Room-Temperature Phosphorescence with Variable Lifetime of Halogen-Comprising Coordination Polymers.

Materials with lifetime-tunable room-temperature phosphorescence are fascinating for multiple encryption-decryption security applications. Herein, by introducing different halogen ions, that is, Cl, Br, and I, together with organic luminescent units to bond to a zinc center, three coordination polymers were hydro(solvo)thermally synthesized. The results show that three coordination polymers present room-temperature phosphorescence with different lifetimes. Furthermore, a multiple encryption-decryption system combining temporal and spatial resolution characteristics was designed.

Construction of a convolutional neural network classifier developed by computed tomography images for pancreatic cancer diagnosis.

BACKGROUND: Efforts should be made to develop a deep-learning diagnosis system to distinguish pancreatic cancer from benign tissue due to the high morbidity of pancreatic cancer. AIM: To identify pancreatic cancer in computed tomography (CT) images automatically by constructing a convolutional neural network (CNN) classifier. METHODS: A CNN model was constructed using a dataset of 3494 CT images obtained from 222 patients with pathologically confirmed pancreatic cancer and 3751 CT images from 190 patients with normal pancreas from June 2017 to June 2018. We established three datasets from these images according to the image phases, evaluated the approach in terms of binary classification (i.e., cancer or not) and ternary classification (i.e., no cancer, cancer at tail/body, cancer at head/neck of the pancreas) using 10-fold cross validation, and measured the effectiveness of the model with regard to the accuracy, sensitivity, and specificity. RESULTS: The overall diagnostic accuracy of the trained binary classifier was 95.47%, 95.76%, 95.15% on the plain scan, arterial phase, and venous phase, respectively. The sensitivity was 91.58%, 94.08%, 92.28% on three phases, with no significant differences (χ 2 = 0.914, P = 0.633). Considering that the plain phase had same sensitivity, easier access, and lower radiation compared with arterial phase and venous phase , it is more sufficient for the binary classifier. Its accuracy on plain scans was 95.47%, sensitivity was 91.58%, and specificity was 98.27%. The CNN and board-certified gastroenterologists achieved higher accuracies than trainees on plain scan diagnosis (χ 2 = 21.534, P < 0.001; χ 2 = 9.524, P < 0.05; respectively). However, the difference between CNN and gastroenterologists was not significant (χ 2 = 0.759, P = 0.384). In the trained ternary classifier, the overall diagnostic accuracy of the ternary classifier CNN was 82.06%, 79.06%, and 78.80% on plain phase, arterial phase, and venous phase, respectively. The sensitivity scores for detecting cancers in the tail were 52.51%, 41.10% and, 36.03%, while sensitivity for cancers in the head was 46.21%, 85.24% and 72.87% on three phases, respectively. Difference in sensitivity for cancers in the head among the three phases was significant (χ 2 = 16.651, P < 0.001), with arterial phase having the highest sensitivity. CONCLUSION: We proposed a deep learning-based pancreatic cancer classifier trained on medium-sized datasets of CT images. It was suitable for screening purposes in pancreatic cancer detection.

Fully distributed containment control for second-order multi-agent systems with communication delay.

In this paper, fully distributed containment control problems of multi-agent systems with double-integrator dynamics are investigated under directed topologies. For the cases with and without communication delay, two new fully distributed control protocols are designed, which do not need any global information of the communication topology graph. Necessary and sufficient conditions are obtained to ensure the solvability of the considered containment control problems. Particularly, for the case with communication delay, the critical value of the maximum allowable time delay of containment control is found. Finally, numerical simulations are presented to demonstrate the effectiveness of the theoretical results.

Containment Control for General Second-Order Multiagent Systems With Switched Dynamics.

This paper investigates the distributed containment control problem for a class of general second-order multiagent systems with switched dynamics, which is composed of a continuous-time (CT) subsystem and a discrete-time (DT) subsystem. For this switched multiagent system under fixed directed topology, a distributed containment control protocol is proposed for each follower based on the relative local measurements of neighboring followers and leaders. Some necessary and sufficient conditions are derived under the condition that the network topology contains a directed spanning forest, and these conditions ensure that the general second-order containment control problem can be solved under arbitrary CT-DT switching. If the general second-order system is reduced to the double integrator system, some simpler containment conditions are presented. Furthermore, the similar results are also obtained under switching directed topology. Finally, some simulation examples are presented to show the efficiency of the theoretical results.

