Extracellular Matrix Composition Modulates the Responsiveness of Differentiated and Stem Pancreatic Cancer Cells to Lipophilic Derivate of Gemcitabine

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease. Gemcitabine (GEM) is used as the gold standard drug in PDAC treatment. However, due to its poor efficacy, it remains urgent to identify novel strategies to overcome resistance issues. In this context, an intense stroma reaction and the presence of cancer stem cells (CSCs) have been shown to influence PDAC aggressiveness, metastatic potential, and chemoresistance. Methods: We used three-dimensional (3D) organotypic cultures grown on an extracellular matrix composed of Matrigel or collagen I to test the effect of the new potential therapeutic prodrug 4-(N)-stearoyl-GEM, called C18GEM. We analyzed C18GEM cytotoxic activity, intracellular uptake, apoptosis, necrosis, and autophagy induction in both Panc1 cell line (P) and their derived CSCs. Results: PDAC CSCs show higher sensitivity to C18GEM treatment when cultured in both two-dimensional (2D) and 3D conditions, especially on collagen I, in comparison to GEM. The intracellular uptake mechanisms of C18GEM are mainly due to membrane nucleoside transporters’ expression and fatty acid translocase CD36 in Panc1 P cells and to clathrin-mediated endocytosis and CD36 in Panc1 CSCs. Furthermore, C18GEM induces an increase in cell death compared to GEM in both cell lines grown on 2D and 3D cultures. Finally, C18GEM stimulated protective autophagy in Panc1 P and CSCs cultured on 3D conditions. Conclusion: We propose C18GEM together with autophagy inhibitors as a valid alternative therapeutic approach in PDAC treatment.     

Hybrid-Trefftz stress elements for plate bending

The hybrid-Trefftz stress element is used to emulate conventional finite elements for analysis of Kirchhoff and Mindlin-Reissner plate bending problems. The element is hybrid because it is based on the independent approximation of the stress-resultant and boundary displacement fields. The Trefftz variant is consequent on the use of the formal solutions of the governing Lagrange equation to approximate the stress-resultant field. In order to emulate conventional elements, nodal functions are used to approximate the displacements on the boundary of the element. Duality is used to set up the element solving system. The associated variational statements and conditions for existence and uniqueness of solutions are recovered. Triangular and quadrilateral elements are tested and characterized in terms of convergence, sensitivity to shear-locking, and shape distortion. Their relative performance is assessed using assumed strain Mixed Interpolation of Tensorial Components (MITC) elements and recently proposed Trefftz-based elements. This relative assessment is extended to a hypersingular problem to illustrate the effect of enriching the domain and boundary approximation bases.     

Effect of flaxseed oil in diet on fatty acid composition in the liver of Nile tilapia (Oreochromis niloticus)

This study analyzed the effects of different concentrations of flaxseed oil (FO) on the proximate composition and the contents of alpha-linolenic acid (LNA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), and docosahexaenoic (DHA, 22:6n-3) fatty acids in the liver of cultured Nile tilapia (Oreochromis niloticus). During the five-month culture period, tilapias were given diets with incremental concentrations of FO (0.00%; 1.25%; 2.50%; 3.75%, and 5.00%) as a replacement of sunflower oil (control). There was no significant difference in moisture and ash content in the liver between treatments. Protein values ranged from 12.1% (treatment II) to 13.9% (treatment V) and total lipids ranged from 5.6% (treatment V) to 7.2% (treatment II). There was no significant difference between most treatments. Fatty acid methyl esters (FAMEs) were quantitatively analyzed by capillary gas chromatography against a C(23:0), internal standard. Variations in concentrations (in mg g(-1) of total lipids) of fatty acids between treatment I and treatment V ranged from 4.2 to 51.2 (LNA), from 0.2 to 2.3 (EPA), and from 10.6 to 56.2 (DHA), respectively. This experiment demonstrated that increasing amounts of LNA in feed may markedly increase the amounts of LNA, EPA, and DHA in the liver of Nile tilapia.     

