Progress in structural biology very much depends upon the development of new high-resolution techniques and tools. Despite decades of study of viruses, bacteria and bacterial spores and their pressing importance in human medicine and biodefense, many of their structural properties are poorly understood. Thus, characterization and understanding of the architecture of protein surface and internal structures of pathogens is critical to elucidating mechanisms of disease, immune response, physicochemical properties, environmental resistance and development of countermeasures against bioterrorist agents. Furthermore, even though complete genome sequences are available for various pathogens, the structure-function relationships are not understood. Because of their lack of symmetry and heterogeneity, large human pathogens are often refractory to X-ray crystallographic analysis or reconstruction by cryo-electron microscopy (cryo-EM). An alternative high-resolution method to examine native structure of pathogens is atomic force microscopy (AFM), which allows direct visualization of macromolecular assemblies at near-molecular resolution. The capability to image single pathogen surfaces at nanometer scale in vitro would profoundly impact mechanistic and structural studies of pathogenesis, immunobiology, specific cellular processes, environmental dynamics and biotransformation.

It is shown that a quantum kinetic theory approach to line broadening, extended to stationary non-equilibrium states, yields corrections to the standard electron impact widths of isolated lines that depend on the population of the radiator internal levels. A consistent classical limit from a general quantum treatment of the perturbing electrons also introduces corrections to the isolated line widths. Both effects are essential in preserving detailed-balance relations. Preliminary analysis indicates that these corrections may resolve existing discrepancies between theoretical and experimental widths of isolated lines. An experimental test of the results is proposed.

The main focus of the work is to develop a better understanding of the distribution of the elements B, Be and Li in melilite, fassaitic clinop clinopy-roxene, anorthite and spinel, which are the primary constituents of calcium-aluminum-rich inclusions (CAIs). These elements are the parent or decay products of short-lived nuclides (specifically, {sup 7}Be and {sup 10}Be) formed by cosmic ray spallation reactions on silicon and oxygen. Recent observations suggest that some CAIs contain ''fossil'' {sup 7}Be and {sup 10}Be in the form of ''excess'' amounts of their decay products (B and Li). The exact timing of {sup 7}Be and {sup 10}Be production is unknown, but if it occurred early in CAI history, it could constrain the birthplace of CAIs to be within a limited region near the infant sun. Other interpretations are possible, however, and bear little significance to early CAI genesis. In order to interpret the anomalies as being ''primary'', and thus originating at high temperature, information on the intermineral partitioning of both parent and daughter elements is required.

Results on charmonium states and searches for pentaquark states at the BABAR experiment are presented.

Solid-state thermal neutron detectors are generally fabricated in a planar configuration by coating a layer of neutron-to-alpha converter material onto a semiconductor. The as-created alpha particles in the material are expected to impinge the semiconductor and create electron-hole pairs which provide the electrical signal. These devices are limited in efficiency to a range near (2-5%)/cm{sup 2} due to the conflicting thickness requirements of the converter layer. In this case, the layer is required to be thick enough to capture the incoming neutron flux while at the same time adequately thin to allow the alpha particles to reach the semiconductor. A three dimensional matrix structure has great potential to satisfy these two requirements in one device. Such structures can be realized by using PIN diode pillar elements to extend in the third dimension with the converter material filling the rest of the matrix. Our strategy to fabricate this structure is based on both ''top-down'' and ''bottom-up'' approaches. The ''top down'' approach employs high-density plasma etching techniques, while the ''bottom up'' approach draws on the growth of nanowires by chemical vapor deposition. From our simulations for structures with pillar diameters from 2 {micro}m down to 100 nm, the detector efficiency is expected …

