Photonic Generation of Ultrawideband Signals Jianping Yao, Jianping Yao; Fei Zeng, Fei Zeng; Qing Wang, Qing Wang
Journal of lightwave technology,
11/2007, Letnik:
25, Številka:
11
Journal Article
Recenzirano
Ultrawideband (UWB) that is regulated by the Federal Communications Commission (FCC) for short-range high-throughput wireless communication and sensor networks with advantageous features, such as ...immunity to multipath fading, extremely short time duration, being carrier free, and having low duty cycle, wide bandwidth, and low power spectral density, has been a topic of interest recently. By wireless transmission, UWB communications systems can only operate in a short distance of a few meters to tens of meters. The convergence of UWB and optical fiber distribution techniques, or UWB over fiber, offers the availability of undisrupted service across different networks and eventually achieves high-data-rate access at any time and from any place. To distribute the UWB signals over the optical fiber, it is also desirable that the UWB signals can be generated in the optical domain without having extra electrical-to-optical conversion. In addition, UWB signals that are generated in the optical domain can be easily tailored to have a spectrum that meets the FCC-specified spectral mask. In this paper, techniques to generate UWB signals in the optical domain will be discussed. These techniques are divided into three categories, with the generation of UWB signals based on the following: 1) phase-modulation-to-intensity-modulation conversion; 2) a photonic microwave delay-line filter; and 3) optical spectral shaping and dispersion-induced frequency-to-time mapping. The areas for future development and the challenge of implementation of these techniques for practical applications will also be discussed.
The response to immune checkpoint inhibitors (ICIs) monotherapy remains unsatisfactory in patients with NSCLC. Thus, combining ICIs with other potential modalities is of great significance to enhance ...the response of single drug alone. Here, we identified that HIF-1α inhibition was capable of promoting anti-tumor immunity in NSCLC. We applied NSCLC cell lines and mouse models to evaluate the synergy of combined HIF-1α inhibition and PD-1 blockade on tumor growth and the function of tumor infiltrating lymphocytes (TILs). Public datasets were utilized to investigate patients' prognosis based on expressions of HIF-1α and LOXL2 as well as EMT-associated markers and CD8+ TILs. Moreover, we explored the correlation between HIF-1α and LOXL2 levels and CD8+ TILs in tumor samples from patients with NSCLC by immunohistochemistry, as well as their association to patients’ survival. In vitro, PX-478, an HIF-1α inhibitor, promoted tumor cell apoptosis induced by T cells when combined with ICIs. Furthermore, mice treated with PX-478 and anti-PD-1 antibodies exhibited a marked delay in tumor growth and prolonged survival, which correlated with increased TILs and granzyme B secretion. Besides, patients with high HIF-1α expression exhibited high levels of EMT-related markers and low TILs, indicating an immunosuppressive phenotype. Mechanistically, we observed that HIF-1α inhibition suppressed the EMT phenotypes induced by hypoxia and further alleviated tumor immunosuppression, which was related to blockage of HIF-1α/LOXL2 signaling pathway. In summary, we identified that HIF-1α inhibition could synergize with anti-PD-1 to impair tumor growth in vitro and in vivo. Our data suggest that HIF-1α inhibitors represent a promising treatment to enhance anti-tumor immunity and provide preclinical rationale to evaluate the combination of ICIs with HIF-1α inhibition clinically in NSCLC.
•Attenuating hypoxia-induced EMT phenotypes may increase tumor infiltrated activating T cells.•Downregulation of EMT by HIF-1α inhibition was associated with suppression of the HIF-1α-LOXL2 signaling pathway.•The combination of HIF-1α inhibition and ICIs can induce significant tumor regression and improve efficacy of immunotherapy.
We propose a novel approach to generating ultrawideband impulse radio signals in the optical domain. The proposed system consists of a laser source, an electrooptic phase modulator (EOPM), a fiber ...Bragg grating (FBG), and a photodetector (PD). The light source is phase modulated by an electrical Gaussian pulse train via the EOPM. The optical phase modulation to intensity modulation conversion is achieved by reflecting the phase modulated light at the slopes of the FBG that serves as a frequency discriminator. Electrical monocycle or doublet pulses are obtained at the output of the PD by locating the wavelength of the optical carrier at the linear or the quadrature slopes of the FBG reflection spectrum. The use of the proposed configuration to implement pulse polarity and pulse shape modulation in the optical domain is discussed. Experimental measurements in both temporal and frequency domains are presented
With the continuous development of society, people have entered a new era. People’s material needs have been basically met, and people are paying more and more attention to spiritual life and ...ecological health. After the problem of food and clothing was solved, people began to pursue leisure sports, which is a brand new direction of consumption. The coastal area has taken the lead in developing the exciting experience of leisure sports. The leisure environment in this area is very romantic and can also bring people a very exciting experience. In recent years, many people have gone to the coastal area to experience this kind of leisure sports, which has also promoted tourism. The economic development of the city in the coastal area has promoted the change of its development mode. We monitor rainfall in coastal areas, which plays an important role in the development of leisure sports. If we can predict the weather changes in advance, we can make timely countermeasures, make reasonable plans for sports time, and make reasonable arrangements for sports content. In this paper, the relationship between cloud cover changes and rainfall data is obtained by monitoring remote sensing cloud images, and a corresponding model is established. This paper also designs some cloud image parameters, uses the corresponding algorithm to explore the relationship between cloud image and rainfall, improves and optimizes the algorithm combined with matrix characteristics, and finally proposes a more efficient algorithm. After a series of experiments, it is proved that the algorithm proposed in this paper has higher timeliness and better accuracy. The research results of this project have been applied to the forecast of rainfall trends in coastal areas. At the same time, certain suggestions and strategies have been put forward for the development of leisure sports activities in coastal areas, which also laid the foundation for the development of subsequent leisure activities.
