Coulomb Artifacts and Breakdown of Perturbative Matching in Lattice NRQCD

By studying an explicit analytical solution of the Coulomb problem on the lattice we demonstrate a breakdown of perturbative matching for the description of the Coulomb artifacts in lattice NRQCD, which leads to a large systematic error in the predictions for the heavy quarkonium spectrum. The breakdown is a result of a fine interplay between the short and long distance effects specific to the lattice regularization of NRQCD. We show how the problem can be solved within the Schrodinger matching procedure.Comment: 11 pages, 1 figure. Journal version (minor revisions implemented

The NuTeV Anomaly, Lepton Universality, and Non-Universal Neutrino-Gauge Couplings

In previous studies we found that models with flavor-universal suppression of the neutrino-gauge couplings are compatible with NuTeV and Z-pole data. In this paper we expand our analysis to obtain constraints on flavor-dependent coupling suppression by including lepton universality data from W, tau, pi and K decays in fits to model parameters. We find that the data are consistent with a variety of patterns of coupling suppression. In particular, in scenarios in which the suppression arises from the mixing of light neutrinos with heavy gauge singlet states (neutrissimos), we find patterns of flavor-dependent coupling suppression which are also consistent with constraints from mu -> e gamma.Comment: REVTeX4, 25 pages, 10 postscript figures. Updated fits using the new top mass. Updated figures. Extended discussion on the status of the determination of B(tau->pi nu

Catch-up growth in the first two years of life in Extremely Low Birth Weight (ELBW) infants is associated with lower body fat in young adolescence

Aim To investigate growth patterns and anthropometrics in former extremely low birth weight (ELBW, <1000 g) children and link these outcomes to neurocognition and body

Determinants of drug absorption in different ECMO circuits

Purpose: The aim of this in vitro study was to evaluate potential determinants of drug loss in different ECMO circuits. Methods: Midazolam, morphine, fentanyl, paracetamol, cefazolin, meropenem and vancomycin were injected into three neonatal roller pump, two paediatric roller pump and two clinically used neonatal roller pump circuits, all with a silicone membrane, and two neonatal centrifugal pump circuits with polypropylene hollow-fibre membranes. Serial blood samples were taken from a post-oxygenator site. Drug recovery was calculated as the ratio between the determined and the theoretical maximum concentration. The latter was obtained by dividing dose by theoretical circuit volume. Results: Average drug recoveries at 180 min in three neonatal silicone membrane roller pump circuits were midazolam 0.62%, morphine 23.9%, fentanyl 0.35%, paracetamol 34.0%, cefazolin 84.3%, meropenem 82.9% and vancomycin 67.8%. There was a significant correlation between the lipophilicity of the drug expressed as log P and the extent of drug absorption, p < 0.001. The recovery of midazolam and fentanyl in centrifugal pump circuits with hollow-fibre membrane oxygenator was significantly higher compared to neonatal roller pump circuits with silicone membranes: midazolam 63.4 versus 0.62%, fentanyl 33.8 versus 0.35%, p < 0.001. Oxygenator size and used circuits do not significantly affect drug losses. Conclusions: Significant absorption of drugs occurs in the ECMO circuit, correlating with increased lipophilicity of the drug. Centrifugal pump circuits with hollow-fibre membrane oxygenators show less absorption for all drugs, most pronounced for lipophilic drugs. These results suggest that pharmacokinetics and hence optimal doses of these drugs may be altered during ECMO

The Role of Osteoimmunology in Periodontal Disease

Periodontal disease is a pathological condition that involves inflammation of the tooth supporting structures. It occurs in response to the presence of bacterial plaque on the tooth structure. The host defense system, including innate and adaptive immunity, is responsible for combating the pathologic bacteria invading the periodontal tissue. Failure to eradicate the invading pathogens will result in a continuous state of inflammation where inflammatory cells such as lymphocytes, PMNs, and macrophages will continue to produce inflammatory mediators in an effort to destroy the invaders. Unfortunately, these inflammatory mediators have a deleterious effect on the host tissue as well as foreign microbes. One of the effects of these mediators on the host is the induction of matrix degradation and bone resorption through activation of proteases and other inflammatory mediators that activate osteoclasts.</jats:p

EFFECT OF LIGHT TRANSMITTING ABILITY OF FIBER POST ON BOND STRENGTH OF SELFADHESIVE RESIN CEMENT TO RADICULAR DENTINE

Aim: to investigate the effect of different light transmitting ability of two fiber posts systems on bond strength to the root canal dentine using dual cure self-adhesive resin cement. Materials and methods: 24 freshly extracted human premolars were decoronated and endodontically treated. Post spaces were prepared to a depth of 8 mm and width of 1.3 mm using manufacture’s supplied drills. Teeth were randomly classified into two main groups (n= 12) according to fiber post light transmission ability; group I; non-light transmitting fiber posts (NLT) (Reforpost, Angelus), group II; light transmitting fiber post (LT) (Exacto, Angelus). Both groups were cemented using self-adhesive resin cement (SpeedCEM, Ivoclar Vivadent). Using low speed saw (IsoMet, Buehler), a 2 mm thickness coronal, middle and apical sections were obtained from each sample. Then they were subjected to push out test using Instron machine (Lloyd Instruments Ltd) until failure. Data was collected and statistically analyzed. Results: the highest means in the coronal and middle parts was found, when using light transmitting fiber post, which scored (11.75, 10.30 MPa) compared with (6.51, 6.98 MPa) when using non-light transmitting group. One-way ANOVA among the groups revealed a significant difference between non-light and light transmitting fiber post. However, there is no significant difference on the middle and the coronal parts. Conclusions: There was no significant difference between non-light and light transmitting fiber post when all sections were added together. There is a reasonable doubt regarding the ability of light to reach more than 4 mm depth

