General Rank Multiuser Downlink Beamforming With Shaping Constraints Using Real-valued OSTBC

In this paper we consider optimal multiuser downlink beamforming in the presence of a massive number of arbitrary quadratic shaping constraints. We combine beamforming with full-rate high dimensional real-valued orthogonal space time block coding (OSTBC) to increase the number of beamforming weight vectors and associated degrees of freedom in the beamformer design. The original multi-constraint beamforming problem is converted into a convex optimization problem using semidefinite relaxation (SDR) which can be solved efficiently. In contrast to conventional (rank-one) beamforming approaches in which an optimal beamforming solution can be obtained only when the SDR solution (after rank reduction) exhibits the rank-one property, in our approach optimality is guaranteed when a rank of eight is not exceeded. We show that our approach can incorporate up to 79 additional shaping constraints for which an optimal beamforming solution is guaranteed as compared to a maximum of two additional constraints that bound the conventional rank-one downlink beamforming designs. Simulation results demonstrate the flexibility of our proposed beamformer design

Efficient Burst Raw Denoising with Variance Stabilization and Multi-frequency Denoising Network

With the growing popularity of smartphones, capturing high-quality images is of vital importance to smartphones. The cameras of smartphones have small apertures and small sensor cells, which lead to the noisy images in low light environment. Denoising based on a burst of multiple frames generally outperforms single frame denoising but with the larger compututional cost. In this paper, we propose an efficient yet effective burst denoising system. We adopt a three-stage design: noise prior integration, multi-frame alignment and multi-frame denoising. First, we integrate noise prior by pre-processing raw signals into a variance-stabilization space, which allows using a small-scale network to achieve competitive performance. Second, we observe that it is essential to adopt an explicit alignment for burst denoising, but it is not necessary to integrate a learning-based method to perform multi-frame alignment. Instead, we resort to a conventional and efficient alignment method and combine it with our multi-frame denoising network. At last, we propose a denoising strategy that processes multiple frames sequentially. Sequential denoising avoids filtering a large number of frames by decomposing multiple frames denoising into several efficient sub-network denoising. As for each sub-network, we propose an efficient multi-frequency denoising network to remove noise of different frequencies. Our three-stage design is efficient and shows strong performance on burst denoising. Experiments on synthetic and real raw datasets demonstrate that our method outperforms state-of-the-art methods, with less computational cost. Furthermore, the low complexity and high-quality performance make deployment on smartphones possible.Comment: Accepted for publication in International Journal of Computer Visio

Prolonged exposure to bacterial toxins downregulated expression of toll-like receptors in mesenchymal stromal cell-derived osteoprogenitors

<p>Abstract</p> <p>Background</p> <p>Human mesenchymal stromal cells (MSCs, also known as mesenchymal stem cells) are multipotent cells with potential therapeutic value. Owing to their osteogenic capability, MSCs may be clinically applied for facilitating osseointegration in dental implants or orthopedic repair of bony defect. However, whether wound infection or oral microflora may interfere with the growth and osteogenic differentiation of human MSCs remains unknown. This study investigated whether proliferation and osteogenic differentiation of MSCs would be affected by potent gram-positive and gram-negative derived bacterial toxins commonly found in human settings.</p> <p>Results</p> <p>We selected lipopolysaccharide (LPS) from <it>Escherichia coli </it>and lipoteichoic acid (LTA) from <it>Streptococcus pyogenes </it>as our toxins of choice. Our findings showed both LPS and LTA did not affect MSC proliferation, but prolonged LPS challenge upregulated the osteogenic differentiation of MSCs, as assessed by alkaline phosphatase activity and calcium deposition. Because toll-like receptors (TLRs), in particularly TLR4 and TLR2, are important for the cellular responsiveness to LPS and LTA respectively, we evaluated their expression profiles serially from MSCs to osteoblasts by quantitative PCR. We found that during osteogenic differentiation, MSC-derived osteoprogenitors gradually expressed TLR2 and TLR4 by Day 12. But under prolonged incubation with LPS, MSC-derived osteoprogenitors had reduced TLR2 and TLR4 gene expression. This peculiar response to LPS suggests a possible adaptive mechanism when MSCs are subjected to continuous exposure with bacteria.</p> <p>Conclusion</p> <p>In conclusion, our findings support the potential of using human MSCs as a biological graft, even under a bacterial toxin-rich environment.</p

The association of RANTES polymorphism with severe acute respiratory syndrome in Hong Kong and Beijing Chinese