Colon cancer is the third most common cancer and the second leading cause of cancer‐related death worldwide. Dysregulated RNA splicing factors have been reported to be associated with tumorigenesis ...and development in colon cancer. In this study, we interrogated clinical and RNA expression data of colon cancer patients from The Cancer Genome Atlas (TCGA) dataset and the Gene Expression Omnibus (GEO) database. Genes regulating RNA splicing correlated with survival in colon cancer were identified and a risk score model was constructed using Cox regression analyses. In the risk model, RNA splicing factor peroxisome proliferator‐activated receptor‐γ coactivator‐1α (PPARGC1) is correlated with a good survival outcome, whereas Cdc2‐like kinase 1(CLK1), CLK2, and A‐kinase anchor protein 8‐like (AKAP8L) with a bad survival outcome. The risk model has a good performance for clinical prognostic prediction both in the TCGA cohort and the other two validation cohorts. In the tumor microenvironment (TME) analysis, the immune score was higher in the low‐risk group, and TME‐related pathway gene expression was also higher in low‐risk group. We further verified the mRNA and protein expression levels of these four genes in the adjacent nontumor, tumor, and liver metastasis tissues of colon cancer patients, which were consistent with bioinformatics analysis. In addition, knockdown of AKAP8L can suppress the proliferation and migration of colon cancer cells. Animal studies have also shown that AKAP8L knockdown can inhibit tumor growth in colon cancer in vivo. We established a prognostic risk model for colon cancer based on genes related to RNA splicing regulation and uncovered the role of AKAP8L in promoting colon cancer progression.
we interrogated transcriptome and the corresponding clinical data of colon cancer patients from the The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) dataset to investigate prognosis associated splicing‐related signature.And our study established a prognostic risk model based on RNA splicing regulation related genes for colon cancer.
Enhancing the catalytic activity of Pt‐based alloy by a rational structural design is the key to addressing the sluggish kinetics of direct alcohol fuel cells. Herein, a facile one‐pot method is ...reported to synthesize PtCuRu nanoflowers (NFs). The synergetic effect among Pt, Cu, and Ru can lower the d‐band center of Pt, regulate the morphology, generate Ru‐rich edge, and allow the exposure of more high index facets. The optimized Pt0.68Cu0.18Ru0.14 NFs exhibit outstanding electrocatalytic performances and excellent anti‐poisoning abilities. The specific activities for the methanol oxidation reaction (MOR) (7.65 mA cm−2) and ethanol oxidation reaction (EOR) (7.90 mA cm−2) are 6.0 and 7.1 times higher than commercial Pt/C, respectively. The CO stripping experiment and the chronoamperometric (5000 s) demonstrate the superior anti‐poisoning property and durability performance. Density functional theory calculations confirm that high metallization degree leads to the decrease of d‐band center, the promotion of oxidation of CO, and improvement of the inherent activity and anti‐poisoning ability. A Ru‐rich edge exposes abundant high index facets to accelerate the reaction kinetics of rate‐determining steps by decreasing the energy barrier for forming *HCOOH (MOR) and CC bond breaking (EOR).
The PtCuRu nanoflowers (NFs) with different morphology are determined by the amount of Ru. The optimized Pt0.68Cu0.18Ru0.14 NFs with Ru‐rich edge and high‐index facets exhibit outstanding catalytic activity and stability for both the methanol and ethanol oxidation reaction, providing the feasibility of designing ternary alloy bifunctional catalyst for the construction of high‐performance direct alcohol fuel cells.
