42 research outputs found
Radio Analytics for Indoor Monitoring and Human Recognition
In the era of Internet of Things (IoT), researchers have been developing new technologies and intelligent systems to answer the question of who, what, when, where, and how of things happening in the environment. Among the various techniques that measure what is happening in the surroundings, wireless sensing stands out because of its ubiquity and prevalence. On one hand, different indoor activities bring distinctive perturbations to wireless radio propagation. On the other hand, thanks to the nature of multipath, indoor environmental information is recorded and embedded in the wireless channel state information (CSI). Hence, by deploying wireless transceivers to sense the radio propagation environment and analyzing the CSI, one can extend human senses and enrich her/his insight into surrounding environments and activities.
By leveraging the natural multipath propagation of electromagnetic (EM) waves, radio analytics is proposed as a promising technology that deciphers radio propagation characteristics and reveals rich environmental information surrounding us. As one approach of radio analytics, time-reversal (TR) technique exploits the information of large degrees-of-freedom delivered by CSI and provides a high-resolution spatial-temporal resonance, by treating each multipath component in a wireless channel as a distributed virtual antenna. The TR spatial-temporal resonance is indeed a resonance of EM field in response to the propagation environment, and it changes whenever the propagation environment changes.
Inspired by the principle of TR and motivated by the development of IoT, in this dissertation, we propose several radio analytic systems that leverage multipath information to realize IoT applications of recognizing different events and identifying people in an indoor environment. In the first part, we design three indoor monitoring systems that analyze different event-determined features extracted from either a single CSI sample or a CSI time series. The first proposed indoor monitoring system distinguishes between different indoor events by matching the instantaneous CSI to a multipath profile calibrated in a training database whose similarity is quantified by the time-reversal resonance strength (TRRS). Later on, we derive the statistics of TRRS, and we propose a new TR based indoor monitoring system that differentiates between different indoor events based on the statistical behavior of TRRS. Unlike the previous two indoor monitoring systems which treats each CSI as an independent feature, we propose the third indoor monitoring system by exploiting the temporal information embedded in the CSI time series as an additional feature to comprehensively understand indoor events. Results of extensive experiments demonstrate the proposed systems as promising solutions to future indoor monitoring IoT applications.
In the second part of this dissertation, we propose the concept of human radio biometrics and design a through-the-wall human identification system that is implemented on commercial WiFi devices. As a human present in an indoor environment, the radio waves propagate around will interact with the human body through reflection and scattering. We define human radio biometrics as the attenuation and alteration of wireless signals brought by human. We achieve an accurate through-the-wall human recognition by utilizing the fact that the radio biometrics are uniquely determined by the biological characteristics of each human. Through extensive experiments, we validate the existence of radio biometrics and evaluate the accuracy of the proposed human identification system. Unlike conventional approaches for biometric recognition, the proposed radio biometrics system can identify human through a wall and supports commercial WiFi infrastructure, thus illustrating its potential for human recognition IoT applications
Dynamic Gardner crossover in a simple structural glass
The criticality of the jamming transition responsible for amorphous
solidification has been theoretically linked to the marginal stability of a
thermodynamic Gardner phase. While the critical exponents of jamming appear
independent of the preparation history, the pertinence of Gardner physics far
from equilibrium is an open question. To fill this gap, we numerically study
the nonequilibrium dynamics of hard disks compressed towards the jamming
