Molecular Dynamics Studies on Structure and Phase Transitions of Nanoconfined Water

The goal of this dissertation was to understand the structure and dynamics of quasi–1D and quasi–2D water confined in low dimensional carbon materials by the use of molecular dynamics simulation methods combined with enhanced sampling strategies. For this goal, a first step was to derive simple but reliable LJ potential models for the interaction between water and carbon sheets of different curvature. These effective models then can be used to carry out a series of MD investigations on water confined inside CNTs and graphene capillaries, comprising the variation of the water model

Experimental Study of Energy Requirement of CO2 Desorption from Rich Solvent

AbstractAmine scrubbing has been considered to be the most feasible route for CO2 capture. However, the main drawback of this technology is high regeneration energy. A better understanding of energy requirement of CO2 desorption from rich solvent is required. In this study the regeneration energy and its three contributions is examined at various process parameters through experimental work. The regeneration process parameters include rich solvent flow rate, MEA concentration, feeding solvent temperature, rich solvent loading, reboiler temperature and stripper operating pressure. It was found that the regeneration energy was sensitive to those process parameters. The regeneration energy of a mixed MEA/MDEA solvent was also examined. The results show that the regeneration energy can be reduced by using a mixed MEA/MDEA solution

Dynamics of Utah\u27s Agricultural Landscapes in Response to Urbanization: A Comparison Between Irrigated and Non-Irrigated Agricultural Lands

In the literature on how urbanization affects agricultural landscapes, little attention has been focused on differentiating and comparing the changes in irrigated agricultural landscapes to non-irrigated agricultural landscapes. Additionally, there have been few applications of landscape metrics for understanding agricultural landscape changes. The objectives of this study were to:(1) analyze and compare the changes of both irrigated and non-irrigated agricultural lands in a rapidly growing region; (2) identify the spatial patterns and hotspots of these changes; and,(3) examine the spatial relationships between changes in agricultural landscapes and urban development. We adopted landscape metrics and gradient analysis to assess where and how agricultural landscape changes occurred in northern Utah over the past 30 years. A revised urban gradient was also developed to detect the changes of agricultural landscapes in relation to new urban development. We found that irrigated agricultural lands were more affected by urban development than non-irrigated agricultural lands, with evidence of more patches, more irregular patch shapes, and less connectivity among patches. This study contributes not only to the existing literature on the dynamics of both irrigated and non-irrigated agricultural lands in relation to urban development, but also helps fill the gap of scant applications of landscape metrics and urban gradient analysis in agricultural areas. Most importantly, such a comprehensive examination of Utah\u27s agricultural landscapes will serve as part of the scientific foundation for informing land use policy in the region, as well as provide lessons for other places that are facing similar agricultural land conversion challenges

Processing Parameters’ Multi-objective Optimization for Compound Machining with Ultrasonic Vibration on SiC Monocrystal

AbstractBecause of SiC monocrystal belongs to difficult-to-process material, improving its processing quality and effect has great significance. This paper carries out a great deal of experimental research of compound processing with ultrasonic vibration on SiC monocrystal, and obtains important factors that influence processing result, i.e., based on relevant regularities of sawing force and processing parameters, processing parameter optimization model is established under the constraints of sawing force, wire saw life, and wire saw tensile stress. Solving the model by means of genetic algorithm, an optimum grouping of processing parameters is obtained. Research result indicates that this method could effectively obtain processing parameters under certain processing conditions, helps to enhance the processing efficiency of SiC monocrystal

Energy and spectral efficiency tradeoff with user association and power coordination in massive MIMO enabled HetNets

In this letter, we investigate the tradeoff between energy efficiency (EE) and spectral efficiency (SE) while ensuring proportional rate fairness in massive multiple-input multiple-output enabled heterogenous networks, where user association and power coordination are jointly considered. It is first formulated as a multi-objective optimization problem, and then transformed into a single-objective optimization problem. To solve this mixed-integer non-convex problem, an effective algorithm is developed, where the original problem is separated into lower level power coordination problem and master user association problem. Simulation results verify that our proposed algorithm can significantly improve the performance of EE-SE tradeoff and obtain higher rate fairness compared with other algorithms

