Band splitting and Modal Dispersion induced by Symmetry braking in Coupled-Resonator Slow-Light Waveguide Structures

We study the dispersion relations in slow-light waveguide structures consisting of coupled microdisk resonators. A group theoretical analysis of the symmetry properties of the propagating modes reveals an interesting phenomenon: The degeneracy of the CW and CCW rotating modes is removed, giving rise to two distinct transmission bands. This effect induces symmetry-based dispersion which may limit usable bandwidth of such structures. The properties of this band splitting and its impact on CROW performance for optical communications are studied in detail

Transmission of Slow Light through Photonic Crystal Waveguide Bends

The spectral dependence of a bending loss of cascaded 60-degree bends in photonic crystal (PhC) waveguides is explored in a slab-type silicon-on-insulator system. Ultra-low bending loss of (0.05+/-0.03)dB/bend is measured at wavelengths corresponding to the nearly dispersionless transmission regime. In contrast, the PhC bend is found to become completely opaque for wavelengths range corresponding to the slow light regime. A general strategy is presented and experimentally verified to optimize the bend design for improved slow light transmission.Comment: 4 pages, 3 figures; submitted to Optics Letter

Stopping Light All-Optically

We show that light pulses can be stopped and stored all-optically, with a process that involves an adiabatic and reversible pulse bandwidth compression occurring entirely in the optical domain. Such a process overcomes the fundamental bandwidth-delay constraint in optics, and can generate arbitrarily small group velocities for light pulses with a given bandwidth, without the use of any coherent or resonant light-matter interactions. We exhibit this process in optical resonator systems, where the pulse bandwidth compression is accomplished only by small refractive index modulations performed at moderate speeds. (Accepted for publication in Phys. Rev. Lett. Submitted on Sept. 10th 2003)Comment: 18 pages including 3 figures. Accepted for publication in Phys. Rev. Let

An analysis of inpatient pediatric sickle cell disease: Incidence, costs, and outcomes

ObjectiveTo identify characteristics of pediatric sickle cell disease (SCD) hospitalizations and to examine admission demographics and medical expenditures.MethodsAdmissions with SCD were identified from the 2009 and 2012 releases of the Healthcare and Cost Utilization Project’s Kids Inpatient Database. Diseaseâ specific secondary diagnoses including acute chest syndrome (ACS), vasoâ occlusive pain crisis (VOC), splenic sequestration, and stroke/transient ischemic attack were analyzed for patient and hospital demographics. Analytical endpoints included total healthcare expenditures and mortality.ResultsWe reviewed 75,234 inpatient hospitalizations with a diagnosis of SCD. Over $900,000,000 was spent annually in associated healthcare expenditure. The median length of hospitalization stay (LOS) for all admissions was 3 days (interquartile range [IQR] 2â 5 days). VOC was the most frequent secondary diagnosis, recording 48,698 total hospitalizations and a median LOS of 3 days (IQR 2â 6 days). Of the 8,490 hospitalizations with ACS, the infant population had a significantly higher mortality rate compared to other age groups (2$18,956), behind ACS ($22,631). A high proportion of Caucasian patients died during hospitalization for VOC (0.4% vs. 0.1%, P = 0.014) and ACS (4% vs. 0.2%, P < 0.001) when compared to nonâ Caucasians.ConclusionInpatient hospitalizations for secondary manifestations of pediatric SCD were associated with significant healthcare expenditures. Patients with an increased statistical risk for death during hospitalization included Caucasians with SCD complications of ACS and VOC, and patients <1â yearâ old with ACS. Further research is needed to substantiate the associated clinical significance of these findings.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140014/1/pbc26758.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/140014/2/pbc26758_am.pd

Observation of a stronger-than-adiabatic change of light trapped in an ultrafast switched GaAs-AlAs microcavity

We study the time-resolved reflectivity spectrum of a switched planar GaAs-AlAs microcavity. Between 5 and 40 ps after the switching (pump) pulse we observe a strong excess probe reflectivity and a change of the frequency of light trapped in the cavity up to 5 linewidths away from the cavity resonance. This frequency change does not adiabatically follow the fast-changing cavity resonance. The frequency change is attributed to an accumulated phase change due to the time-dependent refractive index. An analytical model predicts dynamics in qualitative agreement with the experiments, and points to crucial parameters that control future applications.Comment: Discussed effect of probe bandwidth. Included functional forms of n(z) and R(z

