Polarimetric Calibration of CASMSAR P-Band Data Affected by Terrain Slopes Using a Dual-Band Data Fusion Technique

For airborne synthetic aperture radar (SAR) polarimetric calibration (PolCAL) based on distributed targets, it is important to ensure the removal of both the polarimetric distortion and terrain slope effect. This paper proposes a new technique for PolCAL in mountainous areas, without the use of corner reflectors (CRs). The technique based on dual-band data fusion consists of two steps. First, the polarization orientation angle shift (POAS), as a priori asymmetry information, is derived from X-band interferometry and applied to P-band fully-polarimetric data. Second, the crosstalk and cross-polarization (cross-pol) channel imbalance are iteratively determined using the POAS after dual-band data fusion. The performance and feasibility of the technique was evaluated by CRs. It was demonstrated that the proposed technique is capable of deriving the distortion parameters and performs better than the methods presented in Quegan and Ainsworth et al. The signal-to-noise ratio (SNR) and pedestal height have been investigated in polarimetric signatures. The proposed technique is useful for PolCAL in mountainous areas and for monitoring systems without CRs in long-term operation

A Global Optimal Coherence Method for Multi-baseline InSAR Elevation Inversion

A global optimal coherence method for elevation inversion from multi-baseline polarimetric InSAR data is proposed. The multi-baseline polarimetric InSAR data used in experiments were obtained by Chinese X-SAR system and Germany's E-SAR system. Through combining several full polarimetric InSAR images, the proposed method constructs the multi-baseline polarimetric InSAR coherency matrix, and solves the optimal interferograms under global optimal coherence criterion. The optimal interferograms generated by global optimal coherence method were used to calculate the elevation of target with multi-baseline InSAR elevation inversion method. The proposed method reduces the influence of different scattering centers effectively using multi-baseline InSAR, which improves the accuracy and reliability of the interferometric phase and eventually improves the accuracy of DEM. The results verify the validity of the proposed method

Modified Tributary Area and Pressure Arch Theories for Mine Pillar Stress Estimation in Mountainous Areas

This paper describes a parametric study using discrete element modeling (DEM) of partial mining in a mountain terrain with in situ pillars for overburden support. For room and pillar mining or strip pillar mining, the accurate estimation of pillar stress is essential to ensure pillar stability and mine safety. Classical mine design methods such as the tributary area theory (TAT) and the pressure arch theory (PAT) are commonly used to calculate the pillar stress for mines under a relatively flat terrain. However, mine sites with uneven terrains can result in nonuniform stress distributions in the mine system and the classical methods may underestimate the pillar stresses by several times. In this paper, 1200 DEM mine models with terrains that include either a single slope or a valley, have been constructed. Through rigorous numerical modeling, the effects of several design parameters are identified: The influence factors, influence range, and mechanism of the concentrated pillar stresses computed from the models indicate that the shape of an extended pressure arch (EPA) can dictate the accuracy of the TAT and PAT methods. Based on the EPA estimation, a pillar stress estimation method is proposed for the design of mines in mountainous terrains. This paper updated the method of terrain-induced pillar stress concentrations with an improved EPA theory, and the gap between PAT and TAT theories is addressed by further discussion on their relationship and applicability

Enhancement of Cell Adhesion by Anaplasma phagocytophilum Nucleolin-Interacting Protein AFAP

Anaplasma phagocytophilum, the aetiologic agent of human granulocytic anaplasmosis (HGA), is an obligate intracellular Gram-negative bacterium. During infection, A. phagocytophilum enhances the adhesion of neutrophils to the infected endothelial cells. However, the bacterial factors contributing to this phenomenon remain unknown. In this study, we characterized a type IV secretion system substrate of A. phagocytophilum, AFAP (an actin filament-associated Anaplasma phagocytophilum protein) and found that it dynamically changed its pattern and subcellular location in cells and enhanced cell adhesion. Tandem affinity purification combined with mass spectrometry identified host nucleolin as an AFAP-interacting protein. Further study showed the disruption of nucleolin by RNA interference, and the treatment of a nucleolin-binding DNA aptamer AS1411 attenuated AFAP-mediated cell adhesion, indicating that AFAP enhanced cell adhesion in a nucleolin-dependent manner. The characterization of cell adhesion-enhancing AFAP and the identification of host nucleolin as its interaction partner may help understand the mechanism underlying A. phagocytophilum-promoting cell adhesion, facilitating the elucidation of HGA pathogenesis

Dietary Restriction Affects Neuronal Response Property and GABA Synthesis in the Primary Visual Cortex

<div><p>Previous studies have reported inconsistent effects of dietary restriction (DR) on cortical inhibition. To clarify this issue, we examined the response properties of neurons in the primary visual cortex (V1) of DR and control groups of cats using <i>in vivo</i> extracellular single-unit recording techniques, and assessed the synthesis of inhibitory neurotransmitter GABA in the V1 of cats from both groups using immunohistochemical and Western blot techniques. Our results showed that the response of V1 neurons to visual stimuli was significantly modified by DR, as indicated by an enhanced selectivity for stimulus orientations and motion directions, decreased visually-evoked response, lowered spontaneous activity and increased signal-to-noise ratio in DR cats relative to control cats. Further, it was shown that, accompanied with these changes of neuronal responsiveness, GABA immunoreactivity and the expression of a key GABA-synthesizing enzyme GAD67 in the V1 were significantly increased by DR. These results demonstrate that DR may retard brain aging by increasing the intracortical inhibition effect and improve the function of visual cortical neurons in visual information processing. This DR-induced elevation of cortical inhibition may favor the brain in modulating energy expenditure based on food availability.</p></div

Percentile value of neurons showing different orientation bias (OB) (A) and motion direction bias (DB) (B) for DR cats (open circle) and normal control cats (solid circle).

<p>The total number of neurons was 75 and 88 respectively for DR cats and control cats. A percentile value indicated the percentage of neurons whose OBs or DBs were lower than the corresponding OB or DB value on the horizontal axis. DR cats showed significantly increased OB and DB value compared with control cats (p<0.0001; p<0.0001).</p

Poles with error bars represented the average optical density (OD) value of GABA immunoreactivity in the primary visual cortex of each normal control cat (NC1-4) and DR cat (DR1-4).

<p>The mean OD of GABA immunoreaction in each DR cat was significantly larger than that in any individual control cat (** p<0.001).</p

Immunohistochemical labeling of GABAergic neurons in the primary visual cortex of DR cats (A&C) and normal control cats (B&D).

<p>(A&B) show the distribution of GABA neurons across different cortical layers (layer I, II-III, IV, V and VI) at a low amplification. (C&D) show GABA neurons at a higher amplification. The scale bar equals to 25 μm.</p

The quantity of GAPDH protein measured with enzyme linked immunosorbent assay.

<p>The quantity was expressed as a relative value of GAPDH (μg) to total proteins (g) in V1 samples of each normal control cat (NC1, NC2, NC3, NC4) and DR cat (DR1, DR2, DR3, DR4). Assays for each subject were performed in triplicate. The mean content in DR cats showed no significant difference from that in control cats (F(1,8) = 0.02, p>0.5).</p