Does the bracket-ligature combination affect the amount of orthodontic space closure over three months? A randomized controlled trial

OBJECTIVE: To investigate the effect of bracket-ligature combination on the amount of orthodontic space closure over three months. DESIGN: Randomized clinical trial with three parallel groups. SETTING: A hospital orthodontic department (Chesterfield Royal Hospital, UK). PARTICIPANTS: Forty-five patients requiring upper first premolar extractions. METHODS: Informed consent was obtained and participants were randomly allocated into one of three groups: (1) conventional pre-adjusted edgewise brackets and elastomeric ligatures; (2) conventional pre-adjusted edgewise brackets and Super Slick((R)) low friction elastomeric ligatures; (3) Damon 3MX((R)) passive self-ligating brackets. Space closure was undertaken on 0.019x0.025-inch stainless steel archwires with nickel-titanium coil springs. Participants were recalled at four weekly intervals. Upper alginate impressions were taken at each visit (maximum three). The primary outcome measure was the mean amount of space closure in a 3-month period. RESULTS: A one-way ANOVA was undertaken [dependent variable: mean space closure (mm); independent variable: group allocation]. The amount of space closure was very similar between the three groups (1 mm per 28 days); however, there was a wide variation in the rate of space closure between individuals. The differences in the amount of space closure over three months between the three groups was very small and non-significant (P = 0.718). CONCLUSION: The hypothesis that reducing friction by modifying the bracket/ligature interface increases the rate of space closure was not supported. The major determinant of orthodontic tooth movement is probably the individual patient response

Phase closure nulling of HD 59717 with AMBER/VLTI . Detection of the close faint companion

Aims: The detection of close and faint companions is an essential step in many astrophysical fields, including the search for planetary companions. A new method called "phase closure nulling" has been proposed for the detection of such faint and close companions based on interferometric observations when the system visibility amplitude is close to zero due to the large diameter of the primary star. We aim at demonstrating this method by analyzing observations obtained on the spectroscopic binary HD 59717. Methods: Using the AMBER/VLTI instrument in the K-band with ~1500 spectral resolution, we record the spectrally dispersed closures phases of the SB1 binary HD 59717 with a three-baseline combination adequate for applying phase closure methods. After a careful data reduction, we fit the primary diameter, the binary flux ratio, and the separation using the phase closure data. Results: We detect the 5-mag fainter companion of HD 59717 at a distance of 4 stellar radii from the primary. We determine the diameter of the primary, infer the secondary's spectral type and determine the masses and sizes of the stars in the binary system. This is one of the highest contrasts detected by interferometry between a companion and its parent star. Based on observations collected at the European Southern Observatory, Paranal, Chile, within the commissioning programme 60.A-9054(A)

An inclusion result for dagger closure in certain section rings of abelian varieties

We prove an inclusion result for graded dagger closure for primary ideals in symmetric section rings of abelian varieties over an algebraically closed field of arbitrary characteristic.Comment: 11 pages, v2: updated one reference, fixed 2 typos; final versio

Abdominal decompression for abdominal compartment syndrome in critically ill patients: a retrospective study

Background. The abdominal compartment syndrome (ACS) refers to organ dysfunction that may occur as a result of increased intra-abdominal pressure (IAP). Successful management may require abdominal decompression and temporary abdominal closure (TAC). The aim of this study was to analyze the characteristics of patients requiring abdominal decompression, to describe the methods used for TAC, and to study the outcome of these patients. Methods. A series of critically ill patients who required abdominal decompression for ACS between January 2000 and March 2007 were reviewed retrospectively. Age, gender, severity of organ dysfunction before decompression and the cause of ACS as well as the type of abdominal closure system and length of ICU-stay were recorded. Definitive abdominal closure and in-hospital mortality were the main outcome parameters. Results. Eighteen patients with primary ACS and 6 with secondary ACS required decompressive laparotomy. Patients ages ranged from 18 to 89 years (mean 50.7). The median preoperative IAP was 26mmHg, and IAP decreased to 13mmHg after decompressive laparotomy. Organ function, as quantified by the SOFA scoring system, improved significantly after the intervention. Eight patients had immediate primary fascial closure after the decompressive procedure and 16 patients required TAC. The majority of the survivors underwent planned ventral hernia repair at a later stage. The mean length of stay in the ICU was 23 (+/- 16) days. Overall, fifteen patients survived (63%). Conclusions. Decompressive laparotomy was effective in reducing IAP and was associated with an improvement in organ function. In most of the patients, the abdomen could not be closed after decompression, and fascial repair was delayed

Tight closure and plus closure for cones over elliptic curves

We characterize the tight closure of graded primary ideals in a homogeneous coordinate ring over an elliptic curve by numerical conditions and we show that it is in positive characteristic the same as the plus closure.Comment: Some minor change