Structural study of electrodeposited aluminum-manganese alloys

Aluminum-manganese alloys with compositions ranging between 0 and 27 wt pct Mn were electrodeposited at 150°C onto copper substrates from a chloroaluminate molten salt electrolyte with a controlled addition of MnCl₂. The specimens were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and X-ray diffraction. The addition of small amounts of Mn results in the formation of a supersaturated fcc solid solution of Mn in Al. At the higher Mn content, an amorphous phase is established. The highly faceted crystalline surface of pure Al and Al−Mn solid solution becomes smooth and nearly specular when the amorphous phase is present. The amorphous phase appears in the form of rounded grains and has a lower limit of Mn concentration close to the Al₆Mn composition. There is a concentration discontinuity between the above limit and the higher Mn concentration limit of the fcc phase (about 9 wt pct). Appearance of the amorphous phase in the alloy results in a decrease in the Mn concentration in solid solution to about 2 wt pct. Crystallization of the amorphous phase starts at the fcc-amorphous phase interface at 230°C. As a result of treatment at 230 °C to 340 °C, the amorphous phase completely transforms into Al₆Mn, while the fcc phase is unaffected. Prior to crystallization, the amorphous phase shows a modification that could be interpreted as the formation of a fine-grained icosahedral phase. The formation and distribution of phases by electrodeposition and rapid solidification are discussed.     

Antibodies capable of releasing diphtheria toxin in response to the low pH found in endosomes

Diphtheria toxin (DT) undergoes a rapid conformational change in response to the acidity encountered within endosomes. That transition is integral to the passage of its catalytic domain into the cytosol and thus its lethal action. The importance of this translocation mechanism led us to develop several monoclonal antibodies that bind DT at neutral pH but spontaneously release the toxin when critical epitopes denature or unfold upon lowering the pH to 4.5-5.5. Hybridomas were selected using a microtiter plate assay that measured the pH-dependent detachment of antibody from immobilized toxin. The acid-sensitive epitopes involved were on the catalytic, transmembrane, and receptor binding domains of DT. This pH-induced disruption of the binding of toxin to these monoclonal antibodies was analyzed by sedimentation velocity ultracentrifugation. Antibody combining sites were fully occupied at pH 5.5, partially bound at pH 5.0, and totally empty at pH 4.5. It was estimated that the Ka for antibody-toxin binding was approximately 1000-fold lower at pH 5.0 than at neutral pH. This novel acid-triggered release mechanism provides a basis for delivery of antibody-bound toxin into cells accompanied by its immediate dissociation as the complex enters acidic vesicles.     

Single‐Shot Mesoporous Silica Rods Scaffold for Induction of Humoral Responses Against Small Antigens

Vaccines have shown significant promise in eliciting protective and therapeutic responses. However, most effective vaccines require several booster shots, and it is challenging to generate responses against synthetic molecules and peptides often used to increase target specificity and improve vaccine stability. As continuous antigen uptake and processing by antigen‐presenting cells and persistent toll‐like receptor priming can amplify humoral immunity, it is explored whether a single injection of a mesoporous silica micro‐rod (MSR) vaccine containing synthetic molecules and peptides can generate potent and durable humoral immunity. A single injection of the vaccine targeting a gonadotropin‐releasing hormone (GnRH) decapeptide elicits high anti‐GnRH titer for over 12 months and generated higher titers than bolus or alum formulations. Targeting a Her2/neu peptide within the Trastuzumab binding domain causes immunoreactivity to Her2 on tumor cells and, MSR vaccines against nicotine generated long‐term anti‐nicotine antibodies. A single MSR injection induced germinal center (GC) activity for more than 3 weeks, generated memory B cells, and 7 days of immunostimulation by the vaccine is required to generate effective antibody responses. The MSR vaccine represents a promising technology to bypass the need for multiple immunizations and enhance long‐term antibody production in the context of reproductive biology, cancer, and chronic addiction.     

Loss of fatty acid esters from grape surfaces during drying

Fatty acid esters have been shown to reduce the drying time of grapes by interacting with the waxy surface of the grapes. Laboratory scale procedures were developed to determine the fate of esters during dehydration. Thompson seedless grapes were dipped in a water emulsion containing 2% fatty acid ester, 2% potassium carbonate and an emulsifier. Grapes were dried at ambient, 43 C and 71 C. Drying rates vs. fatty acid ester concentration on the grape surfaces were plotted. The fate of fatty acid esters during dehydration was determined by running the dryer exhaust through a cold trap and extracting the condensate. These studies showed that the large loss of esters during drying lowered the drying rate considerably. An additional dip during drying reduced the drying time significantly. The ester losses appeared to be caused by vapor distillation of the esters during drying.     

A design of a fast pipelined modular multiplier based on a diminished-radix algorithm

We present a new serial-parallel concurrent modular-multiplication algorithm and architecture suitable for standard RSA encryption. In the new scheme, multiplication is performed modulo a multiple of the RSA modulus n, which has a diminished-radix form 2 ^k -v, where k and v are positive integers and v < n. This design is the first concurrent modular multiplier to use a diminished-radix algorithm and to pipeline concurrent modular-reduction to optimize the clock rate. For a modular multiplier of order ranging from 1 to 10 (number of multiplier bits per clock cycle), a faster clock rate and throughput is possible than with other known designs including those of Brickell, Morita, Sedlak and Golze, and Miyaguchi. Throughput estimates for 512-bit RSA decryption range from 100 kbit/s in a serial mode to 650 kbit/s with a modular multiplier of order 10, at a clock rate of 20 MHz on 1.5 m CMOS.     

The impact of unemployment on home ownership

Much of housing policy in Britain and much of the theoretical literature is based on assumptions that home ownership, per se, provides certain distinctive and advantageous characteristics such as independence, security and wealth. This paper provides some empirical evidence as a corrective to these assumptions. It does so by locating their basis not inside but outside the tenure: in particular in the position of individual home owners in the labour market. The paper identifies two sets of costs incurred in home ownership — entry and running costs — and draws on evidence to show how recent changes in the labour market in Britain, which have resulted in widespread unemployment, have affected the ability of many home owners to continue to meet those costs. Specifically it demonstrates that large numbers of home owners experience insecurity of tenure and poor housing conditions.     

Journeys to play: planning considerations to engender inclusive playspaces

Making playspaces inclusive has predominately focused on internal design, addressing factors that constrain play experiences within these spaces for children with diverse impairments and their families. Less attention, however, has been paid to the journey to the site and how that may influence the decision to visit these environments. This paper contributes to this area by discussing the experiences of 10 children with diverse mobility impairments, aged 9–12-years-old, and their families from south-east Queensland, Australia. This person–environment study of their journeys to playgrounds illuminates the role getting to the site and entering the site plays in shaping decisions to actually visit playspaces. The findings also identify key considerations applicable to open space planning and site planning, towards achieving inclusive landscapes for play.     

Expression technology - A review of the performance and interpretation of expression microarrays

Molecular profiling has become a fundamental part of biomedical research, but much more importantly, it is now a direct part of health care. This device for highly parallel measurements of gene expression was once restricted to pure research laboratories. It has now taken its place next to pathology reports as a tool to validate and elaborate upon cellular phenotypes that provide clues to disease status and progression. This article describes general tendencies of the most widely used profiling device, the gene expression array, with some attention paid to other technologies such as head-based devices and e-detection. The paper also examines the characteristics of this technology that makes it so dependent upon robust data normalization and also examines the biological consequence of error