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Precoding for Multiuser Load-Modulated Arrays on the Downlink
No full textLoad-modulated arrays (LMA) use a single central power amplifier (CPA) and tune (modulate) the antenna loads according to the information signal, eliminating the need for traditional RF chains (consisting of DACs, mixers, and filters) at the transmitter. We consider LMAs in multiuser communication on the downlink. A base station is equipped with an LMA to transmit data to multiple users. Toward designing a precoder for this system, the single CPA at the transmitter necessitates the consideration of an instantaneous sum power constraint on the transmitted signal. We propose a precoding scheme which addresses this constraint. The proposed scheme, based on block diagonalization, is such that all the precoded signal vectors lie on the surface of a multidimensional hypersphere. This scheme not only satisfies the power constraint, but also aids power-efficient operation of the CPA due to its constant envelope nature
BET proteins in abnormal metabolism, inflammation, and the breast cancer microenvironment
No full textObesity and its associated pathology Type 2 diabetes are two chronic metabolic and inflammatory diseases that promote breast cancer progression, metastasis, and poor outcomes. Emerging critical opinion considers unresolved inflammation and abnormal metabolism separately from obesity; settings where they do not co-occur can inform disease mechanism. In breast cancer, the tumor microenvironment is often infiltrated with T effector and T regulatory cells programmed by metabolic signaling. The pathways by which tumor cells evade immune surveillance, immune therapies, and take advantage of antitumor immunity are poorly understood, but likely depend on metabolic inflammation in the microenvironment. Immune functions are abnormal in metabolic disease, and lessons learned from preclinical studies in lean and metabolically normal environments may not translate to patients with obesity and metabolic disease. This problem is made more urgent by the rising incidence of breast cancer among women who are not obese but who have metabolic disease and associated inflammation, a phenotype common in Asia. The somatic BET proteins, comprising BRD2, BRD3, and BRD4, are newcritical regulators of metabolism, coactivate transcription of genes that encode proinflammatory cytokines in immune cell subsets infiltrating the microenvironment, and could be important targets in breast cancer immunotherapy. These transcriptional coregulators are well known to regulate tumor cell progression, but only recently identified as critical for metabolism, metastasis, and expression of immune checkpoint molecules. We consider interrelationships among metabolism, inflammation, and breast cancer aggressiveness relevant to the emerging threat of breast cancer among women with metabolic disease, but without obesity
Algorithms and Bounds for Very Strong Rainbow Coloring
No full textA well-studied coloring problem is to assign colors to the edges of a graph G so that, for every pair of vertices, all edges of at least one shortest path between them receive different colors. The minimum number of colors necessary in such a coloring is the strong rainbow connection number (src(G)) of the graph. When proving upper bounds on src(G), it is natural to prove that a coloring exists where, for every shortest path between every pair of vertices in the graph, all edges of the path receive different colors. Therefore, we introduce and formally define this more restricted edge coloring number, which we call very strong rainbow connection number (vsrc(G)). In this paper, we give upper bounds on vsrc(G) for several graph classes, some of which are tight. These immediately imply new upper bounds on src(G) for these classes, showing that the study of vsrc(G) enables meaningful progress on bounding src(G). Then we study the complexity of the problem to compute vsrc(G), particularly for graphs of bounded treewidth, and show this is an interesting problem in its own right. We prove that vsrc(G) can be computed in polynomial time on cactus graphs; in contrast, this question is still open for src(G). We also observe that deciding whether vsrc(G) = k is fixed-parameter tractable in k and the treewidth of G. Finally, on general graphs, we prove that there is no polynomial-time algorithm to decide whether vsrc(G) <= 3 nor to approximate vsrc(G) within a factor n(1-epsilon), unless P = NP
DNA Repair Gene XRCC1 and XPD Polymorphisms and Gastric Cancer Risk: A Case-Control Study Outcome from Kashmir, India
No full textCoding polymorphisms in several DNA repair genes have been reported to affect the DNA repair capacity and are associated with genetic susceptibility to many human cancers, including gastric cancer. An understanding of these DNA repair gene polymorphisms might assess not only the risk of humans exposed to environmental carcinogens but also their responses to different therapeutical approaches, which target the DNA repair pathway. In the present study, polymorphic variants of two DNA repair genes, XRCC1 Arg399Gln and XPD Lys751Gln, were chosen to be studied in association with gastric cancer susceptibility in the Kashmiri population. A total of 180 confirmed cases of gastric cancer (GC) and 200 hospital-based controls from Government Shri Maharaja Hari Singh Hospital, Srinagar, were included in the study. The genotyping for XRCC1 and XPD genes was carried out by polymerase chain reaction-restriction fragment length polymorphism. We found that tobacco smoking is strongly associated with GC risk (OR = 25.65; 95% CI: 5.49-119.7). However, we did not find any association of polymorphism of XRCC1 Arg399Gln (OR = 1.56; 95% CI: 0.32-7.82) and XPD Lys751Gln (OR = 0.46; CI: 0.10-2.19) with GC risk in the study population. The combination of genotypes and gender stratification of XRCC1 and XPD genotypic frequency did not change the results. Consumption of large volumes of salt tea was also not associated with gastric cancer risk. Polymorphic variants of XRCC1 Arg399Gln and XPD Lys751Gln are not associated with the risk of gastric cancer in the Kashmiri population. However, replicative studies with larger sample size are needed to substantiate the findings
Cell type-specific expression profiling unravels the development and evolution of stinging cells in sea anemone
