Cuffless Blood Pressure Measurement Using Smartwatches: A Large-Scale Validation Study.

This study aimed to evaluate the performance of cuffless blood pressure (BP) measurement techniques in a large and diverse cohort of participants. We enrolled 3077 participants (aged 18-75, 65.16% women, 35.91% hypertensive participants) and conducted followed-up for approximately 1 month. Electrocardiogram, pulse pressure wave, and multiwavelength photoplethysmogram signals were simultaneously recorded using smartwatches; dual-observer auscultation systolic BP (SBP) and diastolic BP (DBP) reference measurements were also obtained. Pulse transit time, traditional machine learning (TML), and deep learning (DL) models were evaluated with calibration and calibration-free strategy. TML models were developed using ridge regression, support vector machine, adaptive boosting, and random forest; while DL models using convolutional and recurrent neural networks. The best-performing calibration-based model yielded estimation errors of 1.33 ± 6.43 mmHg for DBP and 2.31 ± 9.57 mmHg for SBP in the overall population, with reduced SBP estimation errors in normotensive (1.97 ± 7.85 mmHg) and young (0.24 ± 6.61 mmHg) subpopulations. The best-performing calibration-free model had estimation errors of -0.29 ± 8.78 mmHg for DBP and -0.71 ± 13.04 mmHg for SBP. We conclude that smartwatches are effective for measuring DBP for all participants and SBP for normotensive and younger participants with calibration; performance degrades significantly for heterogeneous populations including older and hypertensive participants. The availability of cuffless BP measurement without calibration is limited in routine settings. Our study provides a large-scale benchmark for emerging investigations on cuffless BP measurement, highlighting the need to explore additional signals or principles to enhance the accuracy in large-scale heterogeneous populations.

Synthesis of Pyridinic-Rich N, S Co-doped Carbon Quantum Dots as Effective Enzyme Mimics.

N and S co-doped carbon quantum dots (N, S-CQDs) with high N- and S-doping level were synthesized by microwave solid-phase pyrolysis within 50 s. Owing to the dominant pyridinic N injection into the conjugated framework, both high enzyme mimics catalytic activity and photoluminescence quantum yield are achieved simultaneously.

[Study on accumulation law of peimine in different Fritillaria thunbergii cultivar].

In order to study the accumulation of Fritillaria thunbergii cultivar, peimine content in Xiaye, Kuanye, Duozi and Xiaosanzi bulbs of different sizes and parts was determined by HPLC-ELSE. The results indicated that the peimine content varied significantly with the cultivar type, the size and part of bulb. The distribution laws of peimine were as follow: Xiaosanzi > Duozi > Xiaye > Kuanye, small-size bulb > big-size bulb, core bud > scale. The peimine yield per plant in Duozi was the highest.

[Effect of low-temperature vernalization on metabolism of carbon and nitrogen of Isatis indigotica].

OBJECTIVE: The aim of the present study is to investigate the effect of low temperature vernalization on metabolism change of carbon and nitrogen of Isatis indigotica. METHOD: The Yunnan and Beijing I. indigotica seedlings with six leaves were vernalized at 4 degrees C for 25 days, and the metabolism indicators of carbon and nitrogen were measured. RESULT: There appeared a dramatic increase in the soluble sugar content, reducing sugar content and soluble protein content in response to the low temperature, after termination of vernalization it reached the maximum, however, starch and total nitrogen concentration decreased significantly, after termination of vernalization it reached the minimum. CONCLUSION: The high C/N value can promote the low temperature vernalization of I. indigotica.