transition using a broad variety of protocols. We show that dynamic signatures
of Gardner physics can be disentangled from the aging relaxation dynamics. We
thus define a generic dynamic Gardner crossover regardless of the history. Our
results show that the jamming transition is always accessed by exploring
increasingly complex landscape, resulting in the anomalous microscopic
relaxation dynamics that remains to be understood theoretically
Application of statins in management of glioma: Recent advances
Gliomas are common primary intra-cerebral tumors in adults, and seriously threaten the health and life of affected patients, especially highly-malignant gliomas, such as glioblastoma multiforme. The clinical prognosis of glioma patients is poor, even for those who have received comprehensive treatment including surgery and concurrent chemo- and/or radio-therapy. As a structural analog of β-hydroxy-β- methylglutaryl coenzyme A (HMG CoA) reductase, statins are a restrictive enzyme in the metabolism of cholesterol. Recent laboratory studies and clinical trials have demonstrated that statins can exert antitumor effect, improve clinical prognosis and significantly prolong the survival time of glioma patients. This article is aimed to highlight the mechanisms of the anti-glioma effect of statins and review recent advances in the management of the disease.Keywords: Glioma, Glioblastoma multiforme, Intra-cerebral tumors, Statins, Prognosis, Survival time, β-Hydroxy-β-methylglutaryl coenzyme A (HMG CoA) reductas
Role of Iodine Recycling on Sea-Salt Aerosols in the Global Marine Boundary Layer
Heterogeneous uptake of hypoiodous acid (HOI), the dominant inorganic iodine species in the marine boundary layer (MBL), on sea-salt aerosol (SSA) to form iodine monobromide and iodine monochloride has been adopted in models with assumed efficiency. Recently, field measurements have reported a much faster rate of this recycling process than previously assumed in models. Here, we conduct global model simulations to quantify the range of effects of iodine recycling within the MBL, using Conventional, Updated, and Upper-limit coefficients. When considering the Updated coefficient, iodine recycling significantly enhances gaseous inorganic iodine abundance (similar to 40%), increases halogen atom production rates (similar to 40% in I, >100% in Br, and similar to 60% in Cl), and reduces oxidant levels (-7% in O-3, -2% in OH, and -4% in HO2) compared to the simulation without the process. We appeal for further direct measurements of iodine species, laboratory experiments on the controlling factors, and multiscale simulations of iodine heterogeneous recycling.Peer reviewe
Methylation-mediated silencing of PTPRD induces pulmonary hypertension by promoting pulmonary arterial smooth muscle cell migration via the PDGFRB/PLCÎł1 axis
OBJECTIVE: Pulmonary hypertension is a lethal disease characterized by pulmonary vascular remodeling and is mediated by abnormal proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs). Platelet-derived growth factor BB (PDGF-BB) is the most potent mitogen for PASMCs and is involved in vascular remodeling in pulmonary hypertension development. Therefore, the objective of our study is to identify novel mechanisms underlying vascular remodeling in pulmonary hypertension.
METHODS: We explored the effects and mechanisms of PTPRD downregulation in PASMCs and PTPRD knockdown rats in pulmonary hypertension induced by hypoxia.
RESULTS: We demonstrated that PTPRD is dramatically downregulated in PDGF-BB-treated PASMCs, pulmonary arteries from pulmonary hypertension rats, and blood and pulmonary arteries from lung specimens of patients with hypoxic pulmonary arterial hypertension (HPAH) and idiopathic PAH (iPAH). Subsequently, we found that PTPRD was downregulated by promoter methylation via DNMT1. Moreover, we found that PTPRD knockdown altered cell morphology and migration in PASMCs via modulating focal adhesion and cell cytoskeleton. We have demonstrated that the increase in cell migration is mediated by the PDGFRB/PLCÎł1 pathway. Furthermore, under hypoxic condition, we observed significant pulmonary arterial remodeling and exacerbation of pulmonary hypertension in heterozygous PTPRD knock-out rats compared with the wild-type group. We also demonstrated that HET group treated with chronic hypoxia have higher expression and activity of PLCÎł1 in the pulmonary arteries compared with wild-type group.
