4,993 research outputs found

    1α, 25-dihydroxyvitamin D3 suppresses differentiation, maturation and activation of dendritic cells from patients with systemic lupus erythematosus

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    BACKGROUND: Dendritic cells (DC), professional antigen presenting cells, are believed to play a crucial role in the pathogenesis of systemic lupus erythematosus (SLE). 1α, 25-dihydroxyvitamin D3 (VitD3), in addition to its effect on bone metabolism, has been increasingly recognised to have immunomodulatory effects. OBJECTIVE: To examine the effect of VitD3 on the differentiation, maturation, and activation of DCs in SLE patients. METHODS: CD14+ monocyte–derived DCs from SLE patients and age- and sex-matched controls were derived from growth medium cultured with IL-4, GM-CSF. Mature DCs were induced by addition of lipopolysaccharide and tumour necrosis factor-α in the presence or absence of VitD3 (1×10-10 M) and/or dexamethasone (1×10-6 M). The expression of CD1a, a DC marker and markers of maturation and co-stimulatory molecules such as CD80, CD86, CD40, HLA-DR and CD83 were examined by flow cytometry. After stimulation of DCs with CD40L for 24 hours, the production of pro-inflammatory cytokines including IL-12 and IL-6, were measured by ELISA kits. RESULTS: VitD3 suppresses differentiation of monocytes into DCs as showed by the decreased expression of CD1a (P<0.05). VitD3 inhibits the expression of maturation markers including CD86, CD40 and CD83 (P<0.05), but not CD80 and HLA-DR. This effect was more marked in SLE patients (n=14) than controls (n=9). In combination with dexamethasone, VitD3 displayed more potent immunosuppressive effect on DCs. Under the effect of VitD3, stimulated DCs produced less of IL-12 (3.1 vs 10.4 pg/mL, P=0.02) and IL-6 (216.0 vs 224.0 pg/mL, P=0.21) in SLE patients as well as controls (8.0 vs 36.6 μg/mL, P=0.01 for IL-12) and (380.7 vs 415.2 pg/mL, P=0.04 for IL-6). CONCLUSION: VitD3 is found to inhibit differentiation, maturation, and activation of DCs in vitro in both SLE patients and controls and may be considered as immunomodulatory agent in the treatment of SLE.published_or_final_versionThe 15th Medical Research Conference (15th MRC), Department of Medicine, University of Hong Kong, Hong Kong, 16 January 2010. In Hong Kong Medical Journal, 2010, v. 16 n. 1, suppl. 1, p. 57, abstract no. 9

    Activating mechanism of transcriptor NF-kappaB regulated by hepatitis B virus X protein in hepatocellular carcinoma

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    Aim: To investigate the mechanism and significance of NF-κB activation regulated by hepatitis B virus X protein (HBx) in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). Methods: The expression levels of HBx, p65, IκB-α and ubiquitin were detected by immunohistochemistry in HCC tissue microarrays (TMA) respectively, and IκB-α was detected by Western blot in HCC and corresponding liver tissues. Results: The percentage of informative TMA samples was 98.8% in 186 cases with a total of 367 samples. Compared with corresponding liver tissues (60.0%), the HBx expression was obviously decreased in HBV-associated HCC (47.9%, u=2.24, P<0.05). On the contrary, the expressions of p65 (20.6% vs 45.3%, u=4.85, P<0.01) and ubiquitin (8.9% vs 59.0%, u=9.68, P<0.01 ) were notably elevated in HCC. In addition, IκB-α had a tendency to go up. Importantly, positive relativity was observed between HBx and p65 (χ2=10.26, P<0.01), p65 and IκB-α (χ2=16.86, P<0.01), IκB-α and ubiquitin (χ2=8.90, P<0.01) in HCC, respectively. Conclusion: Both active and non-active forms of NF-κB are increased in HBV-associated HCC. Variant HBx is the major cause of the enhancement of NF-κB activity. The activation always proceeds in nucleus and the proteasome complexes play an important role in the activation.published_or_final_versio

    Joint Location and Channel Error Optimization for Beamforming Design for Multi-RIS Assisted MIMO System

