Cornet‐Like Phosphotriazine/Diamine Polymers as Reductant and Matrix for the Synthesis of Silver Nanocomposites with Antimicrobial Activity

The synthesis of silver nanoparticles attached on the surface of a hollow cornet‐like polymer matrix which served as a reductant and host matrix is described. This hybrid organic/inorganic macromolecular matrix is exhibiting anion‐exchange properties, porous structure and hollow morphologies, and absorptions in the visible light region. Due to the anion‐exchange property and the 3D orientation of the macromolecular chains the material is defining a new functional organic/inorganic hybrid. For the synthesis of nanoparticles, no other reducing agents were used and silver nanoparticles with a mean diameter of less than 20 nm were attached on the surface of the polymer, thus inheriting the composite with high antibacterial activity tested in bacterial strains and yeasts.

     

Furanocoumarins in vegetables: influence of farming system and other factors on levels of toxicants

Furanocoumarins are toxic chemicals that occur naturally in edible food plants such as celery, parsnip, carrot, etc. belonging to the Apiaceae family. Lower levels of these phytochemicals are also found in citrus fruits and other crops representing the Rutaceae family. Since their presence in the human diet represents a food safety issue of concern, more knowledge is needed to reduce consumer exposure. This paper provides an overview of various factors influencing the levels of furanocoumarins in vegetables and processed commodities. Special attention is paid to the comparison of crops from organic and conventional farming systems with regard to levels of furanocoumarins and their changes during storage and processing. Copyright © 2007 Society of Chemical Industry     

An experimental investigation of iso-octane ignition phenomena

High-speed digital imaging has been used in rapid compression facility (RCF) studies to investigate ignition phenomena of iso-octane/air mixtures. Sequential images were captured for each experiment. The results indicate the existence of two ignition regimes. In one domain, ignition is rapid, typically less than 76 μs, and ignition occurs simultaneously throughout the test volume. In the other domain, reaction fronts form and propagate within the test volume prior to volumetric ignition. The data span equivalence ratios from ?=0.20 to 1.98, with inert/O₂ gas ratios from 1.38 to 5.89, pressures from 8.7 to 16.6 atm, and temperatures from 903 to 1020 K. The transition between the two regimes is discussed in the context of the mixture composition and experimental conditions. The analysis shows that the fuel mole fraction is a key parameter dictating the boundary between the modes of ignition. Below a critical mole fraction limit, volumetric ignition is observed; above the critical limit, reaction fronts are consistently present prior to volumetric ignition. The ignition delay times for both ignition regimes are well reproduced using a homogeneous simulation with detailed reaction chemistry, when the state conditions are modified to account for the presence of the reaction fronts. The results are discussed in terms of proposed reaction chemistry, ignition theory, and previous studies of iso-octane ignition.     

Diagnosing Czech Patients with Inherited Platelet Disorders

A single-center study was conducted on 120 patients with inherited disorders of primary hemostasis followed at our hematological center. These patients presented a variety of bleeding symptoms; however, they had no definitive diagnosis. Establishing a diagnosis has consequences for the investigation of probands in families and for treatment management; therefore, we aimed to improve the diagnosis rate in these patients by implementing advanced diagnostic methods. According to the accepted international guidelines at the time of study, we investigated platelet morphology, platelet function assay, light-transmission aggregometry, and flow cytometry. Using only these methods, we were unable to make a definitive diagnosis for most of our patients. However, next-generation sequencing (NGS), which was applied in 31 patients, allowed us to establish definitive diagnoses in six cases (variants in ANKRD26, ITGA2B, and F8) and helped us to identify suspected variants (NBEAL2, F2, BLOC1S6, AP3D1, GP1BB, ANO6, CD36, and ITGB3) and new suspected variants (GFI1B, FGA, GP1BA, and ITGA2B) in 11 patients. The role of NGS in patients with suspicious bleeding symptoms is growing and it changes the diagnostic algorithm. The greatest disadvantage of NGS, aside from the cost, is the occurrence of gene variants of uncertain significance.     

Formal schooling for four-year-olds? No.