CONCLUSION: We propose that PTPRD likely plays an important role in the process of pulmonary vascular remodeling and development of pulmonary hypertension in vivo
Biosensors fabricated by laser-induced metallization on DLP composite resin
With the growing emphasis on medical testing, people are seeking more technologies to detect indexes of the human body quickly and at a low cost. The electrochemical biosensors became a research hotspot due to their excellent properties. In this study, dicopper hydroxide phosphate (Cu2(OH)PO4) was incorporated in resin, and the resin sheets were prepared by digital light processing (DLP). The copper base points were activated on the resin sheet surface by Nd: YAG laser and then covered by the electroless copper plating and the electroless silver plating. The laser could effectively activate copper base points on the resin surface. Furthermore, silver electrodes on the detection chips could distinguish glucose solutions of different concentrations well. Finally, a novel detection kit with a three-electrode chip was designed for rapid health testing at home or in medical institutions in the future
Direct field evidence of autocatalytic iodine release from atmospheric aerosol
Reactive iodine plays a key role in determining the oxidation capacity, or cleansing capacity, of the atmosphere in addition to being implicated in the formation of new particles in the marine boundary layer. The postulation that heterogeneous cycling of reactive iodine on aerosols may significantly influence the lifetime of ozone in the troposphere not only remains poorly understood but also heretofore has never been observed or quantified in the field. Here, we report direct ambient observations of hypoiodous acid (HOI) and heterogeneous recycling of interhalogen product species (i.e., iodine monochloride [ICI] and iodine monobromide [IBr]) in a midlatitude coastal environment. Significant levels of ICI and IBr with mean daily maxima of 4.3 and 3.0 parts per trillion by volume (1-min average), respectively, have been observed throughout the campaign. We show that the heterogeneous reaction of HOI on marine aerosol and subsequent production of iodine interhalogens are much faster than previously thought. These results indicate that the fast formation of iodine interhalogens, together with their rapid photolysis, results in more efficient recycling of atomic iodine than currently considered in models. Photolysis of the observed ICI and IBr leads to a 32% increase in the daytime average of atomic iodine production rate, thereby enhancing the average daytime iodine-catalyzed ozone loss rate by 10 to 20%. Our findings provide direct field evidence that the autocatalytic mechanism of iodine release from marine aerosol is important in the atmosphere and can have significant impacts on atmospheric oxidation capacity.Peer reviewe
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Role Conflict Analysis in Global Climate Governance
What are states’ roles in global climate governance? How do they emerge, evolve, and interact with each other? Characterising states with roles is a commonly employed rhetoric which seeks to reflect both the performance of individual players whilst articulating the international community's impression towards them. Exploring the formation, dynamics and policy effects of states’ roles is thus crucial to the analysis of global climate governance. However, the corpus of academic literature on role theory still exhibits some substantial gaps in knowledge regarding role-induced conflicts. Targeting these gaps, this thesis critically engages with the underpinnings of states’ role conflicts and introduces a theoretical framework to analyse the formation, changing dynamics and interactions of states’ roles within international climate mitigation context.
Taking role conflict as the lynchpin connecting a range of diverse approaches (collective action, leadership theory, trade politics and market power theory), the thesis illuminates the integrated spectrum of role conflicts within the context of global climate governance, from agent to structure (introducing the Role Conflict Framework: role mismatch, role threshold, role rent-seeking and role contestation). The evolutionary dynamics between the four types of role conflict identified and elucidated herein demonstrate the little-understood complexity in resolving these issues as they grow from inventive problem to distribution dilemma, from procedural debate to production relations and status competition. The Role Conflict Framework uncovers not only conflictual scenarios, but also inherent conditions influencing the emergence, interaction and evolution of states’ roles. Further, this research examines the two-sided features of conflict in role studies; focusing on the critical nature of conflicts within and between states which bring in positive externalities that could benefit climate practices and global climate initiatives. Accordingly, the assumed negative correlation between states’ role conflict and governance effectiveness needs to be reconsidered.
The thesis derives theoretical, practical and policy insights on the formation and distribution of states’ roles as well as the logic underpinning states’ conflictual performances, providing a new and illuminating perspective in viewing and explaining states’ participation in global climate governance