<p>Abstract</p> <p>Background</p> <p>Chemokines play important roles in inflammation and antiviral action. We examined whether polymorphisms of <it>RANTES, IP-10 </it>and <it>Mig </it>affect the susceptibility to and outcome of severe acute respiratory syndrome (SARS).</p> <p>Methods</p> <p>We tested the polymorphisms of <it>RANTES, IP-10 </it>and <it>Mig </it>for their associations with SARS in 495 Hong Kong Chinese SARS patients and 578 controls. Then we tried to confirm the results in 356 Beijing Chinese SARS patients and 367 controls.</p> <p>Results</p> <p><it>RANTES </it>-28 G allele was associated with SARS susceptibility in Hong Kong Chinese (<it>P </it>< 0.0001, OR = 2.80, 95%CI:2.11–3.71). Individuals with <it>RANTES </it>-28 CG and GG genotypes had a 3.28-fold (95%CI:2.32–4.64) and 3.06-fold (95%CI:1.47–6.39) increased risk of developing SARS respectively (<it>P </it>< 0.0001). This -28 G allele conferred risk of death in a gene-dosage dependent manner (<it>P </it>= 0.014) with CG and GG individuals having a 2.12-fold (95% CI: 1.11–4.06) and 4.01-fold (95% CI: 1.30–12.4) increased risk. For the replication of <it>RANTES </it>data in Beijing Chinese, the -28 G allele was not associated with susceptibility to SARS. However, -28 CG (OR = 4.27, 95%CI:1.64–11.1) and GG (OR = 3.34, 95%CI:0.37–30.7) were associated with admission to intensive care units or death due to SARS (<it>P </it>= 0.011).</p> <p>Conclusion</p> <p><it>RANTES </it>-28 G allele plays a role in the pathogenesis of SARS.</p

Ganoderma lucidum polysaccharides can induce human monocytic leukemia cells into dendritic cells with immuno-stimulatory function

<p>Abstract</p> <p>Background</p> <p>Previous studies demonstrated <it>Ganoderma lucidum </it>polysaccharides (GL-PS), a form of bioactive β-glucan can stimulate the maturation of monocyte-derived dendritic cells (DC). The question of how leukemic cells especially in monocytic lineage respond to GL-PS stimuli remains unclear.</p> <p>Results</p> <p>In this study, we used <it>in vitro</it> culture model with leukemic monocytic cell-lines THP-1 and U937 as monocytic effectors cells for proliferation responses and DCs induction. We treated the THP-1 and U937 cells with purified GL-PS (100 μg/mL) or GL-PS with GM-CSF/IL-4. GL-PS alone induced proliferative response on both THP-1 and U937 cells but only THP-1 transformed into typical DC morphology when stimulated with GL-PS plus GM-CSF/IL-4. The transformed THP-1 DCs had significant increase expression of HLA-DR, CD40, CD80 and CD86 though not as high as the extent of normal monocyte-derived DCs. They had similar antigen-uptake ability as the normal monocyte-derived DCs positive control. However, their potency in inducing allogeneic T cell proliferation was also less than that of normal monocyte-derived DCs.</p> <p>Conclusion</p> <p>Our findings suggested that GL-PS could induce selected monocytic leukemic cell differentiation into DCs with immuno-stimulatory function. The possible clinical impact of using this commonly used medicinal mushroom in patients with monocytic leukemia (AML-M4 and M5) deserved further investigation.</p

Reactivation of Epstein–Barr virus by a dual-responsive fluorescent EBNA1-targeting agent with Zn2+-chelating function

EBNA1 is the only Epstein–Barr virus (EBV) latent protein responsible for viral genome maintenance and is expressed in all EBV-infected cells. Zn2+ is essential for oligomerization of the functional EBNA1. We constructed an EBNA1 binding peptide with a Zn2+ chelator to create an EBNA1-specific inhibitor (ZRL5P4). ZRL5P4 by itself is sufficient to reactivate EBV from its latent infection. ZRL5P4 is able to emit unique responsive fluorescent signals once it binds with EBNA1 and a Zn2+ ion. ZRL5P4 can selectively disrupt the EBNA1 oligomerization and cause nasopharyngeal carcinoma (NPC) tumor shrinkage, possibly due to EBV lytic induction. Dicer1 seems essential for this lytic reactivation. As can been seen, EBNA1 is likely to maintain NPC cell survival by suppressing viral reactivation

The interferon gamma gene polymorphism +874 A/T is associated with severe acute respiratory syndrome

BACKGROUND: Cytokines play important roles in antiviral action. We examined whether polymorphisms of IFN-γ,TNF-α and IL-10 affect the susceptibility to and outcome of severe acute respiratory syndrome (SARS). METHODS: A case-control study was carried out in 476 Chinese SARS patients and 449 healthy controls. We tested the polymorphisms of IFN-γ,TNF-α and IL-10 for their associations with SARS. RESULTS: IFN-γ +874A allele was associated with susceptibility to SARS in a dose-dependent manner (P < 0.001). Individuals with IFN-γ +874 AA and AT genotype had a 5.19-fold (95% Confidence Interval [CI], 2.78-9.68) and 2.57-fold (95% CI, 1.35-4.88) increased risk of developing SARS respectively. The polymorphisms of IL-10 and TNF-α were not associated with SARS susceptibility. CONCLUSION: IFN-γ +874A allele was shown to be a risk factor in SARS susceptibility