A Relay Can Increase Degrees of Freedom in Bursty Interference Networks

We investigate the benefits of relays in multi-user wireless networks with bursty user traffic, where intermittent data traffic restricts the users to bursty transmissions. To this end, we study a two-user bursty MIMO Gaussian interference channel with a relay, where two Bernoulli random states govern the bursty user traffic. We show that an in-band relay can provide a degrees of freedom (DoF) gain in this bursty channel. This beneficial role of in-band relays in the bursty channel is in direct contrast to their role in the non-bursty channel which is not as significant to provide a DoF gain. More importantly, we demonstrate that for certain antenna configurations, an in-band relay can help achieve interference-free performances with increased DoF. We find the benefits particularly substantial with low data traffic, as the DoF gain can grow linearly with the number of antennas at the relay. In this work, we first derive an outer bound from which we obtain a necessary condition for interference-free DoF performances. Then, we develop a novel scheme that exploits information of the bursty traffic states to achieve them.Comment: submitted to the IEEE Transactions on Information Theor

Periodontitis-induced systemic inflammation exacerbates atherosclerosis partly via endothelial-mesenchymal transition in mice.

Growing evidence suggests close associations between periodontitis and atherosclerosis. To further understand the pathological relationships of these associations, we developed periodontitis with ligature placement around maxillary molars or ligature placement in conjunction with Porphyromonas gingivalis lipopolysaccharide injection at the ligature sites (ligature/P.g. LPS) in Apolipoprotein E knock out mice and studied the atherogenesis process in these animals. The mice were fed with high fat diet for 11 weeks and sacrificed for analyzing periodontitis, systemic inflammation, and atherosclerosis. Controls did not develop periodontitis or systemic inflammation and had minimal lipid deposition in the aortas, but mice receiving ligature or ligature/P.g. LPS showed severe periodontitis, systemic inflammation, and aortic plaque formation. The aortic plaque contained abundant macrophages and cells expressing both endothelial and mesenchymal cell markers. The severity of periodontitis was slightly higher in mice receiving ligature/P.g. LPS than ligature alone, and the magnitude of systemic inflammation and aortic plaque formation were also notably greater in the mice with ligature/P.g. LPS. These observations indicate that the development of atherosclerosis is due to systemic inflammation caused by severe periodontitis. In vitro, P.g. LPS enhanced the secretion of pro-inflammatory cytokines from macrophages and increased the adhesion of monocytes to endothelial cells by upregulating the expression of adhesion molecules from endothelial cells. Moreover, secretory proteins, such as TNF-α, from macrophages induced endothelial-mesenchymal transitions of the endothelial cells. Taken together, systemic inflammation induced by severe periodontitis might exacerbate atherosclerosis via, in part, causing aberrant functions of vascular endothelial cells and the activation of macrophages in mice

Mispositioned Neurokinin-1 Receptor-Expressing Neurons Underlie Heat Hyperalgesia in Disabled-1 Mutant Mice.

Reelin (Reln) and Disabled-1 (Dab1) participate in the Reln-signaling pathway and when either is deleted, mutant mice have the same spinally mediated behavioral abnormalities, increased sensitivity to noxious heat and a profound loss in mechanical sensitivity. Both Reln and Dab1 are highly expressed in dorsal horn areas that receive and convey nociceptive information, Laminae I-II, lateral Lamina V, and the lateral spinal nucleus (LSN). Lamina I contains both projection neurons and interneurons that express Neurokinin-1 receptors (NK1Rs) and they transmit information about noxious heat both within the dorsal horn and to the brain. Here, we ask whether the increased heat nociception in Reln and dab1 mutants is due to incorrectly positioned dorsal horn neurons that express NK1Rs. We found more NK1R-expressing neurons in Reln-/- and dab1-/- Laminae I-II than in their respective wild-type mice, and some NK1R neurons co-expressed Dab1 and the transcription factor Lmx1b, confirming their excitatory phenotype. Importantly, heat stimulation in dab1-/- mice induced Fos in incorrectly positioned NK1R neurons in Laminae I-II. Next, we asked whether these ectopically placed and noxious-heat responsive NK1R neurons participated in pain behavior. Ablation of the superficial NK1Rs with an intrathecal injection of a substance P analog conjugated to the toxin saporin (SSP-SAP) eliminated the thermal hypersensitivity of dab1-/- mice, without altering their mechanical insensitivity. These results suggest that ectopically positioned NK1R-expressing neurons underlie the heat hyperalgesia of Reelin-signaling pathway mutants, but do not contribute to their profound mechanical insensitivity

