Fluorinated xerogel-derived microelectrodes for amperometric nitric oxide sensing

An amperometric fluorinated xerogel-derived nitric oxide (NO) microelectrode is described. A range of fluorine-modified xerogel polymers were synthesized via the cohydrolysis and condensation of alkylalkoxy- and fluoroalkoxysilanes. Such polymers were evaluated as NO sensor membranes to identify the optimum composition for maximizing NO permeability while providing sufficient selectivity for NO in the presence of common interfering species. By taking advantage of both the versatility of sol-gel chemistry and the "poly(tetrafluoroethylene)-like" high NO permselective properties of the xerogels, the performance of the fluorinated xerogel-derived sensors was excellent, surpassing all miniaturized NO sensors reported to date. In contrast to previous electrochemical NO sensor designs, xerogel-based NO microsensors were fabricated using a simple, reliable dip-coating procedure. An optimal permselective membrane was achieved by synthesizing xerogels of methyltrimethoxysilane (MTMOS) and 20% (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxysilane (17FTMS, balance MTMOS) under acid-catalyzed conditions. The resulting NO microelectrode had a conical tip of approximately 20 microm in diameter and approximately 55 microm in length and exhibited sensitivities of 7.91 pA x nM (-1) from 0.2 to 3.0 nM (R (2) = 0.9947) and 7.60 nA x microM (-1) from 0.5 to 4.0 microM ( R (2) = 0.9999), detection limit of 83 pM (S/ N = 3), response time ( t 95%) of <3 s, and selectivity (log K NO, j (amp)) of -5.74, <-6, <-6, <-6, <-6, -5.84, and -1.33 for j = nitrite, ascorbic acid, uric acid, acetaminophen, dopamine, ammonia/ammonium, and carbon monoxide. In addition, the sensor proved functional up to 20 d, maintaining >or=90% of the sensor's initial sensitivity without serious deterioration in selectivity.     

Enhancing mechanical and fracture properties of sandwich composites using nanoparticle reinforcement

Polyurethane (PU) foam is reinforced with SiC nanoparticles to develop core materials for sandwich composites. Isocyanate component (Part A) of PU foam was dispersed with SiC nanoparticles, and then mixed with polyol (Part B) to manufacture nanophased core materials. Nanoparticle reinforcement varied from 0.1 to 2.0 wt% of the total polymer. Both pristine and silane functionalized SiC nanoparticles were used in the investigation. Nanophased foams were tested in compression and flexure to determine the mechanical properties. Fracture toughnesses K _IC and G _IC were determined using the SENB test. Sandwich panels were fabricated and tested for face-core debond fracture toughness using the tilted sandwich debond test. The study has revealed that reinforcement of the foam by pristine nanoparticles substantially enhances mechanical properties but degrades fracture toughness. This loss in fracture toughness, however, may be recovered with the use of functionalized nanoparticles. Small concentrations (0.1–0.2 wt%) of functionalized nanoparticles provided large improvement in debond fracture toughness of sandwich specimens.     

Advances in the Application of Magnetic Nanoparticles for Sensing

Magnetic nanoparticles (MNPs) are of high significance in sensing as they provide viable solutions to the enduring challenges related to lower detection limits and nonspecific effects. The rapid expansion in the applications of MNPs creates a need to overview the current state of the field of MNPs for sensing applications. In this review, the trends and concepts in the literature are critically appraised in terms of the opportunities and limitations of MNPs used for the most advanced sensing applications. The latest progress in MNP sensor technologies is overviewed with a focus on MNP structures and properties, as well as the strategies of incorporating these MNPs into devices. By looking at recent synthetic advancements, and the key challenges that face nanoparticle‐based sensors, this review aims to outline how to design, synthesize, and use MNPs to make the most effective and sensitive sensors.     

Optimised relay selection for route discovery in reactive routing

On-demand routing protocols have the potential to provide scalable information delivery in large ad hoc networks. The novelty of these protocols is in their approach to route discovery, where a route is determined only when it is required by initiating a route discovery procedure. Much of the research in this area has focused on reducing the route discovery overhead when prior knowledge of the destination is available at the source or by routing through stable links. Hence, many of the protocols proposed to date still resort to flooding the network when prior knowledge about the destination is un-available. This paper proposes a novel routing protocol for ad hoc networks, called On-demand Tree-based Routing Protocol (OTRP). This protocol combines the idea of hop-by-hop routing (as used by AODV) with an efficient route discovery algorithm called Tree-based Optimised Flooding (TOF) to improve scalability of ad hoc networks when there is no prior knowledge about the destination. To achieve this in OTRP, route discovery overheads are minimised by selectively flooding the network through a limited set of nodes, referred to as branching nodes. The key factors governing the performance of OTRP are theoretically analysed and evaluated, including the number of branch nodes, location of branching nodes and number of Route REQuest (RREQ) retries. It was found that the performance of OTRP (evaluated using a variety of well-known metrics) improves as the number of branching nodes increases and the number of consumed RREQ retries is reduced. Additionally, theoretical analysis and simulation results shows that OTRP outperforms AODV, DYMO, and OLSR with reduced overheads as the number of nodes and traffic load increases.     

