Publications by authors named "Kai Shen"

Vinculin, a cytoskeletal scaffold protein essential for embryogenesis and cardiovascular function, localizes to focal adhesions and adherens junctions, connecting cell surface receptors to the actin cytoskeleton. While vinculin interacts with many adhesion proteins, its interaction with filamentous actin regulates cell morphology, motility, and mechanotransduction. Disruption of this interaction lowers cell traction forces and enhances actin flow rates.

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A novel hybrid photocatalyst (g-C3N4/BiOCl) using g-C3N4 series modified with BiOCl having controllable mass ratios among the g-C3N4 and BiOCl molecules was prepared through hydrolysis process of Bi(3+) onto g-C3N4, using NaBiO3 and g-C3N4 produced from pyrolysis of melamine as the starting materials. The microstructure, morphology and optical properties of the synthesized g-C3N4/BiOCl were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflection spectroscopy (DRS) and photoluminescence (PL) emission spectroscopy. The photoactivity of the g-C3N4/BiOCl was evaluated by photodegradation of Rhodamine B(RhB) from water as a model toxic contaminant.

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Natural odors are usually mixtures; yet, humans and animals can experience them as unitary percepts. Olfaction also enables stimulus categorization and generalization. We studied how these computations are performed with the responses of 168 locust antennal lobe projection neurons (PNs) to varying mixtures of two monomolecular odors, and of 174 PNs and 209 mushroom body Kenyon cells (KCs) to mixtures of up to eight monomolecular odors.

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A novel computer simulator to generate mixed Doppler ultrasound signals from the pulsatile blood flow and vessel wall with mild stenosis is presented in this paper. In-phase and quadrature Doppler blood flow signals are generated using cosine-superposed components modulated by a spectrogram estimated from velocity profile. Meanwhile,Doppler signals echoed from bidirectional moving walls are generated with the input waveforms of the wall velocities.

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We demonstrate that two kinds of 2D eight-fold photonic quasi-crystals (PQCs) can be fabricated by a specially designed prism via single-exposure holographic lithography. The prism with five continuous side surfaces out of common eight symmetrical side surfaces, plus a top surface, is well designed for PQC fabrication. Compared with the traditional method of setting up eight free-space beams in the half-space for an eight-fold PQC fabrication, our specially designed prism reduces the number of beams, avoids the differences of beam-to-beam phases, and simplifies the fabrication process.

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Background: Haemophilus influenzae colonizes the human nasopharynx as a commensal, and is etiologically associated with numerous opportunistic infections of the airway; it is also less commonly associated with invasive disease. Clinical isolates of H. influenzae display extensive genomic diversity and plasticity.

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Background: Esomeprazole provides effective and long lasting inhibition of gastric acid secretion. However, the pharmacokinetics and pharmacodynamics of intravenous esomeprazole in the Chinese population remain unclear.

Aim: To compare the pharmacokinetics and pharmacodynamics of intravenous esomeprazole (injection and infusion) and their clinical safety and tolerability in healthy Chinese subjects.

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Odor pollution of landfill site is a serious problem accompanied with the urbanization process that influences city life. Generally, odor emission points in landfill boundary are detected by experience, but the pollution intensity, distribution and variation in the scope of landfill boundary are difficulty to describe. In this research, odor emission points were disclosed with equal odor concentration curves that were delineated using electric nose and GPS instrument.

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The co-precipitation and citric acid methods were employed to prepare MnO(x)-FeO(x) catalysts for the low-temperature selective catalytic reduction (SCR) of NO(x) by ammonia. It was found that the Mn-Fe (CP) sample obtained from the co-precipitation method, which exhibited low crystalline of manganese oxides on the surface, high specific surface area and abundant acid sites at the surface, had better catalytic activity. The effects of doping different transition metals (Mo, Zr, Cr) in the Mn-Fe (CP) catalysts were further investigated.

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The hMSH2 gene, a member of the mismatch repair (MMR) pathway, plays a key role in the maintenance of genomic integrity. The common sequence variation in hMSH2, IVS12-6 T>C, has been implicated in cancer risk. However, the results of published studies on this polymorphism remain conflicting.

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MYH is an important enzyme in combating DNA oxidative stress in the occurrence and development of various types of tumors. To investigate the correlation between expression of the DNA repair enzyme MYH in esophageal squamous cell carcinoma and 8-oxoguanine (8-oxoG) oxidative damage, as well as the clinical significance of altered MYH expression, tissues from 175 esophageal carcinoma cases were investigated in the present study. MYH expression and 8-oxoG oxidative damage in squamous cell carcinoma and adjacent normal tissue were assessed by immunohistochemistry and Western blotting.

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The purpose of this study was to detect the methylation of the RUNX3 gene promoter in non-small cell lung cancer (NSCLC) tissue and to explore the association of this methylation with clinical features of NSCLC. In 58 samples of NSCLC tissue and normal adjacent tissue, methylation of the RUNX3 gene promoter was measured by methylation-specific polymerase chain reaction. Correlation with clinicopathological characteristics was assessed.

