Differentiation of human fetal mesenchymal stem cells into cells with an oligodendrocyte phenotype

This article is available open access through the publisher’s website at the link below. Copyright @ 2009 Landes Bioscience.The potential of mesenchymal stem cells (MSC) to differentiate into neural lineages has raised the possibility of autologous cell transplantation as a therapy for neurodegenerative diseases. We have identified a population of circulating human fetal mesenchymal stem cells (hfMSC) that are highly proliferative and can readily differentiate into mesodermal lineages such as bone, cartilage, fat and muscle. Here, we demonstrate for the first time that primary hfMSC can differentiate into cells with an oligodendrocyte phenotype both in vitro and in vivo. By exposing hfMSC to neuronal conditioned medium or by introducing the pro-oligodendrocyte gene, Olig-2, hfMSC adopted an oligodendrocyte-like morphology, expressed oligodendrocyte markers and appeared to mature appropriately in culture. Importantly we also demonstrate the differentiation of a clonal population of hfMSC into both mesodermal (bone) and ectodermal (oligodendrocyte) lineages. In the developing murine brain transplanted hfMSC integrated into the parenchyma but oligodendrocyte differentiation of these naïve hfMSC was very low. However, the proportion of cells expressing oligodendrocyte markers increased significantly (from 0.2% to 4%) by pre-exposing the cells to differentiation medium in vitro prior to transplantation. Importantly, the process of in vivo differentiation occurred without cell fusion. These findings suggest that hfMSC may provide a potential source of oligodendrocytes for study and potential therapy

Change of the emission spectra in organic light-emitting diodes by layer thickness modification

The electroluminescence (EL) and photoluminescence properties of organic light-emitting diodes (LED) were analyzed using layer thickness modification. Investigations show that the EL spectra exhibited significant variation with the increase of the viewing angle. It was found that multiple peak emission could be achieved for a certain range of thickness values. It was concluded that near white emission with CIE coordinates (0.32, 0.43) could be obtained for optimized device thickness.published_or_final_versio

Patients with aortic stenosis exhibit early improved endothelial function following transcatheter aortic valve replacement: The eFAST study

BACKGROUND: Patients with severe aortic stenosis (AS) exhibit systemic endothelial dysfunction, which can be associated with myocardial ischaemia in absence of obstructive coronary disease. Transcatheter aortic valve replacement (TAVR) is used to treat severe AS in patients with high or prohibitive surgical risk. However, it remains unknown whether endothelial function recovers post-TAVR. We therefore sought to assess the early and late changes in flow-mediated dilation (FMD), a measure of endothelial function, following TAVR. METHODS: Patients undergoing TAVR for severe AS had ultrasound assessment of brachial endothelial-independent and -dependent FMD. Measurements were performed pre-TAVR, at early follow-up (<48 h post-TAVR) and late follow-up (4-6 weeks post-TAVR). RESULTS: 27 patients (mean age 82.0 ± 7.0; 33.3% female) were recruited; 37.0% had diabetes mellitus and 59.3% had hypertension. Brachial artery FMD increased from 4.2 ± 1.6% (pre-TAVR) to 9.7 ± 3.5% at early follow-up (p < 0.0001). At late follow-up, improvement compared with early follow-up was sustained (8.7 ± 1.9%, p = 0.27). Resting brachial arterial flow velocities decreased significantly at late follow-up (11.24 ± 5.16 vs. 7.73 ± 2.79 cm/s, p = 0.003). Concordantly, at late follow-up, there was decrease in resting wall shear stress (WSS; 14.8 ± 7.8 vs. 10.6 ± 4.8dyne/cm2, p = 0.01), peak WSS (73.1 ± 34.1 vs. 58.8 ± 27.8dyne/cm2, p = 0.03) and cumulative WSS (3543 ± 1852 vs. 2504 ± 1089dyne·s/cm2, p = 0.002). Additionally, a favourable inverse correlation between cumulative WSS and FMD was restored at late follow-up (r = -0.21 vs. r = 0.49). CONCLUSION: Endothelial function in patients with AS improves early post-TAVR and this improvement is sustained. This likely occurs as a result of improved arterial haemodynamics, leading to lower localised WSS and release of vasoactive mediators that may also alleviate myocardial ischaemia

