3D tracking of extracellular vesicles by holographic fluorescence imaging.

Fluorescence microscopy is the method of choice in biology for its molecular specificity and super-resolution capabilities. However, it is limited to a narrow range around one observation plane. Here, we report an imaging approach that recovers the full electric field of fluorescent light with single-molecule sensitivity.

Formamidinium Incorporation into Compact Lead Iodide for Low Band Gap Perovskite Solar Cells with Open-Circuit Voltage Approaching the Radiative Limit.

To bring hybrid lead halide perovskite solar cells toward the Shockley-Queisser limit requires lowering the band gap while simultaneously increasing the open-circuit voltage. This, to some extent divergent objective, may demand the use of large cations to obtain a perovskite with larger lattice parameter together with a large crystal size to minimize interface nonradiative recombination. When applying the two-step method for a better crystal control, it is rather challenging to fabricate perovskites with FA cations, given the small penetration depth of such large ions into a compact PbI film.

Antireflective Transparent Oleophobic Surfaces by Noninteracting Cavities.

Oleophobic surfaces have been so far realized using complex microscale and nanoscale re-entrant geometries, where primary and secondary structures or overhang geometries are typically required. Here, we propose a new design to create them with noninteracting cavities. The suspension of liquid droplets relies on the mechanism of compression of air under the meniscus leading to stable composite oil-air-solid interfaces.

A water-processable cellulose-based resist for advanced nanofabrication.

The ideal nanofabrication technique is one that allows the mass production of high resolution submicrometric features in a cost efficient and environmentally friendly fashion. A great step towards achieving this goal has been the development of nanoimprinting lithography, a procedure with tenths of nanometres resolution while being compatible with roll-to-roll manufacturing. However, an ecofriendly resist that can be efficiently combined with this process is still missing.

Probing the ultimate plasmon confinement limits with a van der Waals heterostructure.

The ability to confine light into tiny spatial dimensions is important for applications such as microscopy, sensing, and nanoscale lasers. Although plasmons offer an appealing avenue to confine light, Landau damping in metals imposes a trade-off between optical field confinement and losses. We show that a graphene-insulator-metal heterostructure can overcome that trade-off, and demonstrate plasmon confinement down to the ultimate limit of the length scale of one atom.

Real-Time Measurement of Nanotube Resonator Fluctuations in an Electron Microscope.

Mechanical resonators based on low-dimensional materials provide a unique platform for exploring a broad range of physical phenomena. The mechanical vibrational states are indeed extremely sensitive to charges, spins, photons, and adsorbed masses. However, the roadblock is often the readout of the resonator, because the detection of the vibrational states becomes increasingly difficult for smaller resonators.

NFAT regulation of cystathionine γ-lyase expression in endothelial cells is impaired in rats exposed to intermittent hypoxia.

Sleep apnea is a risk factor for cardiovascular disease, and intermittent hypoxia (IH, 20 episodes/h of 5% O-5% CO for 7 h/day) to mimic sleep apnea increases blood pressure and impairs hydrogen sulfide (HS)-induced vasodilation in rats. The enzyme that produces HS, cystathionine γ-lyase (CSE), is decreased in rat mesenteric artery endothelial cells (EC) following in vivo IH exposure. In silico analysis identified putative nuclear factor of activated T cell (NFAT) binding sites in the CSE promoter.

Hydrogen sulfide-induced vasodilation mediated by endothelial TRPV4 channels.

Hydrogen sulfide (HS) is a recently described gaseous vasodilator produced within the vasculature by the enzymes cystathionine γ-lyase and 3-mercaptopyruvate sulfurtransferase. Previous data demonstrate that endothelial cells (EC) are the source of endogenous HS production and are required for HS-induced dilation. However, the signal transduction pathway activated by HS within EC has not been elucidated.

Ordered arrays of Au catalysts by FIB assisted heterogeneous dewetting.

Synthesizing Au0.8Si0.2 nanocatalysts that are homogeneous in size and have controlled position is becoming a challenging and crucial prequisite for the fabrication of ordered semiconductor nanowires.