The ribosomally synthesized and post-translationally modified peptide (RiPPs) class of natural products has undergone significant expansion due to the rapid growth in genome sequencing data. Using a ...bioinformatics approach, we identify the dehydrazoles, a novel class of hypermodified RiPPs that contain both side chain dehydration of Ser residues, and backbone heterocyclization at Ser, Thr, and Cys residues to the corresponding azol(in)es. Structure elucidation of the hypermodified peptide carnazolamide, a representative class member, shows that 18 post-translational modifications are installed by just five enzymes. Complete biosynthetic reconstitution demonstrates that dehydration is carried out by an unusual DUF4135 dehydration domain fused to a zinc-independent cyclase domain (CcaM). We demonstrate that CcaM only modifies Ser residues that precede an azole in the core peptide. As heterocyclization removes the carbonyl following the Ser residue, CcaM likely catalyzes dehydration without generating an enolate intermediate. Additionally, CcaM does not require the leader peptide, and this core-dependence effectively sets the order for the biosynthetic reactions. Biophysical studies demonstrate direct binding of azoles to CcaM consistent with this azole moiety-dependent dehydration. Bioinformatic analysis reveals more than 50 related biosynthetic gene clusters that contain additional catalysts that may produce structurally diverse scaffolds.
Lanthipeptides are a class of cyclic peptides characterized by the presence of one or more lanthionine (Lan) or methyllanthionine (MeLan) thioether rings. These cross-links are produced by ...α,β-unsaturation of Ser or Thr residues in peptide substrates by dehydration, followed by a Michael-type conjugate addition of Cys residues onto the dehydroamino acids. Lanthipeptides may be broadly classified into at least five different classes, and the biosynthesis of classes I–IV lanthipeptides requires catalysis by LanC cyclases that control both the site-specificity and the stereochemistry of the conjugate addition. In contrast, there are no current examples of LanCs that occur in class V biosynthetic clusters, despite the presence of lanthionine rings in these compounds. In this work, bioinformatics-guided co-occurrence analysis identifies more than 240 putative class V lanthipeptide clusters that contain a LanC cyclase. Reconstitution studies demonstrate that the cyclase-catalyzed product is notably distinct from the product formed spontaneously. Stereochemical analysis shows that the cyclase diverts the final product to a configuration that is distinct from one that is energetically favored. Structural characterization of the final product by multi-dimensional NMR spectroscopy reveals that it forms a helical stapled peptide. Mutational analysis identified a plausible order for cyclization and suggests that enzymatic rerouting to the final structure is largely directed by the construction of the first lanthionine ring. These studies show that lanthipeptide cyclases are needed for the biosynthesis of some constrained peptides, the formations of which would otherwise be energetically unfavored.
Background and Purpose
PDGF‐BB is an angiogenic factor involved in cardiovascular diseases. Here, we investigated the possible effects of activation of the nicotinic ACh receptor α7 subtype (α7nAChR) ...on PDGF‐BB‐induced proliferation and migration in vascular smooth muscle cells (VSMCs).
Experimental Approach
PNU‐282987, a selective α7nAChR pharmacological agonist, was used to activate α7nAChR. The influences of α7nAChR activation on PDGF‐BB‐induced proliferation and migration, as well as the phosphorylation of focal adhesion kinase (FAK)/Src, a pro‐migration signalling pathway, were determined in VSMCs. A variety of biochemical assays were applied to explore the underlying molecular mechanisms.
Key Results
PDGF‐BB induced pronounced migration and proliferation of VSMCs. Activation of α7nAChRs by PNU‐282987 blocked PDGF‐BB‐induced migration but not proliferation in wild‐type (WT) VSMCs, whereas this effect was absent in α7nAChR‐knockout VSMCs. Accordingly, PNU‐282987 attenuated PDGF‐BB‐induced phosphorylation of FAKTyr397 and SrcTyr416 in WT VSMCs. Mechanistically, PNU‐282987 suppressed PDGF‐BB‐induced oxidative stress, as demonstrated by the alterations in ROS, H2O2 content, superoxide anion and total antioxidant activity. A sirtuin 3 (SIRT3) inhibitor 3‐(1H‐1,2,3‐triazol‐4‐yl) pyridine or shRNA‐mediated SIRT3 knockdown abolished the inhibitory effect of PNU‐282987. PNU‐282987 did not modulate SIRT3 protein expression but enhanced mitochondrial SIRT3 deacetylase activity. In line with this action, PNU‐282987 enhanced the deacetylation of mitochondrial FoxO3. Lastly, PNU‐282987 corrected the PDGF‐BB‐induced mitochondrial dysfunction by increasing mitochondrial citrate synthase activity, ATP content and nicotinamide adenine dinucleotide pool.
Conclusions
Pharmacological activation of α7nAChRs inhibits PDGF‐BB‐induced VSMC migration by activating the mitochondrial deacetylase SIRT3, implying an important role for α7nAChRs in mitochondria biology and PDGF‐related diseases.
Linked Articles
This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc
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