3d Biomimetic Model for Cellular Invasion in Angiogenesis and Cancer

Cell migration is an essential and highly regulated process. Cells migrate to vascularize tissues, to form tissue, and to respond to inflammation. Unfortunately, cell migration is also involved in numerous pathological conditions such as in invasive tumors. Cells can migrate as individual cells or as collective groups of cells. Particularly important in cell migration is the collective migration of cells as it is a hallmark of tissue remodeling events during embryonic morphogenesis, wound repair, and cancer invasion. Perhaps, angiogenesis is one of the most crucial collective migration processes as it is involved in multiple physiological and pathological conditions such as formation of vasculature, wound healing, cancer progression and metastasis. During angiogenesis, endothelial cells migrate collectively from existing vasculature in response to a complex biochemical and mechanical cues to form multicellular structures that eventually develop into new functional blood vessels. Angiogenesis is also a highly dynamic process where multiple cells rearrange and coordinate within a sprout. Such dynamic rearrangement requires different cytoskeletal regulators such as Rho GTPases proteins (RhoA, Rac, and Cdc42). Although the roles of Rho GTPase proteins have been well characterized in 2D cell migration, little is known about their contributions in angiogenic morphogenesis. Here, we engineered a 3D biomimetic microfluidic-based device, called AngioChip, where endothelial cells are induced to migrate collectively from a pre-formed biomimetic cylindrical blood vessel into a 3D interstitial collagen matrix. The sprouts in our AngioChip demonstrate in vivo-like morphogenetic features such as formation of tip-stalk cells, lumen formation, filopodial-like protrusions in leading tip cells, and formation of perfusable neovessels. Using this system, we examine the roles of Cdc42 to regulate many aspects of angiogenic morphogenesis. We find that disturbing Cdc42 activity reduces formation of branches, migration speed, and collective migration. Additionally, Cdc42 also negatively regulate filopodia formation. We also develop the AngioChip into a pancreatic ductal adenocarcinoma (PDAC) on a chip to investigate the interactions between pancreatic cancer cells and blood vessels. Vascular invasion, where PDAC cells invaded towards the vasculature during tumor progression, is a hallmark of metastatic PDAC. Nevertheless, how pancreatic tumor cells interact with the blood vessels remains largely unknown. Using our PDAC-on-a-chip, we reveal a striking observation where PDAC cells invade and de-endothelialize the blood vessels. This de-endothelialization process leads to vascular replacement in the blood vessels and is mediated by proliferation of PDAC through Nodal/Activin-ALK7 signaling

Mining high utility itemsets in massive transactional datasets

Mining High Utility Itemsets from a transaction database is to find itemsets that have utility beyond an user-specified threshold. Existing High Utility Itemsets mining algorithms suffer from many problems when being applied to massive transactional datasets. One major problem is the high memory dependency: the gigantic data structure built is assumed to fit in the computer main memory. This paper proposes a new disk-based High Utility Itemsets mining algorithm, which achieves its efficiency by applying three new ideas. First, transactional data is converted into a new database layout called Transactional Array that prevents multiple scanning of the database during the mining phase. Second, for each frequent item, a relatively small independent tree is built for summarizing co-occurrences. Finally, a simple and non-recursive mining process reduces the memory requirements as minimum candidacy generation and counting is needed. We have tested our algorithm on several very large transactional databases and the results show that our algorithm works efficiently

Diversity of plant-parasitic nematodes on medicinal plants in Melinh station for biodiversity, Vinh Phuc Province, Vietnam

Plant-parasitic nematodes are known as one of the most important pests attacking various plants in the world, and investigating the nematode component is very essential for management of this pest and prevent damage to plants in general. Our survey of plant-parasitic nematodes on medicinal plants in Melinh Station for Biodiversity, a place for conservation of precious plants and animals in Vietnam, identified ten species that belong to nine genera, five families, and two orders of plant-parasitic nematodes parasitizing six medicinal plants. Excoecaria cochinchinensis was parasitized by the highest number of nematode genera (5 genera, including Xiphinema, Discocriconemella, Meloidogyne, Helicotylenchus, and Hemicriconemoides), while Hymenocallis littoralis was associated with the highest number of plant-parasitic nematodes (2060 nematodes/250g soil). The results also showed that Discocriconemella limitanea was found to be a dominant species with the highest number of individuals on 6 medicinal plants, and the genus Helicotylenchus had the highest frequency of appearance (5/6 plants or 83.3%). These nematodes caused symptoms such as yellowing leaves, root galls, and root lesions, which directly affect the quality and yield of medicinal plants. Based on the results, this study showed that plant-parasitic nematodes are a potential threat to the cultivation of medicinal plants in Melinh Station for Biodiversity, and thus, control measures should be applied to ensure sustainable cultivation of medicinal plants in this place

