Human fear conditioning is related to dopaminergic and serotonergic biological markers.

Biological markers for acquisition and extinction of fear conditioning were studied in 40 individuals selected for displaying either good or poor acquisiton of fear conditioning, as estimated by the skin conductance response. Participants with a short serotonin transporter (5-HTT) promoter allele or low monoamine oxidase activity in platelets (trbc-MAO) displayed better acquisition than those with only long alleles or high trbc-MAO, whereas participants with a long dopamine D4 receptor (D4DR) exon III allele showed delayed extinction compared with those with only short alleles. The findings, that D4DR exon III and 5-HTT promotor genotypes and trbc-MAO activity are related to human fear conditioning, a basic form of associative learning, are consistent with animal studies suggesting a genetic contribution to fear conditioning. The authors suggest that in humans these genetic mechanisms are partly dopaminergic and serotonergic in origin. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New Jersey Acts on Energy and Climate Change [Living with Technology]

An unusual aspect of this conference was its focus on state-level energy and climate policies. The lack of federal leadership on these issues within the U.S.A. has opened a window of opportunity at the state level for policy entrepreneurs. California acted in 2005 with an executive order establishing greenhouse gas emission reduction targets, ratified in 2006 by the state legislature. New Jersey acted in 2007, helped along by the fact-finding, target-setting effort leading to this conference. The thoughtful discussions and careful analysis that played out during 2006 and early 2007 played a role in giving policymakers and stake holders the confidence to act decisively. Thus, by February 2007, New Jersey's governor had penned an executive order setting two greenhouse gas targets: reduce emissions to 1990 levels by 2020, and reduce emissions to 80% below current levels by 2050.     

Synthesis and properties of new derivatives of poly[9‐(2,3‐epoxypropyl)carbazole]

BACKGROUND: Carbazole derivatives are well known to exhibit interesting electro‐ and photo‐active properties due to their hole‐transporting ability, strong absorption in the ultraviolet spectral region and blue‐light emission. One of the most widely studied materials among carbazole‐containing oligomers is poly[9‐(2,3‐epoxypropyl)carbazole] (PEPK). The main field of application of this oligomer is electrophotographic microfilming. It is also used for the manufacture of multicolour slides and in the photothermoplastic recording of information. Unfortunately, due to its high ionization potential, which reaches 5.86 eV, the possibilities of application of this compound in optoelectronic devices are rather limited. RESULTS: PEPK‐based charge transporting oligomers, incorporating hydrazone moieties, are reported. The oligomers were prepared by chemical modification of PEPK. The materials obtained were examined using various techniques including differential scanning calorimetry and ultraviolet, infrared and NMR spectroscopy. Electron photoemission spectra of layers of the synthesized oligomers showed ionization potentials (I_p) in the range 5.4–5.5 eV. CONCLUSION: The synthesized oligomers possess a larger π‐conjugated system and show ionization potentials of ca 5.4 eV. Therefore, they are more suitable for use in optoelectronic devices with quicker photoresponse than unmodified PEPK. Copyright © 2008 Society of Chemical Industry     

Aryl Bis‐Sulfonamide Inhibitors of IspF from Arabidopsis thaliana and Plasmodium falciparum

2‐Methylerythritol 2,4‐cyclodiphosphate synthase (IspF) is an essential enzyme for the biosynthesis of isoprenoid precursors in plants and many human pathogens. The protein is an attractive target for the development of anti‐infectives and herbicides. Using a photometric assay, a screen of 40 000 compounds on IspF from Arabidopsis thaliana afforded symmetrical aryl bis‐sulfonamides that inhibit IspF from A. thaliana (AtIspF) and Plasmodium falciparum (PfIspF) with IC₅₀ values in the micromolar range. The ortho‐bis‐sulfonamide structural motif is essential for inhibitory activity. The best derivatives obtained by parallel synthesis showed IC₅₀ values of 1.4 μm against PfIspF and 240 nm against AtIspF. Substantial herbicidal activity was observed at a dose of 2 kg ha^?1. Molecular modeling studies served as the basis for an in silico search targeted at the discovery of novel, non‐symmetrical sulfonamide IspF inhibitors. The designed compounds were found to exhibit inhibitory activities in the double‐digit micromolar IC₅₀ range.     

Different bacterial models for in vitro induction of non‐cavitated enamel caries‐like lesions: Microhardness and polarized light miscroscopy analyses

The aim of this study was to compare different bacterial models for in vitro induction of non‐cavitated enamel caries‐like lesions by microhardness and polarized light microscopy analyses. One hundred blocks of bovine enamel were randomly divided into four groups (n = 25) according to the bacterial model for caries induction: (A) Streptococcus mutans, (B) S. mutans and Lactobacillus acidophilus, (C) S. mutans and L. casei, and (D) S. mutans, L. acidophilus, and L. casei. Within each group, the blocks were randomly divided into five subgroups according to the duration of the period of caries induction (4–20 days). The enamel blocks were immersed in cariogenic solution containing the microorganisms, which was changed every 48 h. Groups C and D presented lower surface hardness values (SMH) and higher area of hardness loss (ΔS) after the cariogenic challenge than groups A and B (P < 0.05). As regards lesion depth, under polarized light microscopy, group A presented significantly lower values, and groups C and D the highest values. Group B showed a higher value than group A (P < 0.05). Groups A and B exhibited subsurface caries lesions after all treatment durations, while groups C and D presented erosion‐type lesions with surface softening. The model using S. mutans, whether or not it was associated with L. acidophilus, was less aggressive and may be used for the induction of non‐cavitated enamel caries‐like lesions. The optimal period for inducing caries‐like lesions was 8 days. Microsc. Res. Tech. 78:444–451, 2015. © 2015 Wiley Periodicals, Inc.     

