Transport and Metabolism of the Endogenous Auxin Precursor lndole-3-Butyric Acid

T Plant growth and morphogenesis depend on the levels and distribution of the plant hormone auxin. Plants tightly regulate cellular levels of the active auxin indole-3-acetic acid (IAA) through synthesis, inactivation, and transport. Although the transporters that move IAA into and out of cells are well characterized and play important roles in development, little is known about the transport of IAA precursors. In this review, we discuss the accumulating evidence suggesting that the IAA precursor indole-3-butyric acid (IBA) is transported independently of the characterized IAA transport machinery along with the recent identification of specific IBA efflux carriers and enzymes suggested to metabolize IBA. These studies have revealed important roles for IBA in maintaining IAA levels and distribution within the plant to support normal development.     

AHighResolvingPowerandMassAccuracyTOFMSforRapidDetectionandIdentificationofMicroorganisms

An exact mass measurement ESI TOF mass spectrometer has been developed for fast pathogen identification and strain typing. This unique technology relies on mass spectrometry-derived base composition signatures of amplicons from PCR (Polymerase Chain Reaction) products, and “intelligent PCR primers” that target broadly conserved regions of microbial genomes that flank variable regions. This rapid detection (30 seconds per sample) and identification of microorganism methodology also associates with a potential biological warfare attack or a natural outbreak of an emerging infectious disease. The strategy to build a high end and low cost ESI TOF machine will be discussed. The performance data particularly in accurate mass measurement, high resolving power and 24 hours stability test will be presented. The discovery of Swine flu virus H1N1 will be presented as an example to illustrate the procedure of detection and identification of microoganisms.     

Evolutionary cyber-psychology: Applying an evolutionary framework to Internet behavior

An evolutionary psychological perspective has much to offer the study of Internet behavior. However, cyber-psychologists have hitherto neglected this rich theoretical tradition and evolutionary psychologists have been slow to apply their perspective to computer-mediated behavior. This paper applies an evolutionary perspective to the study of Internet behavior in four relevant domains: (1) mating and sexual competition, (2) parenting and kinship, (3) trust and social exchange, and (4) personal information management. Both general and specific evolutionary theories are explored in relation to online behavior in each domain, with an emphasis on generating testable hypotheses for future research.     

An Introduction to the Community of Professors: The Engineering Education Scholars Workshop

It can be difficult for new faculty to get the information they need on issues such as teaching, advising, and setting up a research program. While some have excellent mentors, others have come to rely on trial and error or word of mouth. In 1996, the NSF Engineering Education Scholars Workshop began at Carnegie Mellon University to address the needs of new and future engineering faculty by:

• ? providing professional teaching development;
• ? offering guidance in supervising graduate students and conducting research;
• ? discussing likely engineering education and research challenges in the 21^st century; and
• ? providing intellectual and social support with colleagues.

After three years, a significant amount of knowledge and experience has been gathered by the workshop co‐chairs. This paper details the structure of the workshop and discusses the underlying principles and implementation to provide guidance for those planning similar workshops.     

Infrared multiphoton dissociation with a hollow fiber waveguide

A novel scheme for performing infrared multiphoton dissociation (IRMPD) is presented in which a hollow fiber waveguide (HFWG) is used to transmit IR radiation into the ion storage region of a mass spectrometer. Efficient dissociation of oligonucleotide and protein ions is demonstrated on an ESI-FTICR instrument in which IRMPD is performed in the external ion reservoir and on a quadrupole ion trap. Using a simple optical scheme consisting of a single focusing lens and an x, y translator, the 10.6-microm IR laser beam, initially 3.5 mm in diameter, is focused into the vacuum-sealed HFWG. The small internal diameter and the high transfer efficiency of the waveguide allow IR radiation of high power density to be employed for IRMPD. In studies performed on a quadrupole ion trap, a 500-microm-i.d. waveguide was used as a medium to transmit IR radiation directly through a 700-microm orifice in the ring electrode. Efficient IRMPD of both a 12-mer oligonucleotide and the protein melittin were performed at laser powers of 0.5 and 3.2 W, respectively.     

