RESEARCH ON VIDEO-BASED HUMAN BODY MOTION TRACKING

The video-based motion capture system uses cheap equipments, like digital cameras and personal computers, to track a human motion without any sensors or markers attached to the body. This topic has a wide application in areas such as smart surveillance, human computer interaction and athletic performance analysis etc., and it becomes a hot topic of computer vision in recent years. Because of the complexity of the problem and lack of comprehension of human vision system essence, visual tracking is still hard in computer vision

Energy Efficiency Optimization Design of a Forward-Swept Axial Flow Fan for Heat Pump

As one of the key components of the heat pump system, compared to that of a conventional axial fan, the blade tip area of a forward-swept axial fan is much larger than its blade root, which is the main noise source of the fan and also has an important influence on the fan efficiency. Enhancement of the aerodynamic performance and efficiency of a forward-swept axial fan was addressed by utilizing the Bezier function to parameterize the forward-swept curve on blade tops. In order to quickly select an agent model suitable for the project, an ES model was established by integration of the radial basis function model and the Kriging model. When NSGA-II was combined, multi-objective optimization was carried out with the flow rate and total pressure efficiency as optimization goals. Analysis of optimization results revealed that the optimized axial flow fan’s flow rate and total pressure efficiency were improved to some degree. At the design working point, the fan’s flow rate increased by 1.78 m³/min, while the total pressure efficiency increased by 3.0%. These results lay solid foundation for energy saving of the heat pump system

The DNA Sensor AIM2 Maintains Intestinal Homeostasis via Regulation of Epithelial Antimicrobial Host Defense

SummaryMicrobial pattern molecules in the intestine play immunoregulatory roles via diverse pattern recognition receptors. However, the role of the cytosolic DNA sensor AIM2 in the maintenance of intestinal homeostasis is unknown. Here, we show that Aim2−/− mice are highly susceptible to dextran sodium sulfate-induced colitis that is associated with microbial dysbiosis as represented by higher colonic burden of commensal Escherichia coli. Colonization of germ-free mice with Aim2−/− mouse microbiota leads to higher colitis susceptibility. In-depth investigation of AIM2-mediated host defense responses reveals that caspase-1 activation and IL-1β and IL-18 production are compromised in Aim2−/− mouse colons, consistent with defective inflammasome function. Moreover, IL-18 infusion reduces E. coli burden as well as colitis susceptibility in Aim2−/− mice. Altered microbiota in inflammasome-defective mice correlate with reduced expression of several antimicrobial peptides in intestinal epithelial cells. Together, these findings implicate DNA sensing by AIM2 as a regulatory mechanism for maintaining intestinal homeostasis

Mobile Web Adoption in Top Ranked University Libraries: A Preliminary Study

This paper aims to study the level of adoption of mobile access to the academic libraries in the best universities in the world as well as the quality of services offered in order to ascertain if the quality of academic apps and mobile websites are at the level of the overall web impact of world-class universities. For the top 50 universities according to the Ranking Web of Universities (2014), we determined whether there is a mobile website or app for their libraries. Finally we evaluated the services offered against a list of 14 indicators. The results show that 88% of the libraries studied (44) offer mobile access via web or app, showing a high level of mobile adoption in elite universities. The form is clearly uneven: 80% (40) offers mobile web access while only 34% (17) has an app. As to the content, no library offered all 14 points evaluated, and the results are varied. Only 50% of apps meet at least half the indicators. In the case of mobile web this figure improves notably to 74.3%. We can note a high level of mobile web adoption in the world's best universities, although the quality does not reach their level of excellence. (C) 2016 Elsevier Inc. All rights reserved.Torres-Pérez, P.; Méndez-Rodríguez, E.; Orduña Malea, E. (2016). Mobile Web Adoption in Top Ranked University Libraries: A Preliminary Study. Journal of Academic Librarianship. 42(4):329-339. doi:10.1016/j.acalib.2016.05.011S32933942

AXL targeting restores PD-1 blockade sensitivity of STK11/LKB1 mutant NSCLC through expansion of TCF1+ CD8 T cells

Mutations in STK11/LKB1 in non-small cell lung cancer (NSCLC) are associated with poor patient responses to immune checkpoint blockade (ICB), and introduction of a Stk11/Lkb1 (L) mutation into murine lung adenocarcinomas driven by mutant Kras and Trp53 loss (KP) resulted in an ICB refractory syngeneic KPL tumor. Mechanistically this occurred because KPL mutant NSCLCs lacked TCF1-expressing CD8 T cells, a phenotype recapitulated in human STK11/LKB1 mutant NSCLCs. Systemic inhibition of Axl results in increased type I interferon secretion from dendritic cells that expanded tumor-associated TCF1+PD-1+CD8 T cells, restoring therapeutic response to PD-1 ICB in KPL tumors. This was observed in syngeneic immunocompetent mouse models and in humanized mice bearing STK11/LKB1 mutant NSCLC human tumor xenografts. NSCLC-affected individuals with identified STK11/LKB1 mutations receiving bemcentinib and pembrolizumab demonstrated objective clinical response to combination therapy. We conclude that AXL is a critical targetable driver of immune suppression in STK11/LKB1 mutant NSCLC.publishedVersio

