Purification of Anthrax Toxin Protective Antigen Component and Characterization of its Binding Interaction with Bovine Kidney Cells

Protective antigen component of B. anthracis toxin was produced and purified to the \u3e99% level. Toxin was purified from culture supernatant utilizing concentration and liquid chromatography techniques. Purity was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified protective antigen retained biological and antigenic activity as evidenced respectively by lethality in Fischer 344 rats when injected in combination with lethal factor, and by positive results on the Ouchterlony double diffussion assay. Radioiodinated protective antigen was used both in the in vivo and the in vitro experiments. In vivo distribution of labelled protective antigen was determined in Fischer 344 rats. Assay of organ tissues for labelled protective antigen aided in the decision to use Maden-Darby bovine kidney cells for the cell cultures in the protective antigen binding studies. Protective antigen binding studies, all performed at 37°C, evaluated criteria for receptor existence. Labelled protective antigen was found to bind specifically and reversibly to Maden-Darby bovine kidney cells. Receptors proved to be saturable. Scatchard analysis showed a relatively high dissociation constant (KD= 17 X 10-9M) compared to other toxins in similar studies. This indicated moderately low affinity for protective antigen. The receptor was also partially characterized. It was shown that cholera toxin subunit B blocked the binding of labelled protective antigen to Maden-Darby bovine kidney cells and that the protective antigen receptor was insensitive to trypsin treatment. Both of these observations suggest a ganglioside as the receptor for protective antigen

The R∞R_\infty property for nilpotent quotients of generalized solvable Baumslag-Solitar groups

We say a group $G$ has property $R_\infty$ if the number $R(\varphi)$ of twisted conjugacy classes is infinite for every automorphism $\varphi$ of $G$. For such groups, the $R_\infty$-nilpotency degree is the least integer $c$ such that $G/\gamma_{c+1}(G)$ has property $R_\infty$. In this work, we compute the $R_\infty$-nilpotency degree of all Generalized Solvable Baumslag-Solitar groups $\Gamma_n$. Moreover, we compute the lower central series of $\Gamma_n$, write the nilpotent quotients $\Gamma_{n,c}=\Gamma_n/\gamma_{c+1}(\Gamma_n)$ as semidirect products of finitely generated abelian groups and classify which integer invertible matrices can be extended to automorphisms of $\Gamma_{n,c}$.Comment: 11 page

3D thixo-printing : a novel approach for additive manufacturing of biodegradable Mg-Zn alloys

A simple and widely used additive manufacturing technique for polymeric materials is fused filament fabrication (FFF). In the semi-solid state, metallic materials may show rheological features comparable to those of polymers. Thus, they can be processed accordingly. The use of biodegradable Mg-based materials is an interesting approach to avoid removal surgeries and release of toxic corrosion products and wear debris. Therefore, in this study, the FFF technique was applied using a biodegradable Mg-Zn alloy in the semi-solid state. Some preliminary compositions were investigated through thermodynamic simulations to verify their compatibility with the process. Among them, Mg-38Zn was selected to be experimentally evaluated. Metallic filaments were produced via hot extrusion, which also aided in obtaining a globular microstructure in the semi-solid state. FFF was performed at 420 °C without any obstruction at the nozzle channel, which allowed the production of sound parts with acceptable welding between the deposited layers. This indicated that this technique (termed as “3D thixo-printing”) provides a promising additive manufacturing route to produce biodegradable Mg-based implants196CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP405054/2016-52018/10190-

Reinforcement learning in large, structured action spaces: A simulation study of decision support for spinal cord injury rehabilitation

Reinforcement learning (RL) has helped improve decision-making in several applications. However, applying traditional RL is challenging in some applications, such as rehabilitation of people with a spinal cord injury (SCI). Among other factors, using RL in this domain is difficult because there are many possible treatments (i.e., large action space) and few patients (i.e., limited training data). Treatments for SCIs have natural groupings, so we propose two approaches to grouping treatments so that an RL agent can learn effectively from limited data. One relies on domain knowledge of SCI rehabilitation and the other learns similarities among treatments using an embedding technique. We then use Fitted Q Iteration to train an agent that learns optimal treatments. Through a simulation study designed to reflect the properties of SCI rehabilitation, we find that both methods can help improve the treatment decisions of physiotherapists, but the approach based on domain knowledge offers better performance. Our findings provide a "proof of concept" that RL can be used to help improve the treatment of those with an SCI and indicates that continued efforts to gather data and apply RL to this domain are worthwhile.Comment: 31 pages, 7 figure

The Mississippi River System Shallow Draft Barge Market – Perfectly Competitive or Oligopolistic?

