Graphene Enabled Low-Noise Surface Chemistry for Multiplexed Sepsis Biomarker Detection in Whole Blood

Affinity-based electrochemical (EC) sensors offer a potentially valuable approach for point-of-care (POC) diagnostics applications, and for the detection of diseases, such as sepsis, that require simultaneous detection of multiple biomarkers, but their development has been hampered due to biological fouling and EC noise. Here, an EC sensor platform that enables detection of multiple sepsis biomarkers simultaneously by incorporating a nanocomposite coating composed of crosslinked bovine serum albumin containing a network of reduced graphene oxide nanoparticles that prevents biofouling while maintaining electroconductivity is described. Using nanocomposite coated planar gold electrodes, a sensitive procalcitonin (PCT) sensor is constructed and validated in undiluted serum, which produced an excellent correlation with a conventional ELISA (adjusted r²  = 0.95) using clinical samples. A single multiplexed platform containing sensors for three different sepsis biomarkers—PCT, C-reactive protein, and pathogen-associated molecular patterns—is also developed, which exhibits specific responses within the clinically significant range without any cross-reactivity. This platform enables sensitive simultaneous EC detection of multiple analytes in human whole blood, and it can be applied to detect any target analyte with an appropriate antibody pair. Thus, this nanocomposite-enabled EC sensor platform may offer a potentially valuable tool for development of a wide range of clinical POC diagnostics.     

Thiophene‐based copolymers synthesized by electropolymerization for application as hole transport layer in organic solar cells

Electrically conducting thiophene‐based copolymers were synthesized by electropolymerization. The potential range used has a strong influence on the film structure and properties. The extent of oxidation of the copolymers was determined from the ratio of the oxidation to reduction charge, Q_ox/Q_red. The use of wide potential range leads to reduced films, whereas the narrow range leads to partially oxidized films. The copolymers exhibit a characteristic band in UV–vis spectra at ～ 410 nm, which shifts to higher wavelengths for the more doped material. The electrical conductivity of the copolymers was correlated to their morphology and their structure. The copolymer with higher conductivity is partially reduced, has compact morphology and higher ratio of quinoid to benzenoid rings. The energy gap of the copolymers is reversely proportional to their electrical conductivity. The optical and electrical properties of the copolymers make them very well suited for use as hole transport layers (HTL) in organic opto‐electronic devices. We prepared polymer : fullerene solar cells with copolymer HTLs. The solar cell performance was tested with very encouraging initial results. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Structural Effects in Magnetoresistive Manganites and Mechanism of Metal-Insulator Transition

Colossal magnetoresistivity (CMR) is caused by a magnetic field-induced insulator-to-metal transition. It is arguably one of the most dramatic phenomena that occur in solids due to competing forces in a complex system. In the CMR oxides the electron-phonon coupling and spin correlations that favor charge localization are competing against the electron kinetic energy and lattice elasticity that prefer charge delocalization. The CMR phenomenon occurs at the crossover point of charge-localized (insulating) and charge-delocalized (metallic) states, where the system is particularly susceptible to external stimuli such as a magnetic field. The competitions among these forces are usually considered globally as volume averages. However, since the system is complex and the phenomenon is non-linear, local fluctuations dominate the behavior of the system near the critical point. Therefore the system would appear spatially inhomogeneous if the measurement is made with certain time and length scales. To characterize and understand such a system it is required to deploy local approaches in which the competing interactions are evaluated locally. Experimentally, the pulsed neutron pair-density function (PDF) analysis is one of the methods of local structural study. Using the PDF technique it is suggested that the phase transition occurs via local and percolative processes. Also through the analysis of the local structure it is shown that the ionic size effect on the CMR phenomenon is not caused by a change in the band width as is usually assumed, but is due to local structural changes that affect polaron stability. The critical ionic size determined by this approach is in excellent agreement with experimental observations. The PDF results also indicate that the local structure of layered manganites is close to that of perovskite, suggesting that they share common elements of the CMR mechanisms.     

Reversible Diffraction Efficiency of Photochromic Polymer Gratings Related to Photoinduced Dimensional Changes

In this Full Paper, the possibility of reversibly changing the diffraction efficiency of gratings, fabricated by soft molding lithography on polymer films, containing photochromic molecules, is demonstrated. In particular, alternating UV and visible laser irradiation of the gratings causes the doped photochromic molecules to undergo transformations, which induce reversible dimensional changes to the samples. As a result, reversible changes are monitored in the intensity of the beams of a diode laser, transmitted and diffracted from the gratings. These changes affect the diffraction efficiency, which is increased upon irradiation with UV and decreased after irradiation with visible laser light. Such gratings are promising candidates for the fabrication of modern optical components such as optical switching devices.     

Information flow decomposition for network coding

We propose a method to identify structural properties of multicast network configurations, by decomposing networks into regions through which the same information flows. This decomposition allows us to show that very different networks are equivalent from a coding point of view, and offers a means to identify such equivalence classes. It also allows us to divide the network coding problem into two almost independent tasks: one of graph theory and the other of classical channel coding theory. This approach to network coding enables us to derive the smallest code alphabet size sufficient to code any network configuration with two sources as a function of the number of receivers in the network. But perhaps the most significant strength of our approach concerns future network coding practice. Namely, we propose deterministic algorithms to specify the coding operations at network nodes without the knowledge of the overall network topology. Such decentralized designs facilitate the construction of codes that can easily accommodate future changes in the network, e.g., addition of receivers and loss of links.     

