Interferometric Probes of Many-Body Localization

We propose a method for detecting many-body localization (MBL) in disordered spin systems. The method involves pulsed coherent spin manipulations that probe the dephasing of a given spin due to its entanglement with a set of distant spins. It allows one to distinguish the MBL phase from a noninteracting localized phase and a delocalized phase. In particular, we show that for a properly chosen pulse sequence the MBL phase exhibits a characteristic power-law decay reflecting its slow growth of entanglement. We find that this power-law decay is robust with respect to thermal and disorder averaging, provide numerical simulations supporting our results, and discuss possible experimental realizations in solid-state and cold-atom systems.Physic

Transglutaminase 2 Contributes to Apoptosis Induction in Jurkat T Cells by Modulating Ca(2+) Homeostasis via Cross-Linking RAP1GDS1

BACKGROUND: Transglutaminase 2 (TG2) is a protein cross-linking enzyme known to be associated with the in vivo apoptosis program of T cells. However, its role in the T cell apoptosis program was not investigated yet. RESULTS: Here we report that timed overexpression of both the wild type (wt) and the cross-linking mutant of TG2 induced apoptosis in Jurkat T cells, the wt being more effective. Part of TG2 colocalised with mitochondria. WtTG2-induced apoptosis was characterized by enhanced mitochondrial Ca(2+) uptake. Ca(2+)-activated wtTG2 cross-linked RAP1, GTP-GDP dissociation stimulator 1, an unusual guanine exchange factor acting on various small GTPases, to induce a yet uncharacterized signaling pathway that was able to promote the Ca(2+) release from the endoplasmic reticulum via both Ins3P and ryanodine sensitive receptors leading to a consequently enhanced mitochondrial Ca(2+)uptake. CONCLUSIONS: Our data indicate that TG2 might act as a Ca(2+) sensor to amplify endoplasmic reticulum-derived Ca(2+) signals to enhance mitochondria Ca(2+) uptake. Since enhanced mitochondrial Ca(2+) levels were previously shown to sensitize mitochondria for various apoptotic signals, our data demonstrate a novel mechanism through which TG2 can contribute to the induction of apoptosis in certain cell types. Since, as compared to knock out cells, physiological levels of TG2 affected Ca(2+) signals in mouse embryonic fibroblasts similar to Jurkat cells, our data might indicate a more general role of TG2 in the regulation of mitochondrial Ca(2+) homeostasis

Late Outcomes Following Freestyle Versus Homograft Aortic Root Replacement Results From a Prospective Randomized Trial

Objectives The aims of this study were to compare long-term results after homograft versus Freestyle (Medtronic Inc., Minneapolis, Minnesota) aortic root replacement. Background The ideal substitute for aortic root replacement remains undetermined. Methods Between 1997 and 2005, 166 patients (age 65 +/- 8 years) undergoing total aortic root replacement were randomized to receive a homograft (n = 76) or a Freestyle bioprosthesis (n = 90). Six patients randomly assigned to homograft crossed over to Freestyle because of unavailability of suitably sized homografts. Median follow-up was 7.6 years (maximum 11 years; 1,035 patient-years). "Evolving" aortic valve dysfunction was defined as aortic regurgitation >= 2/4 and/or peak gradient >20 mm Hg. Results Patient characteristics were comparable between groups. Concomitant procedures were performed in 44% and 47% of Freestyle and homograft patients, respectively (p = 0.5). Overall hospital mortality was 4.8% (1% for isolated root replacement). Eight-year survival was 80 +/- 5% in the Freestyle group versus 77 +/- 6% in the homograft group (p = 0.9). Freedom from need for reoperation at 8 years was significantly higher after Freestyle root replacement (100 +/- 0% vs. 90 +/- 5% after homograft replacement; p = 0.02). All reoperations were secondary to structural valve deterioration (n = 6). At last echocardiographic follow-up, actuarial freedom from evolving aortic valve dysfunction was 86 +/- 5% for Freestyle bioprostheses versus 37 +/- 7% for homografts (p < 0.001). Clinically, freedom from New York Heart Association functional class III to IV and freedom from valve-related complications were similar between groups (p = 0.7 and p = 0.9, respectively). Conclusions In this patient group, late survival is similar after homograft versus Freestyle root replacement. However, Freestyle aortic root replacement is associated with significantly less progressive aortic valve dysfunction and a lower need for reoperations. (J Am Coll Cardiol 2010; 55: 368-76) (C) 2010 by the American College of Cardiology Foundatio

Long-term outcomes after autograft versus homograft aortic root replacement in adults with aortic valve disease: a randomised controlled trial

Background The ideal substitute for aortic valve replacement in patients with aortic valve disease is not known. Our hypothesis was that the regulatory and adaptive properties of a living valve substitute could improve the long-term outcomes in patients. We therefore compared these outcomes after autograft aortic root replacement (Ross procedure) versus homograft aortic root replacement in adults. Methods Male and female patients (<69 years) requiring aortic valve surgery were randomly assigned in a one-to-one ratio to receive an autograft or a homograft aortic root replacement in one centre in the UK. The random allocation sequence was computer generated. Treatment was not masked. The primary endpoint was survival of patients at 10 years after surgery. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN03530985. Findings 228 patients were randomly assigned to receive an autograft or a homograft aortic root replacement. 12 patients were excluded because they were younger than 18 years; 108 in each group received the surgery they were assigned to and were analysed. There was one (<1%) perioperative death in the autograft group versus three (3%) in the homograft group (p=0.621). At 10 years, four patients died in the autograft group versus 15 in the homograft group. Actuarial survival at 10 years was 97% (SD 2) in the autograft group versus 83% (4) in the homograft group. Hazard ratio for death in the homograft group was 4.61 (95% CI 1.71-16.03; p=0.0060). Survival of patients in the autograft group was similar to that in an age-matched and sex-matched British population (96%). Interpretation Our findings support the hypothesis that a living valve implanted in the aortic position can significantly improve the long-term outcomes in patients