Molecular mechanisms for chemoprevention of colorectal cancer by natural dietary compounds

Colorectal cancer is one of the major causes of cancer-related mortality in both men and women worldwide. This review focuses on preventing the initiation and promotion of neoplastic growth in colorectal cancer, particularly with natural dietary compounds. Chemoprevention is defined as the use of natural dietary compounds and/or synthetic substances that can delay, prevent, or even reverse the development of adenomas, as well as the progression from adenoma to carcinoma. The molecular mechanisms of their chemopreventive action are associated with the modulation of signaling cascades, gene expressions involved in the regulation of cell proliferation, differentiation, and apoptosis and the suppression of chronic inflammation, metastasis, and angiogenesis. Here, we summarize the currently known targets and signaling pathways whereby natural dietary compounds interfere with the development of colorectal cancer, and thus providing evidence for these substances in colonic cancer chemopreventive action.     

湿法硫化在加氢裂化装置的首次应用

分析了湿法硫化方法在中国石油化工股份有限公司金陵分公司1.50 Mt/a加氢裂化装置的工业应用情况,对加氢裂化装置传统的干法硫化与湿法硫化进行了详细的对比分析,并对应用湿法硫化后催化剂的活性、稳定性、产品质量等方面进行了评价.     

Life cycle assessment of Chinese shrimp farming systems targeted for export and domestic sales

We conducted surveys of six hatcheries and 18 farms for data inputs to complete a cradle-to-farm-gate life cycle assessment (LCA) to evaluate the environmental performance for intensive (for export markets in Chicago) and semi-intensive (for domestic markets in Shanghai) shrimp farming systems in Hainan Province, China. The relative contribution to overall environmental performance of processing and distribution to final markets were also evaluated from a cradle-to-destination-port perspective. Environmental impact categories included global warming, acidification, eutrophication, cumulative energy use, and biotic resource use. Our results indicated that intensive farming had significantly higher environmental impacts per unit production than semi-intensive farming in all impact categories. The grow-out stage contributed between 96.4% and 99.6% of the cradle-to-farm-gate impacts. These impacts were mainly caused by feed production, electricity use, and farm-level effluents. By averaging over intensive (15%) and semi-intensive (85%) farming systems, 1 metric ton (t) live-weight of shrimp production in China required 38.3 ± 4.3 GJ of energy, as well as 40.4 ± 1.7 t of net primary productivity, and generated 23.1 ± 2.6 kg of SO(2) equiv, 36.9 ± 4.3 kg of PO(4) equiv, and 3.1 ± 0.4 t of CO(2) equiv. Processing made a higher contribution to cradle-to-destination-port impacts than distribution of processed shrimp from farm gate to final markets in both supply chains. In 2008, the estimated total electricity consumption, energy consumption, and greenhouse gas emissions from Chinese white-leg shrimp production would be 1.1 billion kW·h, 49 million GJ, and 4 million metric tons, respectively. Improvements suggested for Chinese shrimp aquaculture include changes in feed composition, farm management, electricity-generating sources, and effluent treatment before discharge. Our results can be used to optimize market-oriented shrimp supply chains and promote more sustainable shrimp production and consumption.     

Biocompatible transferrin-conjugated sodium hexametaphosphate-stabilized gold nanoparticles: synthesis, characterization, cytotoxicity and cellular uptake

The feasibility of using gold nanoparticles (AuNPs) for biomedical applications has led to considerable interest in the development of novel synthetic protocols and surface modification strategies for AuNPs to produce biocompatible molecular probes. This investigation is, to our knowledge, the first to elucidate the synthesis and characterization of sodium hexametaphosphate (HMP)-stabilized gold nanoparticles (Au-HMP) in an aqueous medium. The role of HMP, a food additive, as a polymeric stabilizing and protecting agent for AuNPs is elucidated. The surface modification of Au-HMP nanoparticles was carried out using polyethylene glycol and transferrin to produce molecular probes for possible clinical applications. In vitro cell viability studies performed using as-synthesized Au-HMP nanoparticles and their surface-modified counterparts reveal the biocompatibility of the nanoparticles. The transferrin-conjugated nanoparticles have significantly higher cellular uptake in J5 cells (liver cancer cells) than control cells (oral mucosa fibroblast cells), as determined by inductively coupled plasma mass spectrometry. This study demonstrates the possibility of using an inexpensive and non-toxic food additive, HMP, as a stabilizer in the large-scale generation of biocompatible and monodispersed AuNPs, which may have future diagnostic and therapeutic applications.     