Examines the recent movement toward enrolling 4-yr-olds in academic programs. The research base and political forces that guided the direction of the movement are considered: remedial intervention programs for economically disadvantaged children, the need for change in decaying school programs, and the urgent need for increased day-care services. It is determined that the research base does not demonstrate that early schooling will be beneficial to middle-class children who constitute the majority of 4-yr-olds. It is suggested that early schooling may be an inappropriate solution to the current crisis in child care for working parents and that children's development may suffer if limited educational funds are expended on nonfunctional programs. Developmentally appropriate care programs carried out in school buildings by specialists in early childhood development are suggested as an alternative. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ichthyoplankton abundance and variance in a large river system concerns for long-term monitoring

System-wide spatial patterns of ichthyoplankton abundance and variability were assessed in the upper Mississippi and lower Illinois rivers to address the experimental design and statistical confidence in density estimates. Ichthyoplankton was sampled from June to August 1989 in primary milieus (vegetated and non-vegated backwaters and impounded areas, main channels and main channel borders) in three navigation pools (8, 13 and 26) of the upper Mississippi River and in a downstream reach of the Illinois River. Ichthyoplankton densities varied among stations of similar aquatic landscapes (milieus) more than among subsamples within a station. An analysis of sampling effort indicated that the collection of single samples at many stations in a given milieu type is statistically and economically preferable to the collection of multiple subsamples at fewer stations. Cluster analyses also revealed that stations only generally grouped by their preassigned milieu types. Pilot studies such as this can define station groupings and sources of variation beyond an a priori habitat classification. Thus the minimum intensity of sampling required to achieve a desired statistical confidence can be identified before implementing monitoring efforts.     

Load control in scalable distributed file structures

The paper presents a family of distributed file structures, coined DiFS, for record structured, disk resident files with key based exact or interval match access. The file is organized into buckets that are spread among multiple servers, where a server may hold several buckets. Client requests are serviced by mapping keys onto buckets and looking up the corresponding server in an address table. Dynamic growth, in terms of file size and access load, is supported by bucket splits and bucket migrations onto the existing or newly created servers.The major problem that we are addressing is achieving scalability in the sense that both the file size and the client throughput can be scaled up by linearly increasing the number of servers and dynamically redistributing the data. Unlike previous work with similar objectives, our data redistribution considers explicitly the cost/performance ratio of the system by aiming to minimize the number of servers that are used to provide the required performance. A new server is added only if the overall server load in the system does not drop below a pre-specified threshold. Simulation results demonstrate the scalability with controlled cost/performance and the importance of global load control. The impact of various tuning parameters on the effectiveness of the load control is studied in detail. Finally, we compare our approach with other approaches known to date and demonstrate that each of the previous approaches can be recast as a special case of our model. Recommended by: Mei HsuThis material is based in part upon work supported by a grant from Hewlett-Packard Corporation and by NSF under grant IRI-9221947.     

Social competence and self-image disparity in psychiatric and nonpsychiatric patients.

The relationship between social competence and self-image disparity in 20 psychiatric and 20 nonpsychiatric patients was investigated. Education, intelligence, occupation, employment history, and marital status were used as indices of social competence. Real-ideal-self and real-social-self disparity were each measured with 2 separate paper-and-pencil instruments. The predictions from a developmental framework were confirmed: (a) high competence Ss would manifest higher real-ideal disparity scores than low Ss on both instruments, (b) this difference would be greater on the instrument permitting more response differentiation, (c) the highs would have larger real-social disparity scores than the lows on the instrument allowing the greater response differentiation. This difference between groups would be less than that found for the real-ideal disparity scores. (21 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A room of their own: A proposal to renovate the Children's Bureau.

Discusses the need to reorganize the Children's Bureau in relation to the necessity of developing coordinated policies to address such problems as child abuse and neglect, unavailable and inadequate childcare, and the health risks of poor children. It is recommended that the Children's Bureau (1) become the central data base on children and families in the US, (2) promote research and demonstration projects, (3) serve as an interagency and interdepartmental coordinator of child and family programs in the federal government, and (4) disseminate information to other government agencies and the general public. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)