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Computational resources have grown exponentially in the past few decades. These machines make possible research and design in fields as diverse as medicine, astronomy, and engineering. Despite ever-increasing computational capabilities, direct simulation of complex systems has remained challenging owing to the degrees of freedom involved. At the cusp of exascale computing, high-resolution simulation of practical problems with minimal model assumptions may soon experience a renaissance. However, growing reliance on modern computers comes at the cost of a growing carbon footprint. To illustrate this, we examine historic computations in fluid dynamics where larger computers have afforded the opportunity to simulate flows at increasingly relevant Reynolds numbers. Under a variety of flow configurations, the carbon footprint of such simulations is found to scale roughly with the fourth power of Reynolds number. This is primarily explained by the computation cost in core-hours, which is also described by similar scaling, though regional differences in renewable energy use also play a role. Using the established correlation, we examine a large database of simulations to develop estimates for the carbon footprint of computational fluid dynamics in a given year. Collectively, the analysis provides an additional benchmark for new computations where, in addition to balancing considerations of model fidelity, carbon footprint should also be considered. [ABSTRACT FROM AUTHOR]

Recent experiments of laser-driven ejecta microjets performed at OMEGA 60 reveal tortuous jets whereby the jets appear to deviate from their initial trajectory as they travel in vacuum. To understand these data, we perform two dimensional numerical simulations, considering different target thicknesses, pressures, and models of the drive conditions. In particular, modeling the finite laser spot size appears essential in reproducing qualitatively the non-planar shock observed in the experiment. Simulations capture jet deflection by accounting for a slight misalignment of the laser pointing with respect to the groove axis along with spatial variation of the laser pulse intensity. The principal physical mechanism appears to be that lateral momentum is imparted by release waves arising from the non-planar drive. The induced off-axis velocity is small in comparison to the jet axial velocity but integrates into a pronounced deflection over the course of the experiment. The analysis of jet axial and lateral mass distributions is found to be reproduced reasonably by the simulations. Simulated radiographs are in qualitative agreement with the experiments, though their differences point to potential shortcomings in modeling strictly three-dimensional experiments using two-dimensional hydrodynamic simulations. The simple analysis is able to explain part of the observed discrepancy in simulated vs experimental jet masses. [ABSTRACT FROM AUTHOR]

The secondary structure in tear lipocalins (TL) was characterized and the participation of the disulphide bond in the stability of the secondary structure was examined via high-pressure liquid chromatography, mass spectrometry methods and capillary zone electrophoresis. The circular dichroic measurements revealed decreased molecular assymmetry, improved unfolding due to the presence of urea and disulphide reduction suggesting the relaxation of the protein structure. The disulphide bond was also found to be reduced by the affinity of TL for retinol.

PURPOSE: There is little information available about radiographic bone changes around immediately restored implants in periodontally compromised patients. The aims of this study were to evaluate the effect of immediate restoration on radiographic bone changes and to compare radiographic changes between arches and between healed and extraction sites in periodontally susceptible patients. MATERIALS AND METHODS: Patients received periodontal treatment. 'All in one' implant surgery was then performed: Hopeless teeth were extracted, debridement around remaining adjacent teeth was performed, implants were inserted guided by a surgical stent, and a prefabricated screwed provisional restoration was immediately delivered on selected implants. Periapical radiographs using a parallelism appliance were taken at implant surgery and 6 and 12 months postsurgery. The distance between the alveolar crest and the implant shoulder was measured at the mesial and distal aspect of each implant. Bone changes were compared between immediately restored, submerged, and nonrestored implants; between arches; and between healed and extraction sites. RESULTS: Nineteen patients received 74 implants. Twelve implants in 4 patients failed within the first 6 months. Mean bone changes (+/- SE) between baseline and 12 months ranged between -1.19 +/- 0.19 mm and -1.88 +/- 0.3 mm. No difference was found between restored versus nonrestored sites or between maxillary and mandibular sites. Bone loss was slightly higher in healed sites. CONCLUSIONS: First-year bone changes around immediately restored dental implants in periodontally susceptible patients were slightly higher than most reports in the literature. This indicates a potential influence of periodontal disease on the success rate of dental implants. [ABSTRACT FROM AUTHOR]

