Structural integrity and healing efficiency study of micro-capsule based composite materials via 1H NMR relaxometry.

In this work we present a novel approach utilizing nuclear magnetic resonance (NMR) relaxometry to assess the structural stability of microcapsules employed as self-healing agents in advanced aerospace composites both in ambient and harsh environmental conditions. We successfully correlate the amount of the encapsulated self-healing agent with the signal intensity and confirm non-destructively the quantity of the encapsulated self-healing agent mass for the first time in the literature using 1H NMR spin-spin relaxation techniques on urea-formaldehyde (UF) microcapsules of different diameters containing an epoxy healing agent. The amount of self-healing agent is shown to increase by reducing the capsule diameter; however, the reduced shell mass renders the capsules more fragile and prone to failure. Most notably, via NMR experiments conducted during thermal cycling simulating flight conditions, we demonstrate that the microcapsule integrity under thermal fatigue varies according to their size. Especially we experimentally verify that the microcapsules with the most sensitive shells are the 147 nm and 133 nm diameter microcapsules, which are the most commonly used in self-healing systems. Finally, we were able to retrieve the same results using a portable NMR spectrometer developed in-house for in situ microcapsule testing, thus demonstrating the potential of NMR relaxometry as a powerful non-destructive evaluation tool for the microcapsule production line.

Advances in biofeedback and neurofeedback studies on smoking.

Smoking is a leading cause of morbidity and premature death constituting a global health challenge. Although, pharmacological and behavioral approaches comprise the mainstay of smoking cessation interventions, the efficacy and safety of pharmacotherapy is not demonstrated for some populations. Non-pharmacological approaches, such as biofeedback (BF) and neurofeedback (NF) could facilitate self-regulation of predisposing factors of relapse such as craving and stress. The current review aims to aggregate the existing evidence regarding the effects of BF and NF training on smokers. Relevant studies were identified through searching in Scopus, PubMed and Cochrane Library, and through hand-searching the references of screened articles. Peer-reviewed controlled and uncontrolled studies, where BF and/or NF training was administered, were included and evaluated according to PICOS framework. Narrative qualitative synthesis of ten eligible studies was performed, aggregated into three categories according to training provided. BF outcomes seem to be affected by smoking behavior prior to training; individualized EEG NF training holds promise for modulating craving-related response while minimizing the required number of sessions. Real-time fMRI NF studies concluded that nicotine-dependent individuals could modulate craving-related brain responses, while mixed results were revealed regarding smokers' ability to modulate brain responses related to resistance towards the urge to smoke. BF and NF training seem to facilitate modulation of autonomous and/or central nervous system activity while also transferring this learned self-regulation to behavioral outcomes. BF and NF training should a) address remaining issues on specificity and scientific validity, b) target diverse demographics, and c) produce robust reproducible methodologies and clinical guidelines for relevant health care providers, in order to be considered as viable complementary tools to standard smoking cessation care.

The peculiar size and temperature dependence of water diffusion in carbon nanotubes studied with 2D NMR diffusion-relaxation D -T 2eff spectroscopy.

It is well known that water inside hydrophobic nano-channels diffuses faster than bulk water. Recent theoretical studies have shown that this enhancement depends on the size of the hydrophobic nanochannels. However, experimental evidence of this dependence is lacking. Here, by combining two-dimensional nuclear magnetic resonance diffusion-relaxation ( D - T 2 e f f ) spectroscopy in the stray field of a superconducting magnet and molecular dynamics simulations, we analyze the size dependence of water dynamics inside Carbon Nanotubes (CNTs) of different diameters ( 1.1 - 6.0 nm), in the temperature range of 265 - 305 K. Depending on the CNT diameter, the nanotube water is shown to resolve in two or more tubular components acquiring different self-diffusion coefficients. Most notably, a favorable CNT diameter range ( 3.0 - 4.5 nm) is experimentally verified for the first time, in which water molecule dynamics at the center of the CNTs exhibits distinctly non-Arrhenius behavior, characterized by ultrafast diffusion and extraordinary fragility, a result of significant importance in the efforts to understand water behavior in hydrophobic nanochannels.

[Autologous fat grafts and supportive enrichment with adipose tissue stromal cells]. / Autologe Fetttransplantation in der Brustchirurgie - Klinische und Experimentelle Konzepte: vom Lipofilling bis zum Fettgewebe Tissue Engineering.

Liposuction is a most common surgical procedure in aesthetic surgery that aims at the local fat reduction. The obtained adipose tissue is currently used as a biocompatible filler. Autologous fat transplantation, also known as lipofilling, has become an attractive treatment method in the field of aesthetic facial surgery and scar tissue reconstruction. Lipofilling may also offer an alternative method to prosthetic breast surgery. Nevertheless, postoperative fat tissue resorption is still a limitiation to lipofilling in breast reconstruction leading to multiple revisions in order to reach the requested clinical outcome. The therapeutic effect of autologous fat grafts does not solely lie in its role as a filler material, but also in its wound healing and angiogenetic properties. The latter is not attributed to the mature adipocytes, but rather to the undifferentiated adipose derived stromal cells (ASC). Thus enrichment of the fat graft with autologous ASC, known as cell-assisted lipotransfer (CAL) may lead to further optimisation of lipofilling concerning fat graft survival. Still aiming to establish the application of autologous fat grafts and ASC in breast reconstruction, there is a necessity for systematic analyses in order to resolve questions regarding the operational technique and qualitative aspects of the ASC manufacturing in accordance with pharmaceutical guidelines and regulations in Germany. Besides, some open questions need to be addressed regarding the ASC differentiation potential in vivo.

Mycotic splenic artery aneurysm secondary to Coxiella burnetii endocarditis.

Mycotic artery aneurysms are rare but potentially lethal vascular lesions due to their high risk of rupture. Bacterial endocarditis as well as trauma and inadequate immunity are predisposing factors. Surgery remains the treatment of choice, although alternative methods have been used. We report the first known case of a 6 cm mycotic splenic artery aneurysm proximal to the splenic hilum, secondary to bacterial endocarditis from Coxiella burnetii. Resection of the aneurysm, splenectomy, and distal pancreatectomy were performed. In all patients with culture-negative endocarditis and mycotic aneurysm, C. burnetii infection should be ruled out.