Discovery, isolation, and characterization of diazeniumdiolate siderophores.

The C-diazeniumdiolate (N-nitrosohydroxylamine) group in the amino acid graminine (Gra) is a newly discovered Fe(III) ligand in microbial siderophores. Graminine was first identified in the siderophore gramibactin, and since this discovery, other Gra-containing siderophores have been identified, including megapolibactins, plantaribactin, gladiobactin, trinickiabactin (gramibactin B), and tistrellabactins. The C-diazeniumdiolate is photoreactive in UV light which provides a convenient characterization tool for this type of siderophore.

High-Index NiO Particle Synthesis in Alkali Chloride Salts: Nonclassical Crystallization Pathways and Thermally-Induced Surface Restructuring.

The formation mechanism(s) of high-index facets in metal oxides is not widely understood but remains a topic of interest owing to the challenges of stabilizing high-energy surfaces. These metal oxide crystal surfaces are expected to provide unique physicochemical characteristics; therefore, understanding crystallization pathways may enable the rational design of materials with controlled properties. Here the crystallization of NiO via thermal decomposition of a nickel source in excess of alkali chlorides is examined, focusing on KCl, which produces trapezohedral NiO (311) particles that are difficult to achieve through alternative methods.

Local Ordering of Molten Salts at NiO Crystal Interfaces Promotes High-Index Faceting.

Given the strong influence of surface structure on the reactivity of heterogeneous catalysts, understanding the mechanisms that control crystal morphology is an important component of designing catalytic materials with targeted shape and functionality. Herein, we employ density functional theory to examine the impact of growth media on NiO crystal faceting in line with experimental findings, showing that molten-salt synthesis in alkali chlorides (KCl, LiCl, and NaCl) imposes shape selectivity on NiO particles. We find that the production of NiO octahedra is attributed to the dissociative adsorption of H O, whereas the formation of trapezohedral particles is associated with the control of the growth kinetics exerted by ordered salt structures on high-index facets.

Synthesis of NiO Crystals Exposing Stable High-Index Facets.

Metal oxides exposing high-index facets are potentially impactful in catalysis and adsorption processes owing to under-coordinated ions and polarities that alter their interfacial properties compared to low-index facets. Here, we report molten-salt syntheses of NiO particles exposing a variety of crystal facets. We show that for a given anion (nitrate or chloride), the alkali cation has a notable impact on the formation of crystals exposing {311}, {611}, {100}, and {111} faces.

Quantitative Live-cell Reporter Assay for Noncanonical Wnt Activity.

Noncanonical Wnt signaling functions independently of the β-catenin pathway to control diverse developmental processes, and dysfunction of the pathway contributes to a number of human pathological conditions, including birth defects and metastatic cancer. Progress in the field, however, has been hampered by the scarcity of functional assays for measuring noncanonical Wnt signaling activity. We recently described the Wnt5a-Ror-Kif26b (WRK) reporter assay, which directly monitors a post-transcriptional regulatory event in noncanonical Wnt signaling.

Kinesin superfamily protein Kif26b links Wnt5a-Ror signaling to the control of cell and tissue behaviors in vertebrates.

Wnt5a-Ror signaling constitutes a developmental pathway crucial for embryonic tissue morphogenesis, reproduction and adult tissue regeneration, yet the molecular mechanisms by which the Wnt5a-Ror pathway mediates these processes are largely unknown. Using a proteomic screen, we identify the kinesin superfamily protein Kif26b as a downstream target of the Wnt5a-Ror pathway. Wnt5a-Ror, through a process independent of the canonical Wnt/β-catenin-dependent pathway, regulates the cellular stability of Kif26b by inducing its degradation via the ubiquitin-proteasome system.

Real-time plasmon spectroscopy study of the solid-state oxidation and Kirkendall void formation in copper nanoparticles.

Oxidation and corrosion reactions have a major effect on the application of non-noble metals. Kinetic information and simple theoretical models are often insufficient for describing such processes in metals at the nanoscale, particularly in cases involving formation of internal voids (nano Kirkendall effect, NKE) during oxidation. Here we study the kinetics of solid-state oxidation of chemically-grown copper nanoparticles (NPs) by in situ localized surface plasmon resonance (LSPR) spectroscopy during isothermal annealing in the range 110-170 °C.

Refractive Index Sensing Using Visible Electromagnetic Resonances of Supported CuO Particles.

Plasmonic metal nanostructures, in colloidal or surface-supported forms, have been extensively studied in the context of metamaterials design and applications, in particular as refractometric sensing platforms. Recently, high refractive index (high-n) dielectric subwavelength structures have been experimentally shown to support strong Mie scattering resonances, predicted to exhibit analogous refractive index sensing capabilities. Here we present the first experimental demonstration of the use of supported high-n dielectric nano/microparticle ensembles as refractive index sensing platforms, using cuprous oxide as a model high-n material.

pH-Dependent Galvanic Replacement of Supported and Colloidal Cu2O Nanocrystals with Gold and Palladium.