Recent cancer incidence trends in an observational clinical cohort of HIV-infected patients in the US, 2000 to 2011

Abstract Background In HIV-infected populations in developed countries, the most recent published cancer incidence trend analyses are only updated through 2008. We assessed changes in the distribution of cancer types and incidence trends among HIV-infected patients in North Carolina up until 2011. Methods We linked the University of North Carolina Center for AIDS Research HIV Clinical Cohort, an observational clinical cohort of 3141 HIV-infected patients, with the North Carolina Cancer registry. Cancer incidence rates were estimated across calendar years from 2000 to 2011. The distribution of cancer types was described. Incidence trends were assessed with linear regression. Results Across 15,022 person-years of follow-up, 202 cancers were identified (incidence rate per 100,000 person-years [IR]: 1345; 95% confidence interval [CI]: 1166, 1544). The majority of cancers were virus-related (61%), including Kaposi sarcoma (N = 32) (IR: 213; 95%CI: 146, 301), non-Hodgkin lymphoma (N = 34) (IR: 226; 95%CI: 157, 316), and anal cancer (N = 16) (IR: 107; 95%CI: 61, 173). Non-Hodgkin lymphoma was observed to decrease from 2000 to 2011 (decline of 15 cases per 100,000 person-years per calendar year, 95%CI: -27, -3). No other changes in incidence or changes in incidence trends were observed for other cancers (all P > 0.20). Conclusions We observed a substantial burden of a variety of cancers in this population in the last decade. Kaposi sarcoma and non-Hodgkin lymphoma were consistently two of the greatest contributors to cancer burden across calendar time. Cancer rates appeared stable across calendar years, except for non-Hodgkin lymphoma, which appeared to decrease throughout the study period

The most reactive amide as a transition-state mimic for cis-trans interconversion.

1-Azatricyclo[3.3.1.1(3,7)]decan-2-one (3), the parent compound of a rare class of 90°-twisted amides, has finally been synthesized, using an unprecedented transformation. These compounds are of special interest as transition-state mimics for the enzyme-catalyzed cis-trans rotamer interconversion of amides involved in peptide and protein folding and function. The stabilization of the amide group in its high energy, perpendicular conformation common to both systems is shown for the rigid tricyclic system to depend, as predicted by calculation, on its methyl group substitution pattern, making 3 by some way the most reactive known "amide".Financial assistance from Enamine Ltd. (www.enamine.net) is gratefully acknowledged. We also thank Dr. V. Stepanenko for valuable advice and encouragement which helped to find the nonstandard solutions to the synthetic problems, and Vitaliy Bilenko for drawing our attention to the instructive EI mass spectrum of compound 8.This is the final published version of the article, originally published in the Journal of the American Chemical Society, 2015, 137 (2), pp 926–93, DOI: 10.1021/ja511460

The Sagnac effect in Coupled-Resonator Slow-Light Waveguide Structures

We study the effect of rotation on the propagation of electromagnetic waves in slow-light waveguide structures consisting of coupled micro-ring resonators. We show that such configurations exhibit new a type of the Sagnac effect which can be used for the realization of highly-compact integrated rotation sensors and gyroscopes

High-throughput in vivo vertebrate screening

We demonstrate a high-throughput platform for cellular-resolution in vivo chemical and genetic screens on zebrafish larvae. The system automatically loads zebrafish from reservoirs or multiwell plates, and positions and rotates them for high-speed confocal imaging and laser manipulation of both superficial and deep organs within 19 s without damage. We performed small-scale test screening of retinal axon guidance mutants and neuronal regeneration assays in combination with femtosecond laser microsurgery.National Institutes of Health (U.S.) (Director’s Innovator Award 1-DP2-OD002989–01)David & Lucile Packard Foundation (Award in Science and Engineering)Alfred P. Sloan Foundation (Award)Broad Institute of MIT and Harvard (Sparc Grant)National Science Foundation (U.S.) (Fellowship)Foxconn (Sponsorship