What LDEF means for development and testing of materials

The Long Duration Exposure Facility (LDEF) served as the ultimate laboratory to provide combined space environmental effects on materials. The LDEF structure and its 57 experiments contained an estimated 12,000 to 14,000 specimens of materials and materials processes. It not only provided information about the resistance of these materials to the space environment but gives us direction into future needs for spacecraft materials development and testing. This paper provides an overview of the materials effects observed on the satellite and suggests recommendations for the future work in space-qualified materials development and space environmental simulation

Trapped radiation

The vulnerability of spacecraft materials and components to trapped radiation in aerospace environment is considered along with which orbits the radiation effects are most likely to occur. It seems that the effects on organic polymers are embrittlement, change of modulus and coefficient of expansion; on optics the effects are discoloration and distortion. The effects on integrated circuits are also listed

Working group written presentation: Trapped radiation effects

The results of the Trapped Radiation Effects Panel for the Space Environmental Effects on Materials Workshop are presented. The needs of the space community for new data regarding effects of the space environment on materials, including electronics are listed. A series of questions asked of each of the panels at the workshop are addressed. Areas of research which should be pursued to satisfy the requirements for better knowledge of the environment and better understanding of the effects of the energetic charged particle environment on new materials and advanced electronics technology are suggested

Spacecraft materials studies on the Aerospace Corporation tray on EOIM-3

A passive tray was flown on the Effects of Oxygen Interaction with Materials experiment on STS-46 (EOIM-3) with 82 samples from The Aerospace Corporation. A variety of advanced materials related to potential uses on future spacecraft were included for evaluation representing optical coatings, lubricants, polymers, composites, carbon-carbon composite protective coatings, graphite protective coatings, thermal-control materials, and some samples of current materials. An overview of the available results from the investigations of these materials is presented

Somatic activating mutations in Pik3ca cause sporadic venous malformations in mice and humans.

Venous malformations (VMs) are painful and deforming vascular lesions composed of dilated vascular channels, which are present from birth. Mutations in the TEK gene, encoding the tyrosine kinase receptor TIE2, are found in about half of sporadic (nonfamilial) VMs, and the causes of the remaining cases are unknown. Sclerotherapy, widely accepted as first-line treatment, is not fully efficient, and targeted therapy for this disease remains underexplored. We have generated a mouse model that faithfully mirrors human VM through mosaic expression of Pik3ca(H1047R), a constitutively active mutant of the p110α isoform of phosphatidylinositol 3-kinase (PI3K), in the embryonic mesoderm. Endothelial expression of Pik3ca(H1047R)resulted in endothelial cell (EC) hyperproliferation, reduction in pericyte coverage of blood vessels, and decreased expression of arteriovenous specification markers. PI3K pathway inhibition with rapamycin normalized EC hyperproliferation and pericyte coverage in postnatal retinas and stimulated VM regression in vivo. In line with the mouse data, we also report the presence of activating PIK3CA mutations in human VMs, mutually exclusive with TEK mutations. Our data demonstrate a causal relationship between activating Pik3ca mutations and the genesis of VMs, provide a genetic model that faithfully mirrors the normal etiology and development of this human disease, and establish the basis for the use of PI3K-targeted therapies in VMs.Postdoctoral fellowships were from EMBO (A LTF 165-2013) to S.D.C, EU Marie Curie (MEIF-CT-2005-010264) to E.T. and EU Marie Curie (PIIF-GA-2009-252846) to I.M.B. M.Z.-T. is supported by the EPSRC Early Career Fellowship of T.L.K. (EP/L006472/1). D.J.S. is a BHF Intermediate Basic Science Research Fellow (FS/15/33/31608). A.L.D is supported by the UK NIHR Joint UCL/University College London Hospitals Biomedical Research Centre. V.E.R.P. was supported by the Wellcome Trust (097721/Z/11/Z). R.K.S. is supported by the Wellcome Trust (WT098498), the Medical Research Council (M RC_MC_UU_12012/5). R.G.K. is supported by the NIHR Rare Diseases Translational Research Collaboration. V.W. is supported by the European FPVI Integrated Project ‘Eurostemcell’. M.F.L. and A.B. are supported by the King’s College London and UCL Comprehensive Cancer Imaging Centre CR-UK and EPSRC, in association with the MRC and DoH (England). W.A.P. is supported by funding from the National Health and Medical Research Council (NHMRC) of Australia. Work in the laboratory of M.G. is supported by research grants SAF2013-46542-P and SAF2014-59950-P from MICINN (Spain), 2014-SGR-725 from the Catalan Government, the People Programme (Marie Curie Actions) from the European Union's Seventh Framework Programme FP7/2007-2013/ (REA grant agreement 317250), the Institute of Health Carlos III (ISC III) and the European Regional Development Fund (ERDF) under the integrated Project of Excellence no. PIE13/00022 (ONCOPROFILE). Work in the laboratory of B.V. is supported by Cancer Research UK (C23338/A15965) and the UK NIHR University College London Hospitals Biomedical Research Centre.This is the author accepted manuscript. The final version is available from the American Association for the Advancement of Science via http://dx.doi.org/10.1126/scitranslmed.aad998