Galvanic replacement reactions (GRRs) on nanoparticles (NPs) are typically performed between two metals, i.e., a solid metal NP and a replacing salt solution of a more noble metal.

Chemical deposition of Cu(2)O nanocrystals with precise morphology control.

Copper(I) oxide nanoparticles (NPs) are emerging as a technologically important material, with applications ranging from antibacterial and fungicidal agents to photocatalysis. It is well established that the activity of Cu2O NPs is dependent on their crystalline morphology. Here we describe direct preparation of Cu2O nanocrystals (NCs) on various substrates by chemical deposition (CD), without the need of additives, achieving precise control over the NC morphology.

Wnt5a-Ror-Dishevelled signaling constitutes a core developmental pathway that controls tissue morphogenesis.

Wnts make up a large family of extracellular signaling molecules that play crucial roles in development and disease. A subset of noncanonical Wnts signal independently of the transcription factor β-catenin by a mechanism that regulates key morphogenetic movements during embryogenesis. The best characterized noncanonical Wnt, Wnt5a, has been suggested to signal via a variety of different receptors, including the Ror family of receptor tyrosine kinases, the Ryk receptor tyrosine kinase, and the Frizzled seven-transmembrane receptors.

Using population-based data to predict the impact of introducing noninvasive prenatal diagnosis for Down syndrome.

Purpose: To compare the number and types of chromosome abnormalities prenatally diagnosed and the number of invasive procedures between current prenatal testing pathways and a pathway where noninvasive prenatal diagnosis for Down syndrome replaces Down syndrome screening tests.

Methods: Numbers and types of chromosome abnormalities for each referral category were extracted from prenatal diagnostic testing reports routinely collected in Victoria, Australia, in 2006 and 2007. These data were then applied to the proposed implementation strategy.

Gabapentin receptor alpha2delta-1 is a neuronal thrombospondin receptor responsible for excitatory CNS synaptogenesis.

Synapses are asymmetric cellular adhesions that are critical for nervous system development and function, but the mechanisms that induce their formation are not well understood. We have previously identified thrombospondin as an astrocyte-secreted protein that promotes central nervous system (CNS) synaptogenesis. Here, we identify the neuronal thrombospondin receptor involved in CNS synapse formation as alpha2delta-1, the receptor for the anti-epileptic and analgesic drug gabapentin.

Architecture and activity-mediated refinement of axonal projections from a mosaic of genetically identified retinal ganglion cells.

Our understanding of how mammalian sensory circuits are organized and develop has long been hindered by the lack of genetic markers of neurons with discrete functions. Here, we report a transgenic mouse selectively expressing GFP in a complete mosaic of transient OFF-alpha retinal ganglion cells (tOFF-alphaRGCs). This enabled us to relate the mosaic spacing, dendritic anatomy, and electrophysiology of these RGCs to their complete map of projections in the brain.

Dysembryoplastic neuroepithelial tumor (DNT)-like oligodendrogliomas or Dnts evolving into oligodendrogliomas: two illustrative cases.

A review of dysembryoplastic neuroepithelial tumors (DNTs) in 14 patients over a 12-year period revealed four patients re-operated because of changes on magnetic resonance imaging (MRI) suggesting tumor recurrence or progression. In three of these, the histological features were identical to the initial DNT. In the fourth patient, persistent DNT was surrounded by WHO grade 2 oligoastrocytoma.

Neuronal pentraxins mediate synaptic refinement in the developing visual system.

Neuronal pentraxins (NPs) define a family of proteins that are homologous to C-reactive and acute-phase proteins in the immune system and have been hypothesized to be involved in activity-dependent synaptic plasticity. To investigate the role of NPs in vivo, we generated mice that lack one, two, or all three NPs. NP1/2 knock-out mice exhibited defects in the segregation of eye-specific retinal ganglion cell (RGC) projections to the dorsal lateral geniculate nucleus, a process that involves activity-dependent synapse formation and elimination.

Quantitation of chromosome 1p and 19q deletions in glial tumours by interphase FISH on formalin-fixed paraffin-embedded tissue.

Deletions on chromosomes 1p and 19q identify oligodendroglial tumours that are likely to have a complete response to some chemotherapy regimens and are associated with prolonged patient survival. Detection of these chromosomal alterations is becoming increasingly important in the evaluation of glial tumours. Interphase fluorescence in situ hybridisation (FISH) is one of a number of techniques for detecting deletions, and is an efficient method for screening large numbers of tumours.

Pulmonary complications in anterior-posterior thoracic lumbar fusions.

Background Context: Surgery for adult spinal deformity may require both an anterior and posterior approach in order to stabilize the spine and achieve the desired correction. These procedures can be associated with significant pulmonary complications, including atelectasis, pneumonia and respiratory failure. The etiology of some of the respiratory complications is clear: poor inspiratory effort from incision pain and previous pulmonary disease.