The formation of an apatite coating on carboxylated polyphosphazenes via a biomimetic process

The biomimetic deposition of an apatite coating on polyphosphazene was investigated. A polyphosphazene having carboxylatophenoxy side groups was synthesized as a candidate polymer with heterogeneous nucleation sites for apatite deposition. Poly[bis(carboxylatophenoxy)phosphazene] (PCPP) was synthesized by a two-step synthetic route involving the synthesis of poly(dichlorophosphazene) (PDP) followed by nucleophilic replacement of the chlorine atoms of PDP with carboxylatophenoxy groups. The surface of the carboxylated polyphosphazene induced the formation of a dense layer of apatite on the surface after incubation in simulated body fluid at 37 °C with an ionic concentration approximately the same as that of human blood plasma. The results suggested an early precipitation of octacalcium phosphate and calcium phosphate intermediates on the surface, both of which are known to promote osteoblast differentiation and proliferation.     

Optical Frequency Metrology of an Iodine-Stabilized He-Ne Laser Using the Frequency Comb of a Quantum-Interference-Stabilized Mode-Locked Laser

We perform optical frequency metrology of an iodine-stabilized He-Ne laser using a mode-locked Ti:sapphire laser frequency comb that is stabilized using quantum interference of photocurrents in a semiconductor. Using this technique, we demonstrate carrier-envelope offset frequency fluctuations of less than 5 mHz using a 1 s gate time. With the resulting stable frequency comb, we measure the optical frequency of the iodine transition [¹²⁷I₂ R(127) 11-5 i component] to be 473 612 214 712.96 ± 0.66 kHz, well within the uncertainty of the CIPM recommended value. The stability of the quantum interference technique is high enough such that it does not limit the measurements.     

Unsupervised Learning for Efficient Texture Estimation From Limited Discrete Orientation Data

The estimation of orientation distribution functions (ODFs) from discrete orientation data, as produced by electron backscatter diffraction or crystal plasticity micromechanical simulations, is typically achieved via techniques such as the Williams–Imhof–Matthies–Vinel (WIMV) algorithm or generalized spherical harmonic expansions, which were originally developed for computing an ODF from pole figures measured by X-ray or neutron diffraction. These techniques rely on ad-hoc methods for choosing parameters, such as smoothing half-width and bandwidth, and for enforcing positivity constraints and appropriate normalization. In general, such approaches provide little or no information-theoretic guarantees as to their optimality in describing the given dataset. In the current study, an unsupervised learning algorithm is proposed which uses a finite mixture of Bingham distributions for the estimation of ODFs from discrete orientation data. The Bingham distribution is an antipodally-symmetric, max-entropy distribution on the unit quaternion hypersphere. The proposed algorithm also introduces a minimum message length criterion, a common tool in information theory for balancing data likelihood with model complexity, to determine the number of components in the Bingham mixture. This criterion leads to ODFs which are less likely to overfit (or underfit) the data, eliminating the need for a priori parameter choices.     

On stability and performance of highly c-oriented columnar AlPO4-5 and CoAPO-5 membranes

Continuous films comprised of highly c-oriented aluminophosphate AlPO₄-5 or cobalt-substituted AlPO₄-5 (CoAPO-5) were grown on porous supports and subjected to heat treatment in order to investigate the potential for membrane applications. A study in the early stages of in-plane crystalline intergrowth revealed a potential mechanism for flake-like crystal formation between the original oriented columnar crystals. Variations in metal substitution (AlPO₄-5, CoAPO-5), support (glass, silicon, porous alumina), and calcination method (conventional, rapid thermal processing) were chosen to examine the conditions by which structural integrity was compromised following secondary (or tertiary) growth, resulting in reduced membrane functionality. Through the use of rapid thermal processing, the structure debilitation could be partially avoided. The membrane quality was inspected through pervaporation measurements consisting of a liquid hydrocarbon feed of n-heptane and 1,3,5-triisopropylbenzene. By investigating the effect of template removal on the oriented, columnar crystalline structure, useful insight is provided into the potential for the membranes to participate in applications such as molecular separations, catalysis, or host-guest assemblies.