74 research outputs found

    Mechanism of Action of Lonicera caerulea Berry Polyphenols in Regulating Intestinal Microecology in Immunosuppressive Mice

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    Objective: In order to explore the effects of Lonicera caerulea berry polyphenols (LCBP) on immunity and intestinal flora in immunosuppressive mice. Methods: Thirty-two mice were randomly divided into a blank control group, a model group, a low-dose LCBP group and a high-dose LCBP group. Cyclophosphamide at 80 mg/(kg mb·d) was injected intraperitoneally after 17, 19 and 21 d of oral administration. Immune organ indices, routine blood biochemical indexes, intestinal microbial diversity and distribution, and the level of short chain fatty acids in colonic contents were investigated and colonic histopathology was examined by hematoxylin-eosin (HE) staining. Results: Compared with the model group, spleen and thymus indexes in the high-dose LCBP group significantly increased (P < 0.01). Also, the number of white blood cells, lymphocytes and platelets increased (P < 0.05), and so did the number of red blood cells and neutrophils (P < 0.01). LCBP increased the relative abundance of Firmicutes, Epsilonbacteraeota, Proteobacteria, Patescibacteria, Actinobacteria and Cyanobacteria in the intestinal tract of immunosuppressive mice and the concentrations of fecal short-chain fatty acids (SCFAs). Conclusion: LCBP can increase the type of intestinal flora, regulate the structural distribution of intestinal flora, alleviate intestinal injury and enhance immune function in immunosuppressive mice

    Arabidopsis Hormone Database: a comprehensive genetic and phenotypic information database for plant hormone research in Arabidopsis

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    Plant hormones are small organic molecules that influence almost every aspect of plant growth and development. Genetic and molecular studies have revealed a large number of genes that are involved in responses to numerous plant hormones, including auxin, gibberellin, cytokinin, abscisic acid, ethylene, jasmonic acid, salicylic acid, and brassinosteroid. Here, we develop an Arabidopsis hormone database, which aims to provide a systematic and comprehensive view of genes participating in plant hormonal regulation, as well as morphological phenotypes controlled by plant hormones. Based on data from mutant studies, transgenic analysis and gene ontology (GO) annotation, we have identified a total of 1026 genes in the Arabidopsis genome that participate in plant hormone functions. Meanwhile, a phenotype ontology is developed to precisely describe myriad hormone-regulated morphological processes with standardized vocabularies. A web interface (http://ahd.cbi.pku.edu.cn) would allow users to quickly get access to information about these hormone-related genes, including sequences, functional category, mutant information, phenotypic description, microarray data and linked publications. Several applications of this database in studying plant hormonal regulation and hormone cross-talk will be presented and discussed

    Structural Characterization of Mesoporous Silica Nanofibers Synthesized Within Porous Alumina Membranes

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    Mesoporous silica nanofibers were synthesized within the pores of the anodic aluminum oxide template using a simple sol–gel method. Transmission electron microscopy investigation indicated that the concentration of the structure-directing agent (EO20PO70EO20) had a significant impact on the mesostructure of mesoporous silica nanofibers. Samples with alignment of nanochannels along the axis of mesoporous silica nanofibers could be formed under the P123 concentration of 0.15 mg/mL. When the P123 concentration increased to 0.3 mg/mL, samples with a circular lamellar mesostructure could be obtained. The mechanism for the effect of the P123 concentration on the mesostructure of mesoporous silica nanofibres was proposed and discussed

    Semiconductor Quantum Dots for Biomedicial Applications

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    Semiconductor quantum dots (QDs) are nanometre-scale crystals, which have unique photophysical properties, such as size-dependent optical properties, high fluorescence quantum yields, and excellent stability against photobleaching. These properties enable QDs as the promising optical labels for the biological applications, such as multiplexed analysis of immunocomplexes or DNA hybridization processes, cell sorting and tracing, in vivo imaging and diagnostics in biomedicine. Meanwhile, QDs can be used as labels for the electrochemical detection of DNA or proteins. This article reviews the synthesis and toxicity of QDs and their optical and electrochemical bioanalytical applications. Especially the application of QDs in biomedicine such as delivering, cell targeting and imaging for cancer research, and in vivo photodynamic therapy (PDT) of cancer are briefly discussed

