A partial wave analysis of the (3π)0 system from the charge exchange reaction π+n→π+π−πop AT 4 GeV/c

From a partial wave analysis of the (3π)^o state in the charge exchange reaction π⁺n→π⁺π^?π^op, we observe strong unnatural parity as well as natural parity production. The observed strong unnatural parity states are identified with well-established resonances. The unnatural parity production is consistent with Reggeized Deck model predictions, with the exception of the I = 1, JP = 1⁺ state. Here there is no evidence for A₁ production at ～1.1 GeV, but the data could support resonance production at higher masses.     

Generation of multicolored,prestained molecular weight markers for gel electrophoresis

Molecular weight marker proteins are routinely used in sodium dodecyl sulfate-polyacrylamide gel electrophoresis to estimate the relative molecular mass of specific proteins within a sample. This report describes a simple procedure for the generation of multicolored molecular weight proteins using a variety of Remazol-reactive textile dyes. These multicolored proteins provide a set of unambiguous markers for gel electrophoresis. Furthermore, the colored markers can be used in conjunction with Western blotting techniques to provide a visual display of marker proteins on the transfer membrane.     

The contact process on finite homogeneous trees

Let ? _d be a homogeneous tree in which every vertex has d + 1 neighbours, where d≥ 2. The contact process on such a tree is known to have three distinct phases. We consider the process on a finite subtree, namely the rooted tree of depth h and branching factor d, and relate the behaviour of the process on the infinite tree to its behaviour on the finite tree for large h. In the phase of strong survival, we show that with probability ɛ independent of h, the process on the subtree starting from a single infection survives for a time which is doubly exponential in h and almost exponential in the number of vertices of the finite tree. In the phase of weak survival on the infinite tree, the survival time on the finite tree is approximately linear in h. In the phase of no survival, the survival time on the finite tree is linear in h if one starts with all vertices initially infected, and bounded by a random variable (independent of h) with an exponential tail if one starts from a single infection. Received: 14 April 2000 / Revised version: 6 January 2001 / Published online: 9 October 2001     

Protein-ligand binding investigated by a single nanoparticle TERS approach

We report TERS imaging of individual 50 nm, biotin-labeled gold nanoparticles bound to a streptavidin-derivatized glass slide. Individual gold nanoparticles detected by a nanoparticle TERS tip generate Raman enhancements in both the biotin and streptavidin signals. These results indicate that nanoparticles are capable of investigating nanoscale spatial and chemical environments with non-resonant Raman enhancements.     

Lipid retention of novel pressurized extraction vessels as a function of the number of static and flushing cycles,flush volume,and flow rate

Lipid retention in novel pressurized solvent extraction vessels was examined as a function of static and flushing cycles, flushing flow rate and flush volume in an effort to decrease lipid elution after extraction. Results indicate that none of these variables plays a pivotal role in lipid retention within this system. Regardless of which variable was altered, lipid elution remained virtually constant at (55 ± 7) %. Findings suggest that lipid elution has more to do with the high flow rate at which extracts are purged from the system at the end of the static cycle.     

Parameter identifiability in application of soft particle electrokinetic theory to determine polymer and polyelectrolyte coating thicknesses on colloids

Soft particle electrokinetic models have been used to determine adsorbed nonionic polymer and polyelectrolyte layer properties on nanoparticles or colloids by fitting electrophoretic mobility data. Ohshima first established the formalism for these models and provided analytical approximations ( Ohshima, H. Adv. Colloid Interface Sci.1995, 62, 189 ). More recently, exact numerical solutions have been developed, which account for polarization and relaxation effects and require fewer assumptions on the particle and soft layer properties. This paper characterizes statistical uncertainty in the polyelectrolyte layer charge density, layer thickness, and permeability (Brinkman screening length) obtained from fitting data to either the analytical or numerical electrokinetic models. Various combinations of particle core and polymer layer properties are investigated to determine the range of systems for which this analysis can provide a solution with reasonably small uncertainty bounds, particularly for layer thickness. Identifiability of layer thickness in the analytical model ranges from poor confidence for cases with thick, highly charged coatings, to good confidence for cases with thin, low-charged coatings. Identifiability is similar for the numerical model, except that sensitivity is improved at very high charge and permeability, where polarization and relaxation effects are significant. For some poorly identifiable cases, parameter reduction can reduce collinearity to improve identifiability. Analysis of experimental data yielded results consistent with expectations from the simulated theoretical cases. Identifiability of layer charge density and permeability is also evaluated. Guidelines are suggested for evaluation of statistical confidence in polymer and polyelectrolyte layer parameters determined by application of the soft particle electrokinetic theory.     

Hannah's Prior Knowledge About Chemicals: A Case Study of One Fourth‐Grade Child

Chemical principles are taught in elementary education across much of the United States because the National Science Education Standards include concepts about the nature of matter, states of matter, and changes in matter among other science concepts within the first to fifth grade levels. “Chemicals” is a word related to the nature of matter that is used not only in formal instruction, but also in everyday conversations. Children's prior knowledge about chemicals gained from everyday experiences will influence how they learn about chemical principles. The research described herein reveals insights into one child's conceptual structure related to the word “chemical,” which includes how she uses the word both inside and outside of school. Hannah was purposefully chosen for this case study because she exemplified “children's science.” Her understanding of chemicals as cleaners, in foods, and used for a purpose were primarily gained from everyday experiences. The implications of these findings are discussed with respect to both future research and elementary science education.     

Formation of hyaluronic acid–ellagic acid microfiber hybrid hydrogels and their applications

Microfiber assemblies prepared from ellagic acid (EA) were functionalized with histidine (His) and dispersed in hyaluronic acid (HA) hydrogel microstructures. Swelling studies indicated that the hybrids had a relatively lower water uptake compared to HA and was pH dependent. The percentage swelling ratio for EA–His–HA hybrids was 48 % when 0.04 mg/mL of HA was incorporated and increased to 70 % when 1.2 mg/mL HA was integrated. Release studies using the dye crystal violet (CV) as a model drug showed that the rates were concentration-dependent. Further the hybrids were found to be thermally stable compared to HA. Cellular toxicity assays performed with normal rat kidney (NRK) cells indicated biocompatibility and adherence of the hybrids to the cells. Thus, we have developed a new family of hybrid hydrogels which readily formed on the EA–His functionalized microfibers and may have potential applications in drug delivery or tissue regeneration applications.