Pure insulin nanoparticle agglomerates for pulmonary delivery

Diabetes is a set of diseases characterized by defects in insulin utilization, either through autoimmune destruction of insulin-producing cells (Type I) or insulin resistance (Type II). Treatment options can include regular injections of insulin, which can be painful and inconvenient, often leading to low patient compliance. To overcome this problem, novel formulations of insulin are being investigated, such as inhaled aerosols. Sufficient deposition of powder in the peripheral lung to maximize systemic absorption requires precise control over particle size and density, with particles between 1 and 5 microm in aerodynamic diameter being within the respirable range. Insulin nanoparticles were produced by titrating insulin dissolved at low pH up to the pI of the native protein, and were then further processed into microparticles using solvent displacement. Particle size, crystallinity, dissolution properties, structural stability, and bulk powder density were characterized. We have demonstrated that pure drug insulin microparticles can be produced from nanosuspensions with minimal processing steps without excipients, and with suitable properties for deposition in the peripheral lung.     

Simulations of information transport in spin chains

Transport of quantum information in linear spin chains has been the subject of much theoretical work. Experimental studies by NMR in solid state spin systems (a natural implementation of such models) is complicated since the dipolar Hamiltonian is not solely comprised of nearest-neighbor XY-Heisenberg couplings. We present here a similarity transformation between the XY Hamiltonian and the double-quantum Hamiltonian, an interaction which is achievable with the collective control provided by radio-frequency pulses. Not only can this second Hamiltonian simulate the information transport in a spin chain, but it also creates coherent states, whose intensities give an experimental signature of the transport. This scheme makes it possible to study experimentally the transport of polarization beyond exactly solvable models and explore the appearance of quantum coherence and interference effects.     

Blue fluorescent 4a-Aza-4b-boraphenanthrenes

[structure: see text]. Phenanthrene analogues with internalized B-N moieties were found to afford blue light emission with good quantum efficiencies, whereas the isomeric species with peripheral B-N moieties displayed only UV emission behavior, like the all-carbon framework.     

Analysis of homonuclear RF gradient NMR spectroscopy

A formalism for describing the spin dynamics of radio frequency (RF) gradient experiments is introduced. It has the advantage over the most straight-forward applications of product operator methods of cleanly separating the steps of coherence transformation and gradient evolution which become confused in many RF gradient methods. The analysis is used to explore the dynamics of RF gradient homonuclear multiple quantum filtering experiments. Experimental results of these new sequences are included.     

Construction of a shallow underground low-background detector for a CTBT radionuclide laboratory

The International Monitoring System is a verification component of the Comprehensive Nuclear-Test-Ban Treaty, and in addition to a series of radionuclide monitoring stations, contains 16 radionuclide laboratories capable of verification of radionuclide station measurements. This paper presents an overview of a new commercially obtained low-background detector system for radionuclide aerosol measurements recently installed in a shallow (>30 meters water equivalent) underground clean-room facility at Pacific Northwest National Laboratory. Specifics such as low-background shielding materials and active shielding methods will be covered.     

Enhancing the selectivity of an iron binding hydrogel

Iron overload is a critical clinical condition that can be controlled by diet and the use of iron-specific chelating agents. An effective oral formulation of an iron chelator should be nontoxic and selective toward iron while maintaining high affinity for iron. In this study, hydrogels containing 2,3 dihydroxybenzoic acid (2,3 DHBA), a portion of the metal chelating domain of enterobactin, were synthesized as a potential non-absorbed chelator for iron in the gastrointestinal tract. A series of polymeric chelators with various hydrogel:DHBA ratios were prepared. The iron-binding properties of the hydrogels were found to depend on the concentration of 2,3 DHBA groups on polymer chains. A 0.005 ratio of PAAm:DHBA was found to have an optimum affinity (log K = 27.01), selectivity, and high binding capacity for Fe(III).     

