Stimulated emission in the ultraviolet by optical pumping from photoionization-produced inner-shell states in Cd++

Stimulated emission on three UV transitions in Cd$+$ has been observed by transferring population from inner-shell d-electron states, populated by photoionization, to outer-shell p-electron states using the output from a narrow-frequency dye laser. The use of similar techniques in other elements could eventually result in a number of new lasers in the UV and VUV

Long Term Follow-Up of the Endovascular Trans-Vessel Wall Technique for Parenchymal Access in Rabbit with Full Clinical Integration

OBJECTIVE: Endovascular techniques are providing options to surgical/percutaneous cell transplantation methods. Some cells, e.g. insulin producing cells, are not suitable for intra-luminal transplantation and for such cells, other options must be found. We have constructed a "nanocatheter" with a penetrating tip for vessel perforation, thereby creating a working channel for parenchymal access by endovascular technique. To finish the procedure safely, the distal tip is detached to provide a securing plug in the vessel wall defect. MATERIALS AND METHODS: We have performed interventions with full clinical integration in the superior mesenteric artery (SMA), the subclavian artery and the external carotid artery in rabbits. No hemorrhagic- or thromboembolic events occurred during the procedure. Stenosis formation and distal embolisation were analyzed by angiography and macroscopic inspection during autopsy at five, 30 and 80 days. All animals and implanted devices were also evaluated by micro-dissections and histochemical analysis. RESULTS: In this study we show safety data on the trans-vessel wall technique by behavioral, angiographical and histological analysis. No stenosis formation was observed at any of the follow-up time points. No animals or organs have shown any signs of distress due to the intervention. Histological examination showed no signs of hemorrhage, excellent biocompatibility with no inflammation and a very limited fibrous capsule formation around the device, comparable to titanium implants. Further, no histological changes were detected in the endothelia of the vessels subject to intervention. CONCLUSIONS: The trans-vessel wall technique can be applied for e.g. cell transplantations, local substance administration and tissue sampling with low risk for complications during the procedure and low risk for hemorrhage, stenosis development or adverse tissue reactions with an 80 days follow-up time. The benefit should be greatest in organs that are difficult or risky to reach with surgical techniques, such as the pancreas, the CNS and the heart

Retinoblastoma protein prevents enteric nervous system defects and intestinal pseudo-obstruction

The retinoblastoma 1 (RB1) tumor suppressor is a critical regulator of cell cycle progression and development. To investigate the role of RB1 in neural crest–derived melanocytes, we bred mice with a floxed Rb1 allele with mice expressing Cre from the tyrosinase (Tyr) promoter. TyrCre(+);Rb1(fl/fl) mice exhibited no melanocyte defects but died unexpectedly early with intestinal obstruction, striking defects in the enteric nervous system (ENS), and abnormal intestinal motility. Cre-induced DNA recombination occurred in all enteric glia and most small bowel myenteric neurons, yet phenotypic effects of Rb1 loss were cell-type specific. Enteric glia were twice as abundant in mutant mice compared with those in control animals, while myenteric neuron number was normal. Most myenteric neurons also appeared normal in size, but NO-producing myenteric neurons developed very large nuclei as a result of DNA replication without cell division (i.e., endoreplication). Parallel studies in vitro found that exogenous NO and Rb1 shRNA increased ENS precursor DNA replication and nuclear size. The large, irregularly shaped nuclei in NO-producing neurons were remarkably similar to those in progeria, an early-onset aging disorder that has been linked to RB1 dysfunction. These findings reveal a role for RB1 in the ENS

Fredholm determinants and the statistics of charge transport

Using operator algebraic methods we show that the moment generating function of charge transport in a system with infinitely many non-interacting Fermions is given by a determinant of a certain operator in the one-particle Hilbert space. The formula is equivalent to a formula of Levitov and Lesovik in the finite dimensional case and may be viewed as its regularized form in general. Our result embodies two tenets often realized in mesoscopic physics, namely, that the transport properties are essentially independent of the length of the leads and of the depth of the Fermi sea.Comment: 30 pages, 2 figures, reference added, credit amende

Universality of Performance Indicators based on Citation and Reference Counts

We find evidence for the universality of two relative bibliometric indicators of the quality of individual scientific publications taken from different data sets. One of these is a new index that considers both citation and reference counts. We demonstrate this universality for relatively well cited publications from a single institute, grouped by year of publication and by faculty or by department. We show similar behaviour in publications submitted to the arXiv e-print archive, grouped by year of submission and by sub-archive. We also find that for reasonably well cited papers this distribution is well fitted by a lognormal with a variance of around 1.3 which is consistent with the results of Radicchi, Fortunato, and Castellano (2008). Our work demonstrates that comparisons can be made between publications from different disciplines and publication dates, regardless of their citation count and without expensive access to the whole world-wide citation graph. Further, it shows that averages of the logarithm of such relative bibliometric indices deal with the issue of long tails and avoid the need for statistics based on lengthy ranking procedures.Comment: 15 pages, 14 figures, 11 pages of supplementary material. Submitted to Scientometric

Intravenous sodium nitrite in acute ST-elevation myocardial infarction: a randomized controlled trial (NIAMI).

AIM: Despite prompt revascularization of acute myocardial infarction (AMI), substantial myocardial injury may occur, in part a consequence of ischaemia reperfusion injury (IRI). There has been considerable interest in therapies that may reduce IRI. In experimental models of AMI, sodium nitrite substantially reduces IRI. In this double-blind randomized placebo controlled parallel-group trial, we investigated the effects of sodium nitrite administered immediately prior to reperfusion in patients with acute ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: A total of 229 patients presenting with acute STEMI were randomized to receive either an i.v. infusion of 70 μmol sodium nitrite (n = 118) or matching placebo (n = 111) over 5 min immediately before primary percutaneous intervention (PPCI). Patients underwent cardiac magnetic resonance imaging (CMR) at 6-8 days and at 6 months and serial blood sampling was performed over 72 h for the measurement of plasma creatine kinase (CK) and Troponin I. Myocardial infarct size (extent of late gadolinium enhancement at 6-8 days by CMR-the primary endpoint) did not differ between nitrite and placebo groups after adjustment for area at risk, diabetes status, and centre (effect size -0.7% 95% CI: -2.2%, +0.7%; P = 0.34). There were no significant differences in any of the secondary endpoints, including plasma troponin I and CK area under the curve, left ventricular volumes (LV), and ejection fraction (EF) measured at 6-8 days and at 6 months and final infarct size (FIS) measured at 6 months. CONCLUSIONS: Sodium nitrite administered intravenously immediately prior to reperfusion in patients with acute STEMI does not reduce infarct size