397 research outputs found
Molecular imaging using high-order harmonic generation and above-threshold ionization
Accurate molecular imaging via high-order harmonic generation relies on
comparing the harmonic emission from a molecule and an adequate reference
system. However, an ideal reference atom with the same ionization properties as
the molecule does not always exist. We show that for suitably designed, very
short laser pulses, a one-to-one mapping between high-order harmonic
frequencies and electron momenta in above-threshold ionization exists.
Comparing molecular and atomic momentum distributions then provides the
electron return amplitude in the molecule for every harmonic frequency. We show
that the method retrieves the molecular recombination transition moments highly
accurately, even with suboptimal reference atoms.Comment: 5 pages, 4 figure
Social Entrepreneurship and Performance: The Role of Perceived Barriers and Risk
This study investigates if and in what way social entrepreneurs are hampered in turning their efforts into sustainable organizations. Using binary logit regressions and unique data containing approximately 26,000 individual-level data points for 36 countries, this
Sustainable Entrepreneurship: The Role of Perceived Barriers and Risk
Entrepreneurs who start a business to serve both self-interests and collective interests by addressing unmet social and environmental needs are usually referred to as sustainable entrepreneurs. Compared with regular entrepreneurs, we argue that sustainable entrepreneurs face specific challenges when establishing their businesses owing to the discrepancy between the creation and appropriation of private value and social value. We hypothesize that when starting a business, sustainable entrepreneurs (1) feel more hampered by perceived barriers, such as the institutional environment and (2) have a different risk attitude and perception than regular entrepreneurs. We use two waves of the Flash Eurobarometer survey on entrepreneurship (2009 and 2012), which contains information on start-up motivations, start-up barriers, and risk perceptions of approximately 3000 (prospective) business owners across 33 countries. We find that sustainable entrepreneurs indeed perceive more institutional barriers in terms of a lack of financial, administrative, and informational support at business start-up than regular entrepreneurs. Further, no significant differences between sustainable and regular entrepreneurs are found in terms of their risk attitudes or perceived financial risks. However, sustainable entrepreneurs are more likely to fear personal failure than regular entrepreneurs, which is explained by their varied and complex stakeholder relations. These insights may serve as an important signal for both governments and private capital providers in enhancing the institutional climate
Sustainable entrepreneurship: The role of perceived barriers and risk
FdR – Publicaties niet-programma gebonde
Goal heterogeneity at start-up: are greener start-ups more innovative?
Coherent privaatrech
Brain retraction injury after elective aneurysm clipping: a retrospective single-center cohort study
Background: BRI is estimated to occur in 10% of skull-base surgery and 5% of aneurysm surgery. These estimates are based on a few studies with unclear methodology. The purpose of this study is to assess the rate of BRI occurrence, its risk factors, and the association between BRI and postoperative focal neurological deficit in patients that underwent elective aneurysm surgery in a single institution. Methods: All patients that underwent elective aneurysm surgery in a single tertiary center in the Netherlands were included. BRI was defined as cortical hypodensities in the surgical trajectory not matching areas of large arterial infarction. Risk ratios were calculated between BRI and (a) the use of temporary parent artery occlusion during clipping, (b) anterior communicating artery (ACom), and (c) middle cerebral artery (MCA) location of the aneurysm, (d) presence of mentioned CVA risk factors, (e) the clipping of > 1 aneurysm during the same procedure, and (f) new focal neurological deficit. Statistical analysis further included t-tests and binary logistical regression analysis on the correlation between age and BRI. Results: BRI was identified postoperatively in 42 of the 94 patients included in this study. A new focal neurological deficit was found in 7 patients in the BRI group. A total of 5 patients had persisting symptoms at 3-month follow-up, of which 2 were caused by BRI. Increasing age is a risk factor for developing BRI. Conclusions: The high rate of BRI and significant risk of new postoperative focal neurological deficit in our patients should be considered when counseling patients for elective aneurysm surgery
Long-term feasibility of the new sutureless excimer laser-assisted non-occlusive anastomosis clip in a pig model
Background: High flow bypass surgery can be a last resort procedure for patients suffering from complex neurovascular pathology. Temporary occlusion of a recipient artery in these patients could result in debilitating neurological deficits. We developed a sutureless, mechanical anastomotic connection device, the SELANA clip (Sutureless Excimer Laser-Assisted Non-occlusive Anastomosis clip: SEcl). In the present study, we aim to determine the long-term non-inferiority of the SEcl technique compared with historical data of the conventional ELANA anastomosis technique. Methods: A total of 18 SEcl bypasses were created on the carotid artery in a porcine model in 6 different survival groups. Mean application times, flap retrieval rates, hemostasis, patency, flow, endothelialization, and remodeling were assessed. Results: The mean application time of the SEcl anastomoses was 15.2 ± 9.6 min, which was faster compared with the conventional ELANA anastomoses. The flap retrieval rate of the SEcl anastomoses was 86% (32/37). Direct hemostasis was achieved in 89% (33/37) SEcl anastomoses. Patency in all surviving animals was 94% (17/18). Bypass flow after six months was 156.5 ± 24.7 mL/min. Full endothelialization of the SEcl pins was observed after 3 weeks. Conclusion: The SEcl technique is not inferior to the ELANA technique regarding patency, flap retrieval rate, flow, and endothelialization. On the basis of a significantly shorter application time and superior hemostasis, the SEcl technique could be preferable over the ELANA technique. A pilot study in patients is a logical next step based on our current results
Do Surgical Interventions Influence Psychosexual and Cosmetic Outcomes in Women with Disorders of Sex Development?
