The Physical projector and topological quantum field theories: U(1) Chern-Simons theory in (2+1)-dimensions

The recently proposed physical projector approach to the quantisation of gauge invariant systems is applied to the U(1) Chern-Simons theory in 2+1 dimensions as one of the simplest examples of a topological quantum field theory. The physical projector is explicitely demonstrated to be capable of effecting the required projection from the initially infinite number of degrees of freedom to the finite set of gauge invariant physical states whose properties are determined by the topology of the underlying manifold. Comment: 24 pages, no figures, plain LaTeX file; one more reference added. Final version to appear in Jour. Phys.

The effect of smoking on survival and bone loss of implants with a fluoride-modified surface: a 2-year retrospective analysis of 1106 implants placed in daily practice

Aim: To compare survival and peri-implant bone loss of implants with a fluoride-modified surface in smokers and nonsmokers. Materials and Methods: Patient files of all patients referred for implant treatment from November 2004 to 2007 were scrutinized. All implants were placed by the same experienced surgeon (BC). The only inclusion criterion was a follow-up time of at least 2 years. Implant survival and bone loss were assessed by an external calibrated examiner (SV) comparing digital peri-apical radiographs taken during recall visits with the post-operative ones. Implant success was determined according to the international success criteria (Albrektsson et al. 1986). Survival of implants installed in smokers and nonsmokers were compared using the log-rank test. Both non-parametric tests and fixed model analysis were adopted to evaluate bone loss in smokers and nonsmokers. Results: 1106 implants in 300 patients (186 females; 114 males) with a mean follow-up of 31 months (SD 7.15; range 24-58) were included. 19 implants in 17 patients failed, resulting in an overall survival rate of 98.3% on implant level and 94.6% on patient level. After a follow-up period of 2 years, the CSR was 96.7% and 99.1% with the patient and implant as statistical unit respectively. Implant survival was significantly higher for nonsmokers compared to smokers (implant level p = 0.025; patient level p = 0.017). The overall mean bone loss was 0.34 mm (n = 1076; SD 0.65; range 0.00-7.10). Smokers lost significantly more bone compared to nonsmokers in the maxilla (0.74 mm; SD 1.07 vs 0.33 mm; SD 0.65; p < 0.001), but not in the mandible (0.25mm; SD 0.65 vs 0.22mm; SD 0.50; p = 0.298). Conclusion: The present study is the first to compare peri-implant bone loss in smokers and nonsmokers from the time of implant insertion (baseline) to at least 2 years of follow-up. Implants with a fluoride-modified surface demonstrated a high survival rate and limited bone loss. However, smokers are at higher risk to experience implant failure and more prone to show peri-implant bone loss in the maxilla. Whether this bone loss is predicting future biological complications remains to be evaluated

Effects of chlorhexidine gluconate oral care on hospital mortality : a hospital-wide, observational cohort study

Chlorhexidine oral care is widely used in critically and non-critically ill hospitalized patients to maintain oral health. We investigated the effect of chlorhexidine oral care on mortality in a general hospitalized population. In this single-center, retrospective, hospital-wide, observational cohort study we included adult hospitalized patients (2012-2014). Mortality associated with chlorhexidine oral care was assessed by logistic regression analysis. A threshold cumulative dose of 300 mg served as a dichotomic proxy for chlorhexidine exposure. We adjusted for demographics, diagnostic category, and risk of mortality expressed in four categories (minor, moderate, major, and extreme). The study cohort included 82,274 patients of which 11,133 (14%) received chlorhexidine oral care. Low-level exposure to chlorhexidine oral care (ae 300 mg) was associated with increased risk of death [odds ratio (OR) 2.61; 95% confidence interval (CI) 2.32-2.92]. This association was stronger among patients with a lower risk of death: OR 5.50 (95% CI 4.51-6.71) with minor/moderate risk, OR 2.33 (95% CI 1.96-2.78) with a major risk, and a not significant OR 1.13 (95% CI 0.90-1.41) with an extreme risk of mortality. Similar observations were made for high-level exposure (> 300 mg). No harmful effect was observed in ventilated and non-ventilated ICU patients. Increased risk of death was observed in patients who did not receive mechanical ventilation and were not admitted to ICUs. The adjusted number of patients needed to be exposed to result in one additional fatality case was 47.1 (95% CI 45.2-49.1). These data argue against the indiscriminate widespread use of chlorhexidine oral care in hospitalized patients, in the absence of proven benefit in specific populations

