Architecture of a Cyberphysical Avatar

REACTION 2012. 1st International workshop on Real-time and distributed computing in emerging applications. December 4th, 2012, San Juan, Puerto Rico.This paper introduces the concept of a cyberphysical avatar which is defined to be a semi-autonomous robotic system that adjusts to an unstructured environment and performs physical tasks subject to critical timing constraints while under human supervision. Cyberphysical avatar integrates the recent advance in three technologies: body-compliant control in robotics, neuroevolution in machine learning and QoS guarantees in realtime communication. Body-compliant control is essential for operator safety since cyberphysical avatars perform cooperative tasks in close proximity to humans. Neuroevolution technique is essential for ”programming” cyberphysical avatars inasmuch as they are to be used by non-experts for a large array of tasks, some unforeseen, in an unstructured environment. QoS-guaranteed realtime communication is essential to provide predictable, boundedtime response in human-avatar interaction. By integrating these technologies, we have built a prototype cyberphysical avatar testbed

A novel 3D non-stationary channel model for 6G indoor visible light communication systems

The visible light communication (VLC) technology has attracted much attention in the research of the sixth generation (6G) communication systems. In this paper, a novel three dimensional (3D) space-time-frequency non-stationary geometry-based stochastic model (GBSM) is proposed for indoor VLC channels. The proposed VLC GBSM can capture unique indoor VLC channel characteristics such as the space-time-frequency non-stationarity caused by large light-emitting diode (LED) arrays in indoor scenarios, long travelling paths, and large bandwidths of visible light waves, respectively. In addition, the proposed model can support special radiation patterns of LEDs, 3D translational and rotational motions of the optical receiver (Rx), and can be applied to angle diversity receivers (ADRs). Key channel properties are simulated and analyzed, including the space-time-frequency correlation function (STFCF), received power, root mean square (RMS) delay spread, and path loss (PL). Simulation results verify the space-time-frequency non-stationarity in indoor VLC channels. In addition, the influence of light source radiation patterns, receiver rotations, and ADRs on channel characteristics have been investigated. Finally, the accuracy and practicality of the proposed model are validated by comparing the simulation result of channel 3dB bandwidth with the existing measurement data. The proposed channel model will play a supporting role in the design of future 6G VLC systems

On the Road to 6G: Visions, Requirements, Key Technologies and Testbeds

Fifth generation (5G) mobile communication systems have entered the stage of commercial development, providing users with new services and improved user experiences as well as offering a host of novel opportunities to various industries. However, 5G still faces many challenges. To address these challenges, international industrial, academic, and standards organizations have commenced research on sixth generation (6G) wireless communication systems. A series of white papers and survey papers have been published, which aim to define 6G in terms of requirements, application scenarios, key technologies, etc. Although ITU-R has been working on the 6G vision and it is expected to reach a consensus on what 6G will be by mid-2023, the related global discussions are still wide open and the existing literature has identified numerous open issues. This paper first provides a comprehensive portrayal of the 6G vision, technical requirements, and application scenarios, covering the current common understanding of 6G. Then, a critical appraisal of the 6G network architecture and key technologies is presented. Furthermore, existing testbeds and advanced 6G verification platforms are detailed for the first time. In addition, future research directions and open challenges are identified for stimulating the on-going global debate. Finally, lessons learned to date concerning 6G networks are discussed

SARS-CoV-2 Host Receptor ACE2 Protein Expression Atlas in Human Gastrointestinal Tract

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects host cells through interactions with its receptor, Angiotensin-converting enzyme 2 (ACE2), causing severe acute respiratory syndrome and death in a considerable proportion of people. Patients infected with SARS-CoV-2 experience digestive symptoms. However, the precise protein expression atlas of ACE2 in the gastrointestinal tract remains unclear. In this study, we aimed to explore the ACE2 protein expression pattern and the underlying function of ACE2 in the gastrointestinal tract, including the colon, stomach, liver, and pancreas.MethodsWe measured the protein expression of ACE2 in the gastrointestinal tract using immunohistochemical (IHC) staining with an ACE2-specific antibody of paraffin-embedded colon, stomach, liver, and pancreatic tissues. The correlation between the protein expression of ACE2 and the prognosis of patients with gastrointestinal cancers was analyzed by the log-rank (Mantel–Cox) test. The influence of ACE2 on colon, stomach, liver, and pancreatic tumor cell line proliferation was tested using a Cell Counting Kit 8 (CCK-8) assay.ResultsACE2 presented heterogeneous expression patterns in the gastrointestinal tract, and it showed a punctate distribution in hepatic cells. Compared to that in parallel adjacent non-tumor tissues, the protein expression of ACE2 was significantly increased in colon cancer, stomach cancer, and pancreatic cancer tissues but dramatically decreased in liver cancer tissues. However, the expression level of the ACE2 protein was not correlated with the survival of patients with gastrointestinal cancers. Consistently, ACE2 did not affect the proliferation of gastrointestinal cancer cells in vitro.ConclusionThe ACE2 protein is widely expressed in the gastrointestinal tract, and its expression is significantly altered in gastrointestinal tumor tissues. ACE2 is not an independent prognostic marker of gastrointestinal cancers