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    Reconfigurable intelligent surface (RIS) has been proved to be a promising approach to enhance the performance of wireless communication because of its intelligently reconfiguring the passive reflecting elements. Previous works only consider the beamforming design for a fixed RIS location/deployment and perfect channel state information (CSI). While RIS's location and perfect CSI can be further optimized to enhance the system performance. In this paper, the robust beamforming design is investigated for multi-RIS assisted multiuser millimeter wave system with imperfect CSI, where the weighted sum-rate maximization (WSM) problem is formulated. The considered WSM maximization problem includes channel estimation error, bandwidth as well as RIS placement variables, which results in a complicated nonconvex optimization problem. To handle this problem, we decouple the original problem into a series of subproblems, where the location, bandwidth, transmit beamforming and passive beamforming are optimized iteratively. Then, we develop an alternating optimization algorithm based on the penalty and gradient projection (GP) methods to alleviate the performance loss caused by the effect of imperfect CSI. Simulations validate that the proposed scheme can bring significant performance gains, especially considering its high spectral efficiency, when designing the location of RIS and imperfect CSI

    Unsupervised visual domain adaptation via dictionary evolution

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    © 2016 IEEE. In real-word visual applications, distribution mismatch between samples from different domains may significantly degrade classification performance. To improve the generalization capability of classifier across domains, domain adaptation has attracted a lot of interest in computer vision. This work focuses on unsupervised domain adaptation which is still challenging because no labels are available in the target domain. Most of the attention has been dedicated to seeking domain-invariant feature by exploring the shared structure between domains, ignoring the valuable discriminative information contained in the labeled source data. In this paper, we propose a Dictionary Evolution (DE) approach to construct discriminative features robust to domain shift. Specifically, DE aims to adapt a discriminative dictionary learnt based on labeled source samples to unlabeled target samples through a gradual transition process. We show that the learnt dictionary is endowed with cross-domain data representation ability and powerful discriminant capability. Empirical results on real world data sets demonstrate the advantages of the proposed approach over competing methods

    Robust Hybrid Beamforming Design for Multi-RIS Assisted MIMO System with Imperfect CSI

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    Reconfigurable intelligent surface (RIS) has been developed as a promising approach to enhance the performance of fifth-generation (5G) systems through intelligently reconfiguring the reflection elements. However, RIS-assisted beamforming design highly depends on the channel state information (CSI) and RIS&#x2019;s location, which could have a significant impact on system performance. In this paper, the robust beamforming design is investigated for a RIS-assisted multiuser millimeter wave system with imperfect CSI, where the weighted sum-rate maximization problem (WSM) is formulated to jointly optimize transmit beamforming of the BS, RIS placement and reflect beamforming of the RIS. The considered WSM maximization problem includes CSI error, phase shifts matrices, transmit beamforming as well as RIS placement variables, which results in a complicated nonconvex problem. To handle this problem, the original problem is divided into a series of subproblems, where the location of RIS, transmit/reflect beamforming and CSI error are optimized iteratively. Then, a multiobjective evolutionary algorithm is introduced to gradient projection-based alternating optimization, which can alleviate the performance loss caused by the effect of imperfect CSI. Simulation results reveal that the proposed scheme can potentially enhance the performance of existing wireless communication, especially considering a desirable trade-off among beamforming gain, user priority and error factor

    Reverse osmosis pretreatment method for toxicity assessment of domestic wastewater using Vibrio qinghaiensis sp.-Q67

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    Luminescent bacterial test is a fast and sensitive method for acute toxicity assessment of water and wastewater. In this study, an improved toxicity testing method was developed using the freshwater luminescent bacteria Vibrio qinghaiensis sp.-Q67 that involved pretreatment of water samples with reverse osmosis (RO) to eliminate the interferences caused by nutrients in concentrated samples and to improve the reliability and sensitivity of the analysis. Because water samples contain low concentrations of several target toxic substances, rapid acute toxicity testing method that is commonly employed does not achieve enough sensitivity. The proposed RO pretreatment could effectively enrich organic and inorganic substances in water samples to enable a more effective and sensitive toxicity evaluation. The kinetic characteristics of toxicity of raw sewage and secondary effluent were evaluated based on the relative luminescence unit (RLU) curves and time-concentration-effect surfaces. It was observed that when the exposure time was prolonged to 8-h or longer, the bacteria reached the logarithmic growth stage. Hence, the stimulating effects of the coexisting ions (such as Na+, K+, NO3-) in the concentrated samples could be well eliminated. A 10-h exposure time in proposed Q67 test was found to quantitatively evaluate the toxicity of the organic and inorganic pollutants in the RO-concentrated samples. © 2013 Elsevier Inc

