Activation of electrospun carbon fibers: the effect of fiber diameter on CO2 and steam reaction kinetics

First, we present a fabrication process for electrospun carbon fiber mats with mean fiber diameters between 108 nm and 623 nm. The carbon fiber mats were produced by electrospinning of polyacrylonitrile (PAN) solutions and subsequent carbonization. The fiber mats feature small variations of their properties that are required for parameter studies. Second, we investigate the kinetics of steam and CO2 activation with three different activation temperatures and times. Both activation methods result in a surface area increase depending on activation temperature and time. Detailed analysis of the macroscopic properties burn-off, surface area, and conductivity reveals insights into the microscopic activation kinetics. The different fiber diameters of the carbon fiber mats enable the distinction of surface driven and bulk processes. Our results indicate, that CO2 activation kinetics are mass transport controlled, and that steam activation kinetics are reaction rate controlled. The turbostratic nature of PAN derived carbon and the distinct characteristics of the activation agents could explain the nonlinear behavior of the burn-off and surface area development

Unraveling local tissue changes within severely injured skeletal muscles in response to MSC-based intervention using MALDI Imaging mass spectrometry

Pre-clinical and clinical studies are now beginning to demonstrate the high potential of cell therapies in enhancing muscle regeneration. We previously demonstrated functional benefit after the transplantation of autologous bone marrow mesenchymal stromal cells (MSC-TX) into a severe muscle crush trauma model. Despite our increasing understanding of the molecular and cellular mechanisms underlying MSC's regenerative function, little is known about the local molecular alterations and their spatial distribution within the tissue after MSC-TX. Here, we used MALDI imaging mass spectrometry (MALDI-IMS) in combination with multivariate statistical strategies to uncover previously unknown peptide alterations within severely injured skeletal muscles. Our analysis revealed that very early molecular alterations in response to MSC-TX occur largely in the region adjacent to the trauma and only to a small extent in the actual trauma region. Using "bottom up" mass spectrometry, we subsequently identified the proteins corresponding to the differentially expressed peptide intensity distributions in the specific muscle regions and used immunohistochemistry to validate our results. These findings extend our current understanding about the early molecular processes of muscle healing and highlights the critical role of trauma adjacent tissue during the early therapeutic response upon treatment with MSC

The Leipzig Prospective Vascular Ultrasound Registry in Radial Artery Catheterization Impact of Sheath Size on Vascular Complications

ObjectivesThis study investigated the impact of sheath size on the rate of radial artery occlusions (RAO) (primary objective) and other access site complications (hemorrhage, pseudoaneurysm, arteriovenous fistula) as secondary objectives after transradial coronary catheterization.BackgroundThe number of vascular access complications in the published data ranges from 5% to 38% after transradial catheterization.MethodsBetween November 2009 and August 2010, 455 patients 65.3 ± 10.9 years of age (62.2% male) with transradial access with 5-F (n = 153) or 6-F (n = 302) arterial sheaths were prospectively recruited. Duplex sonography was obtained in each patient before discharge. Patients with symptomatic RAO were treated with low-molecular-weight heparin (LMWH), and a follow-up was performed.ResultsThe incidence of access site complications was 14.4% with 5-F sheaths compared with 33.1% with 6-F sheaths (p < 0.001). Radial artery occlusion occurred in 13.7% with 5-F sheaths compared with 30.5% with 6-F sheaths (p < 0.001). There was no difference between groups with regard to hemorrhage, pseudoaneurysms, or arteriovenous fistulas. Female sex, larger sheath size, peripheral arterial occlusive disease, and younger age independently predicted RAO in multivariate analysis. In total, 42.5% of patients with RAO were immediately symptomatic; another 7% became symptomatic within a mean of 4 days. Of patients with RAO, 59% were treated with LMWH. The recanalization rates were significantly higher in patients receiving LMWH compared with conventional therapy (55.6% vs. 13.5%, p < 0.001) after a mean of 14 days.ConclusionsThe incidence of RAO by vascular ultrasound was higher than expected from previous data, especially in patients who underwent the procedure with larger sheaths

Increased breath naphthalene in children with asthma and wheeze of the All Age Asthma Cohort (ALLIANCE).

