Extended cavity diode lasers with tracked resonances

We present a painless, almost-free upgrade to present extended cavity diode lasers (ECDLs), which improves the long term mode-hop free performance by stabilizing the resonance of the internal cavity to the external cavity. This stabilization is based on the observation that the frequency or amplitude noise of the ECDL is lowest at the optimum laser diode temperature or injection current. Thus, keeping the diode current at the level where the noise is lowest ensures mode-hop free operation within one of the stable regions of the mode chart, even if these should drift due to external influences. This method can be applied directly to existing laser systems without modifying the optical setup. We demonstrate the method in two ECDLs stabilized to vapor cells at 852 nm and 895 nm wavelength. We achieve long term mode-hop free operation and low noise at low power consumption, even with an inexpensive non-antireflection coated diode.Comment: 5 pages, 6 figure

Treatment Effect Estimation Using Self-Estimated Counterfactuals Under Varying Conditions

Background: Randomized controlled trials (RCTs) are frequently not an option in evaluation practice, which is why evaluators switch to non-experimental methods–such as the “counterfactual as self-estimated by program participants” (CSEPP) for estimating intervention effects. Unfortunately, no systematic attempt has been made to test under what conditions CSEPP provides valid estimates. Purpose: As a first step in this direction, this research compared the performance of CSEPP in terms of bias when applied in different groups of participants with different levels of education, when used for assessing the effects on different outcome variables, and when employed with different question orders within the questionnaire. Setting: NA Intervention: The treatment used in this research was a short educational video, in which the audience is educated about important concepts and aspects of organ donation. Research Design: Since investigating bias in CSEPP is difficult at participant level, a series of 40 studies was conducted and bias was analyzed at study-level. For each study, the effect of the same treatment was estimated by CSEPP and compared with the effect estimated by a simultaneously conducted RCT. Afterwards, it was analyzed whether differences between CSEPP and RCT across the studies were determined by variation in the conditions under which the studies were conducted. Despite small sample sizes of the single trials, the meta-analysis was sufficiently powered to detect even small differences between CSEPP and RCT. Data Collection and Analysis: The data was collected via online surveys on a crowdsourcing portal. For data analysis, we applied meta-analytic methods such as random-effects meta-analysis and meta-regression. Findings: Results show that CSEPP provided accurate effect estimates, no matter under what conditions the method was applied. &nbsp

Primary correction of total anomalous pulmonary venous return with a modified sutureless technique

OBJECTIVES The objective was to evaluate primary sutureless repair of total anomalous pulmonary venous return (TAPVR) in neonates using a modified technique that minimizes hypothermia and circulatory arrest times. METHODS From 2009 to 2011, seven consecutive patients underwent primary sutureless repair for the treatment of TAPVR, by which the prepared posterior pericardium was sutured to an opening in the left atrium. Three patients had the obstructed infracardiac type, and four patients had the unobstructed supracardiac type of TAPVR. Moderate hypothermia was used in all patients with a median temperature of 28°C (26-32). Circulatory arrest was not used except for the opening of the collector, which lasted between 3 and 5 min. The connecting vein was ligated in all seven patients (five during repair and two early postoperatively). The follow-up was 100% complete, with a median duration of 652 (range 370-1023) days. RESULTS There was no operative mortality and no late death. No patient required reoperation. Postoperative echocardiography showed unobstructed pulmonary venous flow in all patients. Recurrent pulmonary venous stenosis was not seen during the follow-up in any patient. CONCLUSIONS The sutureless technique is an effective technique with potential advantages even for the primary correction of TAPVR. With the described technique, the need for circulatory arrest is substantially reduced. Not handling the pulmonary venous collector by avoiding a direct anastomosis may contribute to better compliance, better growth and the absence of subsequent stenosi

Intestinal macrophages: differentiation and involvement in intestinal immunopathologies

Intestinal macrophages, preferentially located in the subepithelial lamina propria, represent the largest pool of tissue macrophages in humans. As an adaptation to the local antigen- and bacteria-rich environment, intestinal macrophages exhibit several distinct phenotypic and functional characteristics. Notably, microbe-associated molecular pattern receptors, including the lipopolysaccharide (LPS) receptors CD14 and TLR4, and also the Fc receptors for IgA and IgG are absent on most intestinal macrophages under homeostatic conditions. Moreover, while macrophages in the intestinal mucosa are refractory to the induction of proinflammatory cytokine secretion, they still display potent phagocytic activity. These adaptations allow intestinal macrophages to comply with their main task, i.e., the efficient removal of microbes while maintaining local tissue homeostasis. In this paper, we review recent findings on the functional differentiation of monocyte subsets into distinct macrophage populations and on the phenotypic and functional adaptations that have evolved in intestinal macrophages in response to their antigen-rich environment. Furthermore, the involvement of intestinal macrophages in the pathogenesis of celiac disease and inflammatory bowel diseases is discusse