Predoctoral Dental Students’ Perceptions of Dental Implant Training: Effect of Preclinical Simulation and Clinical Experience

The aims of this study were to assess 1) differences in perceptions of dental implant training between dental students who received didactic training alone (control group) and those who received didactic plus simulation training (test group); 2) differences in response between students with and without clinical experience in implant dentistry; and 3) the interaction effect of simulation training and clinical experience on students’ satisfaction. A survey was distributed to the control group in 2014 and to the test group in 2015; both groups were at the same U.S. dental school. Data were collected on confidence levels with various implant restorative procedures along with overall satisfaction and number of implant restorations performed by each student. The response rate was 78.7% in the control group and 81.3% in the test group. In the control group, 85.7% of students reported being satisfied with implant training compared to 90.8% of students in the test group. The interaction effect of simulation training and clinical experience on overall student satisfaction was OR=1.5 at 95% CI: 0.8, 3.0. The students who had clinical experience with implant restorative procedures had significantly greater satisfaction than those who did not (OR=4.8, 95% CI: 2.1, 11.1,

On the relationship between the modifications to the Raychaudhuri equation and the canonical Hamiltonian structures

The problem of obtaining canonical Hamiltonian structures from the equations of motion, without any knowledge of the action, is studied in the context of the spatially flat Friedmann-Robertson-Walker models. Modifications to Raychaudhuri equation are implemented independently as quadratic and cubic terms of energy density without introducing additional degrees of freedom. Depending on their sign, modifications make gravity repulsive above a curvature scale for matter satisfying strong energy condition, or more attractive than in the classical theory. Canonical structure of the modified theories is determined demanding that the total Hamiltonian be a linear combination of gravity and matter Hamiltonians. In the quadratic repulsive case, the modified canonical phase space of gravity is a polymerized phase space with canonical momentum as inverse trigonometric function of Hubble rate; the canonical Hamiltonian can be identified with the effective Hamiltonian in loop quantum cosmology. The repulsive cubic modification results in a `generalized polymerized' canonical phase space. Both of the repulsive modifications are found to yield singularity avoidance. In contrast, the quadratic and cubic attractive modifications result in a canonical phase space in which canonical momentum is non-trigonometric and singularities persist. Our results hint on connections between repulsive/attractive nature of modifications to gravity arising from gravitational sector and polymerized/non-polymerized gravitational phase space.Comment: 22 pages with two new plots. Discussion on uniqueness added, and possible links with existing models expanded. Periodicity for 'generalized polymerized' theory and its comparison with standard polymerization discussed. References added. To appear in CQ

Optical tweezer for probing erythrocyte membrane deformability

We report that the average rotation speed of optically trapped crenated erythrocytes is direct signature of their membrane deformability. When placed in hypertonic buffer, discocytic erythrocytes are subjected to crenation. The deformation of cells brings in chirality and asymmetry in shape that make them rotate under the scattering force of a linearly polarized optical trap. A change in the deformability of the erythrocytes, due to any internal or environmental factor, affects the rotation speed of the trapped crenated cells. Here we show how the increment in erythrocyte membrane rigidity with adsorption of $Ca^{++}$ ions can be exhibited through this approach.Comment: Published in Appl. Phys. Lett. 95, 233703 (2009); Two supplementary multimedia files are available at the journal page: http://link.aip.org/mm/APPLAB/1.3272269/083949aplv1.mov and http://link.aip.org/mm/APPLAB/1.3272269/083949aplv2.mo

Geometry modeling and multi-block grid generation for turbomachinery configurations

An interactive 3D grid generation code, Turbomachinery Interactive Grid genERation (TIGER), was developed for general turbomachinery configurations. TIGER features the automatic generation of multi-block structured grids around multiple blade rows for either internal, external, or internal-external turbomachinery flow fields. Utilization of the Bezier's curves achieves a smooth grid and better orthogonality. TIGER generates the algebraic grid automatically based on geometric information provided by its built-in pseudo-AI algorithm. However, due to the large variation of turbomachinery configurations, this initial grid may not always be as good as desired. TIGER therefore provides graphical user interactions during the process which allow the user to design, modify, as well as manipulate the grid, including the capability of elliptic surface grid generation

Algebraic grid adaptation method using non-uniform rational B-spline surface modeling

An algebraic adaptive grid system based on equidistribution law and utilized by the Non-Uniform Rational B-Spline (NURBS) surface for redistribution is presented. A weight function, utilizing a properly weighted boolean sum of various flow field characteristics is developed. Computational examples are presented to demonstrate the success of this technique

Strong CP, Up-Quark Mass, and the Randall-Sundrum Microscope

In the Randall-Sundrum model, setting the ratio of up and down quark masses $m_u/m_d << 1$, relevant to the strong CP problem, does not require chiral symmetry or fine-tuning, due to exponential bulk fermion profiles. We point out that such geometric suppression of the mass of a fermion magnifies the masses of its corresponding Kaluza-Klein (KK) states. In this sense, these KK states act as "microscopes" for probing light quark and lepton masses. In simple realizations, this hypothesis can be testable at future colliders, like the LHC, by measuring the spectrum of level-1 KK fermions. The microscope can then provide an experimental test for the vanishing of $m_u$ in the ultraviolet, independently of non-perturbative determinations, by lattice simulations or other means, at hadronic scales. We also briefly comment on application of our microscope idea to other fermions, such as the electron and neutrinos.Comment: 7 pages. New discussions and references added. Main previous conclusions unchange

Calculation of the neutron electric dipole moment with two dynamical flavors of domain wall fermions

We present a study of the neutron electric dipole moment ($\vec d_N$) within the framework of lattice QCD with two flavors of dynamical lig ht quarks. The dipole moment is sensitive to the topological structure of the gaug e fields, and accuracy can only be achieved by using dynamical, or sea quark, calc ulations. However, the topological charge evolves slowly in these calculations, le ading to a relatively large uncertainty in $\vec d_N$. It is shown, using quenched configurations, that a better sampling of the charge d istribution reduces this problem, but because the CP even part of the fermion determinant is absent, both the topological charge dis tribution and $\vec d_N$ are pathological in the chiral limit. We discuss the statistical and systematic uncertainties arising from the topological charge distr ibution and unphysical size of the quark mass in our calculations and prospects fo r eliminating them. Our calculations employ the RBC collaboration two flavor domain wall fermion and DBW2 gauge action lattices with inverse lattice spacing $a^{-1}\approx$ 1.7 GeV, physical volume $V\approx (2$ fm)$^3$, and light quark mass roughly equal to the strange quark mass ($m_{sea}=0.03$ and 0.04). We determine a value of the electric dipole moment that is zero withi n (statistical) errors, $|\vec d_N| = -0.04(20)$ e-$\theta$-fm at the smaller sea quark mass. Satisfactory results for the magnetic and electric form factors of the proton and neutron are also obtained and presented.Comment: 46 pages. Changed one author addres