The Traveling Salesman Problem: Low-Dimensionality Implies a Polynomial Time Approximation Scheme

The Traveling Salesman Problem (TSP) is among the most famous NP-hard optimization problems. We design for this problem a randomized polynomial-time algorithm that computes a (1+eps)-approximation to the optimal tour, for any fixed eps>0, in TSP instances that form an arbitrary metric space with bounded intrinsic dimension. The celebrated results of Arora (A-98) and Mitchell (M-99) prove that the above result holds in the special case of TSP in a fixed-dimensional Euclidean space. Thus, our algorithm demonstrates that the algorithmic tractability of metric TSP depends on the dimensionality of the space and not on its specific geometry. This result resolves a problem that has been open since the quasi-polynomial time algorithm of Talwar (T-04)

Trajectories of psychological distress among Chinese women diagnosed with breast cancer

Background: The distinct trajectories of psychological distress over the first year of the diagnosis with breast cancer (BC) and its determinants have not been explored. Methods: 285 of 405 Chinese women receiving surgery for BC were assessed at 5-day, 1-month, 4-month, and 8-month post-surgery on measures of psychological distress, optimism, treatment decision-making (TDM) difficulties, satisfaction with treatment outcome, satisfaction with medical consultation, and physical symptom distress. Latent growth mixture modelling identified trajectories of psychological response to BC. Multinominal logistic regression compared TDM difficulties, satisfaction with treatment outcome, satisfaction with medical consultation, optimism, and physical symptom distress, by distress pattern adjusted for age, education, employment status, and stage of disease. Results: Four distinct trajectories of distress were identified, namely, resilience (66%), chronic distress (15%), recovered (12%), and delayed-recovery (7%). TDM difficulties, optimism, satisfaction with consultation, and physical symptom distress predicted distress trajectories. Psychologically resilient women had less physical symptom distress at early post-surgery compared with women with other distress patterns. Compared with the resilient group, women in the recovered or chronic distress groups experienced greater TDM difficulties, whereas women in the delayed-recovery group reported greater dissatisfaction with the initial medical consultation. Women in the chronic distress group reported greater pessimistic outlook. Conclusion: Optimism and better early post-operative treatment outcomes predicted resilience to distress. Pre-operative interventions helping women to establish a realistic expectation of treatment outcome may minimize disappointment with treatment outcome and resultant distress, whereas post-operative rehabilitation should focus on symptom management. © 2009 John Wiley & Sons, Ltd.postprin

The Berkeley Contact Lens Extended Wear Study. Part I : Study design and conduct.

ObjectiveThe primary aim of the Berkeley Contact Lens Extended Wear Study (CLEWS) was to test the hypotheses that extended wear of rigid gas-permeable (RGP) contact lenses with greater oxygen permeability (Dk) reduces the incidence of contact lens-associated keratopathy (CLAK) and increases the survival rate in RGP extended wear (EW). In this article we describe the clinical trial design in detail, present the results of subject recruitment and retention, and provide the baseline demographic and ocular characteristics of the CLEWS subjects, whose data will be analyzed to address the study aims in a companion article.DesignA randomized, concurrently controlled clinical trial.InterventionSubjects were fitted with day wear (DW) high-Dk RGP lenses and then adapted to EW. Subjects who adapted to EW were then randomly assigned to either high- or medium-Dk RGP lenses for 12 months of 6-nights/week EW.Main outcome measuresSlit-lamp assessment and grading of 17 possible keratopathies, measurement of refractive error and corneal curvature, and symptoms. Follow-up data were collected every 3 months.ResultsFrom 545 subjects entering the DW adaptation phase, 201 adapted to EW and were randomly assigned to medium- or high-Dk lenses for 12 months of EW. The baseline characteristics of the two study groups were similar and did not differ from the 344 DW subjects who failed to adapt to EW. The distributions of oxygen transmissibility for the two study groups were disjoint, indicating that each group received distinctly different levels of hypoxia.ConclusionsWe show that CLEWS was appropriately designed to address the study hypotheses, was conducted with regard for the safety of the subjects, and adhered to rigorous protocols designed to control for bias and ensure the integrity of study data. We establish the internal validity of between-group statistical comparisons and characterize our study population to permit informed evaluation of the applicability of our results to the contact lens-wearing population in general

The Berkeley Contact Lens Extended Wear Study. Part II : Clinical results.