Self-organizing criticality among Chinese cities

This dissertation employs the theory of self-organizing criticality (SOC) into the study of Chinese cities. SOC was proposed at the end of the 1980s to explain system complexity by combining both self-organizing and critical behaviors. SOC has been broadly used in explaining phenomena in physical and social sciences. However, few attempts have been made to connect urban studies with SOC because of the extreme complexity of urban phenomena. This study develops a generalized SOC to study Chinese cities at both the inter-urban and the intra-urban levels. At the inter-urban level, this study finds that the rank size distribution of Chinese cities has followed Zipf's law since 1984. In addition, the rank size dynamics of Chinese cities experienced a spatiotemporal shift. Before 1996, city rank increases in a few small- and middle-sized cities because of favorable economic policies offered by the central government. After 1996, a majority of the Chinese cities began to be involved in this rank size shuffling. Cities with increasing ranks present clustered distribution, mainly along the south and east coastal areas. Part of the reason is that the market economy mechanism has transcended policy factors in determining the city competitiveness. At the intra-urban level, the study shows that Shenzhen's urban physical development is currently facing physical environmental thresholds, shifting the development strategies spatiotemporally from fringe and isolated growth to fringe and infill growth. The resulted urban patches show power law relationship both in the area-perimeter distributions and the magnitude-frequency distributions. In summary, this research proves the applicability of the generalized SOC in urban studies. At both the inter-urban and the intra-urban levels, the Chinese cities present the characteristics of SOC. Given a stable condition of power law, shifts occur in the inside dynamics of China's urban system and Shenzhen city. This study is one of the few empirical urban studies based on SOC. The study contributes to the literature on SOC theory and provides theoretical breakthroughs in studying Chinese cities. Finally, this study has potential implications on urban policies and urban development strategies

Diagnostic Value of Transbronchial Needle Aspiration and Endobronchial Ultrasoundguided Transbronchial Needle Aspiration for Hilar and Mediastinal Lymph Nodes in Lung Cancer Patients

Background and objective Transbronchial needle aspiration (TBNA) and endobronchial ultrasoundguided TBNA (EBUS-TBNA) have been applied to the diagnosis for mediastinal lymph nodes. The aim of this study is to evaluate the clinical value and safety of TBNA and EBUS-TBNA on hilar and mediastinal lymph nodes of lung cancer patients. Methods Two hundred fifty patients with suspected lung cancer were enrolled. All petients with hilar and/or mediastinal lymphoadenopathy found by CT scan received TBNA, biopsy and brushing. EBUS-TBNA was performed in 15 patients among them. Results Lung cancer were confirmed in 180 patients by TBNA, biopsy and brushing. The positive rates were 82.86%, 51.24% and 45.45%. Fifteen patients after EBUS-TBNA had a positive rate of 91.67%. Conclusion TBNA and EBUS-TBNA were proved to be safe procedure with a high yield for the diagnosis of hilar and mediastinal lymph nodes in lung cancer patients

Eleutheroside E inhibits doxorubicin-induced inflammation and apoptosis in rat cardiomyocytes by modulating activation of NF-κB pathway

