2,967 research outputs found

    Enhancement of Optical Nonlinearity Through Anisotropic Microstructures

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    We investigate the polarization dependence of optical nonlinearity enhancement for a uniaxial anisotropic composite of metal nanocrystals in a dielectric host. Three cases are distinguished depending on whether the polarization is parallel, perpendicular or unpolarized with respect to the axis of anisotropy. For the parallel polarization, the results show that the 3D results are qualitatively similar to the 2D case reported recently. For the perpendicular polarization, the results are markedly different from the parallel counterpart: In contrast to the absorption, the enhancement factor actually increases with the anisotropy. Thus the separation of the absorption and enhancement peaks becomes even more pronounced than the parallel polarization case. These results indicate a strong polarization dependence of the nonlinear optical response.Comment: 12 pages, LaTeX format, 9 figures, preliminary results were Reported in the 2nd Tohwa University International Meeting on Statistical Physics held on November 4-7, 1997, accepted for publication by Optics Communications on 7 November 199

    Rotective effect of Fengliao-Changweikang extracts, a traditional Chinese herbal medicine formula,on mucosa in rat with chronic gastritis

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    Background: Fengliao-Changwei-Kang(FCK), the Chinese patent drug, is a famous traditional Chinese herbal medicine formula. It has a significant effect on the clinic treatment of gastrointestinal diseases  including gastritis, enteritis and diarrhea for many years. However, there is few research on the  protective effects of FCK on the gastric mucosa of chronic gastritis (CG) model rat. Objective: The present study aimed to explore the effects of FCK extract on mucosa in rats with Chronic Gastritis.Materials and Methods: 50 SD mice were randomly divided into 5 groups with 10 in each group(five per sex). The groups are respectively control group, model group, low, middle and high FCK extracts (FCK I, II and III) group. The CG rat model was induced by synthetic methods. FCK I, II and III group were  administrated with FCK extracts at 2.16g• kg, 4.32g• kg, 8.94g• kg once per day for 21 consecutive  days, and the control group and model group were administrated the same volume of distilled water at 10mL/kg once per day. 16 hours after the last administration, the rats were anesthetized and their blood and stomach were drawn from vena cava and abdominal cavity. The serum levels of EGF was measured by enzyme linked immunosorbent assay(ELISA) method, the expression of growth factor receptor (EGFR) in gastric mucosa was detected by immunohistochemical method, and the mRNA expressions of NF-κB p65 was detected in-situ hybridization.Results: The inflammation grades and the expressions of NF-κB p65 mRNA in gastric mucosa of the model group were markedly higher than those of the control group (P<0.05). The inflammation grades of gastric mucosa and the expressions of NF-κB p65 mRNA in gastric mucosa the FCK extract group are significantly lower than those of the model group, and the FCK extract group at 8.64g/kg could greatly increase the serum levels of EGF and the expressions of EGFR in gastric mucosa. High EGF level was found in FCK extract group at 4.32g/kg, but low in FCK extract groups at 2.16g/kg. There were no marked differences among the rats from control group, model group and FCK extract group on ratio of Ll/L2 (P>0.05).Conclusions: FCK extract could alleviate mucosal inflammation by down regulating the expressions of NF-κB p65 mRNA and promote tissue repair by up regulating EGFR expression in gastric mucosa cell.Keywords: chronic gastritis; fengliao-changwei-kang extract; epidermal growth factor receptor; nuclear factor kappa B

    Involvement of AmphiREL, a Rel-like gene identified in Brachiastoma belcheri, in LPS-induced response: Implication for evolution of Rel subfamily genes

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    AbstractRel/NF-κB family genes are important transcriptional factors regulating vital activities of immunity response, but no Rel/NF-κB gene has been identified in amphioxus. In this study, we have not only identified and characterized a Rel-like gene from Brachiastoma belcheri, but also extensively studied the evolution of Rel gene subfamily. We found that: 1) the amphioxus genome contains an AmphiREL gene encoding a Rel/NF-κB homolog, and AmphiREL gene was involved in the innate immune response of LPS stimulation in amphioxus. 2) Gene synteny comparison and structure comparison suggested that AmphiREL is an orthologous gene of human RELB, and is a paralogous gene of human RELA and REL. 3) Structural changes of Rel subfamily proteins are diverse during the evolution process, and imply their functional diversity. 4) The Rel subfamily genes have undergone very strong purifying selection. Together, our results provide important clues for understanding the evolution and function of Rel subfamily genes

    Polarization bandgaps and fluid-like elasticity in fully solid elastic metamaterials