    Photoacoustic imaging for prostate brachytherapy

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    Photoacoustic (PA) imaging is an emerging imaging modality that relies on the PA effect. The PA effect is caused by exposing an optically absorbing sample to near-infrared light which causes the sample to experience a temporary temperature increase through optical absorption. The heated region undergoes thermoelastic expansion and produces an abrupt and localized pressure change. This change results in a transient PA wave that propagates out toward the sample surface for collection by an ultrasound (US) transducer. Through image reconstruction, the optical property of the sample can be obtained. PA imaging is promising in detecting brachytherapy seeds during prostate brachytherapy. The high absorption coefficient of the metallic seeds leads to high PA imaging contrast. One major drawback is the limited imaging depth due to high optical attenuation of the excitation light in tissue. One of the goals of this thesis is to conduct initial feasibility tests of enhancing the PA contrast through brachytherapy seeds modifications. Seed coated with a contrast enhancing material shows an increase of 18 dB in signal-to-noise ratio (SNR) and two time increase in the imaging depth (5 cm). Another method of silver coating leads to a 5 dB improvement in the SNR of the modified seeds. An alternative approach in using dyed ethanol solution as a contrast enhancing agent by filling the spaces between two seeds is also reported. The result showed improvement comparable to the black paint method. Another goal is to propose a novel method of tissue typing in PA imaging. A temperature change in tissue can lead to changes of several tissue parameters which can be used for tissue typing. One of the parameters is the speed of sound in tissue, which increases in water-based non-fatty tissue and decreases in fatty tissue as temperature is raised. We show that on average, 6.9±1.5 %/min increase and 4.2±1.5 %/min decrease in PA intensity are observed in porcine liver and bovine fat samples respectively through one minute of laser heating. These results demonstrate that by analyzing the PA intensity change of the illuminated sample, one can extract characteristic information that can lead to tissue type differentiation.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat

    A Generic CbITS Authoring Tool Using xAPI

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    Intelligent Tutoring Systems (ITSs) are considered among the most effective and efficient learning systems. The difficulty of authoring content limits the use of ITSs and creates a bottleneck for most ITS researchers and related industries. AutoTutor, a conversation-based ITS, faces the same problem. This paper will introduce the new improvement of AutoTutor Lite using xAPI and its potential as a generic CbITS authoring tool

    Recent Advances in Interface Engineering for Planar Heterojunction Perovskite Solar Cells

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    Organic-inorganic hybrid perovskite solar cells are considered as one of the most promising next-generation solar cells due to their advantages of low-cost precursors, high power conversion efficiency (PCE) and easy of processing. In the past few years, the PCEs have climbed from a few to over 20% for perovskite solar cells. Recent developments demonstrate that perovskite exhibits ambipolar semiconducting characteristics, which allows for the construction of planar heterojunction (PHJ) perovskite solar cells. PHJ perovskite solar cells can avoid the use of high-temperature sintered mesoporous metal oxides, enabling simple processing and the fabrication of flexible and tandem perovskite solar cells. In planar heterojunction materials, hole/electron transport layers are introduced between a perovskite film and the anode/cathode. The hole and electron transporting layers are expected to enhance exciton separation, charge transportation and collection. Further, the supporting layer for the perovskite film not only plays an important role in energy-level alignment, but also affects perovskite film morphology, which have a great effect on device performance. In addition, interfacial layers also affect device stability. In this review, recent progress in interfacial engineering for PHJ perovskite solar cells will be reviewed, especially with the molecular interfacial materials. The supporting interfacial layers for the optimization of perovskite films will be systematically reviewed. Finally, the challenges remaining in perovskite solar cells research will be discussed
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