Background&#xD;Exhaled breath contains numerous volatile organic compounds (VOCs) known to be related to lung disease like asthma. Its collection is non-invasive, simple to perform and therefore an attractive method for the use even in young children. We analysed breath in children of the multicenter All Age Asthma Cohort (ALLIANCE) to evaluate if "breathomics" have the potential to phenotype patients with asthma and wheeze, and to identify extrinsic risk factors for underlying disease mechanisms.&#xD;Methods&#xD;A breath sample was collected from 142 children (asthma: 51, pre-school wheezers: 55, healthy controls: 36) and analysed using gas chromatography-mass spectrometry (GC/MS). Children were diagnosed according to GINA guidelines and comprehensively examined each year over up to seven years. Forty children repeated the breath collection after 24 or 48 months. &#xD;Results&#xD;Most breath VOCs differing between groups reflect the exposome of the children. We observed lower levels of lifestyle-related VOCs and higher levels of the environmental pollutants, especially naphthalene, in children with asthma or wheeze. Naphthalene was also higher in symptomatic patients and in wheezers with recent inhaled corticosteroid use. No relationships with lung function or TH2 inflammation were detected.&#xD;Conclusion&#xD;Increased levels of naphthalene in asthmatics and wheezers and the relationship to disease severity could indicate a role of environmental or indoor air pollution for the development or progress of asthma. Breath VOCs might help to elucidate the role of the exposome for the development of asthma.&#xD;The study was registered at ClinicalTrials.gov (NCT02496468).&#xD;&#xD

2D shear wave liver elastography by aixplorer to detect portal hypertension in cirrhosis: an individual patient data meta-analysis

Background & Aims: Liver stiffness measured with 2-dimensional shear wave elas- tography by Supersonic Imagine (2DSWE-SSI) is well-established for fibrosis diagnos- tics, but non-conclusive for portal hypertension. Methods: We performed an individual patient data meta-analysis of 2DSWE-SSI to identify clinically significant portal hypertension (CSPH), severe portal hyperten- sion and large varices in cirrhosis patients, using hepatic venous pressure gradient and upper endoscopy as reference. We used meta-analytical integration of diagnos- tic accuracies with optimized rule-out (sensitivity-90%) and rule-in (specificity-90%) cut-offs. Results: Five studies from seven centres shared data on 519 patients. After exclu- sion, we included 328 patients. Eighty-nine (27%) were compensated and 286 (87%) had CSPH. 2DSWE-SSI < 14 kPa ruled out CSPH with a summary AUROC (sROC), sensitivity and specificity of 0.88, 91% and 37%, and correctly classified 85% of pa- tients, with minimal between-study heterogeneity. The false negative rate was 60%, of which decompensated patients accounted for 78%. 2DSWE-SSI ≥ 32 kPa ruled in CSPH with sROC, sensitivity, specificity and correct classifications of 0.83, 47%, 89% and 55%. In a subgroup analysis, the 14 kPa cut-off showed consistent sensitivity and higher specificity for patients with compensated cirrhosis, without ascites, viral 2 aetiology or BMI < 25 kg/m . 2DSWE-SSI ruled out severe portal hypertension and large varices with fewer correctly classified and lower sROC, and with minimal benefit for ruling in. Conclusion: Liver stiffness using 2-dimensional shear wave elastography below 14 kPa may be used to rule out clinically significant portal hypertension in cirrhosis patients, but this would need validation in populations of compensated liver disease. 2DSWE-SSI cannot predict varices needing treatment

VIBES: Visionary Ingenuity Boosting European Spacecraft. Managing microvibrations for the future of spaceflight

Microvibrations are mechanical oscillations caused by components such as the reaction wheels of an attitude control system of a spacecraft. These microvibrations are transferred through the spacecraft structure onto important instruments (e.g., optical instruments), causing those to produce diminished results (e.g., reduced image quality, imprecise geolocation etc.). At the present state, microvibrations in spacecraft cannot be actively controlled because their very high frequencies of up to 1000 Hz are above the control bandwidth a current attitude control system can provide. However, being able to reduce the effects of microvibrations on a space mission is becoming increasingly more critical as the envelope of future optical satellite missions expands. Furthermore, the advancements made in the performance of small satellites as well as the growing interest in laser and quantum communication call for a cost-efficient solution for managing microvibrations. This paper describes how cheap MEMS-based measurement systems have already proven that they are a potential solution. Showing high sensitivity and low-noise performance while allowing fast and easy prototyping

