RPA for Light-Front Hamiltonian Field Theory

A self-consistent random phase approximation (RPA) is proposed as an effective Hamiltonian method in Light-Front Field Theory (LFFT). We apply the general idea to the light-front massive Schwinger model to obtain a new bound state equation and solve it numerically.Comment: A major revision in presentation, while the results essentially unchanged. 2 figs. replaced, 1 fig. added, some parts of Sec. V moved to Sec. IV, some wording changed, typos correcte

Computational Model for Electron-Nucleon Scattering and Weak Charge of the Nucleon

We show how computational symbolic packages such as FeynArts and FormCalc can be adopted for the evaluation of one-loop hadronic electroweak radiative corrections for electron-nucleon scattering and applied to calculations of the nucleon weak charge. Several numerical results are listed, and found to be in good agreement with the current experimental data.Comment: 13 pages, 8 figures, results unchanged, minor corrections in the appendi

Order in supported phospholipid monolayers detected by the dichroism of fluorescence excited with polarized evanescent illumination.

A technique is described and demonstrated for measuring the orientation distribution of fluorescent molecules in a two-dimensional system. A laser beam is totally internally reflected at the interface between a glass slide and an aqueous solution, which creates a thin layer of evanescent illumination that excites fluorescent molecules near the interface. Molecules with absorption dipoles at different tilts from the normal to the interface are preferentially excited when the laser polarization is rotated. Approximately one-half of the emitted fluorescence is collected with an inverted microscope using a high-aperture objective. The fluorescence vs. polarization curve yields the value of an order parameter that is related to the orientation distribution of absorption dipoles. This technique is applied to phospholipid monolayers made at an air/water interface and transferred to hydrophobic glass microscope slides. Dipalmitoylphosphatidylcholine monolayers were doped with 2 mol% phosphatidylethanolamine labeled with the fluorescent moiety nitrobenzoxadiazole, either on an acyl chain or on the head group. The measured value of the order parameter for the head-labeled probe decreases as a function of the surface pressure at which the monolayer is transferred to the slide, as the surface pressure increases from 10 to 40 dyne/cm. The measured value of the order parameter for the chain-labeled probe is high for all coating pressures. These results can be interpreted in terms of probe partitioning into coexistent fluid and solid domains. Dimyristoylphosphatidylcholine monolayers were doped with 2 mol% chain-labeled phosphatidylethanolamine, either free or covalently conjugated to a small peptide. In these monolayers, the measured value of the order parameter is high at all pressures. The technique presented here may also prove useful for measuring the orientation distribution of proteins bound to or embedded in a planar model membrane

Dental long axes using digital dental models compared to cone-beam computed tomography

Objective: Standard methods of evaluating tooth long axes are not comparable (digital dental models [DDMs], panoramic and cephalometric radiographs) or expose patients to more radiation (cone-beam computed tomography [CBCT]). This study aimed to compare angular changes in tooth long axes using DDMs vs using CBCTs. Settings and sample population: Secondary data analysis of DDMs and CBCTs, taken before and after orthodontic treatment with piezocision of 24 patients. Methods: Angular changes in tooth long axes were evaluated using landmarks on first molars (centre of the occlusal surface and centre of the furcation), canines and incisors (cusp tip and centre of the root at the cementoenamel junction). Wilcoxon test, intraclass correlation coefficient (ICC) and Bland-Altman plots were used to test intra- and inter-rater agreement and compare DDM and CBCT measurements. Results: The mesiodistal angulation and buccolingual inclination DDM measurements were reproducible. Overall mean differences between DDM and CBCT measurements of mesiodistal angulation, 1.9°±1.5°, and buccolingual inclination, 2.2 ± 2.2°, were not significant for all teeth. ICC between DDM and CBCT measurements ranged from good (0.85 molars) to excellent (0.94 canines; 0.96 incisors). The percentages of measurements outside the range of ±5 were 17.4% for molars, 13.8% for canines and 4.5% for incisors. Conclusions: DDM assessment of changes in tooth long axes has good reproducibility and yields comparable measurements to those obtained from CBCT within a 5° range. These findings lay the groundwork for machine learning approaches that synthesize crown and root canal information towards planning tooth movement without the need for ionizing radiation scans

Development of PVD coating processes informed by plasma diagnostics

SIGLEAvailable from British Library Document Supply Centre- DSC:DXN054734 / BLDSC - British Library Document Supply CentreGBUnited Kingdo