Field Effect and Photoconduction in Au25 Nanoclusters Films

Quantum confined Au nanoclusters exhibit molecule-like properties, including atomic precision and discrete energy levels. The electrical conductivity of Au nanocluster films can vary by several orders of magnitude, and is determined by the strength of the electronic coupling between the individual nanoclusters in the film. Similar to quantum confined, semiconducting quantum dots, the electrical coupling in films is dependent on the size and structure of the Au core and the length and conjugation of the organic ligands surrounding it. Unlike quantum dots, however, semiconducting transport has not been reported in Au nanocluster films. We demonstrate that through a simple yet careful choice of cluster size and organic ligands, stable Au nanocluster films can electronically couple and become semiconducting, exhibiting electric field effect and photoconductivity. The molecule-like nature of the Au nanoclusters is evidenced by a hopping transport mechanism reminiscent of doped, disordered organic semiconductor films. These results demonstrate the potential of metal nanoclusters as a solution processed material for semiconducting devices

Synthesis of Single-Crystalline Lead Sulfide Nanoframes and Nanorings

We present a colloidal synthesis strategy to obtain single-crystalline PbS nanorings. By controlling the ripening process in the presence of halide ions, a transformation of initial PbS nanosheets to framelike structures and finally to nanorings was achieved. We found that the competing ligands oleic acid, oleate, and halide ions play an important role in the formation of these nanostructures. Therefore, we propose a formation mechanism based on a thermally induced ripening of crystal facets dependent on the surface passivation. With this method, it became possible to synthesize colloidal nanorings of cubic crystal phase galena PbS. The synthesis was followed via TEM, and the products are characterized by XRD, AFM, and STEM tomography. Control of the initial nanoframe morphology allows adjusting the later nanoring dimensions

Molecular Doping of Electrochemically Prepared Triazine-Based Carbon Nitride by 2,4,6-Triaminopyrimidine for Improved Photocatalytic Properties

The copolymerization of melamine with 2,4,6-triaminopyrimidine (TAP) in an electrochemical induced polymerization process leads to the formation of molecular doped poly (triazine imide) (PTI). The polymerization is based on the electrolysis of water and evolving radicals during this process. The incorporation of TAP is shown by techniques such as elemental analysis, FTIR and NMR spectroscopy and powder x-ray diffraction (XRD), and it is shown that the carbon content can be tuned by the variation of the molar ratio of the two precursors. This incorporation of TAP directly influences the electronic structure of PTI and as a result a red-shift can be observed in UV-Vis spectroscopy. The smaller bandgap and the increased absorption in the visible range lead to improved photocatalytic properties. In dye degradation experiments it was possible to observe an increase of the rate of the degradation of methylene blue (MB) by a factor of 4 in comparison to undoped PTI or 7 if compared to melon.Comment: 22 pages, 4 figure

OPA1 disease alleles causing dominant optic atrophy have defects in cardiolipin-stimulated GTP hydrolysis and membrane tubulation

The dynamin-related GTPase OPA1 is mutated in autosomal dominant optic atrophy (DOA) (Kjer type), an inherited neuropathy of the retinal ganglion cells. OPA1 is essential for the fusion of the inner mitochondrial membranes, but its mechanism of action remains poorly understood. Here we show that OPA1 has a low basal rate of GTP hydrolysis that is dramatically enhanced by association with liposomes containing negative phospholipids such as cardiolipin. Lipid association triggers assembly of OPA1 into higher order oligomers. In addition, we find that OPA1 can promote the protrusion of lipid tubules from the surface of cardiolipin-containing liposomes. In such lipid protrusions, OPA1 assemblies are observed on the outside of the lipid tubule surface, a protein-membrane topology similar to that of classical dynamins. The membrane tubulation activity of OPA1 is suppressed by GTPγS. OPA1 disease alleles associated with DOA display selective defects in several activities, including cardiolipin association, GTP hydrolysis and membrane tubulation. These findings indicate that interaction of OPA1 with membranes can stimulate higher order assembly, enhance GTP hydrolysis and lead to membrane deformation into tubules

A New Synthesis Approach for Carbon Nitrides: Poly(triazine imide) and Its Photocatalytic Properties