Most transportation textbooks and articles on inland waterway navigation assume a perfectly competitive Mississippi River system barge industry. One study found the 1972 and 1977 grain barge industry to be oligopolistic. A second study of the U.S. barge industry found "intra industry competition for the barge industry on a day-to-day basis with easy entry and exit." Using the concentration ratio and the Herfindahl Index, this study found the Mississippi River barge industry to be oligopolistic. These results suggest that Mississippi River navigation infrastructure studies should not use long run marginal barge costs as a proxy for barge rates

Assessing other children in the household support of exercise and healthy eating

Childhood obesity is on the rise throughout the world. Overweight/obesity in childhood is a major risk factor for serious health consequences (Patchucki, Lovenheim, Harding, 2014). The family unit can address childhood obesity when the family works together to support each other in physical activity (PA) and healthy eating decisions. Sibling support may be particularly important due to the amount of time siblings spend with each other. Siblings’ impact on informal social behavior may be a more powerful motivator compared to formal parenting norms (Patchucki, Lovenheim, Harding, 2014). Having an obese younger sibling creates a five times greater likelihood the older sibling will be obese (Patchucki, Lovenheim, Harding, 2014), thus, interventions aimed at siblings may be particularly effective. The literature suggests this is an understudied topic in need of attention. During February 2015, 22 families from a Boys and Girls Club participated in a 2 week pilot study testing an intervention designed to improve PA and healthy eating within family units. Families were randomly assigned to a treatment group (n=12 families and 20 children) or a measurement-only control group (n=12 families and 15 children). Children in the treatment group participated in 40 minutes of PA and 20 minutes of nutrition education during after school time. Three times a week program staff distributed take home cards to parents that described an exercise or nutrition activity to complete as a family. Families also participated in family night and parents participated in a nutrition educational session. Researchers developed a quantitative survey to assess sibling support by modifying the Coordinated Approach to Child Health questionnaire that was designed to measure parent and friend support for healthy eating and exercise (Nadar, Stone, Perry, Osganian, Kelder et al, 1999). The survey contained 10 questions on PA and nutrition by querying children about the support of other children in their household (i.e., “When I am active, other children in my house smile and cheer for me.”). The three response options were “almost never/never,” “sometimes,” and “almost always/ always.” Other children in the house were defined as brothers, sisters, stepbrothers, stepsisters, cousins or other children that live with the family. Child participants (age 6-11) completed the survey at baseline (pretest) and at the end of the 2-week intervention (posttest). Scores will be added to give an overall score. Changes from baseline to posttest will be compared across treatment groups. Data are expected to be released for dissemination prior to the conference so that the results can be presented. In addition, the process of pilot testing this measure 68 times suggested changes that may improve future iterations of this assessment of sibling support. It would be beneficial to add a question asking if there are other children in the house. Assessing the quality of the sibling relationship could be considered using the Sibling Relationship Questionnaire (SRQ) (Leeuw, Snoek, Leeuwe, Strien, 2007), a higher SRQ score signifies better sibling relationship. The quality of the sibling’s relationship may impact how support for healthy choices is received within the sibling group. Children are prone to picking the extreme answer on a questionnaire based on their current emotional state (Chambers, Johnston, 2002). Thus, it may be beneficial to change the answer choices from “never or almost never” to “almost never” and “always or almost always” to “always” to avoid extreme answers. Siblings participate in PA and mealtime together on a regular basis (Patchucki, Lovenheim, Harding, 2014). This new assessment provides a first step in measuring sibling support for PA and healthy eating. Understanding how siblings can positively influence one another to promote healthy choices may help reduce risk factors for childhood obesity

Integral window hermetic fiber optic components

In the fabrication of igniters, actuators, detonators, and other pyrotechnic devices to be activated by a laser beam, an integral optical glass window is formed by placing a preform in the structural member of the device and then melting the glass and sealing it in place by heating at a temperature between the ceramming temperature of the glass and the melting point of the metal, followed by rapid furnace cooling to avoid devitrification. No other sealing material is needed to achieve hermeticity. A preferred embodiment of this type of device is fabricated by allowing the molten glass to flow further and form a plano-convex lens integral with and at the bottom of the window. The lens functions to decrease the beam divergence caused by refraction of the laser light passing through the window when the device is fired by means of a laser beam