ObjectiveTo describe the principal clinical outcomes associated with 12 months use of rigid gas-permeable (RGP) extended wear contact lenses and address two primary study questions: (1) does extended wear (EW) of high oxygen transmissibility (Dk/t) RGP lenses reduce the incidence of ocular complications, and (2) does the wearing of high-Dk/t lenses reduce the rate of failure to maintain 6-night RGPEW over 12 months?DesignA randomized, concurrently controlled clinical trial.InterventionSubjects who adapted to EW with high Dk (oxygen permeability) RGP lenses were randomized to either high Dk or medium-Dk RGP lenses for 12 months of 6-night EW.Main outcome measuresContact lens-associated keratopathies (CLAK), changes in refractive error and corneal curvature, and survival in EW.ResultsTwo hundred one subjects were randomized to medium or high-Dk lenses for 12 months of EW. Sixty-two percent of the subjects in each group completed 12 months of EW; however, the probability of failure was significantly greater for the medium-Dk group. Although the risk of complications was similar for the two groups, the number of CLAK events that led to termination were 16 versus 5 for the medium-Dk and high-Dk groups, respectively. This suggests that the type of adverse response or the inability to reverse an adverse event was different for the group being exposed to the lower oxygen dose.ConclusionsThe level of oxygen available to the cornea has a significant impact on maintaining successful RGP extended contact lens wear, but not on the initial onset of CLAK. The number of clinical events leading to termination was substantially higher for the medium Dk group, which suggests that corneal hypoxia is an important factor in the development of CLAK. Although overnight contact lens wear should be recommended with caution and carefully monitored for early detection of ocular complications, it appears that high-Dk RGP lenses can be a safe and effective treatment for correction of refractive error for most individuals who can adapt to EW

Atomic physics: An almost lightless laser

Lasers are often described in terms of a light field circulating in an optical resonator system. Now a laser has been demonstrated in which the field resides primarily in the atomic medium that is used to generate the light

State Transfer Between a Mechanical Oscillator and Microwave Fields in the Quantum Regime

Recently, macroscopic mechanical oscillators have been coaxed into a regime of quantum behavior, by direct refrigeration [1] or a combination of refrigeration and laser-like cooling [2, 3]. This exciting result has encouraged notions that mechanical oscillators may perform useful functions in the processing of quantum information with superconducting circuits [1, 4-7], either by serving as a quantum memory for the ephemeral state of a microwave field or by providing a quantum interface between otherwise incompatible systems [8, 9]. As yet, the transfer of an itinerant state or propagating mode of a microwave field to and from a mechanical oscillator has not been demonstrated owing to the inability to agilely turn on and off the interaction between microwave electricity and mechanical motion. Here we demonstrate that the state of an itinerant microwave field can be coherently transferred into, stored in, and retrieved from a mechanical oscillator with amplitudes at the single quanta level. Crucially, the time to capture and to retrieve the microwave state is shorter than the quantum state lifetime of the mechanical oscillator. In this quantum regime, the mechanical oscillator can both store and transduce quantum information

Coherent optical wavelength conversion via cavity-optomechanics

We theoretically propose and experimentally demonstrate coherent wavelength conversion of optical photons using photon-phonon translation in a cavity-optomechanical system. For an engineered silicon optomechanical crystal nanocavity supporting a 4 GHz localized phonon mode, optical signals in a 1.5 MHz bandwidth are coherently converted over a 11.2 THz frequency span between one cavity mode at wavelength 1460 nm and a second cavity mode at 1545 nm with a 93% internal (2% external) peak efficiency. The thermal and quantum limiting noise involved in the conversion process is also analyzed, and in terms of an equivalent photon number signal level are found to correspond to an internal noise level of only 6 and 4x10-3 quanta, respectively.Comment: 11 pages, 7 figures, appendi