SnO2/Graphene Nanocomposites as High-Capacity Anode Materials for Lithium-Ion Batteries: Synthesis and Electrochemical Performance

Lithium ion batteries as a power source are the most commonly used in the electronic devices and electric vehicles (EV) for grid-energy storage. Anode materials with high specific capacity for lithium ion batteries have been developed in recent years. SnO2 has also been considered as a promising candidate to serve as the anode material for lithium ion batteries due to its high theoretical capacity. But the volume expansion effect results in the degradation of active material and limits the complete realization of theoretical capacity. Graphene has recently become one of the most promising matrices for high-capacity anode materials, due to good electrical conductivity, outstanding mechanical flexibility and high theoretical capacity. In this paper, the nanocomposites of SnO2 and graphene as anode materials for lithium ion batteries were facilely synthesized through hydrothermal method. The design of SnO2/graphene nanocomposites could significantly improve the electrochemical performance by increasing electrical conductivity and buffering volume expansion. It is noteworthy that the quality and structural design of graphene is very important to improve the electrochemical performance for SnO2-based materials. Therefore, on the one hand, a new method to prepare highly dispersible edge-selectively oxidized graphene was reported in this paper. On the other hand, we designed a novel three-dimensional graphene named flower-like graphene tube. Furthermore, characterization and electrochemical performance of these materials were also studied by various technologies

Adaptive wireless body medical system

textAdvances in wireless technologies in the last ten years have created considerable opportunities as well as challenges for wireless body medical systems. The foremost challenge is how to build a reliable system connecting heterogeneous body sensors and actuators in an open system environment. In this dissertation, we present our work towards this goal. The system addresses four design issues: the underlying network architecture, the network scheduling disciplines, the location determination and tracking methods, and the embedded application execution architecture. We first present the design of an adaptive wireless protocol (MBStarPlus) to provide the basic wireless platform WBAN (Wireless Body Area Network). MBStarPlus is a real-time, secure, robust and flexible wireless network architecture. It is designed to utilize any low-power wireless radio as its physical layer. The TDMA mechanism is adopted for realtime data delivery. The time-slot length is adjustable for flexibility. Multiple technologies are utilized to provide reliability and security. We next investigate how to coordinate the body sensors/actuators that can optimally select from a range (maximum and minimum) of data rates. Two bandwidth scheduling algorithms are proposed. One is a greedy algorithm that works for sensors with limited computational capability. The other is the UMinMax scheduling algorithm that has better scalability and power-saving performance but is more computationally intensive. The third issue addressed in this proposal is how to achieve location determination and tracking by a mix of high-precision but expensive and lower-precision but cost-effective sensors. This is achieved by a novel collaborative location determination scheme ColLoc that can integrate different types of distance measurements into a location estimation algorithm by weighing them according to their precision levels. Through this, a localization service can be both cost-effective and sufficiently accurate. Fourth, in order to minimize the effects of long network latency when the body network scales up, we propose ControlInGateway, an architectural feature that allows a control application to be executed inside the network gateway without the host's involvement. With ControlInGateway, a wireless system could achieve the same control quality as a wired system.Computer Science

Terlipressin for septic shock patients: a meta-analysis of randomized controlled study

Abstract Background Catecholamines are commonly used in septic shock but face limitations of their hypo-responsiveness and adverse events due to high dose. Terlipressin is a synthetic vasopressin analog with greater selectivity for the V1-receptor. A meta-analysis was conducted to evaluate the efficacy and safety of terlipressin in septic shock. Methods We searched for relevant studies in PubMed, Embase, and the Cochrane database from inception up to July 15, 2018. Randomized controlled trials (RCTs) were included if they reported data on any of the predefined outcomes in patients with septic shock and managed with terlipressin or any catecholamines. Results were expressed as risk ratio (RR) or mean difference (MD) with accompanying 95% confidence interval (CI). Heterogeneity, subgroup analysis, sensitivity analysis, and publication bias were explored. Results Ten studies with 928 patients were included. Despite the shorter duration of mechanical ventilation, use of terlipressin did not reduce the risk of mortality (RR = 0.94; 95% CI, 0.85 to 1.05; I 2 = 0%; P = 0.28) when compared with control. This finding was confirmed by further subgroup and sensitivity analyses. In addition, lactate clearance, length of stay in ICU or hospital, total adverse events, digital ischemia, and arrhythmia were also similar between groups, while terlipressin was associated with shorter duration of mechanical ventilation and less norepinephrine requirements. Conclusions Current results suggest terlipressin did not show added survival benefit in septic shock therapy when compared with catecholamines