least 20 seconds (%HF20sec) and 5 minutes in total recording time, indexes of PN function stability, were significantly reduced in CLD patients compared with controls, and further decreased in CLD patients with NOD compared with non-NOD. %HF20sec was significantly higher in the LTOT group than the NOD group. Furthermore, PaO2 at rest and nocturnal hypoxia were significantly correlated with PN function instability in CLD patients. Conclusion: PN function is unstable at night associated with nocturnal hypoxemia in CLD patients, which may reflect poor quality of sleep.

A Controlled Study of Alprostadil Liposomal Preparation in the Treatment of Blue Toe Syndrome.

The aim of this study is to examine the efficacy of alprostadil liposomal preparation in the treatment of blue toe syndrome. As many as 32 patients with blue toe syndrome were randomized into the test group and a control group. Patients out of the test group were treated with alprostadil liposomal preparation, while those out of the control group received placebo administration. Inter-group comparisons were conducted for the post-therapeutic changes of microcirculation and improvements of clinical symptoms. In the test group, there were eight subjects with marked response (50.0 %), six subjects with partial response (37.5 %), and two subjects with no response (12.5 %), with the overall response rate of 87.5 %. In the control group, there were three cases (18.8 %), one case (6.4 %), and 12 cases (75 %), respectively, with the overall response rate of 25.0 %. The inter-group difference of response was statistically significant (Χ (2) = 12.987, P = 0.002 < 0.05). In the test group, there was one case of administration site redness which could be resolved spontaneously. No other adverse drug reactions were reported. No any complaints were reported for the control group. The inter-group difference of nail-fold microcirculation was not statistically significant (P > 0.05). The post-therapeutic points of nail-fold microcirculation in the test group decreased significantly (P < 0.05), but no significant changes were observed for the control group (P > 0.05). The post-therapeutic waveform changes of photoelectric plethysmography were significant for the test group in comparison to the control. The safety and efficacy of alprostadil liposomal preparation have been demonstrated in the treatment of blue toe syndrome.