    Influence of different functional elements of plasmid pGT232 on maintenance of recombinant plasmids in Lactobacillus reuteri populations in vitro and in vivo

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    Plasmid pGT232 (5.1 kb), an indigenous plasmid of Lactobacillus reuteri 100-23, was determined, on the basis of nucleotide and deduced protein sequence data, to belong to the pC194-pUB110 family of plasmids that replicate via the rolling-circle mechanism. The minimal replicon of pGT232 was located on a 1.7-kb sequence consisting of a double-strand origin of replication and a gene encoding the replication initiation protein, repA. An erythromycin-selectable recombinant plasmid containing this minimal replicon was stably maintained (>97% erythromycin-resistant cells) without antibiotic selection in an L. reuteri population under laboratory growth conditions but was poorly maintained (90% resistant cells) of pGT232-derived plasmids in the lactobacillus population in vivo required an additional 1.0-kb sequence which contained a putative single-strand replication origin (SSO). The SSO of pGT232 is believed to be novel and functions in an orientation-specific manner

    Offset Learning based Channel Estimation for IRS-Assisted Indoor Communication

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    The system capacity can be remarkably enhanced with the help of intelligent reflecting surface (IRS) which has been recognized as a advanced breaking point for the beyond fifth-generation (B5G) communications. However, the accuracy of IRS channel estimation restricts the potential of IRS-assisted multiple input multiple output (MIMO) systems. Especially, for the resource-limited indoor applications which typically contains lots of parameters estimation calculation and is limited by the rare pilots, the practical applications encountered severe obstacles. Previous works takes the advantages of mathematical-based statistical approaches to associate the optimization issue, but the increasing of scatterers number reduces the practicality of statistical approaches in more complex situations. To obtain the accurate estimation of indoor channels with appropriate piloting overhead, an offset learning (OL)-based neural network method is proposed. The proposed estimation method can trace the channel state information (CSI) dynamically with non-prior information, which get rid of the IRS-assisted channel structure as well as indoor statistics. Moreover, a convolution neural network (CNN)-based inversion is investigated. The CNN, which owns powerful information extraction capability, is deployed to estimate the offset, it works as an offset estimation operator. Numerical results show that the proposed OL-based estimator can achieve more accurate indoor CSI with a lower complexity as compared to the benchmark schemes

    Absolute quantitation of DNA methylation of 28 candidate genes in prostate cancer using pyrosequencing

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    This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Aberrant DNA methylation plays a pivotal role in carcinogenesis and its mapping is likely to provide biomarkers for improved diagnostic and risk assessment in prostate cancer (PCa). We quantified and compared absolute methylation levels among 28 candidate genes in 48 PCa and 29 benign prostate hyperplasia (BPH) samples using the pyrosequencing (PSQ) method to identify genes with diagnostic and prognostic potential. RARB, HIN1, BCL2, GSTP1, CCND2, EGFR5, APC, RASSF1A, MDR1, NKX2-5, CDH13, DPYS, PTGS2, EDNRB, MAL, PDLIM4, HLAa, ESR1 and TIG1 were highly methylated in PCa compared to BPH (p < 0.001), while SERPINB5, CDH1, TWIST1, DAPK1, THRB, MCAM, SLIT2, CDKN2a and SFN were not. RARB methylation above 21% completely distinguished PCa from BPH. Separation based on methylation level of SFN, SLIT2 and SERPINB5 distinguished low and high Gleason score cancers, e.g. SFN and SERPINB5 together correctly classified 81% and 77% of high and low Gleason score cancers respectively. Several genes including CDH1 previously reported as methylation markers in PCa were not confirmed in our study. Increasing age was positively associated with gene methylation (p < 0.0001). Accurate quantitative measurement of gene methylation in PCa appears promising and further validation of genes like RARB, HIN1, BCL2, APC and GSTP1 is warranted for diagnostic potential and SFN, SLIT2 and SERPINB5 for prognostic potential
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