Randomized Comparison of a Polymer-Free Sirolimus-Eluting Stent Versus a Polymer-Based Paclitaxel-Eluting Stent in Patients With Diabetes Mellitus The LIPSIA Yukon Trial

ObjectivesThe objective of the study was to assess noninferiority of the polymer-free sirolimus-eluting Yukon Choice stent (Translumina GmbH, Hechingen, Germany) compared with the polymer-based Taxus Liberté stent (Boston Scientific, Natick, Massachusetts) with regard to the primary endpoint, in-stent late lumen loss, at 9 months in patients with diabetes mellitus.BackgroundThe Yukon Choice stent has been evaluated in several randomized controlled trials before, albeit to date, there has been no trial that exclusively enrolled patients with diabetes mellitus.MethodsPatients with diabetes mellitus undergoing percutaneous coronary intervention for clinically significant de novo coronary artery stenosis were randomized 1:1 to receive either the polymer-free sirolimus-eluting Yukon Choice stent or the polymer-based paclitaxel-eluting Taxus Liberté stent.ResultsA total of 240 patients were randomized. Quantitative coronary angiography was available for 79% of patients. Mean in-stent late lumen loss was 0.63 ± 0.62 mm for the Yukon Choice stent and 0.45 ± 0.60 mm for the Taxus Liberté stent. Based on the pre-specified margin, the Yukon Choice stent failed to show noninferiority for the primary endpoint. During follow-up, there were no significant differences between groups regarding death, myocardial infarction, stent thrombosis, target lesion revascularization, target vessel revascularization, or nontarget vessel revascularization.ConclusionsCompared with the Taxus Liberté stent, the polymer-free sirolimus-eluting Yukon Choice stent failed to show noninferiority with regard to the primary endpoint, in-stent late lumen loss, in patients with diabetes mellitus after 9-month follow-up. Both stents showed comparable clinical efficacy and safety. (Yukon Choice Versus Taxus Liberté in Diabetes Mellitus; NCT00368953

Quantum dot single-photon emission coupled into single-mode fibers with 3D printed micro-objectives

User-friendly single-photon sources with high photon-extraction efficiency are crucial building blocks for photonic quantum applications. For many of these applications, such as long-distance quantum key distribution, the use of single-mode optical fibers is mandatory, which leads to stringent requirements regarding the device design and fabrication. We report on the on-chip integration of a quantum dot (QD) microlens with a 3D-printed micro-objective in combination with a single-mode on-chip fiber coupler. The practical quantum device is realized by the deterministic fabrication of the QD-microlens via in situ electron-beam lithography and the 3D two-photon laser writing of the on-chip micro-objective and fiber chuck. A QD with a microlens is an efficient single-photon source, whose emission is collimated by the on-chip micro-objective. A second polymer microlens is located at the end facet of the single-mode fiber and ensures that the collimated light is efficiently coupled into the fiber core. For this purpose, the fiber is placed in an on-chip fiber chuck, which is precisely aligned to the QD-microlens thanks to the sub-micrometer processing accuracy of high-resolution two-photon direct laser writing. The resulting quantum device has a broadband photon extraction efficiency, a single-mode fiber-coupling efficiency of 22%, a measured single-photon flux of 42 kHz (8.9 kHz) under cw (pulsed) optical excitation, which corresponds to 1.5 MHz (0.3 MHz) at the single-mode fiber output, and a multi-photon probability in terms of g(2)(0) = 0.00±0.04/0.00 (0.13 ± 0.05) under cw (pulsed) optical excitation. The stable design of the developed fiber-coupled quantum device makes it highly attractive for integration into user-friendly plug-and-play quantum applications.BMBF, 16KIS0862, Verbundprojekt: Q.Link.Extension - Q.Link.X -; Teilvorhaben: Komponenten und Aufbau einer Demonstratorstrecke zur speicher-assistierten QuantenschlüsselübertragungDFG, 255652081, SPP 1839: Tailored Disorder - A science- and engineering-based approach to materials design for advanced photonic applicationsDFG, 273920612, SPP 1929: Giant Interactions in Rydberg Systems (GiRyd