N332-Directed Broadly Neutralizing Antibodies Use Diverse Modes of HIV-1 Recognition: Inferences from Heavy-Light Chain Complementation of Function

<div><p>Dozens of broadly neutralizing HIV-1 antibodies have been isolated in the last few years from the sera of HIV-1-infected individuals. Only a limited number of regions on the HIV-1 spike, however, are recognized by these antibodies. One of these regions (N332) is characterized by an <i>N</i>-linked glycan at residue 332 on HIV-1 gp120 and is recognized by antibody 2G12 and by the recently reported antibodies PGT121-137, the latter isolated from three donors. To investigate the diversity in mode of antibody recognition at the N332 site, we used functional complementation between antibody heavy and light chains as a means of assessing similarity in mode of recognition. We examined a matrix of 12 PGT-heavy chains with each of 12 PGT-light chains. Expression in 96-well format for the 144 antibodies (132 chimeric and 12 wild-type) was generally consistent (58±10 µg/ml). In contrast, recognition of HIV-1 gp120 was bimodal: when the source of heavy and light chains was from the same donor, recognition was good; when sources of heavy and light chains were from different donors, recognition was poor. Moreover, neutralization of HIV-1 strains SF162.LS and TRO.11 generally followed patterns of gp120 recognition. These results are consistent with published sequence, mutational, and structural findings, all of which indicate that N332-directed neutralizing antibodies from different donors utilize different modes of recognition, and provide support for a correlation between functional complementation of antibody heavy and light chains and similarity in antibody mode of recognition. Overall, our results add to the growing body of evidence that the human immune system is capable of recognizing the N332-region of HIV-1 gp120 in diverse ways.</p> </div

DFIRE scores of homology modeling of PGT121-137, based on PGT128, PGT121 and 2G12 template structures.

<p>Sequences alignment and homology modeling were carried out with sequences for PGT121-137 heavy and light chain and PGT128, PGT121 and 2G12 structural templates. Low scores indicate good homology modeling and were lowest for the PGT128 sequence modeled on the PGT128 structure (or PGT121 sequence modeled on PGT121 structure). DFIRE score <0.4 are shown in red, 0.4–0.45 in yellow and 0.45–0.5 in green.</p

Relative interdonor complementation for N332-directed antibodies versus VRC01-like antibodies.

<p>Relative neutralization of inter and intra-donor chimeric antibodies. The neutralization of the chimeric antibodies relative to the average neutralization of the wild-type antibodies for the heavy and light chain components is plotted for the N332-directed antibodies (produced by 96-well microplate-formatted expression method) and VRC01-like antibodies (produced by small scale protein production method). The mean N332 intra-donor relative neutralization is 0.82±0.4 while the inter-donor mean is far lower at 0.11±0.16 revealing a functional complementation in the intra-donor chimeras that is not seen with the inter-donor antibodies (p<0.0001). Conversely the VRC01-like antibodies display similar results for intra (0.61±0.45) and inter-donor (0.66±0.43) complementation (p = 0.58). Neutralization values of VRC01-like chimeras were taken from 50 µg/ml concentration points used in previously published neutralization titers (31). Results for strains in which the wild-type neutralization was below 50% were excluded from the analysis.</p

ELISA binding to HIV-1 gp120 by PGT121-137 antibodies and chimeric variants in units of OD₄₅₀

<p> <b>nm.</b> Strong binding is coded in red (>1.0 OD450 nm), intermediate in yellow (0.5–1.0 OD450 nm) and weak in green (0.3–0.5 OD450 nm). Each reported value is the average from three individual measurements, with the absorbance normalized by the expression titer. Note that in cases when the expression level of the antibodies was more than 2-fold different from the average, the normalization is probably not accurate and these numbers have been marked with a star. For comparison, the raw ELISA data has been added as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0055701#pone.0055701.s004" target="_blank">Figure S4</a>.</p

Heavy and light chain nucleotide sequence diversity derived from phylogenetic analysis of PGT121-137 antibodies.

<p>Neighbor-joining (NJ) method was used to calculate the dendrogram. Antibody branches are color-coded according to donors with putative V and J genes labeled under the donor specification.</p