Hybridization between wild and cultivated potato species in the Peruvian Andes and biosafety implications for deployment of GM potatoes

The nature and extent of past and current hybridization between cultivated potato and wild relatives in nature is of interest to crop evolutionists, taxonomists, breeders and recently to molecular biologists because of the possibilities of inverse gene flow in the deployment of genetically-modified (GM) crops. This research proves that natural hybridization occurs in areas of potato diversity in the Andes, the possibilities for survival of these new hybrids, and shows a possible way forward in case of GM potatoes should prove advantageous in such areas

Immune-Complex Mimics as a Molecular Platform for Adjuvant-Free Vaccine Delivery

Protein-based vaccine development faces the difficult challenge of finding robust yet non-toxic adjuvants suitable for humans. Here, using a molecular engineering approach, we have developed a molecular platform for generating self-adjuvanting immunogens that do not depend on exogenous adjuvants for induction of immune responses. These are based on the concept of Immune Complex Mimics (ICM), structures that are formed between an oligomeric antigen and a monoclonal antibody (mAb) to that antigen. In this way, the roles of antigens and antibodies within the structure of immune complexes are reversed, so that a single monoclonal antibody, rather than polyclonal sera or expensive mAb cocktails can be used. We tested this approach in the context of Mycobacterium tuberculosis (MTB) infection by linking the highly immunogenic and potentially protective Ag85B with the oligomeric Acr (alpha crystallin, HspX) antigen. When combined with an anti-Acr monoclonal antibody, the fusion protein formed ICM which bound to C1q component of the complement system and were readily taken up by antigen-presenting cells in vitro. ICM induced a strong Th1/Th2 mixed type antibody response, which was comparable to cholera toxin adjuvanted antigen, but only moderate levels of T cell proliferation and IFN-γ secretion. Unfortunately, the systemic administration of ICM did not confer statistically significant protection against intranasal MTB challenge, although a small BCG-boosting effect was observed. We conclude that ICM are capable of inducing strong humoral responses to incorporated antigens and may be a suitable vaccination approach for pathogens other than MTB, where antibody-based immunity may play a more protective role

QCD and strongly coupled gauge theories : challenges and perspectives

We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

Microstructural examination of solar-beam-irradiated TiN hard coatings

Microstructural examination and characterization of hard coatings may enable engineers to improve coating deposition processes and bring tribologists a step closer to the understanding of tribological mechanisms responsible for the failure of hard coatings. Since a thin oxide film on top of hard coatings could act as a solid lubricant and improve the wear and fretting behaviour of these coatings, the examination of such films is of special interest. The oxide films were produced on physical-vapour-deposited TiN coatings a few micrometres thick by irradiation with concentrated solar energy in ambient atmosphere at 800-degrees-C and for holding times between 10 and 350 s. For the analysis and characterization of the oxidized coating microstructure, micro-Raman spectroscopy and atomic force microscopy have been performed on oxidized surfaces. Light optical and scanning electron microscopy were done,on polished low angle and fractured coating cross-sections, while transmission electron microscopy has been performed on thin foils showing the coatings either parallel or cross-sectional to the surface. The dark grey oxide films found on TiN have been identified as rutile TiO2. These layers appeared with a uniform thickness but contain a non-uniform porosity over the oxide film thickness. Close to the TiN interface generally a higher porosity has been observed in the rutile. No sharp interface between TiN and rutile could be found. The TiN-rutile interface is characterized by oxide formation along the TiN grain boundaries.status: publishe

Surface modification of TiN hard coatings with concentrated solar energy

Physical vapour deposited TiN coatings were partially oxidized by a beam induced heat treatment using concentrated solar radiation, in a search for the tailoring of the functionality of hard ceramic coatings. The TiN coatings were heated in ambient air up to 800-degrees-C at a mean heating rate of 1.2-degrees-C/s and held at this temperature for periods of 10, 60, and 350 s. The solar treated samples were characterized using techniques as Rutherford backscattering spectrometry, grazing incidence X-ray diffraction, and cross-sectional transmission electron microscopy. At the surface of the heat treated TiN coatings, single oxide layers consisting of the rutile polymorph of TiO2 were identified. The oxide microstructure was found to be porous and non-uniform across the layer thickness, in particular near the interface between oxide and nitride. The growth of a dense recrystallized oxide layer at the outer surface was observed after a prolonged solar beam treatment of 350 s.status: publishe

Comparative investigation by laser profilometry, scanning electron microscopy and atomic force microscopy of wear on solar-beam-irradiated partially oxidized TiN coatings

TiN coatings produced by physical or chemical vapour deposition have been successfully introduced in industry, eg. for cutting and forming of materials. The potential of an additional oxide film on such coatings has been investigated with respect to wear protection. Partial oxidation of TiN coatings was realized by concentrated solar beam irradiation at 800-degrees-C for 10 s. Wear testing under controlled conditions was done by reciprocating sliding of coated flat partially oxidized TiN, as-deposited TiN and bulk Al2O3 samples against non-reactive corundum balls. The wear tracks were investigated by laser profilometry, scanning electron microscopy and atomic force microscopy. The essential benefit of atomic force microscopy appears to be the high resolution study of debris and wear damage on the nanometre scale. This technique appears to be complementary to profilometry and scanning electron microscopy. The coefficient of friction showed higher values on partially oxidized TiN in comparison with as-plated TiN; the lowest value was obtained for Al2O3. Notwithstanding the high coefficient of friction, the wear volume on partially oxidized TiN was considerably smaller in comparison with as-plated TiN owing to a difference in wear mechanism. Small plateaus of compacted wear debris were observed in the wear tracks on the oxidized TiN, while loose wear debris was found in the wear track on TiN.status: publishe