Approximation of mild solutions of the linear and nonlinear elliptic equations

In this paper, we investigate the Cauchy problem for both linear and semi-linear elliptic equations. In general, the equations have the form $$\frac{\partial^{2}}{\partial t^{2}}u\left(t\right)=\mathcal{A}u\left(t\right)+f\left(t,u\left(t\right)\right),\quad t\in\left[0,T\right],$$ where $\mathcal{A}$ is a positive-definite, self-adjoint operator with compact inverse. As we know, these problems are well-known to be ill-posed. On account of the orthonormal eigenbasis and the corresponding eigenvalues related to the operator, the method of separation of variables is used to show the solution in series representation. Thereby, we propose a modified method and show error estimations in many accepted cases. For illustration, two numerical examples, a modified Helmholtz equation and an elliptic sine-Gordon equation, are constructed to demonstrate the feasibility and efficiency of the proposed method.Comment: 29 pages, 16 figures, July 201

Pre-treatment potential of electro-coagulation process using aluminum and titanium electrodes for instant coffee processing wastewater

This study aimed at investigating the potential of electrocoagulation (EC) process using Al-Al and Al-Ti electrodes for the pre-treatment of instant coffee processing wastewater. Effects of various operating conditions, including cell voltage, time of treatment, inter-electrode distance, pH of solution, solution conductivity and agitation speed on the removals of chemical oxygen demand (COD) and color were considered. The maximum removal of COD and color was achieved at 87% and 99%, respectively, corresponding to COD and color in the effluents of 359-384 mg/L and 58-101 Pt-Co. Biodegradability of treated wastewater was significantly improved since BOD5/COD increased from initial value of 0.42 to 0.65 after treatment. Nether mixing nor adding of electrolyte was recommended. Moreover, the COD removal kinetics during EC process appeared to follow the first-order kinetic model. The operating costs were also determined as a reference for cost assessment of the treatment

Amélioration de l’amortissement des oscillations de puissance du réseau électrique avec les dispositifs FACTS et les mesures à distance

Ce travail de recherche présente une méthode d’analyse et de la conception des systèmes de commande globale pour amortir des oscillations électromécaniques les plus critiques dans un réseau électrique. Nous utilisons une structure commune de commande hiérarchique, dans laquelle le contrôleur global fonctionne en parallèle avec les boucles de commande locale. Pour cette structure de commande il est désiré que le contrôleur global améliore l’amortissement des modes d’oscillation critiques, sans causer de mauvaises interactions aux autres dynamiques du réseau. Pour atteindre cet objectif, nous proposons tout d’abord un schéma de commande spécial, qui utilise la modulation bang bang et l’identification en ligne pour atténuer l’oscillation critique du réseau. Cette approche de commande permet à la fois de maximiser l’effort de commande et de minimiser les interactions. Une méthode d’analyse de robustesse de ce schéma de commande est aussi élaborée, pour évaluer sa robustesse au changement du mode d’opération et au délai de communication. Cette méthode d’analyse est aussi applicable pour tout type de commande linéaire d’amortissement du réseau. Un résultat important avec cette méthode est que le lien entre le délai de communication et la détérioration de l’amortissement de certains modes d’oscillation peut être analysé quantitativement. Une analyse de sélection des boucles commande globale est aussi proposée dans ce travail. Un indice de l’interaction est proposé pour permettre de classifier plus facilement les boucles de commande, selon leurs interactions avec tous les modes du réseau

Stakeholder engagement in late-stage translation phase 4 research for noncommunicable diseases in low- and middle-income countries : what works and why—the Vietnam experience (UMMS–Vietnam Team)

Background: Stakeholder engagement is crucial for conducting high-quality implementation research as well as for the incorporation and adoption of health interventions and policies in the community. Objectives: This study sought to build a mutually rewarding collaboration between stakeholders in Vietnam and investigators in the United States. Methods: A collaboration was established between investigators from several institutions in Vietnam and the University of Massachusetts Medical School that was built on mutual trust, cross-cultural learning, and shared experiences. This collaborative arrangement has led to sustainable stakeholder engagement in Vietnam. We formed a multidisciplinary transnational research team and maintained regular contact both online and in person. We also conducted a needs assessment study, in which several focus group discussions and in-depth interviews of stakeholders in Vietnam were carried out. Results: The formal collaboration between investigators in Vietnam and the University of Massachusetts Medical School began in 2011 and has strengthened over time. The U.S. team provided expertise in study and intervention design, data collection and analysis, and trial implementation, whereas the team in Vietnam brought a deep understanding of local health care delivery systems and expertise in the delivery of health care interventions at the grassroots level. Our initial partnership has now grown to include committed individuals at the government, academic, and community levels including the Vietnam Ministry of Health, key governmental and nongovernmental research institutions and agencies, medical and public health universities, and communities in rural settings. The needs assessment study found that there are important gaps in the delivery of hypertension management practices in many rural communities in Vietnam and that stakeholders are fully engaged in our ongoing, community-based, hypertension-control project. Conclusions: Multiple layers of stakeholders and communities in Vietnam are fully engaged with, and have contributed significantly to, our ongoing hypertension control research project in Northern Vietnam. © 2019 World Heart Federation (Geneva). **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Huy Nguyen” is provided in this record*