Real-Time Tracking of Metal Nucleation via Local Perturbation of Hydration Layers

The real-time visualization of stochastic nucleation events at electrode surfaces is one of the most complex challenges in electrochemical phase formation. The early stages of metal deposition on foreign substrates are characterized by a highly dynamic process in which nanoparticles nucleate and dissolve prior to reaching a critical size for deposition and growth. Here, high-speed non-contact lateral molecular force microscopy employing vertically oriented probes is utilized to explore the evolution of hydration layers at electrode surfaces with the unprecedented spatiotemporal resolution, and extremely low probe-surface interaction forces required to avoid disruption or shielding the critical nucleus formation. To the best of our knowledge, stochastic nucleation events of nanoscale copper deposits are visualized in real time for the first time and a highly dynamic topographic environment prior to the formation of critical nuclei is unveiled, featuring formation/re-dissolution of nuclei, two-dimensional aggregation and nuclei growth.Electrochemical deposition is important for industrial processes however, tracking the early stages of metallic phase nucleation is challenging. Here, the authors visualize the birth and growth of metal nuclei at electrode surfaces in real time via high-speed non-contact lateral molecular force microscopy

In vivo rate-determining steps of tau seed accumulation in Alzheimer's disease.

[Figure: see text].We acknowledge funding from Sidney Sussex College Cambridge (GM) and the European Research Council Grant Number 669237 (to D.K.) and the Royal Society (to D.K.). The Cambridge Brain Bank is supported by the NIHR Cambridge Biomedical Research Centre

Evaluation of a Mixed Meal Test for Diagnosis and Characterization of PancrEaTogEniC DiabeTes Secondary to Pancreatic Cancer and Chronic Pancreatitis: Rationale and Methodology for the DETECT Study From the Consortium for the Study of Chronic Pancreatitis, Diabetes, and Pancreatic Cancer

Pancreatogenic diabetes mellitus is most commonly the result of chronic pancreatitis but can also occur secondary to pancreatic cancer. The early identification of pancreatogenic diabetes and distinction from the more prevalent type 2 diabetes are clinically significant; however, currently, there is no validated method to differentiate these diabetes subtypes. We describe a study, "Evaluation of a Mixed Meal Test for Diagnosis and Characterization of PancrEaTogEniC DiabeTes Secondary to Pancreatic Cancer and Chronic Pancreatitis: the DETECT study," that seeks to address this knowledge gap. The DETECT study is a multicenter study that will examine differences in hormone and glucose excursions after a mixed meal test. The study will also create a biorepository that will be used to evaluate novel diagnostic biomarkers for differentiating these diabetes subtypes

Deep Surface Trap States at ZnO Nanorods Arrays

ABSTRACTDeep surface trap states present in hydrothermally grown ZnO nanorod (NR) arrays are monitored by photoelectrochemical and impedance spectroscopy. NR arrays were grown on a thin compact ZnO film deposited by pulsed laser deposition. Photocurrent responses upon square-wave illumination and lock-in detection of the as-grown NR arrays in the presence of Na2SO3 at pH 10 were characterized by a complex potential dependence indicating the presence of deep trap states. At a given frequency of light perturbation, the photocurrent amplitude increases as the potential bias is shifted towards values more positive than the flat band potential. Increasing the potential further than 0.8 V positive to the flat band potential leads to a decrease in the photocurrent amplitude. The potential of maximum photocurrent amplitude overlaps with a sharp decrease in the interfacial capacitance. The dependence of the photocurrent amplitude on bias potential strongly suggests the presence of deep electron trap states. The effect of the deep trap states are minimized by annealing of the NR arrays in air at 340° C.</jats:p

The effect of time of harvest, irrigation treatments and kilning temperature on Eucalyptus globulus seed germination response to high temperature stress

Low seedling emergence rates of some Eucalyptus globulus seed-lots have been reported and hypothesised to be caused by high temperature stress. This study tested the effects of time of seed harvest, kilning temperature at seed extraction and irrigation treatments applied to E. globulus trees on seed germination traits. Seeds were harvested from three genotypes at 11 months from commencement of flowering (early), 13 months (commercial) and 15 months (late) and kiln dried at 30, 40 or 50C. Irrigation treatments were full irrigation, half irrigation and no irrigation. Six traits describing the proportion and rate of seed germination and early seedling development were studied. The kilning temperature of capsules and irrigation treatments applied to trees had no effect on the germination traits studied. Time of seed harvest affected the rates of seed germination and normal seedling development. There was little delay in germination rate at 32C in early-harvested seeds compared with that experienced by the commercial- and late-harvested seeds, suggesting that it has a higher temperature threshold. However, the effect of harvest date on germination was genotype dependent which may be related to different heat sums to which developing seeds are exposed

Paternal and maternal effects on the response of seed germination to high temperatures in Eucalyptus globulus

High temperature stress in nurseries germinating Eucalyptus globulus seed is an important problem affecting germination synchrony and rate. Where there is a risk of high temperature stress, then the choice of female parent may be important. This issue is particularly relevant to the production of full-sib families from mass-supplementary pollination where there may be opportunities for seed producers to manipulate the directionality of the crossing done in seed orchards

The impact of flower density and irrigation on capsule and seed set in Eucalyptus globulus seed orchards

Low capsule set is a major factor limiting the productivity of Eucalyptus globulus seed orchards. This study tested the effect of flower density, as well as two common irrigation techniques on capsule and seed set. Ramets with high flower density had significantly lower capsule set (69.7%) than those with low flower density (81.7%). In a regulated deficit irrigation trial, the non-irrigated ramets set a higher proportion of capsules (63.6%) than the ramets that received conventional irrigation (CI) (51.4%). In a partial root zone drying (PRD) trial, capsule set was highest in the absence of irrigation (74.7%) followed by the PRD treatment (67.8%) and then CI (53.7%). The CI treatment tended to produce the highest number of seed per capsule. Increased water availabilityresulted in increased vegetative growth, which was associated with higher levels of abortion in developing capsules but those surviving tended to have higher seed set. It is argued that the observed effects of irrigation and flower density can be explained by resource competition between vegetative and reproductive growth as well as competition among reproductive structures themselves

Density of Deep Trap States in Oriented TiO₂ Nanotube Arrays

Correlations between the population of deep trap states in an array of TiO₂ nanotubes (NT) and the dynamic photocurrent responses under supra-band-gap illumination are investigated. Ordered arrays of TiO₂ NT of 10 μm length, 125 nm inner diameter, and 12 nm wall thickness featuring strong anatase character were obtained by anodization of Ti in ethylene glycol solution containing NH₄F. Cyclic voltammograms at pH 10 show the characteristic responses for nanostructured TiO₂ electrodes, in particular a sharp cathodic peak as the electron density in the film increases. These responses are associated with the population of deep trap states with an average value of 5 × 10⁴ electrons per NT. Dynamic photocurrent measurements clearly show that the characteristic rise time of the photocurrent increases as the potential is increased above the onset region for charging deep trap states. At potentials in which deep trap states are fully depopulated in the dark, photocurrent rise time approaches values just below 1 s, which is more than 3 orders of magnitude slower than the estimated <i>RC</i> time constant. The occupancy of the deep trap states under photostationary conditions is a fraction of the density of states estimated from voltammetric responses. These findings are discussed in the context of current views about trap states in high surface area TiO₂ electrodes