Accelerator mass spectrometry (AMS) is a highly sensitive analytical methodology used to quantify the content of radioisotopes, such as {sup 14}C, in a sample. The primary goals of this work were to demonstrate the utility of AMS in determining cellular [{sup 14}C]doxorubicin (DOX) concentrations and to develop a sensitive assay that is superior to high performance liquid chromatography (HPLC) for the quantification of DOX at the tumor level. In order to validate the superior sensitivity of AMS versus HPLC with fluorescence detection, we performed three studies comparing the cellular accumulation of DOX: one in vitro cell line study, and two in vivo xenograft mouse studies. Using AMS, we quantified cellular DOX content up to 4 hours following in vitro exposure at concentrations ranging from 0.2 pg/ml (345 fM) to 2 {micro}g/ml (3.45 {micro}M) [{sup 14}C]DOX. The results of this study show that, compared to standard fluorescence-based HPLC, the AMS method was over five orders of magnitude more sensitive. Two in vivo studies compared the sensitivity of AMS to HPLC using a nude mouse xenograft model in which breast cancer cells were implanted subcutaneously. After sufficiently large tumors formed, DOX was administered intravenously at two dose levels. Additionally, we tested the …

We present a measurement of the time-dependent CP-violating asymmetry in B{sup 0} {yields} K*{sup 0}{gamma} decays with K*{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0} based on 232 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. In a sample containing 157 {+-} 16 signal decays, we measure S{sub K*{sup 0}{gamma}} = -0.21 {+-} 0.40 {+-} 0.05 and C{sub K*{sup 0}{gamma}} = -0.40 {+-} 0.23 {+-} 0.03, where the first error is statistical and the second systematic. We also explore B{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0}{gamma} decays with 1.1 < m{sub K{sub S}{sup 0}{pi}{sup 0}} < 1.8 GeV/c{sup 2} and find 59 {+-} 13 signal events with S{sub K{sub S}{sup 0}{pi}{sup 0}{gamma}} = 0.9 {+-} 1.0 {+-} 0.2 and C{sub K{sub S}{sup 0}{pi}{sup 0}{gamma}} = -1.0 {+-} 0.5 {+-} 0.2.

In its present form, the Final Focus Test Beam (FFTB) is a transport line designed to transmit 50 GeV electron beams of SLC emittance (3 x 10{sup -10} radian-meters) straight through the central arm of the Beam Switchyard (BSY C line) with a final focus point out in the Research Yard but relatively near the end of the switchyard tunnel. The axis of the incident beam coincides with that of the SLAC linear accelerator; the final focus, some 300 meters downstream of the end of the accelerator, is displaced from this axis by about 2 meters horizontally.

Emissions produced or initiated by a 30 GeV electron beam propagating through a {approx}1 m long heat pipe oven containing neutral and partially ionized vapor have been measured near atomic spectral lines in a beam-plasma wakefield experiment. The Cerenkov spatial profile has been studied as a function of oven temperature and pressure, observation wavelength, and ionizing laser intensity and delay. The Cerenkov peak angle is affected by the creation of plasma; estimates of plasma and neutral density have been extracted. Increases in visible background radiation consistent with increased plasma recombination emissions due to dissipation of wakefields were simultaneously measured.

We report studies of B {yields} X{sub u}{ell}{nu} decays, based on a sample of 88 million B{bar B} events recorded with the BABAR detector. From both tagged and untagged B{bar B} events we have isolated inclusive charmless decays in kinematic regions for which the dominant background from B {yields} X{sub c}{ell}{nu} is reduced by making requirements on different variables: the electron energy E{sub l}, the momentum transfer q{sup 2}, and the hadronic mass m{sub X}. Using theoretical calculations we extrapolate to the total decay rate to determine the CKM matrix element |V{sub ub}|. In addition, we have measured the branching fraction for exclusive semileptonic decays, such as B {yields} {pi}({rho}, {omega}, {eta}, a{sub 0}){ell}{nu}. A high signal purity is achieved by selecting events in which a decay of the second B meson is either fully or partially reconstructed.

