Split-disk micro-lasers: Tunable whispering gallery mode cavities

Optical micro-cavities of various types have emerged as promising photonic structures, for both the investigation of fundamental science in cavity quantum electrodynamics and simultaneously for various applications, e.g., lasers, filters, or modulators. In either branch a demand for adjustable and tunable photonic devices becomes apparent, which has been mainly based on the modification of the refractive index of the micro-resonators so far. In this paper, we report on a novel type of whispering gallery mode resonator where resonance tuning is achieved by modification of the configuration. This is realized by polymeric split-disks consisting of opposing half-disks with an intermediate air gap. Functionality of the split-disk concept and its figures of merit like low-threshold lasing are demonstrated for laser dye-doped split-disks fabricated by electron beam lithography on Si substrates. Reversible resonance tuning is achieved for split-disks structured onto elastomeric substrates by direct laser writing. The gap width and hence the resonance wavelength can be well-controlled by mechanically stretching the elastomer and exploiting the lateral shrinkage of the substrate. We demonstrate a broad spectral tunability of laser modes by more than three times the free spectral range. These cavities have the potential to form a key element of flexible and tunable photonic circuits based on polymers

Simultaneous Robotic Manipulation and Functional Magnetic Resonance Imaging: Feasibility in Children with Autism Spectrum Disorders

An unanswered question concerning the neural basis of autism spectrum disorders (ASD) is how sensorimotor deficits in individuals with ASD are related to abnormalities of brain function. We previously described a robotic joystick and video game system that allows us to record functional magnetic resonance images (FMRI) while adult humans make goal- directed wrist motions. We anticipated several challenges in extending this approach to studying goal-directed behaviors in children with ASD and in typically developing (TYP) children. In particular we were concerned that children with autism may express increased levels of anxiety as compared to typically developing children due to the loud sounds and small enclosed space of the MRI scanner. We also were concerned that both groups of children might become restless during testing, leading to an unacceptable amount of head movement. Here we performed a pilot study evaluating the extent to which autistic and typically developing children exhibit anxiety during our experimental protocol as well as their ability to comply with task instructions. Our experimental controls were successful in minimizing group differences in drop-out due to anxiety. Kinematic performance and head motion also were similar across groups. Both groups of children engaged cortical regions (frontal, parietal, temporal, occipital) while making goal- directed movements. In addition, the ASD group exhibited task- related correlations in subcortical regions (cerebellum, thalamus), whereas correlations in the TYP group did not reach statistical significance in subcortical regions. Four distinct regions in frontal cortex showed a significant group difference such that TYP children exhibited positive correlations between the hemodynamic response and movement, whereas children with ASD exhibited negative correlations. These findings demonstrate feasibility of simultaneous application of robotic manipulation and functional imaging to study goal-directed motor behaviors in autistic and typically developing children. The findings also suggest the presence of marked changes in neural activation during a sensorimotor task requiring goal- directed movement

Measuring the Plasticity of Social Approach: A Randomized Controlled Trial of the Effects of the PEERS Intervention on EEG Asymmetry in Adolescents with Autism Spectrum Disorders

This study examined whether the Program for the Education and Enrichment of Relational Skills (PEERS: Social skills for teenagers with developmental and autism spectrum disorders: The PEERS treatment manual, Routledge, New York, 2010a) affected neural function, via EEG asymmetry, in a randomized controlled trial of adolescents with Autism spectrum disorders (ASD) and a group of typically developing adolescents. Adolescents with ASD in PEERS shifted from right-hemisphere gamma-band EEG asymmetry before PEERS to left-hemisphere EEG asymmetry after PEERS, versus a waitlist ASD group. Left-hemisphere EEG asymmetry was associated with more social contacts and knowledge, and fewer symptoms of autism. Adolescents with ASD in PEERS no longer differed from typically developing adolescents in left-dominant EEG asymmetry at post-test. These findings are discussed via the Modifier Model of Autism (Mundy et al. in Res Pract Persons Severe Disabl 32(2):124, 2007), with emphasis on remediating isolation/withdrawal in ASD

Brief Report: Assessment of Intervention Effects on In Vivo Peer Interactions in Adolescents with Autism Spectrum Disorder (ASD)

This study aimed to evaluate the effectiveness of a randomized controlled trial of a social skills intervention, the Program for the Education and Enrichment of Relational Skills (PEERS: Laugeson et al. in J Autism Dev Disord 39(4): 596–606, 2009), by coding digitally recorded social interactions between adolescent participants with ASD and a typically developing adolescent confederate. Adolescent participants engaged in a 10-min peer interaction at pre- and post-treatment. Interactions were coded using the Contextual Assessment of Social Skills (Ratto et al. in J Autism Dev Disord 41(9): 1277–1286, 2010). Participants who completed PEERS demonstrated significantly improved vocal expressiveness, as well as a trend toward improved overall quality of rapport, whereas participants in the waitlist group exhibited worse performance on these domains. The degree of this change was related to knowledge gained in PEERS

Safety of an intravenous formulation of lamotrigine

AbstractPurposeIntravenous (IV) formulations are useful when treating patients where oral administration is not possible and to study certain pharmacokinetic parameters such as bioavailability. We developed a stable-labeled IV formulation of lamotrigine (LTG) for studying pharmacokinetics in epilepsy patients.MethodsStable-labeled IV LTG was given to 20 persons with epilepsy (6 men; 14 women) with a mean age of 34.8 years (SD 11.7). A 50mg dose of LTG (stable labeled) was given intravenously and replaced 50mg of the regular morning oral dose of LTG (unlabeled, commercially available formulation).ResultsNo significant changes in blood pressure, heart rate, or adverse events including rash were attributed to administration of a 50-mg dose of the intravenous LTG formulation.ConclusionOur results show that LTG base that is complexed with 2-hydroxypropyl-β-cyclodextrin and stable-labeled can be given safely as a tracer replacement dose

Pharmacokinetics and Safety of Prolonged Paracetamol Treatment in Neonates: An Interventional Cohort Study

Aims To investigate the pharmacokinetics and safety of prolonged paracetamol use (\u3e72 h) for neonatal pain. Methods Neonates were included if they received paracetamol orally or intravenously for pain treatment. A total of 126 samples were collected. Alanine aminotransferase and bilirubin were measured as surrogate liver safety markers. Paracetamol and metabolites were measured in plasma. Pharmacokinetic parameters for the parent compound were estimated with a nonlinear mixed-effects model. Results Forty-eight neonates were enrolled (38 received paracetamol for \u3e72 h). Median gestational age was 38 weeks (range 25–42), and bodyweight at inclusion was 2954 g (range 713–4750). Neonates received 16 doses (range 4–55) over 4.1 days (range 1–13.8). The median (range) dose was 10.1 mg/kg (2.9–20.3). The median oxidative metabolite concentration was 14.6 μmol/L (range 0.12–113.5) and measurable \u3e30 h after dose. There was no significant difference (P \u3e .05) between alanine aminotransferase and bilirubin measures at \u3c72 h or \u3e72 h of paracetamol treatment or the start and end of the study. Volume of distribution and paracetamol clearance for a 2.81-kg neonate were 2.99 L (% residual standard error = 8, 95% confidence interval 2.44–3.55) and 0.497 L/h (% residual standard error = 7, 95% confidence interval 0.425–0.570), respectively. Median steady-state concentration from the parent model was 50.3 μmol/L (range 30.6–92.5), and the half-life was 3.55 h (range 2.41–5.65). Conclusion Our study did not provide evidence of paracetamol-induced liver injury nor changes in metabolism in prolonged paracetamol administration in neonates