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CO(2) was converted into value-added hydrocarbons (methanol) by laser-induced photocatalytic reduction of CO(2) over commercially available silicon-carbide (SiC) granules as catalyst. The conversion of CO(2) was carried out in a glass reactor having quartz window and equipped with stirring system and was provided with continuous CO(2) flow at ambient conditions. Laser radiations of 355 nm, which were generated by third harmonics of Nd:YAG laser (1060 nm) were applied as an excitation source.

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TiO(2)-ZrO(2) (hereafter denoted as Ti-Zr) supported V(2)O(5) catalysts with different loadings of CeO(2) were synthesized, and their physicochemical properties were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), in situ Fourier transform infrared spectroscopy (in situ FT-IR) and temperature-programmed reduction (TPR). Their catalytic activities toward the NO(x) reduction reaction with NH(3) were tested. We found that with the addition of CeO(2), more NO was removed in a wide temperature range of 220-500 °C.

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Objective: To evaluate the learning curve of complete mesocolic excision(CME) for colon cancer.

Methods: Clinical data of 75 cases in whom CME was performed by a group of surgeons in the Department of Gastrointestinal Surgery, Peking University People's Hospital from November 2009 to June 2011 were reviewed. The patients were divided into three groups(groups A, B, C, 25 cases in each group) by operative chronologic sequence.

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Vinculin is an essential and highly conserved cell adhesion protein, found at both focal adhesions and adherens junctions, where it couples integrins or cadherins to the actin cytoskeleton. Vinculin is involved in controlling cell shape, motility, and cell survival, and has more recently been shown to play a role in force transduction. The tail domain of vinculin (Vt) contains determinants necessary for binding and bundling of actin filaments.

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Objective: To analyze and explore the value of MRI in distinguishing fresh from old vertebral compression fractures.

Methods: The features of MRI in 43 cases with compression fractures of thoracic or lumbar vertebral bodies were analyzed. MRI sequences included T1WI, T2WI and STIR.

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We propose that stem cells that display specific phenotypic and functional characteristics exist in human uterine myometrium. Under hypoxic circumstances, estrogen signaling pathways in certain myometrial stem cells are aberrantly activated, which leads to continuous differentiation of this portion of cells into leiomyoma cells. This process also protects the cells from undergoing physiological apoptotic or dedifferentiation.

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The phosphatidylethanolamine-binding protein 4 (PEBP4) is a member of the PEBP family. It not only plays a role in the inhibition of the MAPK signaling pathway but also is involved in the inhibition of the JNK pathway that promotes the activation of AKT. Recent research has also shown that overexpression of PEBP4 was related to the development, invasion, and metastasis of a variety of tumors.

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Cyanobacterial toxins, especially the microcystins, are found in eutrophied waters throughout the world, and their potential to impact on human and animal health is a cause for concern. Microcystin-LR (MC-LR) is one of the common toxic microcystin congeners and occurs frequently in diverse water systems. Recent work suggested that apoptosis plays a major role in the toxic effects induced by MC-LR in hepatocytes.

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Angiotensin II (Ang II) plays a profound regulatory effect on NADPH oxidase and the functional features of vascular adventitial fibroblasts, but its role in antioxidant enzyme defense remains unclear. This study investigated the effect of Ang II on expressions and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in adventitial fibroblasts and the possible mechanism involved. Ang II decreased the expression and activity of CAT in a dose- and time-dependent manner, but not that of SOD and GPx.

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A novel ultrasonic-modified MnO(x)/TiO(2) catalyst was prepared and compared with two different kinds of MnO(x)/TiO(2) catalysts in the process of low-temperature selective catalytic reduction of NO with NH(3). The physicochemical properties of the catalysts were studied by using various characterization techniques, such as Brunauer-Emmett-Teller (BET) surface measurement, X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ultrasonic-modified process introduced ultrasound in the solution impregnation step of traditional impregnation method for MnO(x)/TiO(2) catalyst preparation.

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Chitosan composite rods (CS-Fe(3+)) were prepared via an in situ precipitation method. The relationships among the preparation, structures, and properties of the CS-Fe(3+) composite rods have been investigated. The results of Fourier-transform infrared spectroscopy (FTIR) and core electron X-ray photoelectron spectroscopy (XPS) indicate that the CS and Fe(3+) are coordinated via a chelation mechanism.

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InGaN nanorod arrays have been grown by molecular beam epitaxy on bare and high-temperature AIN-buffered Si(111) substrates. It has been found that well vertically aligned InGaN nanorod arrays can be grown by using the high-temperature AIN buffer layer. On bare Si substrate, high-resolution transmission electron microscopy revealed an amorphous SiNx layer generated at the interface, and the thickness and flatness of the SiNx layer may affect the relative alignment of the nanorods with the substrate.

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