PURPOSE: Immediate restoration of dental implants in patients with a history of periodontal disease was examined. The influence of insertion torque and implant stability quotient (ISQ) on the survival rate was compared in immediately restored, nonrestored, and submerged implants. MATERIALS AND METHODS: Patients received periodontal treatment after which 'all in one' implant surgery was performed: hopeless teeth were extracted, debridement around remaining adjacent teeth was performed, implants were inserted and, in some cases, a prefabricated screw-retained provisional restoration was immediately delivered. Insertion torque and ISQ were recorded at baseline and 6 and 12 months postsurgery. RESULTS: Nineteen patients were treated, and 74 implants were placed. Twelve implants, 10 of which were maxillary, failed in 4 patients. Survival rates were 100% in partial-arch restorations, 94% in the mandible, and 78% in the maxilla. The survival rate of restored implants was 65% in extraction sites versus 94% in healed, nonextraction sites. Implants exhibited a decrease in ISQ at 6 months followed by an increase at 12 months. There were no statistically significant differences in insertion torque or ISQ between failed and successful implants, restored and nonrestored implants, or extraction-site and nonextraction-site implants. Mandibular implants demonstrated higher insertion torque and higher ISQ at baseline and 6 and 12 months. CONCLUSIONS: Within the limits of this study, immediate restoration of dental implants in periodontally susceptible patients had a variable success rate. Several factors were shown to affect these results. [ABSTRACT FROM AUTHOR]

Polymer thin films were deposited by laser ablation using infrared radiation both resonant (2.90, 3.40, 3.45, and 8.96 µm) and nonresonant (3.30, 3.92, and 4.17 µm) with vibrational modes in the starting material, polyethylene glycol. The chemical structure of the films was characterized by Fourier transform infrared spectroscopy, while the molecular weight distribution was investigated using gel permeation chromatography. The films deposited by resonant irradiation are superior to those deposited with nonresonant radiation with respect to both the chemical structure and the molecular weight distribution of the films. However, the molecular-weight distributions of films deposited at nonresonant infrared wavelengths show marked polymer fragmentation. Fluence and wavelength dependence studies show that the effects may be related to the degree of thermal confinement, and hence to the relative absorption strengths of the targeted vibrational modes. [ABSTRACT FROM AUTHOR]

Highly oriented indium tin oxide (ITO) thin films were grown by pulsed-laser deposition (PLD) on glass and single-crystal yttria-stabilized zirconia (YSZ) substrates. The structural, electrical, and optical properties of these films were investigated as a function of oxygen partial pressure. Films were deposited at substrate temperature of 300 °C in mixed gases (12 mTorr of argon and 1–50 mTorr of oxygen) using a KrF excimer laser (248 nm and 30 ns full width at half maximum) at a fluence of 1.2 J/cm2. ITO films (300 nm thick), deposited by PLD on YSZ at 300 °C in a gas mixture of 12 mTorr of argon and 6 mTorr of oxygen, exhibit a low electrical resistivity (1.6×10[sup -4] Ω cm) with a high transparency (∼74%) at 550 nm. ITO films deposited on both glass and YSZ substrates have been used as an anode contact in organic light-emitting diodes. A comparison of the device performance for the two substrates shows that the device fabricated on the ITO/YSZ has a higher external quantum efficiency than that of the device fabricated on the ITO glass. [ABSTRACT FROM AUTHOR]

