Hollow aluminum microspheres with high mass extinction coefficients in the long wave infrared.

Previous electromagnetic computations of multilayered dielectric/metallic spheres identified the ideal dimensions and composition for achieving optimized mass extinction coefficients (/). A hollow metallic sphere, with a thin metallic shell, is one such example of a spherical structure that can theoretically achieve high mass extinction coefficients in the long wave infrared (LWIR) region (8-12 µm). To this end, we endeavored to demonstrate a cost-effective and scalable manufacturing approach for synthesizing and experimentally validating the mass extinction coefficients of hollow metallic spheres.

Implementation Research to Address the United States Health Disadvantage: Report of a National Heart, Lung, and Blood Institute Workshop.

Four decades ago, U.S. life expectancy was within the same range as other high-income peer countries.

Refining Current Scientific Priorities and Identifying New Scientific Gaps in HIV-Related Heart, Lung, Blood, and Sleep Research.

The National Heart, Lung, and Blood Institute (NHLBI) AIDS Program's goal is to provide direction and support for research and training programs in areas of HIV-related heart, lung, blood, and sleep (HLBS) diseases. To better define NHLBI current HIV-related scientific priorities and with the goal of identifying new scientific priorities and gaps in HIV-related HLBS research, a wide group of investigators gathered for a scientific NHLBI HIV Working Group on December 14-15, 2015, in Bethesda, MD. The core objectives of the Working Group included discussions on: (1) HIV-related HLBS comorbidities in the antiretroviral era; (2) HIV cure; (3) HIV prevention; and (4) mechanisms to implement new scientific discoveries in an efficient and timely manner so as to have the most impact on people living with HIV.

Reducing Health Inequities in the U.S.: Recommendations From the NHLBI's Health Inequities Think Tank Meeting.

The National, Heart, Lung, and Blood Institute convened a Think Tank meeting to obtain insight and recommendations regarding the objectives and design of the next generation of research aimed at reducing health inequities in the United States. The panel recommended several specific actions, including: 1) embrace broad and inclusive research themes; 2) develop research platforms that optimize the ability to conduct informative and innovative research, and promote systems science approaches; 3) develop networks of collaborators and stakeholders, and launch transformative studies that can serve as benchmarks; 4) optimize the use of new data sources, platforms, and natural experiments; and 5) develop unique transdisciplinary training programs to build research capacity. Confronting health inequities will require engaging multiple disciplines and sectors (including communities), using systems science, and intervening through combinations of individual, family, provider, health system, and community-targeted approaches.

Perspectives from NHLBI Global Health Think Tank Meeting for Late Stage (T4) Translation Research.

Almost three-quarters (74%) of all the noncommunicable disease burden is found within low- and middle-income countries. In September 2014, the National Heart, Lung, and Blood Institute held a Global Health Think Tank meeting to obtain expert advice and recommendations for addressing compelling scientific questions for late stage (T4) research-research that studies implementation strategies for proven effective interventions-to inform and guide the National Heart, Lung, and Blood Institute's global health research and training efforts. Major themes emerged in two broad categories: 1) developing research capacity; and 2) efficiently defining compelling scientific questions within the local context.

Integrated tunable CMOS laser.

An integrated tunable CMOS laser for silicon photonics, operating at the C-band, and fabricated in a commercial CMOS foundry is presented. The III-V gain medium section is embedded in the silicon chip, and is hermetically sealed. The gain section is metal bonded to the silicon substrate creating low thermal resistance into the substrate and avoiding lattice mismatch problems.

Free-carrier absorption modulation in silicon nanocrystal slot waveguides.

Free-carrier absorption (FCA) has proven to be an important obstacle in the development of a silicon-based laser; however, FCA may serve as a potential advantage in active silicon-based switches or modulators. In this work, we present FCA modulation in slot waveguides with silicon nanocrystals (Si-ncs) embedded in SiO(2) as the low-index slot material. Slot waveguides were fabricated with and without Si-ncs, and the presence of Si-ncs was shown to increase the pump-induced FCA loss in the waveguides by a factor of 4.

Mitigation of Si nanocrystal free carrier absorption loss at 1.5 microm in a concentric microdisk structure.

We study the mitigation of Si nanocrystal (Si-nc) free carrier absorption (FCA) loss at telecom wavelengths in a concentric microdisk design. The concentric microdisk design relies on using the Si-nc emission as an optical pump for the surrounding Er-based lasing media without subjecting the lasing mode to the FCA loss present in the Si-ncs. We analyze the FCA loss as a function of overhang width in this design and show that for large enough overhang width the FCA loss is negligible.

