Quantum dot emission from site-controlled ngan/gan micropyramid arrays

InxGa1−xN quantum dots have been fabricated by the selective growth of GaN micropyramid arrays topped with InGaN/GaN quantum wells. The spatially, spectrally, and time-resolved emission properties of these structures were measured using cathodoluminescence hyperspectral imaging and low-temperature microphotoluminescence spectroscopy. The presence of InGaN quantum dots was confirmed directly by the observation of sharp peaks in the emission spectrum at the pyramid apices. These luminescence peaks exhibit decay lifetimes of approximately 0.5 ns, with linewidths down to 650 me

Synthesis of Subject-Specific Human Balance Responses using a Task-Level Neuromuscular Control Platform

Many activities of daily living require a high level of neuromuscular coordination and balance control to avoid falls. Complex musculoskeletal models paired with detailed neuromuscular simulations complement experimental studies and uncover principles of coordinated and uncoordinated movements. Here, we created a closed-loop forward dynamic simulation framework that utilizes a detailed musculoskeletal model (19 degrees of freedom, and 92 Muscles) to synthesize human balance responses after support-surface perturbation. In addition, surrogate response models of task-level experimental kinematics from two healthy subjects were provided as inputs to our closedloop simulations to inform the design of the task-level controller. The predicted muscle EMGs and the resulting synthesized subject joint angles showed good conformity with the average of experimental trials. The simulated whole-body center of mass displacements, generated from a single kinematics trial per perturbation direction, were on average, within 7 mm (anterior perturbations) and 13 mm (posterior perturbations) of experimental displacements. Our results confirmed how a complex subject-specific movement can be reconstructed by sequencing and prioritizing multiple task-level commands to achieve desired movements. By combining the multidisciplinary approaches of robotics and biomechanics, the platform demonstrated here offers great potential for studying human movement control and subject-specific outcome prediction

Is the Lambda CDM Model Consistent with Observations of Large-Scale Structure?

The claim that large-scale structure data independently prefers the Lambda Cold Dark Matter model is a myth. However, an updated compilation of large-scale structure observations cannot rule out Lambda CDM at 95% confidence. We explore the possibility of improving the model by adding Hot Dark Matter but the fit becomes worse; this allows us to set limits on the neutrino mass.Comment: To appear in Proceedings of "Sources and Detection of Dark Matter/Energy in the Universe", ed. D. B. Cline. 6 pages, including 2 color figure

New experimental measurements of solvent induced swelling in nanofiltration membranes

The paper describes developmental apparatus for in-situ determinations of membrane swelling and shows representative examples of the data that can be acquired. The apparatus principally comprises a linear inductive probe and electronic column gauge with an overall resolution of 0.1 μm which was used in two configurations to assess the swelling propensity of polyacrylonitrile (PAN)/polydimethylsiloxane (PDMS) nanofiltration membranes in a range of alkane, aromatic and alcohol solvents. In the absence of an applied pressure on the membrane, experiments showed a maximum expansion for the PDMS layer of 169% using an n-heptane solvent whose solubility parameter (δ) was close to that of PDMS. With more polar solvents falling in the range δ = 23.6-29.2 MPa0.5, swelling of the PDMS was much reduced (<14%) and comparable shrinkage of the PAN support layer was also observed. If a mechanical pressure was applied to the membrane then swelling was reduced. For example with a xylene solvent, over the pressure range 0-10 bar a progressive decline in membrane swelling from 118% to 50% was observed. At 20 bar swelling was further reduced to 33%. When xylene or heptane solvent was mixed with methanol, ethanol or propanol, reduced swelling of the PDMS layer occurred as the concentration of alcohol increased. The extent of swelling was closely related to the value of the mixture solubility parameter (δmixture) where a higher value of δmixture led to less swelling. The results of the swelling experiments are compared to some of the authors previously published results for crossflow nanofiltration and shown to support the salient features

A family of proteins with gamma-adaptin and VHS domains that facilitate trafficking between the trans-Golgi network and the vacuole/lysosome.

