Aging is the greatest risk factor for late-onset Alzheimer's disease (LOAD), which accounts for >95% of Alzheimer's disease (AD) cases. The mechanism underlying the aging-related susceptibility to ...LOAD is unknown. Cellular senescence, a state of permanent cell growth arrest, is believed to contribute importantly to aging and aging-related diseases, including AD. Senescent astrocytes, microglia, endothelial cells, and neurons have been detected in the brain of AD patients and AD animal models. Removing senescent cells genetically or pharmacologically ameliorates β-amyloid (Aβ) peptide and tau-protein-induced neuropathologies, and improves memory in AD model mice, suggesting a pivotal role of cellular senescence in AD pathophysiology. Nonetheless, although accumulated evidence supports the role of cellular senescence in aging and AD, the mechanisms that promote cell senescence and how senescent cells contribute to AD neuropathophysiology remain largely unknown. This review summarizes recent advances in this field. We believe that the removal of senescent cells represents a promising approach toward the effective treatment of aging-related diseases, such as AD.
This paper deals with the path-planning problem for mobile wheeled- or tracked-robot which drive in 2.5-D environments, where the traversable surface is usually considered as a 2-D-manifold embedded ...in a 3-D ambient space. Specially, we aim at solving the 2.5-D navigation problem using raw point cloud as input. The proposed method is independent of traditional surface parametrization or reconstruction methods, such as a meshing process, which generally has high-computational complexity. Instead, we utilize the output of 3-D tensor voting framework on the raw point clouds. The computation of tensor voting is accelerated by optimized implementation on graphics computation unit. Based on the tensor voting results, a novel local Riemannian metric is defined using the saliency components, which helps the modeling of the latent traversable surface. Using the proposed metric, we prove that the geodesic in the 3-D tensor space leads to rational path-planning results by experiments. Compared to traditional methods, the results reveal the advantages of the proposed method in terms of smoothing the robot maneuver while considering the minimum travel distance.
Patients who had any of the following features at the time of, or after, admission were classified as severe cases: (1) respiratory distress (≥30 breaths per min); (2) oxygen saturation at rest ≤93%; ...(3) ratio of partial pressure of arterial oxygen to fractional concentration of oxygen inspired air ≤300 mm Hg; or (4) severe disease complications (eg, respiratory failure, requirement of mechanical ventilation, septic shock, or non-respiratory organ failure). Parameters did not differ significantly between the groups, except that patients in the severe group were significantly older than those in the mild group, as expected.4 No patient died from the infection. 23 (77%) of 30 severe cases received intensive care unit (ICU) treatment, whereas none of the mild cases required ICU treatment. All samples were collected according to WHO guidelines.5 The mean viral load of severe cases was around 60 times higher than that of mild cases, suggesting that higher viral loads might be associated with severe clinical outcomes.
•The antibacterial activity of fucoidans from Laminaria japonica was evaluated.•The unprocessed fucoidans did not exhibit obvious antibacterial activity.•The depolymerized fucoidans exhibited ...excellent antibacterial activity.•Low molecular weight and strong anionic property improve antibacterial activity.•Depolymerized fucoidans inhibit bacterial growth by destroying membrane integrity.
Fucoidans, sulfated polysaccharides in brown algae, were depolymerized though high-pressure hydrolysis, and their antibacterial activity, structural properties, and antibacterial mechanisms were investigated in this work. The fucoidans from Laminaria japonica show no antibacterial activity before depolymerization; however, their depolymerized products can effectively (p<0.05) inhibit the proliferation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The structure–activity study demonstrated that lower molecular weight and stronger polyanionic property can promote the antibacterial activity. And the depolymerized fucoidans exhibited better antibacterial activity against E. coli than against S. aureus. The results also indicated that the bactericidal pathway of depolymerized fucoidans should be through destruction of the cytomembranes and the target molecules are the membrane proteins, which can result in changed membrane fluidity and/or activated autophagocytosis. Therefore, the depolymerized fucoidans possess potential appliance values in partly or totally replacing antibiotics in our daily life.
Abstract
The quasi-static compression, three-point bending and low-speed impact behavior of E690 high-strength steel lattice corrugated sandwich panels after corrosion in a marine environment were ...simulated by a non-linear finite element method. The uniform corrosion model was used to calculate the effects of different levels and duration of corrosion on the bearing capacity and energy absorption of an E690 panel. The results show that the corrosion of the outer panel has the least influence on the decrease of the mechanical properties; the structure’s mechanical properties are greatly reduced by the inner panel and core corrosion, and a new deformation pattern could be observed. Considering the influence of corrosion duration, the mechanical performance ranges from bad to good: outer+inner > inner > outer. Furthermore, the difference becomes more obvious with longer corrosion times, indicating that necessary corrosion protection measures should be taken to protect the panel from corrosion in marine environment, especially for the internal part of the panel.