Pulsed pumping of silicon nanocrystal light emitting devices.

Typical silicon nanocrystal light emitting devices (LEDs) operate under direct current (DC) biasing conditions that require high electric fields or high current densities. The electroluminescence (EL) under these conditions relies on impact excitation that can be damaging to the material. In this work, we present bipolar injection into silicon nanocrystal LEDs using a pulsed pumping scheme.

Comparison of raised-microdisk whispering-gallery-mode characterization techniques.

We compare the two prevailing raised-microdisk whispering-gallery-mode (WGM) characterization techniques, one based on coupling emission to a tapered fiber and the other based on collecting emission in the far field. We applied both techniques to study WGMs in Si nanocrystal raised microdisks and observed dramatically different behavior. We explain this difference in terms of the radiative bending loss on which the far-field collection technique relies and discuss the regimes of operation in which each technique is appropriate.

Integration of silicon nanocrystals and erbium ring cavities for a silicon pumped Er:SiO2 laser.

In this work we present a novel two-stage approach to achieve electrically pumped lasing on a CMOS compatible material platform in the telecom region. The proposed design consists of an electrically pumped silicon nanocrystal (Si-nc) light source acting as an optical pump for an Erbium doped silicate (Er:SiO2) lasing cavity. The integrated design, based on concentric disks of Si-nc and Er:SiO2, provides a means of coupling the Si-nc pump signal to the Er ions without requiring overlap of the Er based lasing mode with the Si-nc material.

Developmental expression of a functional TASK-1 2P domain K+ channel in embryonic chick heart.

Background: Background K+ channels are the principal determinants of the resting membrane potential (RMP) in cardiac myocytes and thus, influence the magnitude and time course of the action potential (AP).

Methods: RT-PCR and in situ hybridization are used to study the distribution of TASK-1 and whole-cell patch clamp technique is employed to determine the functional expression of TASK-1 in embryonic chick heart.

Results: Chicken TASK-1 was expressed in the early tubular heart, then substantially decreased in the ventricles by embryonic day 5 (ED5), but remained relatively high in ED5 and ED11 atria.

Coupling Si nanocrystal microdisk emission to whispering-gallery modes in a concentric SiO2 ring.

We present a concentric microdisk design in which luminescence from an inner disk of Si nanocrystals (Si-ncs) contributes to resonant modes in an outer ring of SiO2. Photoluminescence from fabricated structures reveals the excitation of whispering-gallery modes (WGMs) with quality factors as high as 2850, limited by the spectral resolution of our spectrometer. Two-dimensional finite-difference time-domain simulations provide insight into the WGM properties and the role of disk and ring geometry.

Thin film solar cell design based on photonic crystal and diffractive grating structures.

In this paper we present novel light trapping designs applied to multiple junction thin film solar cells. The new designs incorporate one dimensional photonic crystals as band pass filters that reflect short light wavelengths (400 - 867 nm) and transmit longer wavelengths(867 -1800 nm) at the interface between two adjacent cells. In addition, nano structured diffractive gratings that cut into the photonic crystal layers are incorporated to redirect incoming waves and hence increase the optical path length of light within the solar cells.

Temperature-sensitive TREK currents contribute to setting the resting membrane potential in embryonic atrial myocytes.

TREK channels belong to the superfamily of two-pore-domain K(+) channels and are activated by membrane stretch, arachidonic acid, volatile anaesthetics and heat. TREK-1 is highly expressed in the atrium of the adult heart. In this study, we investigated the role of TREK-1 and TREK-2 channels in regulating the resting membrane potential (RMP) of isolated chicken embryonic cardiac myocytes.

Electromagnetic modeling of active silicon nanocrystal waveguides.

In this paper we propose an electromagnetic analysis of active silicon nano-crystal (Si-nc) waveguide devices. To account for the nonlinearity in the active medium we introduce a four level rate equation model whose parameters are based on experimentally reported material properties. The electromagnetic polarization serves to couple the quantum mechanical and electromagnetic behavior within the ADE-FDTD scheme.

Investigating nanoscale cellular dynamics with cross-sectional spectral domain phase microscopy.

We report on cross-sectional imaging of dynamic biological specimens using a spectral domain phase microscopy (SDPM) system capable of operating at a line rate of 19 kHz. This system combines the time-sensitive capabilities of SDPM with the multi-point acquisition features of related phase-sensitive techniques. The presented phase portraits and B-scan phase images of spontaneously beating embryonic cardiomyocytes and cytoplasmic flow in A.