A study of quantum error correction by geometric algebra and liquid-state NMR spectroscopy

Quantum error correcting codes enable the information contained in a quantum state to be protected from decoherence due to external perturbations. Applied to NMR, this procedure does not alter normal relaxation, but rather converts the state of a 'data' spin into multiple quantum coherences involving additional ancilla spins. These multiple quantum coherences relax at differing rates, thus permitting the original state of the data to be approximately reconstructed by mixing them together in an appropriate fashion. This paper describes the operation of a simple, three-bit quantum code in the product operator formalism, and uses geometric algebra methods to obtain the error-corrected decay curve in the presence of arbitrary correlations in the external random fields. These predictions are confirmed in both the totally correlated and uncorrelated cases by liquid-state NMR experiments on ¹³C-labelled alanine, using gradient-diffusion methods to implement these idealized decoherence models. Quantum error correction in weakly polarized systems requires that the ancilla spins be prepared in a pseudo-pure state relative to the data spin, which entails a loss of signal that exceeds any potential gain through error correction. Nevertheless, this study shows that quantum coding can be used to validate theoretical decoherence mechanisms, and to provide detailed information on correlations in the underlying NMR relaxation dynamics.     

Reaction kinetics of nanometric aluminum and iodine pentoxide

Owing to increasing threats of biological attacks, new methods for the neutralization of spore-forming bacteria are currently being examined. Thermites may be an effective method to produce high-temperature reactions, and some compositions such as aluminum (Al) and iodine pentoxide (I₂O₅) also have biocidal properties. This study examines the thermal degradation behavior of I₂O₅ mixed with micron and nanometer scale aluminum (Al) particles. Differential scanning calorimetry (DSC) and thermogravimetric (TG) analyses were performed in an argon environment on both particle scales revealing a non-reaction for micron Al and a complex multistep reaction for the nanometer scale Al. Results show that upon I₂O₅ decomposition, iodine ion sorption into the alumina shell passivating Al particles is the rate-controlling step of the Al–I₂O₅ reaction. This pre-ignition reaction is unique to nano-Al mixtures and attributed to the significantly higher specific surface area of the nanometric Al particles which provide increased sites for I⁻ sorption. A similar pre-ignition reaction had previously been observed with fluoride ions and the alumina shell passivating Al particles.     

Investigating Essential Characteristics of Scientific Practices in Elementary Science Learning Environments: The Practices of Science Observation Protocol (P‐SOP)

Within the field of science education, there remains little agreement as to the definition and characteristics of classroom inquiry. The emerging emphasis on scientific practices in science education reform discourse is underpinned by a need to better articulate the constituent elements of inquiry‐based science. While a small number of observation‐based instruments have been developed to characterize science learning environments, few are explicitly aligned with theoretical constructs articulated by the National Research Council and/or have been substantially field‐tested. We employ a newly developed instrument, the Practices of Science Observation Protocol (P‐SOP), to investigate essential features of inquiry and scientific practices in which early learners engage in elementary classrooms. This research is part of a multiyear professional development program designed to support elementary teachers (K‐5) in a large, urban school district to learn to better engage students in scientific practices. Project teachers video‐recorded enacted science lessons (n = 124) which were used as data. Findings illustrate both essential features of inquiry and scientific practices observed in elementary classrooms, as well as establish the P‐SOP as a valid and reliable observation protocol. These findings have important implications for the design of elementary science learning environments and associated research and development efforts in the field.     

Asymptotic analysis of collision-induced timing shifts in return-to-zero quasi-linear systems with predispersion and postdispersion compensation

An asymptotic method for calculating the collision-induced frequency and timing shifts for quasi-linear pulses in return-to-zero, wavelength-division multiplexed systems with predispersion and postdispersion compensation is developed. Predictions of the asymptotic theory agree well with quadrature and direct numerical simulations. Using this theory, computational savings of many orders of magnitude can be realized over direct numerical simulations.