Face mask detection and classification via deep transfer learning.

Wearing a mask is an important way of preventing COVID-19 transmission and infection. German researchers found that wearing masks can effectively reduce the infection rate of COVID-19 by 40%. However, the detection of face mask-wearing in the real world is affected by factors such as light, occlusion, and multi-object. The detection effect is poor, and the wearing of cotton masks, sponge masks, scarves and other items greatly reduces the personal protection effect. Therefore, this paper proposes a new algorithm for mask detection and classification that fuses transfer learning and deep learning. Firstly, this paper proposes a new algorithm for face mask detection that integrates transfer learning and Efficient-Yolov3, using EfficientNet as the backbone feature extraction network, and choosing CIoU as the loss function to reduce the number of network parameters and improve the accuracy of mask detection. Secondly, this paper divides the mask into two categories of qualified masks (N95 masks, disposable medical masks) and unqualified masks (cotton masks, sponge masks, scarves, etc.), creates a mask classification data set, and proposes a new mask classification algorithm that the combines transfer learning and MobileNet, enhances the generalization of the model and solves the problem of small data size and easy overfitting. Experiments on the public face mask detection data set show that the proposed algorithm has a better performance than existing algorithms. In addition, experiments are performed on the created mask classification data set. The mask classification accuracy of the proposed algorithm is 97.84%, which is better than other algorithms.

A Multicenter, Randomized, Controlled Trial of Electroacupuncture for Perimenopause Women with Mild-Moderate Depression.

OBJECTIVE: Up to 62% of perimenopausal women have depression symptoms. However, there is no efficacy treatment. The aim of this study is to compare the clinical efficacy and safety of EA therapy and escitalopram on perimenopause women with mild-moderate depressive symptom. METHOD: A multicenter, randomized, positive-controlled clinical trial was conducted at 6 hospitals in China. 242 perimenopause women with mild-moderate depressive symptom were recruited and randomly assigned to receive 36 sessions of EA treatment or escitalopram treatment. The primary outcome measure was the 17-item Hamilton Depression Rating Scale (HAMD-17). The secondary outcome measures include menopause-specific quality of life (MENQOL) and serum sexual hormones which include estrogen, follicle-stimulating hormone, and luteinizing hormone. RESULTS: 221 (91.3%) completed the study, including 116 in the EA group and 105 in the escitalopram group. The baseline levels of demographic and outcome measurements were similar in the two groups. In the intervention period, there was no difference between two groups. However, in the follow-up, both HAMD-17 and MENQOL were significantly decreased, and at week 24 the mean differences were -2.23 and -8.97, respectively. There were no significant differences in the change of serum sexual hormones between the two groups. No serious adverse events occurred. CONCLUSION: EA treatment is effective and safe in relieving depression symptom and improving the quality of life in the perimenopausal depression. Further research is needed to understand long-term efficacy and explore the mechanism of this intervention. This study is registered with ClinicalTrials.gov NCT02423694.

Chiral expression from molecular to macroscopic level via pH modulation in terbium coordination polymers.

Chiral expression from the molecular to macroscopic level is common in biological systems, but is difficult to realise for coordination polymers (CPs). The assembly of homochiral CPs in both crystalline and helical forms can provide a bridge for understanding the relationship between the molecular and macroscopic scales of chirality. Herein, we report homochiral helices of [Tb(R- or S-pempH)3]∙2H2O (R - or S -1) (pempH2 = (1-phenylethylamino)methylphosphonic acid) and their crystalline counterparts (R - or S -3), which are formed at different pH of the reaction mixtures under hydrothermal conditions. By combining the experiments and molecular simulations, we propose that the formation of helices of R -1 or S -1 occurs via a hierarchical self-assembly route, which involves twisted packing due to the geometric incompatibility of the different types of chains. The observed chiral transcription from molecules to morphologies is significant for understanding bio-related self-assembly processes on the nano- to macro-scale.