Northern Hemisphere Glaciation during the Globally Warm Early Late Pliocene

The early Late Pliocene (3.6 to ~3.0 million years ago) is the last extended interval in Earth's history when atmospheric CO2 concentrations were comparable to today's and global climate was warmer. Yet a severe global glaciation during marine isotope stage (MIS) M2 interrupted this phase of global warmth ~3.30 million years ago, and is seen as a premature attempt of the climate system to establish an ice-age world. Here we propose a conceptual model for the glaciation and deglaciation of MIS M2 based on geochemical and palynological records from five marine sediment cores along a Caribbean to eastern North Atlantic transect. Our records show that increased Pacific-to-Atlantic flow via the Central American Seaway weakened the North Atlantic Current and attendant northward heat transport prior to MIS M2. The consequent cooling of the northern high latitude oceans permitted expansion of the continental ice sheets during MIS M2, despite near-modern atmospheric CO2 concentrations. Sea level drop during this glaciation halted the inflow of Pacific water to the Atlantic via the Central American Seaway, allowing the build-up of a Caribbean Warm Pool. Once this warm pool was large enough, the Gulf Stream–North Atlantic Current system was reinvigorated, leading to significant northward heat transport that terminated the glaciation. Before and after MIS M2, heat transport via the North Atlantic Current was crucial in maintaining warm climates comparable to those predicted for the end of this century

The impact of an interventional counselling procedure in families with a BRCA1/2 gene mutation : efficacy and safety

Background: Predictive genetic testing has high impact on cancer prevention for BRCA carriers and passing this information in BRCA families is important. Mostly, this is proband-mediated but this path is defective and denies relatives lifesaving information. Objective: To assess the efficacy/safety of an intervention, in which relatives are actively informed. Design: Sequential prospective study in new BRCA families. The proband informed relatives about predictive testing (phase I). After 6 months, a letter was sent to adult relatives who had not been reached (phase II). Then a phone call was made to obtain a final notion of their wishes. All subjects received psychometric testing (State-Trait Anxiety Inventory, STAI), an interview and routine counselling. Results: Twenty families were included. Twenty-four of the relatives could not be reached, 59 were 'decliners', 47 participated by the proband and 42 by the letter. Predictive testing was performed in 98 % of the participants of which 30 were mutation carriers. The intervention is psychologically safe: the 95 % CI for the estimated mean difference in STAI DY1 between phase II/I subjects (mean difference -1.07, 95 % CI -4.4 to 2.35, p = 0.53) shows that the mean STAI DY1 score (measured at first consult) for phase II is no more than 2.35 units higher than for phase I, which is not relevant. Conclusions: A protocol directly informing relatives nearly doubles the number of relatives tested and is psychologically safe. This should lead to a change in counselling guidelines in families with a strong germline predisposition for cancer

Influence of chronic azithromycin treatment on the composition of the oropharyngeal microbial community in patients with severe asthma

Background: This study of the oropharyngeal microbiome complements the previously published AZIthromycin in Severe ASThma (AZISAST) clinical trial, where the use of azithromycin was assessed in subjects with exacerbationprone severe asthma. Here, we determined the composition of the oropharyngeal microbial community by means of deep sequencing of the amplified 16S rRNA gene in oropharyngeal swabs from patients with exacerbationprone severe asthma, at baseline and during and after 6 months treatment with azithromycin or placebo. Results: A total of 1429 OTUs were observed, of which only 59 were represented by more than 0.02% of the reads. Firmicutes, Bacteroidetes, Fusobacteria, Proteobacteria and Actinobacteria were the most abundant phyla and Streptococcus and Prevotella were the most abundant genera in all the samples. Thirteen species only accounted for two thirds of the reads and two species only, i.e. Prevotella melaninogenica and Streptococcus mitis/pneumoniae, accounted for one fourth of the reads. We found that the overall composition of the oropharyngeal microbiome in patients with severe asthma is comparable to that of the healthy population, confirming the results of previous studies. Long term treatment (6 months) with azithromycin increased the species Streptococcus salivarius approximately 5-fold and decreased the species Leptotrichia wadei approximately 5-fold. This was confirmed by Boruta feature selection, which also indicated a significant decrease of L. buccalis/L. hofstadtii and of Fusobacterium nucleatum. Four of the 8 treated patients regained their initial microbial composition within one month after cessation of treatment. Conclusions: Despite large diversity of the oropharyngeal microbiome, only a few species predominate. We confirm the absence of significant differences between the oropharyngeal microbiomes of people with and without severe asthma. Possibly, long term azithromycin treatment may have long term effects on the composition of the oropharygeal microbiome in half of the patients