XI. Yeast sequencing reports. The complete sequencing of a 24·6 kb segment of yeast chromosome XI identified the known loci URA1, SAC1 and TRP3, and revealed 6 new open reading frames including homologues to the threonine dehydratases,membrane transporters,hydantoinases and the phospholipase A2-activating protein

We report the entire sequence of a 26·4 kb segment of chromosome XI of Saccharomyces cerevisiae. Identification of the known loci URA1, TRP3 and SAC1 revealed a translocation compared to the genetic map. Additionally, six unknown open reading frames have been identified. One of them is similar to catabolic threonine dehydratases. Another one contains characteristic features of membrane transporters. A third one is homologous in half of its length to the prokaryotic hydantoinase HyuA and in the other half to hydatoinase HyuB. A fourth one is homologous to the mammalian phospholipase A₂-activating protein. A fifth one, finally, is homologous to the hypothetical open reading frame YCR007C of chromosome III. The sequence has been deposited in the EMBL data library under Accession Number X75951.     

Prefiltered space-time M-BCJR equalizer for frequency-selectivechannels

This paper addresses the problem of soft equalization for space-time-coded transmissions over frequency-selective fading channels. The structure of the space-time code is embedded in the channel impulse response for efficient joint equalization and decoding. The proposed equalization/decoding approach uses a prefilter to concentrate the effective channel power in a small number of taps followed by a reduced-complexity maximum a posteriori probability (MAP) equalizer/decoder to produce soft decisions. The prefilter introduces residual intersymbol interference which degrades the performance of MAP when applied to the trellis of the shortened channel. However, the shape of the overall shortened channel impulse response allows the M-algorithm to approximate the prefiltered MAP performance with a small number of states. Based on this general framework, we investigate several enhancements such as using different prefilters for the forward and backward recursions, concatenating two trellis steps during decoding, and temporal oversampling. The performance is evaluated through simulations over the EDGE typical urban channel     

Designing with scenarios: A critical review of current research and practice

There is a great deal of requirements engineering specifically, and information systems development research in general, in the area of scenarios as the ‘vocabulary’ for discussing and characterising designs for new artefacts. This is partly due to opening up the design process to a variety of participants in a project, and making explicit their ways of working, thinking and interactions with the design products. Scenarios, being concrete, and easy to understand and use, provide the means to describe the design vocabulary. They are used to focus on episodic cases, exchange ideas and thoughts about them effectively, and generally describe requirements and designs for a new artefact from the user’s perspective. In this paper, we review the effectiveness of the current state-of-practice in scenario-based approaches. The objective of this evaluation exercise is to define the requirements for improved ‘by scenario’ approaches to cope with requirements and designs for developing new artefacts.     

Quality control and storage studies of virgin olive oil: Exploiting UV spectrophotometry potential

The present work was undertaken in order to examine whether K₂₃₂ values and other UV absorbance characteristics could replace the determination of peroxide value (PV) in routine quality control and also in storage studies of virgin olive oil (VOO). For this reason, PV and extinction coefficients were determined for a large number of VOO samples (n = 40). The samples were then stored at 45 °C for several weeks. Changes in the lipid matrices were monitored by periodic measurements of the same quality indices. UV absorption spectra and the respective derivative ones were obtained before and during storage. Regression data showed that the PV is correlated with the K₂₃₂ value not only at time zero but also during storage. Evidence derived from the first derivative spectrum is strongly related to the oxidative status of the oil. The findings may be used (a) to simplify the decision tree suggested for “the verification of consistency of a VOO sample with commercial category declared” in the EEC Regulation N^o 1989 (2003), which takes into account acidity measurement, PV and absorbance values (K₂₇₀, ΔK, K₂₃₂), and (b) to collect qualitative and quantitative information about the oxidation process during storage.     

The influence of carrying a backpack on college student pedestrian safety

University students walk frequently, and individuals ages 18-22 have among the highest rates of pedestrian injury among any age group in the United States. These injuries are caused by a wide range of individual, interpersonal, and environmental factors, but one factor that has not been previously considered carefully is the influence of wearing a heavy backpack on pedestrian safety. Backpacks are known to slow walking speed and disrupt perception of one's environment, so it is reasonable to question whether they might also influence safe pedestrian behavior. Ninety-six college students engaged in 20 street-crossings within a virtual pedestrian environment. Half the crossings were completed while bearing a backpack weighing 12% of their body weight; the other half were completed without any burdens. Results suggest that participants walked more slowly, left less safe time to spare after crossing the virtual street, and experienced more frequent hits or close calls with traffic when crossing while carrying the backpack. They also missed fewer safe opportunities to cross while carrying the backpack. Our tests of several demographic characteristics, pedestrian behaviors, and backpack use, as covariates suggest the finding holds across all subsamples included in our study. Implications for pedestrian safety and future research are discussed.