Clinical practice developed to promote psychosexual well-being in DSD is under scrutiny. Although techniques for genital surgery have much improved lately, long-term studies on psychosexual functioning and cosmetic outcome on which to base treatment and counseling are scarce. We studied 91 women with a DSD. Feminizing surgery was performed in 64% of the women; in 60% of them, resurgery in puberty was needed after a single-stage procedure. Both patients and gynecologists were satisfied with the cosmetic appearance of the genitalia. However, forty percent of these females experienced sexuality-related distress and 66% was at risk for developing a sexual dysfunction, whether they had surgery or not. Recognizing the difficulty of accurate assessment, our data indicate that feminizing surgery does not seem to improve nor hamper psychosexual outcome, especially in patients with severe virilization
The deepest record of the octocoral Acanthogorgia from the Red Sea
Octocorals (Cnidaria: Anthozoa) have a global distribution and form benthic assemblages along the depth gradient, from shallow to deep waters. They often occur below SCUBA diving limits, where they can become dominant habitat builders and aggregate different taxa. During a cruise in February 2023, one octocoral specimen was collected at 1453 m depth at Kebrit Deep, in the northern Saudi Arabian Red Sea axis, an area with extremely high temperature and salinity profiles at depth. Morphological analysis coupled with DNA barcoding using two mitochondrial markers (COI and mtMuts), revealed that the coral belongs to Acanthogorgia, a genus of azooxanthellate octocorals known to occur from 3 to 2300 m depths in cold, temperate and tropical waters. In the Red Sea, the genus was previously only known from shallower waters. Hence, we report the deepest record of the genus Acanthogorgia from the warm and saline Red Sea basin. This finding provides novel insights on deep-water octocoral diversity in the Red Sea, a still scantily explored area of the world, while emphasizing the need for further explorations at depth
A placebo-controlled proof-of-concept study of alirocumab on postprandial lipids and vascular elasticity in insulin-treated patients with type 2 diabetes mellitus
Aim: Type 2 diabetes mellitus (T2DM) is associated with an increased risk of cardiovascular disease (CVD) linked to atherogenic dyslipidaemia and postprandial hyperlipidaemia. Alirocumab, a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor, improves CVD risk by reducing the concentration of low-density lipoprotein-cholesterol (LDL-C). However, effects of PCK9 inhibitors on other aspects of diabetic dyslipidaemia, particularly in the postprandial situation, are less clear. Material and Methods: Twelve male patients with T2DM on an intensive insulin regimen completed a 6-week randomized, double-blind, placebo-controlled, proof-of-concept study. Participants received three biweekly dosages of subcutaneous alirocumab (150 mg) or placebo. Before and after the intervention, fasting and postprandial triglyceride (TG) plasma levels, apolipoprotein (apo) B48, lipoprotein composition isolated by ultracentrifugation, vascular function and markers of inflammation were evaluated. Results: Alirocumab treatment reduced fasting plasma TG levels (between group median change −24.7%; P = 0.018) and fasting apoB48 serum levels (−35.9%; P = 0.039) compared with placebo. Alirocumab reduced the plasma TG area under the curve (AUC) (−26.4%; P = 0.006) and apoB48 AUC (−55.7%; P = 0.046), as well as plasma TG incremental AUC (−21.4%; P = 0.04) and apoB48 incremental AUC (−26.8%; P = 0.02). In addition, alirocumab reduced fasting and postprandial TG levels in very low-density lipoprotein (VLDL) and LDL. Alirocumab improved fasting pulse wave velocity, but no changes in postprandial markers of inflammation were observed. Conclusions: In addition to the well-known LDL-C-reducing effects, 6 weeks of alirocumab treatment lowered both fasting and postprandial plasma TG levels by reducing the TG levels in VLDL and LDL and the concentration of intestinal remnants
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