Review: optically-triggered phase-transition droplets for photoacoustic imaging

Qiyang Chen,Jaesok Yu,Kang Kim 대한의용생체공학회 2018 Biomedical Engineering Letters (BMEL) Vol.8 No.2

Optically-triggered phase-transition droplets have been introduced as a promising contrast agent for photoacoustic andultrasound imaging that not only provide significantly enhanced contrast but also have potential as photoacoustic theranosticmolecular probes incorporated with targeting molecules and therapeutics. For further understanding the dynamics ofoptical droplet vaporization process, an innovative, methodical analysis by concurrent acoustical and ultrafast opticalrecordings, comparing with a theoretical model has been employed. In addition, the repeatability of the droplet vaporization-recondensation process, which enables continuous photoacoustic imaging has been studied through the sameapproach. Further understanding the underlying physics of the optical droplet vaporization and associated dynamics mayguide the optimal design of the droplets. Some innovative approaches in preclinical studies have been recently demonstrated,including sono-photoacoustic imaging, dual-modality of photoacoustic and ultrasound imaging, and super-resolutionphotoacoustic imaging. In this review, current development of optically triggered phase-transition droplets andunderstanding on the vaporization dynamics, their applications are introduced and future directions are discussed.

Numerical Simulation of the Coalescence Behavior of Intermittent Structures with Fissures

Qianqian Dong,Yulin Wu,Qiyang Chen 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.4

To further study the failure behavior of the rock-like materials containing intermittent fissures subjected to uniaxial compression, 3D printing technology was adopted to manufacture specimens with prefabricated kinked and straight fissures (K-S fissure). The order of average peak strength was -45o > -90o > +90o > +45o. The influence of different parameters, including the effective length and inclination angle of branch fissure, on the coalescence pattern was discussed. Results showed that two failure modes were observed: Model I represented tensile-shear composite failure in the rock bridge area, while Model II showed non-coalescence occurring. The effective length parameter presented a relatively larger influence than the inclination angle on the failure behavior. Additionally, Model I was discovered to tend to occur in the rock bridge region when the branch fissure turned anticlockwise. Based on numerical simulation using the Realistic Failure Process Analysis (RFPA2D), a quick damage criterion approach was proposed to estimate the coalescence behavior in the rock bridge, which was beneficial to determine coalescence pattern and failure behavior. Based on the curve fitted by the simulation, the coalescence pattern of cracks initiated from pre-existing intermittent fissures occurs in the tensile-shear composite fracture pattern, while non-coalescence occurs in the rock bridge below the curve.

FoxM1 contributes to progestin resistance and epithelial-to-mesenchymal transition in endometrial carcinoma

Wang Lianhua,Shi Qiyang,Chen Shaorong 대한독성 유전단백체 학회 2023 Molecular & cellular toxicology Vol.19 No.2

Background Progestin resistance remains a major issue that is urgently needed to solve in progestin therapy for patients with endometrial carcinoma (EC). Increasing research indicated the critical role of FoxM1 in drug resistance of diverse cancers. Objective This study aims to explore whether FoxM1 contributes to medroxyprogesterone acetate (MPA, a commonly used progestin) resistance in EC. Results It was observed that FoxM1 is highly expressed in MPA-resistant ECC-1 (ECC-1/MPA) cells at both protein and mRNA levels when compared with ECC-1 cells. Knocking down FoxM1 in ECC-1/MPA cells signifi cantly decreased the IC50 value of MPA, and rendered ECC-1/MPA cells more sensitive to MPA treatment. In vivo assay exhibited a similar tendency. Simultaneously, FoxM1 knockdown also suppressed proliferation, migration, and invasion of ECC-1/MPA cells. Furthermore, FoxM1 knockdown also suppressed epithelial-to-mesenchymal transition (EMT), as revealed by an elevation in E-cadherin expression and a decrease in N-cadherin and Vimentin expressions in ECC-1/MPA cells. Conclusion These fi ndings indicated the role of FoxM1 in the MPA resistance of EC. Down-regulated FoxM1 expression might be a potential strategy for overcoming MPA resistance.

Study on the Relationship between Fractal Characteristics and Mechanical Properties of Tensile Fracture of Reinforced Concrete Structures

Chenxu Ding,Tianci Xu,Qiyang Chen,Chengguang Su,Pingrui Zhao 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.5

In the present study, experiments are carried out to investigate the behavior of the tensile crack of the reinforced concrete structure. Moreover, the fracture morphology and mechanical properties of the tensile crack are analyzed with the fractal geometry theory and reverse engineering. The obtained results show that the axial force of the tensile crack increases with the crack sequence. When the crack reaches a stable state, the number of cracks does not change, while the width of the crack increases. It is found that fractures of the structural tensile crack have distinct fractal characteristics and the fractal dimension shows a decreasing trend as the cracking axial force increases. Obtained results show that the correlation between the crack axial force and the fractal dimension of the fracture follows a power function. It is demonstrated that the fractal dimension of the fracture depends on different parameters, including the tensile strength of the concrete, cross-sectional area of the structure, ratio of the elastic modulus of the steel bar to that of the concrete, and the reinforcement ratio. Moreover, the fractal dimension of the tensile crack is calculated to evaluate the tensile force of the structure. Based on the obtained results, it is found that appropriate and timely measurements can avoid the built-in steel bars reaching yield and causing the structure to lose its bearing capacity completely.