Poly (triazine imide) (PTI) is a material belonging to the group of carbon nitrides and has shown to have competitive properties compared to melon or g-C3N4, especially in photocatalysis. As most of the carbon nitrides PTI is usually synthesized by thermal or hydrothermal approaches. We present and discuss an alternative synthesis for PTI which exhibits a pH dependent solubility in aqueous solutions. This synthesis is based on the formation of radicals during electrolysis of an aqueous melamine solution, coupling of resulting melamine radicals and the final formation of PTI. We applied different characterization techniques to identify PTI as the product of this reaction and report the first liquid state NMR experiments on a triazine-based carbon nitride. We show that PTI has a relatively high specific surface area and a pH dependent adsorption of charged molecules. This tunable adsorption has a significant influence on the photocatalytic properties of PTI which we investigated in dye degradation experiments

Colloidal lead iodide nanorings

Colloidal chemistry of nanomaterials experienced a tremendous development in the last decades. In the course of the journey 0D nanoparticles, 1D nanowires, and 2D nanosheets have been synthesized. They have in common to possess a simple topology. We present a colloidal synthesis strategy for lead iodide nanorings, with a non-trivial topology. First, two-dimensional structures were synthesized in nonanoic acid as the sole solvent. Subsequently, they underwent an etching process in the presence of trioctylphosphine, which determines the size of the hole in the ring structure. We propose a mechanism for the formation of lead iodide nanosheets which also explains the etching of the two-dimensional structures starting from the inside, leading to nanorings. In addition, we demonstrate a possible application of the as-prepared nanorings in photodetectors. These devices are characterized by a fast response, high gain values, and a linear relation between photocurrent and incident light power intensity over a large range. The synthesis approach allows for inexpensive large-scale production of nanorings with tunable properties.Comment: 26 pages, 7 figures, 2 scheme

Peruvian Red Uakaris (Cacajao calvus ucayalii) Are Not Flooded-Forest Specialists

In the literature, particularly in primatological books, the Peruvian red uakari (Cacajao calvus ucayalii) is generally considered as a species that is specialized on living in flooded forest, despite existing evidence to the contrary. Here we review all available information on habitats where Cacajao calvus ucayalii have been observed. Most sightings are from terra firme, including palm swamps, or from mixed habitats, including terra firme and flooded forest. Therefore, we conclude that the species is not a flooded-forest specialist, but is flexible in its habitat requirements and generally uses terra firme forests or a mixture of habitats. Proper recognition of habitat requirements is important for understanding the ecoethological adaptations of a species and for appropriate conservation measures

The role of substance P in secondary pathophysiology after traumatic brain injury

It has recently been shown that substance P (SP) plays a major role in the secondary injury process following traumatic brain injury (TBI), particularly with respect to neuroinflammation, increased blood-brain barrier (BBB) permeability, and edema formation. Edema formation is associated with the development of increased intracranial pressure (ICP) that has been widely associated with increased mortality and morbidity after neurotrauma. However, a pharmacological intervention to specifically reduce ICP is yet to be developed, with current interventions limited to osmotic therapy rather than addressing the cause of increased ICP. Given that previous publications have shown that SP, NK1 receptor antagonists reduce edema after TBI, more recent studies have examined whether these compounds might also reduce ICP and improve brain oxygenation after TBI. We discuss the results of these studies, which demonstrate that NK1 antagonists reduce posttraumatic ICP to near normal levels within 4 h of drug administration, as well as restoring brain oxygenation to near normal levels in the same time frame. The improvements in these parameters occurred in association with an improvement in BBB integrity to serum proteins, suggesting that SP-mediated increases in vascular permeability significantly contribute to the development of increased ICP after acute brain injury. NK1 antagonists may therefore provide a novel, mechanistically targeted approach to the management of increased ICP.Robert Vink, Levon Gabrielian and Emma Thornto

International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

A New Synthesis Approach for Carbon Nitrides: Poly(triazine imide) and Its Photocatalytic Properties

Poly(triazine imide) (PTI) is a materialbelonging to the group of carbon nitrides and has shown tohave competitive properties compared to melon or g-C3N4,especially in photocatalysis. As most of the carbon nitrides, PTIis usually synthesized by thermal or hydrothermal approaches.We present and discuss an alternative synthesis for PTI whichexhibits a pH-dependent solubility in aqueous solutions. Thissynthesis is based on the formation of radicals duringelectrolysis of an aqueous melamine solution, coupling ofresulting melamine radicals and the final formation of PTI. Weapplied different characterization techniques to identify PTI asthe product of this reaction and report the first liquid stateNMR experiments on a triazine-based carbon nitride. We showthat PTI has a relatively high specific surface area and a pHdependentadsorption of charged molecules. This tunable adsorption has a significant influence on the photocatalytic propertiesof PTI, which we investigated in dye degradation experiments