The authors present a measurement of the partial branching fractions and mass spectra of the exclusive radiative penguin processes B {yields} K{pi}{pi}{gamma} in the range m{sub K{pi}{pi}} < 1.8 GeV/c{sup 2}. They reconstruct four final states: K{sup +}{pi}{sup -}{pi}{sup +}{gamma}, K{sup +}{pi}{sup -}{pi}{sup 0}{gamma}, K{sub S}{sup 0}{pi}{sup -}{pi}{sup +}{gamma}, and K{sub S}{sup 0}{pi}{sup +}{pi}{sup 0}{gamma}, where K{sub S}{sup 0} {yields} {pi}{sup +}{pi}{sup -}. Using 232 million e{sup +}e{sup -} {yields} B{bar B} events recorded by the BABAR experiment at the PEP-II asymmetric-energy storage ring, they measure the branching fractions {Beta}(B{sup +} {yields} K{sup +}{pi}{sup -}{pi}{sup +}{gamma}) = (2.95 {+-} 0.13(stat.) {+-} 0.20(syst)) x 10{sup -5}, {Beta}(B{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0}{gamma}) = (4.07 {+-} 0.22(stat.) {+-} 0.31(syst.)) x 10{sup -5}, {Beta}(B{sup 0} {yields} K{sup 0}{pi}{sup +}{pi}{sup -}{gamma}) = (1.85 {+-} 0.21(stat.) {+-} 0.12(syst.)) x 10{sup -5}, and {Beta}(B{sup +} {yields} K{sup 0}{pi}{sup +}{pi}{sup 0}{gamma}) = (4.56 {+-} 0.42(stat.) {+-} 0.31(syst.)) x 10{sup -5}.

With the development of ever higher energy particle accelerators comes the need for compactness and high gradient, which in turn require very high frequency high power rf sources. Recent development work in W-band accelerating techniques has spurred the development of a high-power W-band source. Axisymmetric sources suffer from fundamental power output limitations (P{sub sat} {approx} {lambda}{sup 2}) brought on by the conflicting requirements of small beam sizes and high beam current. The sheet beam klystron allows for an increase in beam current without substantial increase in the beam current density, allowing for reduced cathode current densities and focusing field strengths. Initial simulations of a 20:1 aspect ratio sheet beam/cavity interaction using the 3 dimensional particle-in-cell code Magic3D have demonstrated a 35% beam-power to RF power extraction efficiency. Calculational work and numerical simulations leading to a prototype W-band sheet beam klystron will be presented, together with preliminary cold test structure studies of a proposed RF cavity geometry.

Smoothed Particle Hydrodynamics (SPH) is a meshless Lagrangian technique for modeling hydrodynamics, and as such offers some unique advantages when applied to problems of material failure and breakup. The two most important of these advantages are: (1) SPH is Lagrangian and robust--i.e., it is never necessary to advect or remap. Damage models typically involve a number of complex history variables (such as the damage associated with the Lagrangian mass, crack orientations, etc.), and advecting these quantities as is required in a mesh based algorithm is a very challenging problem. (2) SPH allows the Lagrangian points to move about, reconnect, or separate as dictated by the material flow. This naturally allows for the points to move apart as distinct fragments of material form, resulting in gaps or cracks between the fragments. Typically mesh based algorithms represent the ''cracks'' between fragments as zones of failed material, which is quite different than allowing voids devoid of material to form.

Lawrence Livermore National Laboratory (LLNL) is evaluating design alternatives to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell and pulse-power system. The goal is to create a more mono-energetic electron beam. When an electron beam crosses the energized gap of an accelerator cell, the electron energy is increased. However, the beam with the associated electromagnetic wave also looses a small amount of energy because of the increased impedance seen across the gap. The beam-induced voltage at the gap is time varying. This creates beam energy variations that we need to understand and control. A high-fidelity computer simulation of the beam and cell interaction has been completed to quantify the time varying induced voltage at the gap. The cell and pulse-power system was characterized using a Time-domain Reflectometry (TDR) measurement technique with a coaxial air-line to drive the cell gap. The beam-induced cell voltage is computed by convoluting the cell impedance with measured beam current. The voltage was checked against other measurements to validate the accuracy.

