A review of routing strategies for optical burst switched networks

The exact contribution of this paper is a review of existing state-of-the-art routing strategies for optical burst switched networks developed by researchers to deal with burst contention before it happens. Routing schemes are implemented in space domain, which make them simple and cost effective. Additionally, the paper points out the importance of routing as an effective way to deal with burst contention compared to other solutions. It also underlines the main differences between contention avoidance schemes and contention resolution techniques for optical burst switched networks. We believe that this review will help different optical burst switched researchers involved in the development of route optimization algorithms to control burst contention

Highly-photostable and mechanically flexible all-organic semiconductor lasers

Two formats of all-organic distributed-feedback lasers with improved photostability, respectively called nanocomposite and encapsulated lasers, are reported. These lasers are compatible with mechanically-flexible platforms and were entirely fabricated using soft-lithography and spin-coating techniques. The gain elements in both types of lasers were monodisperse pi-conjugated star-shaped macromolecules (oligofluorene truxene, T3). In the nanocomposites lasers, these elements were incorporated into a transparent polyimide matrix, while in the encapsulated devices a neat layer of T3 was overcoated with Poly(vinyl alcohol) (PVA). The T3-nanocomposite devices demonstrated a 1/e degradation energy dosage up to similar to 27.0 +/- 6.5 J/cm(2) with a threshold fluence of 115 +/- 10 mu J/cm(2). This represents a 3-fold improvement in operation lifetime under ambient conditions compared to the equivalent laser made with neat organic films, albeit with a 1.6-time increase in threshold. The PVA-encapsulated lasers showed the best overall performance: a 40-time improvement in the operation lifetime and crucially no-trade-off on the threshold, with respectively a degradation energy dosage of similar to 280 +/- 20 J/cm(2) and a threshold fluence of 36 +/- 8 mu J/cm(2)

Review article: mesenchymal stromal cell therapy for inflammatory bowel diseases

Background Inflammatory bowel diseases (IBD) are chronic relapsing diseases in which pro-inflammatory immune cells and cytokines induce intestinal tissue damage and disability. Mesenchymal stromal cells (MSCs) exert powerful immunomodulatory effects and stimulate tissue repair. Aim To review the current data on mesenchymal stromal cell therapy in IBD. Method We searched PubMed and ‘ClinicalTrials.gov’ databases using the terms ‘mesenchymal stromal cells’, ‘mesenchymal stem cell transplantation’, ‘inflammatory bowel diseases’, ‘Crohn disease’ and ‘colitis, ulcerative’. Additional publications were identified from individual article reference lists. Results MSCs include inhibition of Th1/Th17 lymphocytes and recruitment of regulatory T lymphocytes, induction of antigen-presenting cells into a regulatorylike profile, and stimulation of epithelial cell differentiation and proliferation. More than 200 patients with refractory fistulas have been treated with local injections of MSCs, resulting in complete response in more than half, and in overall response in approximately two thirds of patients. In refractory luminal Crohn’s disease, 49 cases of systemic MSC infusions have been reported, while trials with autologous MSCs resulted in mitigated responses, studies using allogeneic MSCs were promising, with around 60% of patients experiencing a response and around 40% achieving clinical remission. Conclusions Mesenchymal stromal cells might represent a promising therapy for IBD, especially for Crohn’s disease. There remain many unsolved questions concerning the optimal origin and source of mesenchymal stromal cells, dosage and modalities of administration. Moreover, mesenchymal stromal cells still need to prove their effectiveness compared with conventional treatments in randomised controlled trials

Analysis of collision avoidance via ground-based laser momentum transfer

There is little potential of action in case of conjunctions where neither chaser nor target can be controlled by spacecraft operators. Nevertheless, potential collisions between such objects pose a significant threat to the space environment. In view of that, some recent studies and developments addressed the concept of momentum transfer (MT) from ground-based lasers for orbit modification and, therefore, collision avoidance. However, achievable delta-v increments are highly constrained (pass geometry) and uncertain (tracking accuracy, atmospheric turbulence, object properties). Therefore, we present and study a probabilistic model for MT-based collision avoidance. We derive requirements on laser power, MT success rate, and orbit prediction uncertainty as a function of turbulence compensation capability, time to event, conjunction angle, and area-to-mass ratio. Our results demonstrate capabilities and limitations of the method given currently available technology