Lopsided Schumpeterian Competition and the Superstar Firm Phenomenon

In many industries worldwide, gains from technological innovation have increasingly accrued only to the largest and most resource-endowed companies, while most companies lag in implementation of vital new technologies. As a result, the phenomenon of so-called “superstar” firms that outdistance industry rivals has become a major topic in technology management.https://dc.suffolk.edu/ciclseries/1000/thumbnail.jp

Cognitive Multihop Wireless Sensor Networks over Nakagami-m Fading Channels

This work is supported by the National Science Foundation of China (NSFC) under Grant 61372114, by the National 973 Program of China under Grant 2012CB316005, by the Joint Funds of NSFC-Guangdong under Grant U1035001, and by Beijing Higher Education Young Elite Teacher Project (no. YETP0434)

Control of strain relaxation in tensile and compressive oxide thin films

Tensile and compressive solid-solution thin films based on LaAlO3 and CaZrO3 compositions were grown on perovskite oxide substrates using pulsed laser deposition to study growth mode transitions and strain relaxation. A buried layer of SrRuO3 between the thin film and the SrTiO3 substrate was also introduced to provide an auxiliary embedded strain gauge, which helps identify the critical conditions for the onset of catastrophic strain relaxation events – cracking and dislocation cascades. The results are compared with theoretical predictions to provide guidelines on some general deposition conditions that may be used to obtain smooth, crystalline and defect-free thin films of interest to perovskite-based heterostructures

Strained relaxation in buried SrRuO\u3csub\u3e3\u3c/sub\u3e layer in (Ca\u3csub\u3e1-\u3cem\u3ex\u3c/em\u3e\u3c/sub\u3eSr\u3csub\u3e\u3cem\u3ex\u3c/em\u3e\u3c/sub\u3e) (Zr\u3csub\u3e1-\u3cem\u3ex\u3c/em\u3e\u3c/sub\u3eRu\u3csub\u3e\u3cem\u3ex\u3c/em\u3e\u3c/sub\u3e)O\u3csub\u3e3\u3c/sub\u3e/SrRuO\u3csub\u3e3\u3c/sub\u3e/SrTiO\u3csub\u3e3\u3c/sub\u3e System

A novel relaxation phenomenon occurs in buried SrRuO3 layers in strained (Ca1-xSrx) (Zr1-xRux)O3/SrRuO3/SrTiO3 (001) thin film system. The lightly strained SrRuO3 buried layer is initially clamped by the SrTiO3 substrate. After a heavily strained (Ca1-xSrx) (Zr1-xRux)O3 overlayer is deposited, localized strain relaxation develops in the buried layer. This is manifested by a crosshatch pattern of 〈100〉 corrugations on the surface, due to the slip of 〈100〉 {100} threading dislocations. The phenomenon can be controlled by tuning the growth kinetics and strain energy of the overlayer

Effect of Al addition on microstructure of AZ91D

Casting is a net shape or near net shape forming process so work-hardening will not be applicable for improving properties of magnesium cast alloys. Grain refinement, solid-solution strengthening, precipitation hardening and specially designed heat treatment are the techniques used to enhance the properties of these alloys. This research focusses on grain refinement of magnesium alloy AZ91D, which is a widely used commercial cast alloy. Recently, Al-B based master alloys have shown potential in grain refining AZ91D. A comparative study of the grain refinement of AZ91D by addition of 0.02wt%B, 0.04wt%B, 0.1wt%B, 0.5wt%B and 1.0wt%B of A1-5B master alloy and equivalent amount of solute element aluminium is described in this paper. Hardness profile of AZ91D alloyed with boron and aluminium is compared