Thin films of polyethylene glycol of average molecular weight 1400 amu have been deposited by matrix-assisted pulsed laser evaporation (MAPLE). The deposition was carried out in vacuum (∼10[sup -6] Torr) with an ArF (λ=193 nm) laser at a fluence of 220–230 mJ/cm2. Films were deposited on NaCl plates and glass microscope slides. Both deionized water (H[sub 2]O) and chloroform (CHCl[sub 3]) were used as matrices. The physiochemical properties of the films are compared via Fourier transform infrared spectroscopy, and electrospray ionization mass spectrometry. The results show that the matrix used during MAPLE can greatly affect the chemical structure and molecular weight distribution of the deposited film. The infrared absorption spectrum shows evidence for C–Cl bond formation when CHCl[sub 3] is used as a matrix, while there is little evidence in the IR data for photochemical modification when H[sub 2]O is used as a matrix. Time-of-flight analysis was performed using a quadrupole mass spectrometer to monitor evaporation of a frozen CHCl[sub 3] target during laser exposure. Using this approach, we determined that the TOF spectra for m/z=35 (Cl) and m/z=85 (CHCl[sub 2]) differed significantly in both width and peak arrival time, indicating that neutral chlorine atoms were produced at the target surface. We attribute the reduction in molecular weight and structural modification of the film deposited using CHCl[sub 3] to the presence of these highly reactive species. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The emitted particles from pulsed-laser ablation (PLA), λ=193 nm and fluence=88–400 mJ/cm[sup 2], of frozen glycerol was examined using time-of-flight mass spectrometry. The data are analyzed using supersonic molecular-beam theory and the result is interpreted using a thermal/fluid-dynamic model. Both intact and fragmented glycerol are emitted in the PLA process at all fluences and their concentration ratio is fluence dependent. Fragmentation occurs predominantly at one of the C–C bonds forming CH[sub 2]–OH (31 amu) and HO–CH[sub 2]–CH–OH (61 amu). CH[sub 3] is produced at the target which requires the protonation of a CH[sub 2] fragment. At fluences higher than 250 mJ/cm2, ions are detected. These ions have very high velocity, >2000 m/s, and their intensity increases with fluences. PLA is thus not suitable for glycerol transfer under these conditions due to fragmentation. The data show that particle emission proceeds as a simple thermal vaporization process at fluences <200 mJ/cm2. Higher fluences will yield a Knudsen layer (KL), which is formed in front of the target surface. For fluences >300 mJ/cm2, particles from the KL go through unsteady adiabatic expansion prior to free flight. Models of particle and ion formation and interaction are proposed and discussed. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Pulsed laser deposition (PLD) has been used to fabricate polymer/carbon nanocomposite thin films for use in chemical sensors (chemiresistors). Ethylene vinyl acetate copolymer (EVA) films (undoped and 20% carbon by weight) were deposited using an ArF excimer laser (193 nm) at fluences between 150 and 300 mJ/cm2. The structure and morphology of the deposited films were characterized using Fourier transform infrared spectroscopy (FTIR), Raman scattering, and transmission and scanning electron microscopy (TEM). An analysis of the FTIR spectra indicates that a film deposited using an undoped EVA target is primarily polyethylene, suggesting that the acetate group is photochemically or photothermally removed from the starting material. Gas phase measurements of the laser-evaporated material using a quadrupole time of flight mass spectrometer confirm the production of the acetyl radical on the target surface. Analysis of TEM of films deposited using C-doped targets shows that the carbon black particles (initially 50 nm particles in 1 μm agglomerates) are broken down into particles that are ≤50 nm in the deposited film. Incorporation of carbon into the target reduces the degree of photochemical damage of the starting material, as shown in the FTIR spectra of the deposited film. The sensitivity and response time of chemiresistors fabricated from 6 μm thick composite films on top of gold electrodes were measured using toluene vapor (548 ppm). The chemiresistors exhibited a reversible and fast (<1.3 s) response to the vapor. In comparison to data reported in the literature, chemiresistors fabricated from PLD films are significantly better than devices fabricated using a more conventional polymer film growth technique. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Reports on microwave dielectric properties of strained thin films grown on manganese oxide by pulsed laser deposition. Correlation between thin films' structure and microwave dielectric properties; Tetragonal distortion of epitaxially grown films; Phenomenological thermodynamic theory based on the strain along in-plane direction of films.

The authors review the publications on laser use for thin films of polymers and biomaterials. The topics of interest include the applications of thin films for polymers and biomaterials, and the interactions of laser radiation with polymers and biomaterials.

Objective: The ESCAPE multicentre survey was designed to (a) compare the agreement of three relevant aesthetic scoring systems among different centres, and (b) evaluate the reproducibility of each question of the questionnaires. Materials and Methods: EFP centres (n = 14) were involved in an e‐survey. Forty‐two participants (28 teachers, 14 postgraduate students) were asked to score the one‐year aesthetic outcomes of photographs using the Before–After Scoring System (BASS), the Pink Esthetic Score (PES) and the Root coverage Esthetic Score (RES). Mean values of kappa statistics performed on each question were provided to resume global agreement of each method. Results: Between teachers, a difference of kappa ≥ 0.41 (p = .01) was found for BASS (75%) and PES (57%). Similarly, RES (84%) and PES (57%) were different (p < .001). No difference was found between BASS (75%) and RES (84%). No difference was found between students, whatever the scoring system. Questions of each scoring system showed differences in their reproducibility. Conclusions: The outcomes of this study indicate that BASS and RES scoring systems are reproducible tools to evaluate aesthetic after root coverage therapies between different centres. Among the various variables, lack of scar, degree of root coverage, colour match and gingival margin that follows the CEJ show the best reliability. [ABSTRACT FROM AUTHOR]

