Synthesis, solution structure and immune recognition of an epidermal growth factor-like domain from Plasmodium falciparum merozoite surface protein-1

The Plasmodium falciparum merozoite surface protein-1 19 kDa fragment (MSP-1(19)) comprises two closely packed EGF-like domains (EGF=epidermal growth factor), each stabilized by three disulfide bonds. The native conformation of this protein is important for eliciting P. falciparum growth inhibitory antibodies. Here we show that the N-terminal EGF domain alone can be chemically synthesized and efficiently refolded to a native-like state, as shown by its solution structure as determined by NMR spectroscopy. In order to study its immunogenicity, the domain was coupled through its N terminus to a phospholipid and incorporated into reconstituted influenza virus-like particles (virosomes). When used to immunize mice, the peptide-loaded virosomes elicited potent humoral immune responses that were shown by Western blots and immunofluorescence assays to cross-react with native MSP-1 on the surfaces of P. falciparum blood stage parasites. This opens the way for a medicinal chemistry-oriented approach to the study and optimization of the antigenicity of the protein as a potential malaria vaccine candidate, whilst exploiting the immunopotentiating properties of influenza virosomes as a delivery vehicle.     

Movie exposure to smoking cues and adolescent smoking onset: A test for mediation through peer affiliations.

Objective: To determine whether the effect of movie exposure to smoking on adolescent smoking onset is mediated through increased affiliation with peers who smoke. Design: A longitudinal study was conducted with a sample of 5th- 8th graders; persons who were nonsmokers at the baseline assessment (N = 2,614) were followed up 18 months later. Movie exposure to smoking cues was assessed at baseline with a rigorous coding procedure. Main Outcome Measure: A school-based survey and follow-up telephone interview determined whether the participant smoked cigarettes. Results: Longitudinal structural modeling analysis indicated movie-smoking exposure was related to smoking onset both through an indirect effect involving increased affiliation with peer smokers and through a direct effect. The analysis controlled for demographics, parenting style, rebelliousness and sensation seeking, school performance, parental smoking, and sibling smoking; several of these variables also had mediated or direct effects to smoking onset. Conclusion: The effect of movie exposure on adolescent smoking onset is attributable in part to a social mechanism. Implications of media effects for prevention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Content-adaptive feature extraction using image variance

The problem of scale is of fundamental interest in image processing, as the features that we visually perceive and find meaningful vary significantly depending on their size and extent. It is well known that the strength of a feature in an image may depend on the scale at which the appropriate detection operator is applied. It is also the case that many features in images exist significantly over a limited range of scales, and, of particular interest here, that the most salient scale may vary spatially over the feature. Hence, when designing feature detection operators, it is necessary to consider the requirements for both the systematic development and adaptive application of such operators over scale- and image-domains.

We present a new approach to the design of scalable derivative edge detectors, based on the finite element method, that addresses the issues of method and scale adaptability. The finite element approach allows us to formulate scalable image derivative operators that can be implemented using a combination of piecewise-polynomial and Gaussian basis functions. The issue of scale is addressed by partitioning the image in order to identify local key scales at which significant edge points may exist. This is achieved by consideration of empirically designed functions of local image variance.     

Effects of target bias voltage on indium tin oxide films deposited by high target utilisation sputtering

Indium tin oxide (ITO) films were deposited by reactive High Target Utilisation Sputtering (HiTUS) onto glass and polyimide substrates. The ion plasma was generated by an RF power source while the target bias voltage was varied from 300 V to 500 V using a separate DC power supply. The deposition rate, at constant target power, increased with DC target voltage due to increased ion energy reaching 34 nm/min at 500 V. All the films were polycrystalline and showed strong (400) and (222) reflections with the relative strength of latter increasing with target bias voltage. The resistivity was lowest at 500 V with values of 1.8 × 10^− 4 Ω cm and 2.4 × 10^− 4 Ω cm on glass and polyimide, respectively but was still less than 5 × 10^− 4 Ω cm at 400 V. All films were highly transparent to visible light, (> 80%) but the NIR transmittance decreased with increasing target voltage due to higher free carrier absorption. Therefore, ITO films can be deposited onto semiconductor layers such as in solar cells, with minimal ion damage while maintaining low resistivity.     