The rice endosperm plays crucial roles in nourishing the embryo during embryogenesis and seed germination. Although previous studies have provided the general information about rice endosperm, a ...systematic investigation throughout the entire endosperm developmental process is still lacking. In this study, we examined in detail rice endosperm development on a daily basis throughout the 3o-day period of post-fertilization development. We observed that coenocytic nuclear division occurred in the first 2 days after pollination （DAP）, cellularization occurred between 3 and 5 DAP, differentiation of the aleurone and starchy endosperm occurred between 6 and 9 DAP, and accumulation of storage products occurred concurrently with the aleurone/starchy endosperm differentiation from 6 DAP onwards and was accomplished by 21 DAP. Changes in cytoplasmic membrane permeability, possibly caused by programmed cell death, were observed in the central region of the starchy endosperm at 8 DAP, and expanded to the whole starchy endosperm at 21 DAP when the aleurone is the only living component in the endosperm. Further, we observed that a distinct multi-layered dorsal aleurone formed near the dorsal vascular bundle, while the single- or occasionally two-cell layered aleurone was located in the lateral and ventral positions of endosperm. Our results provide in detail the dynamic changes in mitotic divisions, cellularization, cell differentiation, storage product accumulation, and programmed cell death that occur during rice endosperm development.
Based on the data of PM2.5 concentrations and Air Quality Index of 73 Chinese cities in 2013, this study empirically investigates the socioeconomic influential factors of urban PM2.5 concentrations ...in China. Specifically, it examines whether and how the socioeconomic development indicators such as GDP per capita, industry and transport would affect the air quality. Due to the existence of spatial autocorrelation of air pollution, conventional regression techniques that ignore the spatial autocorrelation would yield biased and inconsistent estimation results. Therefore, in this study two spatial econometric models, namely Spatial Lag Model (SLM) and Spatial Error Model (SEM), are utilized to control for spatial effects. According to the estimation results, the relationship between PM2.5 concentrations and per capita GDP is inverted U-shaped, suggesting the existence of the inverted-U shaped Environmental Kuznets Curve (EKC) for air quality in China. In addition, the vehicle population and the secondary industry have significant and positive influences on urban PM2.5 concentrations. As a result, a series of comprehensive measures in both social and economic aspects as well as the regional coordination of environmental policies are needed to hold China's air pollution in check.
•The influential factors of urban PM2.5 concentrations in China are investigated.•Two spatial econometric models are used to control for the spatial correlation of air pollution.•The EKC relationship between PM2.5 concentrations and economic development is verified.•Vehicle population and the secondary industry influence urban PM2.5 concentrations positively.
A recent analysis by the LHCb Collaboration suggests the existence of three narrow pentaquarklike states-the P_{c}(4312), P_{c}(4440), and P_{c}(4457)-instead of just one in the previous analysis the ...P_{c}(4450). The closeness of the P_{c}(4312) to the Dover ¯Σ_{c} threshold and the P_{c}(4440) and P_{c}(4457) to the Dover ¯^{*}Σ_{c} threshold suggests a molecular interpretation of these resonances. We show that these three pentaquarklike resonances can be naturally accommodated in a contact-range effective field theory description that incorporates heavy-quark spin symmetry. This description leads to the prediction of all the seven possible S-wave heavy antimeson-baryon molecules that is, there should be four additional molecular pentaquarks in addition to the P_{c}(4312), P_{c}(4440), and P_{c}(4457), providing the first example of a heavy-quark spin symmetry molecular multiplet that is complete. If this is confirmed, it will not only give us an impressive example of the application of heavy-quark symmetries and effective field theories in hadron physics, it will also uncover a clear and powerful ordering principle for the molecular spectrum, reminiscent of the SU(3)-flavor multiplets to which the light hadron spectrum conforms.
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Designing a cost-effective phase change thermal storage system involves two challenging aspects: one is to select a suitable storage material and the other is to increase the heat transfer between ...the storage material and the heat transfer fluid as the performance of the system is limited by the poor thermal conductivity of the latent heat storage material. When used for storing energy in concentrated solar thermal power plants, the solar field operation temperature will determine the PCM melting temperature selection. This paper reviews concentrated solar thermal power plants that are currently operating and under construction. It also reviews phase change materials with melting temperatures above 300°C, which potentially can be used as energy storage media in these plants. In addition, various techniques employed to enhance the thermal performance of high temperature phase change thermal storage systems have been reviewed and discussed. This review aims to provide the necessary information for further research in the development of cost-effective high temperature phase change thermal storage systems.
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