Progress in Fabrication and Applications of Cholesteric Liquid Crystal Microcapsules.

Liquid crystals (LCs) are well known for inherent responsiveness to external stimuli, such as light, thermal, magnetic, and electric fields. Cholesteric LCs are among the most fascinating, since they possess distinctive optical properties due to the helical molecular orientation. However, the good flow, easy contamination, and poor stability of small-molecule LCs limit their further applications, and microencapsulation as one of the most effective tools can evade these disadvantages. Microencapsulation can offer shell-core structure with LCs in the core can strengthen their stability, avoiding interference with the environment while maintaining the stimuli-responsiveness and optical properties. Here, we report recent progress in the fabrication and applications of cholesteric LC microcapsules (CLCMCs). We summarize general properties and basic principles, fabrication methods including interfacial polymerization, in-situ polymerization, complex coacervation, solvent evaporation, microfluidic and polymerization of reactive mesogens, and then give a comprehensive overview of their applications in various popular domains, including smart fabrics, smart sensor, smart displays, anti-counterfeiting, information encryption, biomedicine and actuators. Finally, we discuss the currently facing challenges and the potential development directions in this field.

Correlation between characteristics of intracranial atherosclerotic plaques and ischemic stroke in high-resolution vascular wall MRI.

BACKGROUND: Intracranial atherosclerotic stenosis is a major cause of ischemic stroke, accounting for 30% of ischemic strokes in Asian populations. PURPOSE: To investigate the relationship between the degree of arterial stenosis and enhancement grade of intracranial atherosclerotic disease (ICAD), the plaque characteristics in different remodeling patterns, and its potential impact. MATERIAL AND METHODS: A total of 210 patients diagnosed with ICAD were enrolled in this retrospective study. Patients were divided into the middle cerebral artery (MCA) group (101 cases), posterior cerebral artery (PCA) group (14 cases), basilar artery (BA) group (71 cases), and intracranial segment of vertebral artery (VA) group (90 cases) according to the difference of diseased vessels. Data on presence or absence of ischemic infarction, intracranial vascular position of lesions, plaque characteristics, ICAD enhancement grade, remodeling index, and degree of arterial stenosis were collected for analysis. RESULTS: The incidence of ischemic infarction in enhancement grade 2 was significantly higher than that in enhancement grade 1 in MCA group (P = 0.019). Enhancement grade 2 of ICAD was an independent risk factor for the development of ischemic infarction (odds ratio = 4.60; 95% confidence interval: 1.91-11.03; P = 0.001). There was no significant statistical difference in infarct rate between different remodeling modalities (P>0.05). CONCLUSION: Enhancement grade of ICAD is significantly associated with the degree of stenosis and the occurrence of ischemic stroke, which varies in different intracranial vessels. The pattern of vascular remodeling varies among different intracranial vessels, and the pattern of vascular remodeling has a significant impact on plaque characteristics.

A Study on the Persistent Trigeminal Artery and Its Classification Based on Magnetic Resonance Angiograph Images.

BACKGROUND: The persistent trigeminal artery (PTA) is the most common remnant of primitive circulation, communicating the developing carotid and vertebrobasilar junction. PURPOSE: This study aimed to evaluate the implementation of magnetic resonance angiography for the detection of PTA and to reclassify the variations based on Weon typing. Moreover, the correlation of various Weon types with the posterior cerebral artery (PCA), Willis ring, basilar artery (BA) dysplasia, and the relationship between PTA and arteriosclerosis were analyzed. METHODS: From November 2017 to October 2019, a total of 48,184 patients underwent magnetic resonance angiography examination in our hospital, and 79 patients were diagnosed with PTA. Of these, 70 patients with complete radiological and clinical information were included in this study. RESULTS: Among the 70 patients with complete data, 27 were classified as Weon type I (38.6%), 7 as type II (10%), 14 as type III (20%), 8 as type IV (11.4%), and 3 as type V (4.3%: type Va, 1 case; type Vb, 2 cases). The remaining 11 cases were PCA with mixed blood supply, so the new type VI was divided into 3 subtypes: type VIa, type VIb, and type VIc, and each subtype of type V was further refined into 4 subtypes. There were 32 cases of PTA with BA dysplasia, including 14 with type I (51.9%), 5 with type II (71.4%), 2 with type III (14.3%), 5 with type IV (62.5%), and 6 with type VI (54.5%). Cerebral infarction was found in 55 cases (78.6%) of PTA, among which 11 had a cerebral infarction in the posterior circulation blood supply area. There were 46 cases (65.7%) accompanied by intracranial arteriosclerosis, and in 6 cases, arteriosclerosis mainly occurred in the posterior circulation. CONCLUSIONS: We redefined the classification of PTA based on Weon typing for a better understanding of clinical symptoms and surgical risks. Moreover, PTA was correlated with the fetal origin of PCA, BA dysplasia, and posterior circulation arteriosclerosis. These factors may increase the incidence of cerebral infarction in the posterior circulation blood supply area.

HR-MRI findings of intracranial artery stenosis and distribution of atherosclerotic plaques caused by different etiologies.

OBJECTIVE: To investigate the etiology of intracranial artery stenosis and the distribution characteristics of intracranial artery atherosclerotic stenosis using high-resolution magnetic resonance imaging (HR-MRI). METHODS: A total of 262 patients with intracranial artery stenosis that underwent HR-MRI from November 2019 to December 2020 were retrospectively enrolled. The etiology of intracranial anterior and posterior circulation artery stenosis was analyzed, and the relationship between the location of plaques and the distribution characteristics of plaques and the occurrence of ischemic stroke was summarized. RESULTS: A total of 276 plaques were identified with HR-MRI. There were 101 cases (36.59%) in the middle cerebral artery (MCA), 14 cases (5.07%) in the posterior cerebral artery (PCA), 90 cases (32.62%) in vertebral artery (VA), and 71 cases (25.72%) in the basilar artery (BA). The infarct rate of ventral and superior wall MCA plaques was higher than that of dorsal and inferior wall (63.33% vs 31.25% P = 0.021) (100.00% vs 50% P = 0.022). MCA with plaques throughout the course had the greatest degree of stenosis (P < 0.001). Sphenoid segment (M1) of MCA was most susceptible (85 cases, 84.16%), MCA plaques were most common in the proximal M1 segment (35 cases, 34.65%), and most BA plaques were found in the distal segment (28 cases, 39.44%). PCA plaques were most frequently involved in traffic anterior segment (P1) (7 cases, 50.00%). CONCLUSION: HR-MRI could provide accurate imaging reference for clinical evaluation of intracranial arterial stenosis and formulation of treatment plans. The intracranial arterial plates mostly appeared in the middle cerebral artery and vertebral artery. Middle cerebral arteries with atherosclerotic plaques are more likely to narrow.