Depth profiling of 4-acetamindophenol-doped poly(lactic acid) films using cluster secondary ion mass spectrometry

The feasibility of using cluster secondary ion mass spectrometry for depth profiling of drug delivery systems is explored. The behavior of various biodegradable polymer films under dynamic SF(5)(+) primary ion bombardment was investigated, including several films doped with model drugs. The SF(5)(+) depth profiles obtained from these biodegradable polymer films showed very little degradation in secondary ion signal as a function of increasing primary ion dose, and it was discovered that the characteristic ion signals for the polymers remained constant for ion doses up to approximately 5 x 10(15) ions/cm(2). These results suggest that the polyester structure of the biodegradable polymers studied here allows for a greater ability to depth profile due to ease of main chain scission. Attempts were also made to depth profile through a series of poly(lactic acid) (PLA) films containing varying concentrations of the drug 4-acetamidophenol. The depth profiles obtained from these films show very little decrease in both the 4-acetamidophenol molecular ion and PLA fragment ion signals as a function of increasing SF(5)(+) primary ion dose. Similar results were obtained with theophylline-doped PLA films. These results show that, in some drug delivery devices, it is possible to monitor the distribution of a drug as a function of depth by using cluster primary ion beams.     

The Effect of Mixing on the Mechanical Properties of Hyaluronan‐Based Injectable Hydrogels

A method for determining the correlation between the mixing of two reactive polymers and the structural and mechanical properties of the formed hydrogels is presented. Rheological measurements show that insufficient mixing gives rise to soft and not fully crosslinked hydrogels while excessive mixing beyond gel point results in weaker hydrogels due to potential breakage of their 3D network. Furthermore, the hydrogels swell significantly more in cell culture medium than in phosphate‐buffered saline, attributed to interactions with additional molecules such as proteins. Thus, moderate mixing gives rise to the most homogenous and mechanically stable hydrogels and the choice of medium e.g., for release experiments, should be consistent in order to avoid unnecessary variations in the data caused by different swelling profiles.

     

Home Foreclosures as Early Warning Indicator of Neighborhood Decline

Problem, research strategy, and findings: Ideally, planners would intervene in neighborhood processes before substantial forces of decline have gained momentum. Unfortunately, currently there is no guidance about which neighborhood indicators forecast future neighborhood changes. This study seeks a neighborhood early warning indicator that is readily available, frequently updated, and that predicts with substantial foresight and accuracy future changes in key aspects of neighborhood market processes and quality of life. We search over a range of neighborhood indicators for one or more that clearly lead others in a temporal sense, instead of lagging behind them. We employ Granger causality tests with indicators related to public safety, housing market, and economic activity that are based on data from Chicago neighborhoods between 1998 and 2009. Our key finding is that only one indicator analyzed, completed home foreclosures, systematically precedes other neighborhood indicators but does not systematically follow after them. All other indicators are enmeshed in complicated, often mutually causal temporal patterns, which render them inappropriate for forecasting. We conclude that completed home foreclosures is an appropriate early warning indicator of neighborhood decline in several dimensions.

Takeaway for practice: Planners interested in identifying imminently emerging problems in their constituents’ neighborhoods should regularly acquire and map data on home foreclosures as soon as they become available, and then undertake compensatory actions as quickly as feasible.     

Auditory registration without learning.

In 3 studies, the authors explore how repeated exposure to a spoken word affects memory for perceptual attributes associated with the word (such as a talker's voice or a word's plurality). Subjects heard a list of words; particular words were repeated differing numbers of times. At test, subjects estimated the frequency of each word, with instructions to give frequency judgments of "zero" to words with changed attributes. The experiments demonstrate that memory for perceptual attributes improves very little after the first few repetitions, although word memory continues to improve. The experiments extend the registration without learning effect (D. L. Hintzman, T. Curran, and B. Oppy, 1992) to auditory words, to complex attributes (voice), and to conditions of low and high stimulus variability (two or many voices). (PsycINFO Database Record (c) 2010 APA, all rights reserved)