Thick films (10–12 μm) of NiZn-ferrite (Ni[sub 0.6]Zn[sub 0.4]Fe[sub 2]O[sub 4]) were grown on single-crystal (100) magnesium oxide substrates using pulsed laser deposition (PLD). The morphology, phase, orientation, strain, and magnetic properties of the as-deposited films were investigated as a function of substrate temperamre (400–700°C) and O[sub 2] background pressure (50–200 mTorr). Compositional analysis shows that the PLD NiZn-ferrite films are about 45% Zn deficient when grown using a standard polycrystalline single phase Ni[sub 0.4]Zn[sub 0.6]Fe[sub 2]O[sub 4] target regardless of substrate temperature or O[sub 2] pressure. However, Zn-rich targets were successfully used to compensate for the Zn deficiency in the NiZn-ferrite films. PLD NiZn-ferrite films grown at 700 °C exhibit the highest degree of crystalline quality and nearly bulk saturation magnetization values (i.e., 5000 G). At low O[sub 2] pressures (<75 mTorr) the films, which were grown at 700 °C, are under a significant compressive stress. The stress decreases when the PLD NiZn-ferrite films are grown in higher O[sub 2] pressures but the crystalline quality and surface morphology deteriorate. The compressive stress produces a planar anisotropy field of about 1000–3500 Oe depending on the O[sub 2] pressure, which is consistent with the stress results from x-ray diffraction measurements on the NiZn-ferrite films. It is hypothesized that the film stress is largely the result of oxygen loss from the films during deposition. © 1997 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Investigates the presence of inhomogeneous hopping resistance among magnetic domains in a sample of colossal magnetoresistive material. Role of non-Gaussian noise to test the presence of magnetic inhomogeneities in manganites; Frequent resolution of individual resistance switches; Implications for modeling of noise statistics in transport.

Presents a study which determined the thermal expansion coefficients along the a axis and c axis of barium hexaferrite. Introduction to the coefficient of thermal expansion; Methodology; Results.

Discusses a study that focused on the measurement of the dispersed emission in the vacuum ultraviolet from the plasma generated by the interaction of a krypton fluoride excimer laser with an aluminum and a YBa[sub2]Cu[sub3]0[sub7] target. Capacity of the emission spectra; Regions that the spatial variation indicated; Nature of the spectra obtained.

Focuses on the fabrication of epitaxial thin films of barium hexaferrite by the pulsed laser deposition technique on basal plane sapphire. Film preparation and characterization; Ferromagnetic resonance experiments; Conclusions.

Examines the effects of light on high-temperature superconductor microstrip transmission lines under conditions for which a bolometric photoresponse is expected. Illustration of sample geometry and experimental setup; Schematic of a microstrip line composed of several segments.

Background: Surgical complications are a recognized morbidity of the treatment of patients (pts) with Wilms tumors. This study examines the incidence of surgical complications in the most recently completed NWTSG study. Methods: NWTS-4 enrolled 3,335 pts from August 1986 to August 1994. A representative random sample of 534 pts were selected from 2,290 eligible pts randomized to treatment regimens or enrolled in the followed category and treated according to NWTSG protocol. The pt records received at the NWTSG Data and Statistical Center were analyzed for surgical complications (intraoperative and postoperative). Results: Seventy-six complications occurred in 68 pts, 12.7% of pts had at least one complication. Intestinal obstruction was the most common complication (5.1% of pts), followed by extensive hemorrhage (1.9%), wound infection and vascular injury (1.1% each). Multiple factors previously shown to be associated with an increased risk for surgical complications were analyzed by multiple logistic regression analysis. None of the previously identified risk factors such as higher local tumor stage, and intracaval involvement was associated with an increased risk of complications. Nephrectomy performed through a flank or paramedian incision was associated with increased complications (p=0.05). The risk of complications was higher if the nephrectomy was performed by a general surgeon or urologist who deals mostly with adults (RR 8.58, p=0.03, RR 3.07, p=0.08, respectively) rather than a pediatric surgeon (PR 1.0) or pediatric urologist (RR 0.66). Conclusions: The incidence of surgical complications in NWTIS-4 was significantly lower than NWTS-3 (12.7% vs. 19.8%, p [is less than] 0.001). There has been a marked decrease in the risk of extensive intraoperative bleeding and major intraoperative complications. Factors (tumor stage, IVC involvement) previously associated with an increased risk for complications are no longer significant. This may represent the smaller sample of pts studied in this review and that a higher percentage of high risk pts now receive preoperative chemotherapy., M. Ritchey, MD, FAAP, R. Shamberger, MD, FAAP, G. Haase, MD, FAAP, J. Horwitz, MD, T. Bergmann, N. Breslow, PhD, Dept of Surgery, Univ. Texas-Houston Medical School, Houston, [...]