Probing the quantum-gravity realm with slow atoms

For the study of Planck-scale modifications of the energy-momentum dispersion relation, which had been previously focused on the implications for ultrarelativistic (ultrafast) particles, we consider the possible role of experiments involving nonrelativistic particles, and particularly atoms. We extend a recent result establishing that measurements of "atom-recoil frequency" can provide insight that is valuable for some theoretical models. And from a broader perspective we analyze the complementarity of the nonrelativistic and the ultrarelativistic regimes in this research area.Comment: LaTex, 13 page

Constraints on the quantum gravity scale from kappa - Minkowski spacetime

We compare two versions of deformed dispersion relations (energy vs momenta and momenta vs energy) and the corresponding time delay up to the second order accuracy in the quantum gravity scale (deformation parameter). A general framework describing modified dispersion relations and time delay with respect to different noncommutative kappa -Minkowski spacetime realizations is firstly proposed here and it covers all the cases introduced in the literature. It is shown that some of the realizations provide certain bounds on quadratic corrections, i.e. on quantum gravity scale, but it is not excluded in our framework that quantum gravity scale is the Planck scale. We also show how the coefficients in the dispersion relations can be obtained through a multiparameter fit of the gamma ray burst (GRB) data.Comment: 9 pages, final published version, revised abstract, introduction and conclusion, to make it clear to general reade

Subclinical interstitial lung abnormalities in stable renal allograft recipients in the era of modern immunosuppression.

BACKGROUND: Interstitial lung abnormalities have been detected in up to 24% of kidney transplant patients receiving traditional immunosuppressive therapies (eg, cyclosporine, azathioprine); they usually occur early after transplantation and tend to resolve over time. Newer immunosuppressants such as mycophenolic acid and, particularly, mammalian target of rapamycin (mTOR) inhibitors (eg, sirolimus) may cause significant lung toxicity. However, the prevalence and severity of interstitial lung lesions in long-term, stable kidney transplant patients receiving either traditional or newer immunosuppressants is not known. METHODS: We conducted a prospective, cross-sectional study examining high-resolution lung computed tomography (CT) scans in 63 stable kidney transplant recipients whose immunosuppressive therapy had remained unchanged for over 24 months. We compared CT findings of patients taking newer (mycophenolic acid and mTOR inhibitors) and traditional (calcineurin inhibitors and azathioprine) immunosuppressive drugs. RESULTS: Interstitial lung alterations were observed in only 3/63 patients (4.8%); the prevalence was 11.5% (3/26) versus 0% (0/37) among the newer versus traditional immunosuppressive therapy groups, respectively (P = .065). The CT patterns were usual interstitial pneumonia and nonspecific interstitial pneumonia-like. The median time between transplant and CT was 49 months in the three patients with CT alterations and 95 months in the remaining 23 patients on newer immunosuppressants. It was 75 months for all patients on newer immunosuppressive drugs and 133 months for those on traditional therapies (P = .0015). A follow-up CT, performed in 2/3 patients with interstitial abnormalities, showed that the lesions were stable in one, while they had disappeared in the other. CONCLUSIONS: Interstitial lung abnormalities are infrequent and mild in stable kidney transplant patients treated with newer as well as traditional immunosuppressive drugs. As such abnormalities were detected in patients screened earlier after transplantation, the time since transplantation rather than the drug type is probably the major determinant

Current aspects and future prospects of total anorectal reconstruction-a critical and comprehensive review of the literature

PURPOSE: Many rectal cancer patients undergo abdominoperineal excision worldwide every year. Various procedures to restore perineal (pseudo-) continence, referred to as total anorectal reconstruction, have been proposed. The best technique, however, has not yet been defined. In this study, the different reconstruction techniques with regard to morbidity, functional outcome and quality of life were analysed. Technical and timing issues (i.e. whether the definitive procedure should be performed synchronously or be delayed), oncological safety, economical aspects as well as possible future improvements are further discussed. METHODS: A MEDLINE and EMBASE search was conducted to identify the pertinent multilingual literature between 1989 and 2013. All publications meeting the defined inclusion/exclusion criteria were eligible for analysis. RESULTS: Dynamic graciloplasty, artificial bowel sphincter, circular smooth muscle cuff or gluteoplasty result in median resting and squeezing neo-anal pressures that equate to the measurements found in incontinent patients. However, quality of life was generally stated to be good by patients who had undergone the procedures, despite imperfect continence, faecal evacuation problems and a considerable associated morbidity. Many patients developed an alternative perception for the urge to defecate that decisively improved functional outcome. Theoretical calculations suggested cost-effectiveness of total anorectal reconstruction compared well to life with a permanent colostomy. CONCLUSIONS: Many patients would be highly motivated to have their abdominal replaced by a functional perineal colostomy. Given the considerable morbidity and questionable functional outcome of current reconstruction technique improvements are required. Tissue engineering might be an option to design an anatomically and physiologically matured, and customised continence organ