Novel hyperbranched polyamidoamine nanoparticles for transfecting skeletal myoblasts with vascular endothelial growth factor gene for cardiac repair

We investigated the feasibility and efficacy of hyperbranched polyamidoamine (hPAMAM) mediated human vascular endothelial growth factor-165 (hVEGF₁₆₅) gene transfer into skeletal myoblasts for cardiac repair. The hPAMAM was synthesized using a modified one-pot method. Encapsulated DNA was protected by hPAMAM from degradation for over 120 min. The transfection efficiency of hPAMAM in myoblasts was 82.6 ± 7.0% with cell viability of 94.6 ± 1.4% under optimal conditions. The hPAMAM showed much higher transfection efficiency (P < 0.05) than polyetherimide and Lipofectamine 2000 with low cytotoxicity. The transfected skeletal myoblasts gave stable hVEGF₁₆₅ expression for 18 days. After transplantation of hPAMAM–hVEGF₁₆₅ transfected cells, apoptotic myocardial cells decreased at day 1 and heart function improved at day 28, with increased neovascularization (P < 0.05). These results indicate that hPAMAM-based gene delivery into myoblasts is feasible and effective and may serve as a novel and promising non-viral DNA vehicle for gene therapy in myocardial infarction.     

Experimental simulation on the integration of solid oxide fuel cell and micro-turbine generation system

Solid oxide fuel cell (SOFC) is characterized in high performance and high temperature exhaust, and it has potential to reach 70% efficiency if combined with gas turbine engine (GT). Because the SOFC is in developing stage, it is too expensive to obtain. This paper proposes a feasibility study by using a burner (Comb A) to simulate the high temperature exhaust gas of SOFC. The second burner (Comb B) is connected downstream of Comb A, and preheated hydrogen is injected to simulate the condition of sequential burner (SeqB). A turbocharger and a water injection system are also integrated in order to simulate the situation of a real SOFC/GT hybrid system. The water injection system is used to simulate the water mist addition at external reformer.     

The performance of miniature metallic PEM fuel cells

A prototype of metallic PEM fuel cell with thin stainless steel bipolar plates was tested for their potential applications in portable electronic products. The flow field pattern was grown from the stainless steel plates by the electroforming process. The main flow channel has the dimensions of 300 μm (width) × 300 μm (depth). The dimensions of the micro-features were 100 μm width × 50 μm depth and 50 μm width × 50 μm depth. The material of the electroformed flow field pattern is nickel. A prototype of a single cell with total thickness of 2.6 mm, overall reaction area of 4 cm² and bipolar plate area of 16 cm² was assembled for this study. In order to improve its corrosion resistance, the bipolar plates were coated with 5 μm thick of multi-layered corrosion resistant material.     

A study of the backup reprovisioning problem for FIPP p-cycles on WDM networks

As networks grow in size and complexity, both the probability and the impact of failures increase. The pre-allocated backup bandwidth cannot provide 100% protection guarantee when multiple failures occur in a network. In this article, we focus on how to recover the protecting capabilities of FIPP (Failure-independent path-protecting) p-cycles against the subsequent links failure on WDM networks, after recovering the working paths affected by the failure of link. Two recovering policies are designed to recover the protecting capabilities of the FIPP p-cycles if possible, unless there is no sufficient network resource. They are Cycle Recovery Policy and Path Recovery Policy. In addition, a Cycle Adjust algorithm is proposed and used to recover the affected cycles. The simulation results of the proposed methods are also given.     

An Automatic Presence Service for Low Duty-Cycled Mobile Sensor Networks

We consider providing presence service for duty-cycled wireless sensor networks through a multihop approach. The presence service is to ensure automatic network monitoring by which each node would know whether the sink node is reachable or not. Towards providing such presence service, we tackle three problems: 1) efficient neighbor discovery due to not-always-awake nature of duty-cycling and the mobile environment, 2) light presence message passing from the sink node to all reachable nodes given broadcasting is expensive and difficult in an embedded duty-cycling network, and 3) automatic network monitoring if there is node failure and network partition. In our protocol, in order to save power consumption, an online node which is reachable from the sink node only book-keeps the broadcast schedule of its parent in a breadth-first-search spanning tree in order to trace the online status all along. The offline node which is not reachable from the sink node stays awake periodically based on quorum-based wakeup scheduling, and probes the beacons which may come from online nodes. The presence protocol can automatically detect link failure or network partition, and it can also automatically recover online status for each sensor node if there is a path to the sink node, which is significant for applications that are sensitive to end-to-end latency constraints. The presence protocol proposed is implemented through a layered approach so that it is independent from any specific MAC and routing protocols. We make extensive simulations in order to validate the energy efficiency and reliability of our design.