Leaf epidermal characteristics of Cissampelos L. (Menispermaceae) species from Northeastern Brazil

The morphological similarities among the species of Cissampelos are remarkable and the difficult to distinguish them as well. This article presents a comparative anatomical study of the leaves of common Northeastern Brazilian species of Cissampelos, carried out using light and scanning electron microscopy. The leaf epidermal was studied to obtain data on epidermal characteristics and to evaluate their taxonomic significance. As results, some micromorphological characters on the leaf epidermal like the cuticular waxes, the presence of papillae in epidermis and nonglandular trichomes, the anticlinal walls epidermal cells, the distribution, density and type of trichomes, and also the type and distribution of epicuticular wax proved to be the most useful characteristics to distinguish the species in taxonomic studies. Microsc. Res. Tech., 2011. © 2010 Wiley‐Liss, Inc.     

Mode III interlaminar fracture of carbon/epoxy laminates using the Six-Point Edge Crack Torsion (6ECT)

The recently proposed Six-Point Edge Crack Torsion (6ECT) test was used to evaluate the mode III interlaminar fracture of carbon/epoxy laminates. Plate specimens with starter delaminations in 0/0, 0/90 and 0/45 interfaces were tested. Data reduction was performed with an effective crack scheme validated in a previous numerical study. The tests allowed the evaluation of fairly unambiguous initiation G_IIIC values and of subsequent R-curves. Examinations of specimen cross-section showed considerable lengths of pure interlaminar propagation in specimens with starter delaminations in 0/90 and 0/45 interfaces. The latter specimens had the lowest initiation G_IIIC values.     

嵌入式应用中的能耗调试

优化软件和外设的使用率对于节能是至关重要的在越来越多的嵌入式系统应用中,节能和效率已成为开发人员最优先考虑的因素。这种情况可能是出于以下原因：政府管制、增加电池寿命的需求或者仅仅是需要降低用电量。     

A Distributed and Collaborative Intrusion Detection Architecture for Wireless Mesh Networks

Wireless Mesh Network (WMN) is an emerging heterogeneous network architecture that is growing in importance among traditional wireless communication systems as a cost-effective way of providing Internet services. However, WMNs are particularly vulnerable to malicious nodes given their inherent attributes such as decentralized infrastructure and high dependence of node cooperation. We then propose a distributed and Collaborative Intrusion Detection System (CIDS) architecture for detecting insider attacks at real-time, which comprises: i) a Routing Protocol Analyzer (RPA) to analyze the collected routing traffic and generate respective Routing Events; ii) a Distributed Intrusion Detection Engine (DIDE) that treats the Routing Events by applying Routing Constraints and calculate related Misbehaving Metrics; iii) a Cooperative Consensus Mechanism (CCM) to check the Misbehaving Metrics using a proposed threshold scheme and to track down the source of intrusion. The entire CIDS solution is implemented in a virtualized mesh network platform. The experimental results show the proposed CIDS architecture efficiently detects message fabrication attacks with good precision and low resource consumption.     

Assessment of novel diazinon immunoassays for water analysis

Diazinon is a broad organophosphate insecticide used in agricultural and other treatments, resulting in widespread water contamination. The development of easy-to-use screening immunoanalytical methods is an interesting tool to study environmental pollution impact. Two novel strategies for diazinon hapten synthesis are addressed. One of them attaches the spacer arm to the oxygen atom of the diazinon aromatic ring. The other one retains the diazinon basic structure linking the spacer to an aromatic carbon. A total of eight diazinon haptens were synthesized, demonstrating that they are suitable for immunoreagent (protein conjugates and polyclonal antibodies) production. The optimized ELISA is based on conjugate-coated format and had a detection limit of 0.40 microg/L, showing little or no cross-reactivity to similar tested compounds. The immunoassays were used as a tool to quantify diazinon in natural waters. Results are in agreement with those given by GC-MS reference method. Mean recoveries ranging between 99% and 105% confirm the potential of our approach to determine diazinon in samples without purification or preconcentration steps, being applied as a screening method for field monitoring of diazinon in river waters.