Performance of Rock-like Materials Containing Filled Kinked Fissures under Uniaxial Tension at Failure

Yulin Wu,Qianqian Dong,Jian He,Qiyang Chen 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.3

To investigate the tensile failure phenomenon of rock masses with filled natural defects, the mechanical behavior of 3D printed rock-like materials containing filled kinked fissures under uniaxial tension was identified. Different inclination angles of branch fissure were considered, and cement and gypsum slurry were selected as the infilling materials. It was found that filling materials enhanced the strength of the specimen, which presented to be cement filling > gypsum filling > no filling. The change of inclination angle of branch fissure had significant influence on the strength and failure mode of the specimen and the strength order was -135o> -45o > 90o and +45o > 90o > +135o. Two types of failure pattern, namely tip failure and non-tip failure, were observed in the experiment. Three types of newborn cracks were identified using a high-speed camera. The result achieved by using the digital image correlation technology indicated that different filling conditions led to the position change of high-strain zone. The displacement field of the filled specimen developed from being continuous to being discontinuous. Furthermore, the extended finite element method was adopted to simulate the filled and unfilled specimens, consistent with the experimental results. This study can provide a reliable reference for studying the tensile stress zones in rock exploration.

Charge separation behaviors of novel AgI/BiOI heterostructures with enhanced solar-photocatalytic performance

Qi Yang,Jiao Huang,Junbo Zhong,Jiufu Chen,Jianzhang Li,Siyang Sun 한국물리학회 2017 Current Applied Physics Vol.17 No.9

The photocatalytic efficiency of the bare BiOI has been greatly restricted because of the high recombination rate of electron-hole charge pairs. To further regulate the photocatalytic performance of BiOI, in this work AgI was employed to couple with BiOI. A serial of novel AgI/BiOI heterostructures with improved sunlight-driven photocatalytic activities were prepared in-situ by a hydrothermal method. The results reveal that the presence of AgI in the composites alters band gap of the samples and greatly affects the photo-induced charge separation rate benefited from the strong interaction between AgI and BiOI. $OH and $O2 were observed using electron spin-resonance (ESR) spectroscopy. The photocatalytic activities of AgI/BiOI heterostructures for the decay of methyl orange (MO) and phenol solution under the simulated sunlight irradiation were investigated, the results display that the composite photocatalysts exhibit higher photocatalytic activity than the bare BiOI and excellent stability. The charge separation and transfer mechanism was proposed based on the experimental results.

Photo-induced charge separation properties of NiO/Bi2O3 heterojuctions with efficient simulated solar-driven photocatalytic performance

Qi Yang,Junbo Zhong,Jian zhang Li,Jiufu Chen,Zhen Xiang,Tao Wang,Minjiao Li 한국물리학회 2017 Current Applied Physics Vol.17 No.4

The inherent drawbacks of Bi2O3 greatly limit the practical application of Bi2O3, thus it is crucial to boost the photocatalytic activity of Bi2O3, and therefore NiO was employed to couple with Bi2O3. In this paper, NiO/Bi2O3 heterostructures with improved sunlight driven -photocatalytic activity were constructed by a pore impregnating method. The samples were studied by Brunauer -Emmett- Teller (BET) method, X-ray diffraction (XRD), UVeVis diffuse reflectance spectroscopy (DRS), high-resolution transmission electron microscopy (HRTEM), surface photovoltage (SPV) spectroscopy and electron spin-resonance (ESR) spectroscopy. The photocatalytic activities of NiO/Bi2O3 heterostructures toward discoloration of methyl orange (MO) aqueous solutions were evaluated. The results display that the presence of NiO in the heterojuctions increases the specific surface area, the absorbance in the visible light region, the separation rate of the photo-induced charge pairs and the formation of $O2 in the photocatalytic system.

Adsorption-coupled reduction of bromate by Fe(II)–Al(III) layered double hydroxide in fixed-bed column: Experimental and breakthrough curves analysis

Qi Yang,Yu Zhong,Xiaoming Li,Xin Li,Kun Luo,Xiuqiong Wu,Hongbo Chen,Yang Liu,Guangming Zeng 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.28 No.-

In this study, the bromate removal was investigated in continuous fixed-bed column using Fe(II)–Al(III)layered double hydroxide (LDH). With increase of column bed depth from 1.0 to 3.0 cm, breakpoint time(tb) increased from 51 to 175 h while throughput volume raised from 12.24 to 42.00 L at breakthroughpoint. The bromate removal was attributed to the reduction of Fe(II) present in LDH. The breakthroughcurve was simulated well by Thomas model, but BDST model was the only effective to initial part(1–10%). The maximum removal capacity (N0) calculated by Thomas model reached 71.01 mmol/g atflow rate (3 mL/min).