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    Elastic waves exhibit rich polarization characteristics absent in acoustic and electromagnetic waves. By designing a solid elastic metamaterial based on three-dimensional anisotropic locally resonant units, here we experimentally demonstrate polarization bandgaps together with exotic properties such as 'fluid-like' elasticity. We construct elastic rods with unusual vibrational properties, which we denote as 'meta-rods'. By measuring the vibrational responses under flexural, longitudinal and torsional excitations, we find that each vibration mode can be selectively suppressed. In particular, we observe in a finite frequency regime that all flexural vibrations are forbidden, whereas longitudinal vibration is allowed-a unique property of fluids. In another case, the torsional vibration can be suppressed significantly. The experimental results are well interpreted by band structure analysis, as well as effective media with indefinite mass density and negative moment of inertia. Our work opens an approach to efficiently separate and control elastic waves of different polarizations in fully solid structures.G.M., C.F., and P.S. acknowledge the support of the Hong Kong Research Grants Council (Grant No. AoE/P-02/12). Y.L. and G.W. thank the State Key Program for Basic Research of China (No. 2014CB360505, No. 2012CB921501), National Natural Science Foundation of China (No. 11374224, No. 61671314), and a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). J.C. acknowledges the support from the European Research Council (ERC) through the Starting Grant 714577 PHONOMETA

    Numerical Simulation and Flow Behaviors of Taylor Flow in Co-Axial Rotating Cylinder

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    This work uses the incense as the trace of flow to perform flow visualization of Taylor-Couette flow. The test section was made of a rotational inner cylinder and a stationary outer cylinder. Two modes of inner cylinder were employed. One had a smooth wall, and the other had an annular ribbed wall. Clear and complete Taylor vortices were investigated in both smooth and ribbed wall of co-axial rotating cylinder. Besides, a steady-state, axis-symmetrical numerical model was provided to simulate the present flow field. The Taylor vortices could be also successfully predicted. However, the assumption of steady-state flow might reduce some flow perturbations, resulting in an over-predicted critical Taylor number. A transient simulation is suggested to be performed in the future

    Seasonal variation of total carotenoids content in the tissues of male and female golden noble scallops Chlamys nobilis

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    The noble scallop Chlamys nobilis is an economically important edible marine bivalve that has been cultivated in the Southern Sea of China since the 1980s. Noble scallops, particularly the golden scallops, are rich in carotenoids, are of interest for their potential beneficial uses in human healthcare, food processing and pharmaceuticals. However, very little is known about the seasonal variation of total carotenoids content (TCC) in the golden scallops. Therefore, present study was conducted to determine the seasonal variation of TCC in the tissues of male and female of golden scallops. The results of present study revealed that the TCC in adductor, mantle and gonads of golden scallops were ranged from 16.79 to 138.86 μg/ g, 92.86 to 312.98 μg/ g, and 71.5 to 750.0 μg/ g, respectively. Generally, the gonads of golden scallops contain the highest TCC, followed by the mantle and adductor. In comparison of male and female scallops, TCC in the same tissue (except for gonad) was not statistically significant. However, female gonads contain much higher TCC than male gonads. The temporal variation of the TCC in golden scallops showed the highest in March to April and the lowest in October. The findings of current study can be very useful for scallop farmers and industry to determine the best harvest time to obtain the highest quality of golden scallops with high TCC

    Species and sex comparisons of karyotype and genome size in two <em>Kurixalus tree</em> frogs (Anura, Rhacophoridae)

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    Kurixalus is a rhacophorid genus of tree frogs that are similar in morphology but vary in reproductive behavior. We investigated the cytogenetic features and genome size using conventional G-banding, C-banding and silver-staining techniques, fluorescence in situ hybridization (FISH), and flow cytometry in two representatives of Kurixalus (K. eiffingeri Boettger, 1895 and K. idiootocus Kuramoto and Wang, 1987) and compared the data between species and sex. The two Kurixalus species share a diploid chromosome number 2n = 26 and fundamental number FN = 52. Prominent differences between species were noted in the distribution of secondary constriction (SC)/nucleolus organizer region (NOR) and dense heterochromatin. Other interspecies differences including variations in the number of metacentric and submetacentric chromosomes and staining intensity of heterochromatin were also found. The cytogenetic results are consistent with the observed differences in their genome sizes. FISH with telomeric motif (TTAGGG)n for both species detected signals in the terminal regions. Intersex comparisons revealed no differences in terms of cytogenetic features and genome size in the two species. Despite the apparent highly conserved diploid chromosome number, data on the karyotype microstructure characterize the cytogenetic profile of the two Kurixalus species that contribute to clarification of the chromosomal homologies and the rearrangement mechanisms occurring during the karyotype evolution of Kurixalus. No heteromorphic chromosome pair in both species is consistent with the view that homomorphic sex chromosome is common in amphibians
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