[Preliminary finite element analysis of anterior inferior tibiofibular syndesmosis injuries treated with screw and tight-rope fixation].

OBJECTIVE: To establish finite element models of anterior inferior tibiofibular syndesmosis injuries (AITSI), screw fixation and Tight-rope(TR) fixation, and to compare its force and displacement, so as provide evidence for clinical diagnosis and treatment. METHODS: A three-dimensional model of a healthy ankle complex was developed by computed tomography (CT) images, and anterior inferior tibiofibular syndesmosis injuries(AITSI) model also established, then a screw was inserted into AITSI model to obtain a screw fixation model, and a Tight-rope system was put into AITSI model to obtain a TR model. Simulated loads were applied under three conditions:neutral position with single-foot standing, internal and external rotation of the ankle. The focus was on the stress of distal tibia, distal fibula and talus articular surface, and displacement of distal tibia and fibula. RESULTS: AITSI increased the stress of distal tibia, distal fibula and talus articular surface, which also increased the displacement of distal tibia and fibula. when AITSI existing, either a screw or TR could restrict excessive displacement of distal tibia and fibula. However, screw fixation severely limited normal physiological activity of ankle, and increased the force of distal tibia, distal fibula and articular surface of talus. The forces were concentrated on the screw. In the screw fixation model, the maximum force of tibia and fibula was more than 1.3 times that of TR model, and the contact force of talus articular surface was about 1.8 times. In the screw fixation model, the displacement of tibial attachment point of anterior tibiofibular ligaments was approximately 0.6 times that of the normal model. While the data in the TR model is about 1.1 times, but TR has poor control of the displacement of fibula. CONCLUSIONS: Severe anterior inferior tibiofibular syndesmosis injuries could cause stress and displacement distribution of ankle joint to change ankle instability and should be treated with internal fixation. Both of the screw and TR could be effective for AITSI. Tight-rope has advantages over screw fixation in terms of skeletal force, activity of ankle joint, and internal fixation fracture, but Tight-rope has disadvantage in fibular rotation. Patients with Weber type C ankle fractures and obesity are more suitable for screw fixation.

[Relationship between pterygium onset and ultraviolet rays exposure time].

OBJECTIVE: To investigate the dose-effect relationship between the radiation of ultraviolet ray and the onset of pterygium quantitatively. METHODS: Interrogation was conducted to 95 patients with pterygium in Yacheng district, Sanya City, Hainan Province, 37 males and 58 females, aged 55.7 +/- 13.8 (20 - 80), and 95 local volunteers in 1:1 pairs matched in age, sex, race, and similar habits of wearing glasses and caps (control group). Both the pterygium group and control group were re-divided into three sub-groups: youth (aged < or = 40), middle-aged (aged 41 - 60), and elderly (aged > 60). The time of exposing to ultraviolet ray was calculated. Photo of the pterygium was taken. The length of the pterygium invading into cornea was measured. RESULTS: The ultraviolet ray exposure time of the youth subgroup, pterygium group, was 35,637 +/- 13,587 hours, significantly higher than that of the youth subgroup, control group (26,188 +/- 17,423 hours, t = 3.352, P = 0.006). The ultraviolet ray exposure time of the middle-aged subgroup, pterygium group, was 73,412 +/- 23,082 hours, significantly higher than that of the middle-aged subgroup, control group (63,368 +/- 25,091 hours, t = 2.322, P = 0.024). However, there was no significant difference in the ultraviolet ray exposure time between the elderly subgroups of both groups. The length of the pterygium invading into cornea was positively correlated with the ultraviolet ray exposure time (r = 0.361, P < 0.05), and the length showed a trend of increased with aging. CONCLUSION: There is a certain dose-effect correlation between ultraviolet ray exposure and the etiology of pterygium.