Infrared dichroism of gold nanorods controlled using a magnetically addressable mesophase

Gold nanorods have unique optical properties, which make them promising candidates for building nano-structured materials using a "bottom-up" strategy. We formulate stable bulk materials with anisotropic optical properties by inserting gold and iron oxide nanorods within a lamellar mesophase. Quantitative measurements of the order parameter by modelling the absorbance spectra show that the medium is macroscopically aligned in a direction defined by an external magnetic field. Under field, the system exhibits significant absorption dichroism in the infrared range, at the position of the longitudinal plasmon peak of the gold nanorods (about 1200 nm), indicating strong confinement of these particles within the water layers of the lamellar phase. This approach can yield soft and addressable optical elements

A Study of Dark Matter and QCD-Charged Mediators in the Quasi-Degenerate Regime

We study a scenario in which the only light new particles are a Majorana fermion dark matter candidate and one or more QCD-charged scalars, which couple to light quarks. This scenario has several interesting phenomenological features if the new particles are nearly degenerate in mass. In particular, LHC searches for the light scalars have reduced sensitivity, since the visible and invisible products tend to be softer. Moreover, dark matter-scalar co-annihilation can allow even relatively heavy dark matter candidates to be consistent thermal relics. Finally, the dark matter nucleon scattering cross section is enhanced in the quasi-degenerate limit, allowing direct detection experiments to use both spin-independent and spin-dependent scattering to probe regions of parameter space beyond those probed by the LHC. Although this scenario has broad application, we phrase this study in terms of the MSSM, in the limit where the only light sparticles are a bino-like dark matter candidate and light-flavored squarks.Comment: 24 pages, 5 figures; as published in PRD with significant revision

The effects of high pressure and temperature environments on the properties of 6061-T651 aluminum

During this experimental testing program the effects of the simultaneous application of high pressure and temperature environments on the mechanical properties of 6061-T651 aluminum were analyzed. From the data obtained at the yield and ultimate points a yield and ultimate model was developed based upon the parameters effective stress, effective strain, and the hydrostatic component of stress. This model was obtained solely from the data acquired from uniaxial tensile specimen tested at various pressures and temperatures. Two other loading paths--biaxial tension and torsion--were then used to verify the accuracy of the model. From the testing program, data were also obtained for the effects of the pressure and temperature environments on the other material properties such as Young\u27s Modulus, Poisson\u27s Ratio, and ductility. The third objective of this testing program was to develop test fixtures which would be able to perform the required tests as well as to operate under the extreme environmental conditions --Abstract, page iii

Immunisation and antibody reactions: a series of experimental studies

1. By means o f many animal experiments, a thorough investigation has been made into the principles upon which our knowledge of immunity is based. The general conclusion I have drawn from a consideration of the investigation as a whole is , that the question of immunity is of such great complicity that only a few of the most elementary details are understood. If no benefit, other than the realisation of our ignorance and the difficulties with which we have to contend, resulted from this work, I should still be satisfied.I have heard well known clinicians lecture to students on the subject of infection and immunity in such a way that the audience must have believed that the subject had been completely investigated and that no doubts now remained about the methods by which a patient overcomes an infection. From the researches described in Part II, the real truth is, that we are not in a position to dogmatise on even the simplest immunological reaction. For instance, from the experiments prepared with B. suipestifer vaccines, we saw that immunised animals could possess large amounts of antibodies and yet show no immunity to a lethal dose of living organisms. On the other hand, in the pneumococcal investigation it was shown that animals could possess a high degree of immunity with an apparent absence of antibodies. While lastly in the tuberculin investigations, animals which had been immunised with large quantities of tuberculin appeared to be susceptible both to the infection and also to produce very limited amounts of antibody. The correlation of such facts is at present beyond our powers. My plea is that we should re-investigate the whole problem of immunity from the very beginning. Let us freely admit our ignorance and the difficulties of the subject. Carefully controlled researches will unravel the problems and, when a solution is forth ­ coming, the whole therapeutic field of medicine will be revolutionised.2. Apart from a general investigation into the problems of immunity, I set out to discover if the physical and chemical processes employed in the production of detoxicated and defatted vaccines affected the antigenic values of these vaccines. Fortunately, a definíte clear- cut answer to this question can be be given which is based on the experimental results described in Chapters I . - V. Part II.I can state with every degree of confidence that as judged byI. The production of antibodies andII. Protection to a lethal dose of organismsthe physical and chemical processes employed in the manufacture of detoxicated and defatted vaccines have destroyed their antigenic value