Solute additions of zirconium are believed to decrease RIS and dislocation density through point defect trapping and recombination, which in turn reduces grain boundary sensitization and IGSCC. In this work, the effect of zirconium on the microstructure, microchemistry, hardening and IGSCC behavior of 316SS doped with zirconium to levels of 0.31 and 0.45 wt% was studied. These alloys were then irradiated with 3.2 MeV protons to doses up to 7 dpa at a temperature of 400 C. Zr additions had relatively little effect on radiation hardening. Dislocation densities were reduced and average sizes slightly increased for the +Zr alloys relative to the 316SS. Although a low amount of swelling was seen in 316SS at 3 dpa, no voids were observed in either of the +Zr alloys at 3 or 7 dpa. The difference in RIS of Cr and Ni between 316SS and 316+LoZr at 3 dpa was negligible, though RIS for 316+HiZr was considerably less than 316+LoZr at 7 dpa. The link between the oversize solute addition of Zr and its effect on IASCC shows that although the percent strain to failure increased substantially for 316+LoZr compared to the 316SS, cracking behavior was substantially worse as the number of cracks …

GEONET is a database system developed at the Stanford Linear Accelerator Center for the alignment of the Stanford Linear Collider. It features an automated data flow, ranging from data collection using HP110 handheld computers to processing, storing and retrieving data and finally to adjusted coordinates. This paper gives a brief introduction to the SLC project and the applied survey methods. It emphasizes the hardware and software implementation of GEONET using a network of IBM PC/XT's.

High transverse momentum single (non-photonic) electrons are shown to be sensitive to the stopping power of both bottom, b, and charm, c, quarks in AA collisions. We apply the DGLV theory of radiative energy loss to predict c and b quark jet quenching and compare the FONLL and PYTHIA heavy flavor fragmentation and decay schemes. We show that single electrons in the p{sub T} = 5-10 GeV range are dominated by the decay of b quarks rather than the more strongly quenched c quarks in Au+Au collisions at {radical}s = 200 AGeV. The smaller b quark energy loss, even for extreme opacities with gluon rapidity densities up to 3500, is predicted to limit the nuclear modification factor, R{sub AA}, of single electrons to the range R{sub AA} {approx} 0.5-0.6, in contrast to previous predictions of R{sub AA} {le} 0.2-0.3 based on taking only c quark jet fragmentation into account.

A Dalitz plot analysis of approximately 12,500 D{sup 0} events reconstructed in the hadronic decay D{sup 0} {yields} {bar K}{sup 0} K{sup +}K{sup -} is presented. This analysis is based on a data sample of 91.5 fb{sup -1} collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage rings at SLAC running at center-of-mass energies on and 40 MeV below the {Upsilon}(4S) resonance. The events are selected from e{sup +}e{sup -} {yields} c{bar c} annihilations using the decay D*{sup +} {yields} D{sup 0}{pi}{sup +}. The following ratio of branching fractions has been obtained: BR = {Lambda}(D{sup 0} {yields} {bar K}{sup 0}K{sup +}K{sup -})/{Lambda}(D{sup 0} {yields} {bar K}{sup 0}{pi}{sup +}{pi}{sup -}) = (15.8 {+-} 0.1(stat.) {+-} 0.5 (syst.)) x 10{sup -2}. Estimates of fractions and phases for resonant and non-resonant contributions to the Dalitz plot are also presented. The a{sub 0}(980) {yields} {bar K}K projection has been extracted with little background. A search for Cp asymmetries on the Dalitz plot has been performed.