EFFECT OF LIGHT TRANSMITTING ABILITY OF FIBER POST ON BOND STRENGTH OF SELFADHESIVE RESIN CEMENT TO RADICULAR DENTINE

Aim: to investigate the effect of different light transmitting ability of two fiber posts systems on bond strength to the root canal dentine using dual cure self-adhesive resin cement. Materials and methods: 24 freshly extracted human premolars were decoronated and endodontically treated. Post spaces were prepared to a depth of 8 mm and width of 1.3 mm using manufacture’s supplied drills. Teeth were randomly classified into two main groups (n= 12) according to fiber post light transmission ability; group I; non-light transmitting fiber posts (NLT) (Reforpost, Angelus), group II; light transmitting fiber post (LT) (Exacto, Angelus). Both groups were cemented using self-adhesive resin cement (SpeedCEM, Ivoclar Vivadent). Using low speed saw (IsoMet, Buehler), a 2 mm thickness coronal, middle and apical sections were obtained from each sample. Then they were subjected to push out test using Instron machine (Lloyd Instruments Ltd) until failure. Data was collected and statistically analyzed. Results: the highest means in the coronal and middle parts was found, when using light transmitting fiber post, which scored (11.75, 10.30 MPa) compared with (6.51, 6.98 MPa) when using non-light transmitting group. One-way ANOVA among the groups revealed a significant difference between non-light and light transmitting fiber post. However, there is no significant difference on the middle and the coronal parts. Conclusions: There was no significant difference between non-light and light transmitting fiber post when all sections were added together. There is a reasonable doubt regarding the ability of light to reach more than 4 mm depth

EVALUATION OF AN EXPERIMENTAL SCREW-RETAINED RETRIEVABLE CROWN VERSUS CONVENTIONAL CROWN DESIGN

Statement of problem: Removing cemented crowns is usually a complicated procedure that may lead to irreversible damage to the tooth/crown and mostly necessitate remake of crown with added effort for both patient and clinician. Purpose: This in-vitro study evaluated an experimental two-component, screw-retained retrievable crown design in comparison to the conventional design. Materials and methods: A total of 120 extracted maxillary 2nd premolars received root canal treatment and were divided into two groups (n=60 each) according to the crown design they will receive. Gp CC received a threaded modified post, a composite core and a metal coping, while Gp RC received a two-component retrievable crown design. Fracture resistance was assessed by a 90 degrees vertical load to the center of the occlusal surface, using universal testing machine, under a constant crosshead speed of 0.5 mm/min until failure. Microleakage was assessed by placing specimens in methylene blue dye for 12 hours, sectioning the teeth longitudinally, and then examining the sectioned samples under stereomicroscope. Retrievability testing was conducted by 5 prosthodontists who attempted to uncover and unscrew the posts. Data were statistically evaluated using computer software (SPSS version 17; SPSS Inc.). Results: No significant difference between the 2 designs tested regarding microleakage tests (P=.34) whereas the experimental design, was significantly more resistant to fracture and more retrievable than the conventional one (P\u3e.5). Conclusions: The proposed retrievable crown design showed promising results and may be considered as an option to substitute the conventional design. Further studies are needed to confirm that

A COMPARISON BETWEEN THE EFFECT OF DIFFERENT PRESSURES OF AIR PARTICLE ABRASION BEFORE AND AFTER SINTERING WITH AND WITHOUT ZIRCONIA LINER ON BOND STRENGTH OF RESIN TO ZIRCONIA SURFACE

This study aimed to compare the effect of different pressures of air particle abrasion 2 and 4 bars before and after sintering with and without zirconia liner on SBS of resin to zirconia Surface. Materials and Methods: 54 zirconia cuboids 8×8×3 mm were milled and divided into 6 equal groups (N=9) according to surface treatment; sintered with ceramic liner application and 2 bars pressure (SL2) and with 4 bars pressure (SL4), sintered with no ceramic liner and 2 bars pressure (SN2) and 4 bars pressure (SN4), unsintered with no ceramic liner and 2 bars pressure (UN2) and 4 bars pressure (UN4). Specimens underwent thermocycling (1000 cycles) between 5 ̊ and 55 ̊ Celsius with dwell time of 10 seconds, and submitted to SBS test. Data was statistically analysed. Results: All 4 bars APA groups showed higher SBS than 2 bars groups with significant difference between SL4 group (4.7±2.07) and SL2 group (2.58±1.94). Groups with APA before sintering (12.42±2.56) showed significantly higher SBS than APA after sintering (6.35±3.7). SL2 group showed least SBS with significant difference (2.58±1.94) compared to UN2 (11.83±3.35) and SN2 (7.87±2.12). SL4 group (4.7±2.07) showed the least SBS compared to the UN4 (13±1.38), and SN4 (10.24±2.94) groups. Conclusion: It was found that APA of zirconia surface before sintering yielded superior performance than APA after sintering, also 4 bars APA pressure application showed higher SBS than 2 bars pressure, application and firing of ceramic liner onto zirconia surface didn’t enhance SBS