Modeling Enterococcus densities measured by quantitative polymerase chain reaction and membrane filtration using environmental conditions at four Great Lakes beaches

Data collected by the US Environmental Protection Agency (EPA) during the summer months of 2003 and 2004 at four US Great Lakes beaches were analyzed using linear regression analysis to identify relationships between meteorological, physical water characteristics, and beach characteristics data and the fecal indicator bacteria, Enterococcus. Water samples were analyzed for Enterococcus densities by quantitative polymerase chain reaction (qPCR) and membrane filtration (MF). This paper investigates the ability of regression models to accurately predict Enterococcus densities above or below a threshold value, using environmental data on a beach-by-beach basis for both methods. The ability to create statistical models for real-time water quality analysis would allow beach managers to make more accurate decisions regarding beach safety. Results from linear regression models indicate that environmental factors explain more of the variability in Enterococcus densities measured by MF than Enterococcus densities measured by qPCR. Results also show that models for both methods did not perform well at predicting occurrences in which water quality levels exceeded a threshold.     

穿越黑色时空的光影世界——间离剧

正一家在上海创办的建筑与室内设计事务所,致力于根据客户的需求制定美观新颖的空间解决方案。我们对概念的艺术性和施工的工艺同样重视。每个项目都根据其环境和条件量身定做,并在有限的造价和时间里做出最好的效果。来到这个剧院的观众,都是自己这出戏的演员和导演。间离剧以独特的形态,为观众提供了别具一格     

A comprehensive meta-analysis on evidence of Mediterranean diet and cardiovascular disease: Are individual components equal?

Many studies have reported that higher adherence to Mediterranean diet may decrease cardiovascular disease (CVD) incidence and mortality. We performed a meta-analysis to explore the association in prospective studies and randomized control trials (RCTs) between Mediterranean diet adherence and CVD incidence and mortality. The PubMed database was searched up to June 2014. A total of 17 studies were extracted and 11 qualified for the quantitative analysis. Individuals in the highest quantile of adherence to the diet had lower incidence [relative risk (RR): 0.76, 95% confidence intervals (CI): 0.68, 0.83] and mortality (RR: 0.76, 95% CI: 0.68, 0.83) from CVD compared to those least adherent. A significant reduction of risk was found also for coronary heart disease (CHD) (RR: 0.72, 95% CI: 0.60, 0.86), myocardial infarction (MI) (RR: 0.67; 95% CI: 0.54, 0.83), and stroke (RR: 0.76; 95% CI: 0.60, 0.96) incidence. Pooled analyses of individual components of the diet revealed that the protective effects of the diet appear to be most attributable to olive oil, fruits, vegetables, and legumes. An average reduced risk of 40% for the aforementioned outcomes has been retrieved when pooling results of RCTs. A Mediterranean dietary pattern is associated with lower risks of CVD incidence and mortality, including CHD and MI. The relative effects of specific food groups should be further investigated.     

A brief review of the ionic conductivity enhancement for selected oxide electrolytes

The advantages of lowering the operation temperature of SOFCs have attracted great interest worldwide. One of the major barriers to decreasing the operation temperature is the ohmic loss of the electrolyte. Maximizing the electrolyte ionic conductivity is of significant importance, especially in the absence of new electrolyte materials. The ionic conductivity of electrolytes can be influenced by many parameters. There has been an enormous effort in the literature for the improvement of the electrolyte ionic conductivity. From a practical point of view, this paper reviews various approaches to enhancing the ionic conductivity of polycrystalline zirconia- and ceria-based oxide electrolytes in the light of composition, microstructure, and processing. Suggestions are given for future work.     

Simultaneous segmentation of prostatic zones using Active Appearance Models with multiple coupled levelsets

In this work we present an improvement to the popular Active Appearance Model (AAM) algorithm, that we call the Multiple-Levelset AAM (MLA). The MLA can simultaneously segment multiple objects, and makes use of multiple levelsets, rather than anatomical landmarks, to define the shapes. AAMs traditionally define the shape of each object using a set of anatomical landmarks. However, landmarks can be difficult to identify, and AAMs traditionally only allow for segmentation of a single object of interest. The MLA, which is a landmark independent AAM, allows for levelsets of multiple objects to be determined and allows for them to be coupled with image intensities. This gives the MLA the flexibility to simulataneously segmentation multiple objects of interest in a new image.In this work we apply the MLA to segment the prostate capsule, the prostate peripheral zone (PZ), and the prostate central gland (CG), from a set of 40 endorectal, T2-weighted MRI images. The MLA system we employ in this work leverages a hierarchical segmentation framework, so constructed as to exploit domain specific attributes, by utilizing a given prostate segmentation to help drive the segmentations of the CG and PZ, which are embedded within the prostate. Our coupled MLA scheme yielded mean Dice accuracy values of .81, .79 and .68 for the prostate, CG, and PZ, respectively using a leave-one-out cross validation scheme over 40 patient studies. When only considering the midgland of the prostate, the mean DSC values were .89, .84, and .76 for the prostate, CG, and PZ respectively.     

Confidence intervals in repeated-measures designs: The number of observations principle.

Since the publication of Loftus and Masson’s (1994) method for computing confidence intervals (CIs) in repeated-measures (RM) designs, there has been uncertainty about how to apply it to particular effects in complex factorial designs. Masson and Loftus (2003) proposed that RM CIs for factorial designs be based on number of observations rather than number of participants. However, determining the correct number of observations for a particular effect can be complicated, given the variety of effects occurring in factorial designs. In this paper the authors define a general “number of observations” principle, explain why it obtains, and provide step-by-step instructions for constructing CIs for various effect types. The authors illustrate these procedures with numerical examples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)