Changes in regulation of sodium/calcium exchanger of avian ventricular heart cells during embryonic development.

It has been suggested that the sodium/calcium exchanger NCX1 may have a more important physiological role in embryonic and neonatal hearts than in adult hearts. However, in chick heart sarcolemmal vesicles, sodium-dependent calcium transport is reported to be small and, moreover, to be 3-12 times smaller in hearts at embryonic day (ED) 4-5 than at ED18, the opposite of what would be expected of a transporter that is more important in early development. To better assess the role of NCX1 in calcium regulation in the chick embryonic heart, we measured the activity of NCX1 in chick embryonic hearts as extracellular calcium-activated exchanger current (I(NCX)) under controlled ionic conditions.

Cardiac arterial pole alignment is sensitive to FGF8 signaling in the pharynx.

Morphogenesis of the cardiac arterial pole is dependent on addition of myocardium and smooth muscle from the secondary heart field and septation by cardiac neural crest cells. Cardiac neural crest ablation results in persistent truncus arteriosus and failure of addition of myocardium from the secondary heart field leading to malalignment of the arterial pole with the ventricles. Previously, we have shown that elevated FGF signaling after neural crest ablation causes depressed Ca2+ transients in the primary heart tube.

Expression of a two-pore domain K+ channel (TASK-1) in developing avian and mouse ventricular conduction systems.

In this study, we report the identification and amino acid sequence of a novel two-pore domain potassium channel (TASK-1) in chicken. This protein, cTASK-1, is highly similar to mouse and human TASK-1 particularly within the pore regions. We describe the expression profile of both chicken and mouse TASK-1 in the embryonic heart as the ventricular conduction system develops.

Spectral-domain phase microscopy.

Broadband interferometry is an attractive technique for the detection of cellular motions because it provides depth-resolved phase information via coherence gating. We present a phase-sensitive technique called spectral-domain phase microscopy (SDPM). SDPM is a functional extension of spectral-domain optical coherence tomography that allows for the detection of nanometer-scale motions in living cells.

A mutation in the TRPC6 cation channel causes familial focal segmental glomerulosclerosis.

Focal and segmental glomerulosclerosis (FSGS) is a kidney disorder of unknown etiology, and up to 20% of patients on dialysis have been diagnosed with it. Here we show that a large family with hereditary FSGS carries a missense mutation in the TRPC6 gene on chromosome 11q, encoding the ion-channel protein transient receptor potential cation channel 6 (TRPC6). The proline-to-glutamine substitution at position 112, which occurs in a highly conserved region of the protein, enhances TRPC6-mediated calcium signals in response to agonists such as angiotensin II and appears to alter the intracellular distribution of TRPC6 protein.

Effects of eugenol, an essential oil, on the mechanical and electrical activities of cardiac muscle.

Eugenol (EUG) acts as a calcium antagonist but effects on the contractile proteins could also occur. We investigated inotropic effects of EUG in rat left ventricular papillary muscles, measuring isometric force, time variables, and post rest potentiation and EUG actions on the effects of Ca2+ (0.62 to 2.

L-type Ca2+ channel function in the avian embryonic heart after cardiac neural crest ablation.

In avian and mammalian embryos, surgical ablation or severely reduced migration of the cardiac neural crest leads to a failure of outflow tract septation known as persistent truncus arteriosus (PTA) and leads to embryo lethality due partly to impaired excitation-contraction coupling stemming primarily from a reduction in the L-type Ca(2+) current (I(Ca),(L)). Decreased I(Ca,L) occurs without a corresponding reduction in the alpha(1)-subunit of the Ca(2+) channel. We hypothesize that decreased I(Ca),(L) is due to reduced function at the single channel level.

Transitions in ventricular activation revealed by two-dimensional optical mapping.

While cardiac function in the mature heart is dependent on a properly functioning His-Purkinje system, the early embryonic tubular heart efficiently pumps blood without a distinct specialized conduction system. Although His-Purkinje system precursors have been identified using immunohistological techniques in the looped heart, little is known whether these precursors function electrically. To address this question, we used high-resolution optical mapping and fluorescent dyes with two CCD cameras to describe the motion-corrected activation patterns of 76 embryonic chick hearts from tubular stages (stage 10) to mature septated hearts (stage 35).