Intermittent hypoxia in rats reduces activation of Ca2+ sparks in mesenteric arteries.

Ca(+) sparks are vascular smooth muscle cell (VSMC) Ca(2+)-release events that are mediated by ryanodine receptors (RyR) and promote vasodilation by activating large-conductance Ca(2+)-activated potassium channels and inhibiting myogenic tone. We have previously reported that exposing rats to intermittent hypoxia (IH) to simulate sleep apnea augments myogenic tone in mesenteric arteries through loss of hydrogen sulfide (H2S)-induced dilation. Because we also observed that H2S can increase Ca(2+) spark activity, we hypothesized that loss of H2S after IH exposure reduces Ca(2+) spark activity and that blocking Ca(2+) spark generation reduces H2S-induced dilation.

Time-domain separation of optical properties from structural transitions in resonantly bonded materials.

The extreme electro-optical contrast between crystalline and amorphous states in phase-change materials is routinely exploited in optical data storage and future applications include universal memories, flexible displays, reconfigurable optical circuits, and logic devices. Optical contrast is believed to arise owing to a change in crystallinity. Here we show that the connection between optical properties and structure can be broken.

Nanopatterned graphene on a polymer substrate by a direct peel-off technique.

A graphene (Gr) on a polyimide (PI) polymer film (Gr-PI film), obtained by a direct peel-off technique, is proposed and investigated. Thanks to its high transparency, electrical conductivity, mechanical strength, and chemical durability, the Gr-PI film is an ideal substrate for flexible electronic and optoelectronic devices, including transistors, light-emitting diodes, and plasmonic antennas. It is obtained using a straightforward method.

Children and young adults with CF in the USA have better lung function compared with the UK.

Background: People with cystic fibrosis (CF) are managed differently in the USA and UK providing an opportunity to learn from differences in practice patterns.

Objectives: To compare cross-sectional demographics, practice patterns and clinical outcomes between US and UK CF patients.

Methods: This was a cross-sectional study using 2010 data from patients in the US Cystic Fibrosis Foundation and the UK Cystic Fibrosis patient registries.

Web-based self-management for young cancer survivors: consideration of user requirements and barriers to implementation.

Purpose: As the population of young cancer survivors increases, there is a need to develop alternative ways of providing post-treatment support. Online systems potentially offer self-management and e-learning support following cancer treatment. This research aims to explore the self-management support needs of teenage and young adult cancer survivors and consider whether those needs can be met through a web-based self-management resource.

Modulation of hydrogen sulfide by vascular hypoxia.

Hydrogen sulfide (HS) has emerged as a key regulator of cardiovascular function. This gasotransmitter is produced in the vasculature and is involved in numerous processes that promote vascular homeostasis, including vasodilation and endothelial cell proliferation. Although HS plays a role under physiological conditions, it has become clear in recent years that hypoxia modulates the production and action of HS.

Monitoring the kinetic evolution of self-assembled SiGe islands grown by Ge surface thermal diffusion from a local source.

In this paper we experimentally study the growth of self-assembled SiGe islands formed on Si(001) by exploiting the thermally activated surface diffusion of Ge atoms from a local Ge source stripe in the temperature range 600-700 °C. This new growth strategy allows us to vary continuously the Ge coverage from 8 to 0 monolayers as the distance from the source increases, and thus enables the investigation of the island growth over a wide range of dynamical regimes at the same time, providing a unique birds eye view of the factors governing the growth process and the dominant mechanism for the mass collection by a critical nucleus. Our results give experimental evidence that the nucleation process evolves within a diffusion limited regime.

Endothelin-1-induced vasoconstriction does not require intracellular Ca²⁺ waves in arteries from rats exposed to intermittent hypoxia.