To obtain micrometer resolution of materials using acoustics requires frequencies around 1 GHz. Attenuation of such frequencies is high, limiting the thickness of the parts that can be characterized. Although acoustic microscopes can operate up to several GHz in frequency, they are used primarily as a surface characterization tool. The use of a pulsed laser for acoustic generation allows generation directly in the part, eliminating the loss of energy associated with coupling the energy from a piezoelectric transducer to the part of interest. The use of pulsed laser acoustic generation in combination with optical detection is investigated for the non-contact characterization of materials with features that must be characterized to micrometer resolution.

The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1.8 Megajoule, 500-Terawatt, ultra-violet laser system together with a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. When completed, NIF will be the world's largest and most energetic laser experimental system, providing an international center to study inertial confinement fusion and physics of matter at extreme densities and pressures. The NIF is operated by the Integrated Computer Control System (ICCS), which is a layered architecture of over 700 lower-level front-end processors attached to nearly 60,000 control points and coordinated by higher-level supervisory subsystems in the main control room. A shot automation framework has been developed and deployed during the past year to orchestrate and automate shots performed at the NIF using the ICCS. The Shot Automation framework is designed to automate 4-8 hour shot sequences, that includes deriving shot goals from an experiment definition, set up of the laser and diagnostics, automatic alignment of laser beams, and a countdown to charge and fire the lasers. These sequences consist of set of preparatory verification shots, leading to amplified system shots followed by post-shot analysis and archiving. The …

Radiation can have a dramatic effect on the material properties of low density plasmas, altering bulk properties such as energy density and specific heat as well as spectral characteristics such as opacity and emissivity. The response of the material to radiation must be considered when constructing transport algorithms that are intended to provide self-consistent solutions for both the radiation field and plasma properties. It consistent can affect almost every aspect of the numerical solution, from the overall solution strategy down to details of the acceleration algorithms. We discuss these issues in the context of one approach towards improving the stability and convergence of the solution, with examples relevant to high-energy density physics. We also present a direct solution technique for the energy linearized multigroup radiation transport equations that sidesteps the need for a multigroup acceleration process and can be used to benchmark the performance of iterative algorithms.

The National Nuclear Security Administration (NNSA) Ground-Based Nuclear Explosion Monitoring Research and Engineering (GNEM R&E) Program has made significant progress enhancing the process of deriving seismic calibrations and performing scientific integration with automation tools. We present an overview of our software automation and scientific data management efforts and discuss frameworks to address the problematic issues of very large datasets and varied formats utilized during seismic calibration research. The software and scientific automation initiatives directly support the rapid collection of raw and contextual seismic data used in research, provide efficient interfaces for researchers to measure/analyze data, and provide a framework for research dataset integration. The automation also improves the researchers ability to assemble quality controlled research products for delivery into the NNSA Knowledge Base (KB). The software and scientific automation tasks provide the robust foundation upon which synergistic and efficient development of, GNEM R&E Program, seismic calibration research may be built. The task of constructing many seismic calibration products is labor intensive and complex, hence expensive. However, aspects of calibration product construction are susceptible to automation and future economies. We are applying software and scientific automation to problems within two distinct phases or ''tiers'' of the seismic calibration process. The first …

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We present a preliminary measurement of the branching fraction of the B meson decay B{sup 0} {yields} a{sub 1}{sup +}(1260){pi}{sup -}with a{sub 1}{sup +}(1260) {yields} {pi}{sup +}{pi}{sup +}{pi}{sup -}. The data sample corresponds to 218 x 10{sup 6} B{bar B} pairs produced in e{sup +}e{sup -} annihilation through the {Upsilon}(4S) resonance. We find the branching fraction (40.2 {+-} 3.9 {+-} 3.9) x 10{sup -6}, where the first error quoted is statistical and the second is systematic. The fitted values of the a{sub 1}(1260) parameters are m{sub a{sub 1}} = 1.22 {+-} 0.02 GeV/c{sup 2} and {Lambda}{sub a{sub 1}} = 0.423 {+-} 0.050 GeV/c{sup 2}.