We have cloned and characterized members of a novel family of proteins, the GGAs. These proteins contain an NH(2)-terminal VHS domain, one or two coiled-coil domains, and a COOH-terminal domain homologous to the COOH-terminal "ear" domain of gamma-adaptin. However, unlike gamma-adaptin, the GGAs are not associated with clathrin-coated vesicles or with any of the components of the AP-1 complex. GGA1 and GGA2 are also not associated with each other, although they colocalize on perinuclear membranes. Immunogold EM shows that these membranes correspond to trans elements of the Golgi stack and the TGN. GST pulldown experiments indicate that the GGA COOH-terminal domains bind to a subset of the proteins that bind to the gamma-adaptin COOH-terminal domain. In yeast there are two GGA genes. Deleting both of these genes results in missorting of the vacuolar enzyme carboxypeptidase Y, and the cells also have a defective vacuolar morphology phenotype. These results indicate that the function of the GGAs is to facilitate the trafficking of proteins between the TGN and the vacuole, or its mammalian equivalent, the lysosome

Diffusion and anomalous diffusion of light in two-dimensional photonic crystals

The transport properties of electromagnetic waves in disordered, finite, two-dimensional photonic crystals composed of circular cylinders are considered. Transport parameters such as the transport and scattering mean free paths and the transport velocity are calculated, for the case where the electromagnetic radiation has its electric field along the cylinder axes. The range of the parameters in which the diffusion process can take place is specified. It is shown that the transport velocity [Formula presented] can be as much as [Formula presented] times less than its free space value, while just outside the cluster [Formula presented] can be 0.3c. The effects of weak and strong disorders on the transport velocity are investigated. Different regimes of the wave transport—ordered propagation, diffusion, and anomalous diffusion—are demonstrated, and it is inferred that Anderson localization is incipient in the latter regime. Exact numerical calculations from the Helmholtz equation are shown to be in good agreement with the diffusion approximation. © 2003 The American Physical Society

A mobile app and dashboard for early detection of infectious disease outbreaks: development study

©Euijoon Ahn, Na Liu, Tej Parekh, Ronak Patel, Tanya Baldacchino, Tracy Mullavey, Amanda Robinson, Jinman Kim. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 09.03.2021. This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Public Health and Surveillance, is properly cited. The complete bibliographic information, a link to the original publication on http://publichealth.jmir.org, as well as this copyright and license information must be included

Hepatitis C treatment: where are we now?

Chronic hepatitis C infection affects millions of people worldwide and confers significant morbidity and mortality. Effective treatment is needed to prevent disease progression and associated complications. Previous treatment options were limited to interferon and ribavirin regimens, which gave low cure rates and were associated with unpleasant side effects. The era of direct acting antiviral (DAA) therapies began with the development of the first-generation of NS3/4A protease inhibitors (PI) in 2011. They vastly improved outcomes for patients, particularly those with genotype 1 infection, the most prevalent genotype globally. Since then a multitude of DAAs have been licensed for use and outcomes for patients have improved further, with fewer side effects and cure rates approaching 100%. Recent regimens are interferon-free, and in many cases, ribavirin-free and involve a combination of DAA agents. This review summarises the treatment options currently available and discusses potential barriers that may delay the global eradication of hepatitis C

Chirped pulse Raman amplification in warm plasma: towards controlling saturation

Stimulated Raman backscattering in plasma is potentially an efficient method of amplifying laser pulses to reach exawatt powers because plasma is fully broken down and withstands extremely high electric fields. Plasma also has unique nonlinear optical properties that allow simultaneous compression of optical pulses to ultra-short durations. However, current measured efficiencies are limited to several percent. Here we investigate Raman amplification of short duration seed pulses with different chirp rates using a chirped pump pulse in a preformed plasma waveguide. We identify electron trapping and wavebreaking as the main saturation mechanisms, which lead to spectral broadening and gain saturation when the seed reaches several millijoules for durations of 10&apos;s - 100&apos;s fs for 250 ps, 800 nm chirped pump pulses. We show that this prevents access to the nonlinear regime and limits the efficiency, and interpret the experimental results using slowly-varying-amplitude, current-averaged particle-in-cell simulations. We also propose methods for achieving higher efficiencies.close0