Sleep apnea is associated with cardiovascular disease, and patients with sleep apnea have elevated plasma endothelin (ET)-1 concentrations. Rats exposed to intermittent hypoxia (IH), a model of sleep apnea, also have increased plasma ET-1 concentrations and heightened constriction to ET-1 in mesenteric arteries without an increase in global vascular smooth muscle cell Ca(2+) concentration ([Ca(2+)]). Because ET-1 has been shown to increase the occurrence of propagating Ca(2+) waves, we hypothesized that ET-1 increases Ca(2+) wave activity in mesenteric arteries, rather than global [Ca(2+)], to mediate enhanced vasoconstriction after IH exposure.

Strain-induced generation of silicon nanopillars.

Silicon metal-assisted chemical etching (MACE) is a nanostructuring technique exploiting the enhancement of the silicon etch rate at some metal-silicon interfaces. Compared to more traditional approaches, MACE is a high-throughput technique, and it is one of the few that enables the growth of vertical 1D structures of virtually unlimited length. As such, it has already found relevant technological applications in fields ranging from energy conversion to biosensing.

Towards real-time VMAT verification using a prototype, high-speed CMOS active pixel sensor.

This work investigates the feasibility of using a prototype complementary metal oxide semiconductor active pixel sensor (CMOS APS) for real-time verification of volumetric modulated arc therapy (VMAT) treatment. The prototype CMOS APS used region of interest read out on the chip to allow fast imaging of up to 403.6 frames per second (f/s).

Hydrogen sulfide dilates rat mesenteric arteries by activating endothelial large-conductance Ca²⁺-activated K⁺ channels and smooth muscle Ca²⁺ sparks.

We have previously shown that hydrogen sulfide (H₂S) reduces myogenic tone and causes relaxation of phenylephrine (PE)-constricted mesenteric arteries. This effect of H₂S to cause vasodilation and vascular smooth muscle cell (VSMC) hyperpolarization was mediated by large-conductance Ca(2+)-activated potassium channels (BKCa). Ca(2+) sparks are ryanodine receptor (RyR)-mediated Ca(2+)-release events that activate BKCa channels in VSMCs to cause membrane hyperpolarization and vasodilation.

Universal distance-scaling of nonradiative energy transfer to graphene.

The near-field interaction between fluorescent emitters and graphene exhibits rich physics associated with local dipole-induced electromagnetic fields that are strongly enhanced due to the unique properties of graphene. Here, we measure emitter lifetimes as a function of emitter-graphene distance d, and find agreement with a universal scaling law, governed by the fine-structure constant. The observed energy transfer rate is in agreement with a 1/d(4) dependence that is characteristic of two-dimensional lossy media.

Phosphoinositide-dependent kinase-1 and protein kinase Cδ contribute to endothelin-1 constriction and elevated blood pressure in intermittent hypoxia.

Obstructive sleep apnea (OSA) is associated with cardiovascular complications including hypertension. Previous findings from our laboratory indicate that exposure to intermittent hypoxia (IH), to mimic sleep apnea, increases blood pressure in rats. IH also increases endothelin-1 (ET-1) constrictor sensitivity in a protein kinase C (PKC) δ-dependent manner in mesenteric arteries.

Optical nano-imaging of gate-tunable graphene plasmons.

The ability to manipulate optical fields and the energy flow of light is central to modern information and communication technologies, as well as quantum information processing schemes. However, because photons do not possess charge, a way of controlling them efficiently by electrical means has so far proved elusive. A promising way to achieve electric control of light could be through plasmon polaritons—coupled excitations of photons and charge carriers—in graphene.

Hybrid graphene-quantum dot phototransistors with ultrahigh gain.

Graphene is an attractive material for optoelectronics and photodetection applications because it offers a broad spectral bandwidth and fast response times. However, weak light absorption and the absence of a gain mechanism that can generate multiple charge carriers from one incident photon have limited the responsivity of graphene-based photodetectors to ∼10(-2) A W(-1). Here, we demonstrate a gain of ∼10(8) electrons per photon and a responsivity of ∼10(7) A W(-1) in a hybrid photodetector that consists of monolayer or bilayer graphene covered with a thin film of colloidal quantum dots.