Analytical formulas and scaling laws for peak interaction forces in dynamic atomic force microscopy

Determining the peak interaction force between an oscillating nanoscale tip and a sample surface has been a fundamental yet elusive goal in amplitude-modulated atomic force microscopy. Closed form analytical expressions are derived using nonlinear asymptotic theory for the peak attractive and repulsive forces that approximate with a high degree of accuracy the numerically simulated peak forces under ambient or vacuum conditions. Scaling laws involving van der Waals, chemical forces, nanoscale elasticity, and oscillator parameters are identified to demonstrate approximate similitude for the peak interaction forces under practical operating conditions

Nonlinear dynamics and force spectroscopy in dynamic atomic force microscopy

As one branch of atomic force microscopy (AFM), dynamic atomic force microscopy (Dynamic AFM) uses a resonating probe with frequency (FM-AFM) or amplitude modulation (AM-AFM) to measure sample topography and material properties of nanostructures with nanometer resolution. Under the influence of tip-sample interaction forces, the dynamics of the probe become highly nonlinear and can affect the imaging stability and interaction forces. On the other hand, the tip-sample interaction forces can also be extracted from the nonlinear response, opening up new possibilities for nanoscale material property measurements. This thesis combines analytical, experimental, and computational works to (a) investigate the nonlinear response of AFM cantilevers, (b) understand and develop approximate scaling laws for peak interaction forces in dynamic AFM, and to (c) reconstruct the tip-sample interactions from conveniently acquired experimental data. First the nonlinear frequency response of an AFM microcantilever interacting in AM-AFM with the sample is investigated systematically through theoretical, numerical, analytical and experimental analyses. A discretized dynamic model with Derjaguin-Müller-Toporov (DMT) contact mechanics interaction potential is developed to explore various nonlinear phenomena in AM-AFM. Accurate tip vibration responses are computed numerically using the DDASKR routine with root finding algorithm in Fortran for highly nonlinear and non-smooth differential equations. The periodic averaging method is implemented to analytically predict the tip vibration nonlinear response. Numerical computations, analytical predictions using the averaging method, and experimental measurements all match excellently for large setpoint amplitude ratios. The results indicate that attractive van der Waals interactions lead to a initial softening nonlinearity of the periodic solution response while the repulsive DMT interactions lead to a subsequent hardening nonlinear response. Next the theoretical approach above is used to tackle a long-standing theoretical question in dynamic AFM. Determining the peak interaction force between an oscillating nanoscale tip and a sample surface has been a fundamental yet elusive goal in dynamic atomic force microscopy. Closed form analytical expressions are derived using nonlinear asymptotic theory for the peak attractive and repulsive forces that approximate with a high degree of accuracy the numerically simulated peak forces under ambient or vacuum conditions. Scaling laws involving van der Waals, chemical forces, nanoscale elasticity and oscillator parameters are identified to demonstrate approximate similitude for the peak interaction forces under practical operating conditions. Finally, a detailed investigation is performed on the feasibility of reconstructing tip-sample interaction forces from data typically acquired in AM-AFM. Dynamic force spectroscopy, that is reconstruction of the interaction forces from the experimentally measured frequency vs distance curve, has become a standard routine for FM-AFM. However, to date a general method for dynamic force spectroscopy for AM-AFM has not been demonstrated. Based on the harmonic balance method and the Chebyshev polynomial expansion method, it is shown that the conservative tip sample interaction forces can be reconstructed and used to experimentally determine the peak interaction forces in AM-AFM using standard measurements. The results are especially important for nanoscale dynamic material analysis (Nano DMA) and peak interaction force estimation and optimization for AM-AFM

Chaos in Atomic Force Microscopy

Chaotic oscillations of microcantilever tips in dynamic atomic force microscopy (AFM) are reported and characterized. Systematic experiments performed using a variety of microcantilevers under a wide range of operating conditions indicate that softer AFM microcantilevers bifurcate from periodic to chaotic oscillations near the transition from the noncontact to the tapping regimes. Careful Lyapunov exponent and noise titration calculations of the tip oscillation data confirm their chaotic nature. AFM images taken by scanning the chaotically oscillating tips over the sample show small, but significant metrology errors at the nanoscale due to this ‘‘deterministic’’ uncertainty

Inverting amplitude and phase to reconstruct tip-sample interaction forces in tapping mode atomic force microscopy

Quantifying the tip-sample interaction forces in amplitude-modulated atomic force microscopy (AM-AFM) has been an elusive yet important goal in nanoscale imaging, manipulation and spectroscopy using the AFM. In this paper we present a general theory for the reconstruction of tip-sample interaction forces using integral equations for AM-AFM and Chebyshev polynomial expansions. This allows us to reconstruct the tip-sample interactions using standard amplitude and phase versus distance curves acquired in AM-AFM regardless of tip oscillation amplitude and in both the net attractive and repulsive regimes of oscillation. Systematic experiments are performed to reconstruct interaction forces on polymer samples to demonstrate the power of the theoretical approach