Detection of Legionella spp. and some of their amoeba hosts in floating biofilms from anthropogenic and natural aquatic environments

Floating biofilms develop at the water-air interface and harbor numerous microorganisms, some of which are human pathogens like Legionella pneumophila. The presence of Legionella spp. and especially L. pneumophila in such biofilms was investigated. In parallel, the occurrence of Naegleria spp., Acanthamoeba spp., Willaertia spp., Vahlkampfia spp. and Hartmanella spp. was determined and it was examined whether Acanthamoeba spp. isolates were naturally infected with L. pneumophila bacteria. Eight anthropogenic and 37 natural aquatic environments were sampled between June and August 2005. Both Legionella spp. and L. pneumophila were present in 100% of the floating biofilms of the anthropogenic aquatic systems. Eighty-one percent of all natural floating biofilm samples were positive for Legionella spp. and 70% of these samples were positive for L. pneumophila. Legionella concentrations were in the range of 10(1)-10(2)cells/cm(2). Naegleria spp. and Acanthamoeba spp., two well-known L. pneumophila amoeba hosts, were present in 50-92% and 67-72% of floating biofilm samples, respectively. Acanthamoeba spp. isolates appeared to be naturally infected with L. pneumophila bacteria as proved by fluorescent in situ hybridization.     

Temperature-Dependent Re-alignment of the Short Multifunctional Peptide BP100 in Membranes Revealed by Solid-State NMR Spectroscopy and Molecular Dynamics Simulations

BP100 is a cationic undecamer peptide with antimicrobial and cell-penetrating activities. The orientation of this amphiphilic α-helix in lipid bilayers was examined under numerous conditions using solid-state ¹⁹F, ¹⁵N and ²H NMR. At high temperatures in saturated phosphatidylcholine lipids, BP100 lies flat on the membrane surface, as expected. Upon lowering the temperature towards the lipid phase transition, the helix is found to flip into an upright transmembrane orientation. In thin bilayers, this inserted state was stable at low peptide concentration, but thicker membranes required higher peptide concentrations. In the presence of lysolipids, the inserted state prevailed even at high temperature. Molecular dynamics simulations suggest that BP100 monomer insertion can be stabilized by snorkeling lysine side chains. These results demonstrate that even a very short helix like BP100 can span (and thereby penetrate through) a cellular membrane under suitable conditions.     

Recombinant tropomyosin from Penaeus aztecus (rPen a 1) for measurement of specific immunoglobulin E antibodies relevant in food allergy to crustaceans and other invertebrates

Immunoglobulin E (IgE)-mediated food allergy to crustaceans and mollusks is relatively common and affected individuals typically react to a range of different species. The only known major allergen of shrimp was first described over 20 years ago and later identified as the muscle protein tropomyosin. This protein may be useful as a defined and relevant diagnostic marker for allergic sensitization to invertebrate foods. In order to generate an assay reagent suitable for this purpose, tropomyosin from the shrimp Penaeus aztecus (Pen a 1) was produced as a recombinant protein in Escherichia coli and characterized with respect to IgE antibody binding properties in comparison to natural shrimp tropomyosin. Hexahistidine-tagged rPen a 1 accumulated as a predominantly soluble protein in the E. coli expression host and a two-step chromatographic procedure provided a high yield of pure and homogeneous protein. rPen a 1 displayed chromatographic and folding characteristics similar to those of purified natural shrimp tropomyosin. Serum preincubation with serial protein dilutions revealed similar capacity of recombinant and natural tropomyosin to compete with immobilized shrimp extract for IgE binding. rPen a 1 was further shown to extensively and specifically compete for IgE binding to extracts of other crustacean species, house dust mite and German cockroach.     

Influence of pressure losses on compressor performance in a pressurized fuel cell air supply system for airplane applications

Low ambient pressures at elevated flight altitudes lead to power losses in fuel cell powered aircrafts. As countermeasure ambient air can be pressurized with a suitable fuel cell air supply system. In this study the influence of low ambient pressures and pressure losses within the system on the performance of two turbo compressors and the resulting stack power are examined theoretically and the findings validated experimentally. Results show that decreasing ambient pressures and pressure losses in front and after the compressor reduce the maximum pressure from 2.4 to 1.6 bar(a) in the examined system. Air compression may require a significant share of the fuel cell stack power and the maximum system power is reduced from 54 to 41 kW. For air pressures higher than 1.8 bar(a) the fuel cell stack power gain due to pressurization is found to be cancelled out by the increasing power required for air compression.