Purpose: To identify the effects of eleutheroside E (EE) on apoptosis and   inflammation induced by doxorubicin (DOX) in H9c2 cells and to investigate the underlying mechanisms.Methods: The effect of EE on H9c2 cell viability was determined using Cell Counting Kit-8 (CCK8). EE effect on DOX-induced apoptosis and inflammation in H9c2 cells was studied by comparison between cells treated with DOX alone and DOX+EE; the relationship between EE effects and NF-κB signaling pathway was evaluated by the addition of NF-κB inhibitor PDTC. Cell apoptosis was examined by flow cytometry while IL-1β, IL-6, and TNF-α levels were determined by ELISA. The phosphorylation level of NF-κB p65 was measured by Western blot.Results: Compared with control group, cell viability was notably elevated after  treatment with 50-100 μM EE for 48 or 72 h. DOX induced higher rates of cell  apoptosis in H9c2 cells (29.5 ± 3.56 %) compared with control group (6.39 ± 0.67 %); however, with EE pretreatment (50 and 80 μM), apoptosis rate decreased to 16.8 ± 2.16 and 13.54 ± 2.08 %, respectively, which are significantly lower than that of DOX group; furthermore, the levels of IL-1β, IL-6, and TNF-α also reduced. In addition, DOX-induced phosphorylation of NF-κB p65 was suppressed by EE pretreatment (10, 50 and 80 μM) to 11.51 ± 1.25, 40.2 ± 5.17 and 52.97 ± 6.74 %, respectivelyConclusion: The results suggest that EE treatment reduced DOX-induced apoptosis and inflammation by interacting with NF-κB signaling pathway. This finding sheds some light on probable new strategies on the application of DOX for cancer treatment.Keywords: Eleutheroside E, Doxorubicin, Inflammation, Apoptosis, Cardiomyocytes, NF-κ

The Activation of Macrophage and Upregulation of CD40 Costimulatory Molecule in Lipopolysaccharide-Induced Acute Lung Injury

To study the activation of macrophage and upregulation of costimulatory molecule of CD40 in lipopolysaccharide- (LPS-) induced acute lung injury (ALI) model, and to investigate the pathogenecy of ALI, mice were randomly divided into two groups. ALI model was created by injecting 0.2 mg/kg LPS in phosphate saline (PBS) in trachea. The pathologic changes of mice lungs were observed by HE staining at 24 and 48 hours after LPS treatment, then the alveolar septum damage, abnormal contraction, alveolar space hyperemia, and neutrophils or other inflammatory cells infiltration in the LPS group, but not in the control group, were observed. The expression of CD40 mRNA and CD40 protein molecules were higher in LPS group as compared to the control group by Northern blot and flow cytometry, respectively. Expression of Toll-like receptor-4 (TLR4) in activated macrophage (AMΦ) was higher in LPS group as compared to the control group by RT-PCR. The activation of NF-κB binding to NF-κB consensus oligos increased in LPS group by EMSA in macrophage. The concentrations of TNF-α, MIP-2, and IL-1β cytokines from bronchoalveolar lavage fluid (BALF) were increased significantly in LPS group as compared to the control group by ELISA. The activation of AM and upregulation of costimulatory molecule CD40 induced all kinds of inflammatory cytokines releasing, then led to ALI. Therefore, both of them played vital role in the process of development of ALI

Learning a More Continuous Zero Level Set in Unsigned Distance Fields through Level Set Projection

Latest methods represent shapes with open surfaces using unsigned distance functions (UDFs). They train neural networks to learn UDFs and reconstruct surfaces with the gradients around the zero level set of the UDF. However, the differential networks struggle from learning the zero level set where the UDF is not differentiable, which leads to large errors on unsigned distances and gradients around the zero level set, resulting in highly fragmented and discontinuous surfaces. To resolve this problem, we propose to learn a more continuous zero level set in UDFs with level set projections. Our insight is to guide the learning of zero level set using the rest non-zero level sets via a projection procedure. Our idea is inspired from the observations that the non-zero level sets are much smoother and more continuous than the zero level set. We pull the non-zero level sets onto the zero level set with gradient constraints which align gradients over different level sets and correct unsigned distance errors on the zero level set, leading to a smoother and more continuous unsigned distance field. We conduct comprehensive experiments in surface reconstruction for point clouds, real scans or depth maps, and further explore the performance in unsupervised point cloud upsampling and unsupervised point normal estimation with the learned UDF, which demonstrate our non-trivial improvements over the state-of-the-art methods. Code is available at https://github.com/junshengzhou/LevelSetUDF .Comment: To appear at ICCV2023. Code is available at https://github.com/junshengzhou/LevelSetUD