No full textBackground: Cnidocytes are specialized cells that define the phylum Cnidaria. They possess an ``explosive'' organelle called cnidocyst that is important for prey capture and anti-predator defense. An extraordinary morphological and functional complexity of the cnidocysts has inspired numerous studies to investigate their structure and development However, the transcriptomes of the cells bearing these unique organelles are yet to be characterized, impeding our understanding of the genetic basis of their biogenesis. Results: In this study, we generated a nematocyte reporter transgenic line of the sea anemone Nematostella vectensis using the CRISPR/Cas9 system. By using a fluorescence-activated cell sorter (FACS), we have characterized cell type-specific transcriptomic profiles of various stages of cnidocyte maturation and showed that nematogenesis (the formation of functional cnidocysts) is underpinned by dramatic shifts in the spatiotemporal gene expression. Among the genes identified as upregulated in cnidocytes were Cnido-Jun and Cnido-Fos1-cnidarian-specific paralogs of the highly conserved c-Jun and c-Fos proteins of the stress-induced AP-1 transcriptional complex. The knockdown of the cnidocyte specific c-Jun homolog by microinjection of morpholino antisense oligomer results in disruption of normal nematogenesis. Conclusions: Here, we show that the majority of upregulated genes and enriched biochemical pathways specific to cnidocytes are uncharacterized, emphasizing the need for further functional research on nematogenesis. The recruitment of the metazoan stress-related transcription factor c-Fos/c-Jun complex into nematogenesis highlights the evolutionary ingenuity and novelty associated with the formation of these highly complex, enigmatic, and phyletically unique organelles. Thus, we provide novel insights into the biology, development and evolution of cnidocytes
The vertebrate limb: An evolving complex of self-organizing systems
No full textThe paired appendages (fins or limbs) of jawed vertebrates contain an endoskeleton consisting of nodules, bars and, in some groups, plates of cartilage, or bone arising from replacement of cartilaginous templates. The generation of the endoskeletal elements occurs by processes involving production and diffusion of morphogens, with, variously, positive and negative feedback circuits, adhesion, and receptor dynamics with similarities to the mechanism for chemical pattern formation proposed by Alan Turing. This review presents a unified interpretation of the evolution and functioning of these mechanisms. Studies are described indicating that protocondensations, compacted mesenchymal cell aggregates that prefigure the appendicular skeleton, arise through the adhesive activity of galectin-1, a matricellular protein with skeletogenic homologs in all jawed vertebrates. In the cartilaginous and lobe-finned fishes (and to a variable extent in ray-finned fishes) it additionally cooperates with an isoform of galectin-8 to constitute a self-organizing network capable of generating arrays of preskeletal nodules, bars and plates. Further, in the tetrapods, a putative galectin-8 control module was acquired that may have enabled proximodistal increase in the number of protocondensations. In parallel to this, other self-organizing networks emerged that acted, via Bmp, Wnt, Sox9 and Runx2, as well as transforming factor-beta and fibronectin, to convert protocondensations into skeletal tissues. The progressive appearance and integration of these skeletogenic networks over evolution occurred in the context of an independently evolved system of Hox protein and Shh gradients that interfaced with them to tune the spatial wavelengths and refine the identities of the resulting arrays of elements. (C) 2018 Elsevier Ltd. All rights reserved
Media-Based Modulation for the Uplink in Massive MIMO Systems
No full textMedia-based modulation (MBM) is an attractive modulation scheme, which can achieve high data rates using multiple radio frequency (RF) mirrors (parasitic elements) and fewer transmit antennas/RF chains. In this paper, we consider MBM for the uplink in a massive multiple input multiple output (MIMO) system consisting of tens of users and tens to hundreds of base station receive antennas. Each user employs MBM with one transmit antenna and multiple RF mirrors placed near it. The ON/OFF status of the RF mirrors conveys information bits in addition to the bits conveyed through conventional modulation symbols. We show that the multiuser MBM (MU-MBM) system achieves very good bit error performance compared to other conventional multiuser MIMO systems. We propose two types of low-complexity detection algorithms for massive MU-MBM systems. The first type is based on compressive sensing that exploits the inherent sparse nature of the MBM transmit vectors. The second type is based on message passing that performs both detection and channel estimation at low computational complexity. To do this, it exploits the ``channel hardening'' phenomenon that occurs in large MIMO channels. It is shown that the proposed algorithms are not only computationally less complex, but also provide very good bit error performance in massive MU-MBM systems
A unique methodology of objective regime classification for two phase flow based on the intensity of digital images
No full textIt is proposed that digital images can uniquely be used to identify the regimes during the flow of mixed phases using the temporal and spatial features of the flow. To demonstrate the potential of the postulation, the digital videographs of gas-liquid two-phase flow through a 50 mm diameter vertical tube are considered. The intensity of each pixel is estimated through image processing. The time series of area-averaged intensity contains unique features to identify the flow regimes like that obtained from any conventional sensor. Further, the intensity values along lines in the direction of flow and perpendicular to it can be utilised to produce the spatio-temporal plots and the time history of the interfacial evolution which give signatures of the flow phenomenon hitherto unavailable from the use of conventional sensors. The methodology, compared successfully with the well-established flow regime map has enough potential to be applied for multiphase flow of various types