scholarly journals Coupling plasmonic catalysis and nanocrystals growth through cyclic regeneration of NADH

Nanoscale ◽  
2021 ◽  
Author(s):  
Ana Sánchez-Iglesias ◽  
Joscha Kruse ◽  
Andrey Chuvilin ◽  
Marek Grzelczak
Keyword(s):  
Reducing Agent ◽  
Colloidal Synthesis ◽  
Naturally Occurring ◽  
Nanocrystal Growth ◽  
Cyclic Regeneration

In a typical colloidal synthesis, the molecules of the reducing agent are irreversibly oxidized during nanocrystal growth. Such a scenario is of questionable sustainability when confronted with naturally occurring processes...

The ‘easily reducible’ manganese of soils

1947 ◽  
Vol 37 (1) ◽  
pp. 17-22 ◽  
Author(s):  
H. G. Dion ◽  
P. J. G. Mann ◽  
S. G. Heintze
Keyword(s):  
Salt Solution ◽  
Small Proportion ◽  
Reducing Agent ◽  
Factors Influencing ◽  
Naturally Occurring ◽  
Reducible Oxides ◽  
Reducible Fraction

1. In studying the factors influencing the ‘easily reducible’ manganese in soils, results were obtained to indicate that the estimation is dependent on the pH of the system, the nature of the salt solution, the nature of the reducing agent and the time of contact, in addition to the amount and nature of the higher oxides of manganese present.2. Pyrolusite (MnO2) and a synthetic preparation of manganite hydroxide are ‘easily reducible’ oxides, while manganite (MnO(OH)) and naturally occurring hausmannite (Mn Mn2O4) are apparently ‘difficultly reducible’ forms.3. Since pyrolusite occurs in the easily reducible fraction, those deficient soils which contain only a small proportion of their manganese in the easily reducible form must contain the larger part in a form less reactive than pyrolusite.

The synthesis of naturally occurring 4-alkyl- and 4-alkenyl-γ-lactones using the asymmetric reducing agent -3-pinanyl-9-borabicyclo[3.3.1]nonane

1980 ◽  
Vol 21 (37) ◽  
pp. 3549-3552 ◽  
Author(s):  
M.Mark Midland ◽  
Alfonso Tramontano
Keyword(s):  
Reducing Agent ◽  
Naturally Occurring

Dysprosium-Containing Nanocrystals for Thermal Neutron Detection

2011 ◽  
Vol 1341 ◽  
Author(s):  
Antonio C. Rivera ◽  
Natasha N. Glazener ◽  
Nathaniel C. Cook ◽  
Nathan J. Withers ◽  
John B. Plumley ◽  
...  
Keyword(s):  
Optical Properties ◽  
Thermal Neutron ◽  
Neutron Detection ◽  
Colloidal Synthesis ◽  
Attractive Alternative ◽  
False Alarms ◽  
Thermal Neutrons ◽  
Naturally Occurring ◽  
Optical And Mechanical Properties ◽  
Novel Concept

ABSTRACTWe propose a novel concept of optical detection of thermal neutrons in a passive device that exploits transmutation of Dy-164, a dominant, naturally occurring isotope of dysprosium, into a stable isotope of either holmium Ho-165 or erbium Er-166. Combination of the high thermal neutron capture cross section of ~2,650 barns and transmutation into two other lanthanides makes Dy-164 a very attractive alternative to traditional methods of neutron detection that will be completely insensitive to gamma irradiation, thus reducing greatly the likelihood of false alarms. The optically enabled neutron detection relies on significant differences in optical properties of Dy, Ho, and Er that are not sensitive to a particular isotope, but change considerably from one element to another. While the concept applies equally well to bulk materials and to nanocrystals, nanocrystalline approach is much more attractive due to its significantly lower cost, relative ease of colloidal synthesis of high quality nanocrystals (NCs), and superior optical and mechanical properties of NCs compared to their bulk counterparts. We report on colloidal synthesis of DyF3 NCs, both doped and undoped with Ho and co-doped with Ce and Eu to enhance their optical properties. We also report on DyF3:10%Ce and DyF3:10%Eu NCs irradiated with thermal neutrons from a Cf-252 source and their optical characterization.

scholarly journals Diffusion dynamics controlled colloidal synthesis of highly monodisperse InAs nanocrystals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Taewan Kim ◽  
Seongmin Park ◽  
Sohee Jeong
Keyword(s):  
Molecular Diffusion ◽  
Continuous Process ◽  
Precursor Solution ◽  
Particle Growth ◽  
Injection Rate ◽  
Colloidal Synthesis ◽  
Synthetic Process ◽  
Nanocrystal Growth ◽  
Diffusion Dynamics ◽  
Continuous Injection

AbstractHighly monodisperse colloidal InAs quantum dots (QDs) with superior optoelectronic properties are promising candidates for various applications, including infrared photodetectors and photovoltaics. Recently, a synthetic process involving continuous injection has been introduced to synthesize uniformly sized InAs QDs. Still, synthetic efforts to increase the particle size of over 5 nm often suffer from growth suppression. Secondary nucleation or interparticle ripening during the growth accompanies the inhomogeneity in size as well. In this study, we propose a growth model for the continuous synthetic processing of colloidal InAs QDs based on molecular diffusion. The experimentally validated model demonstrates how precursor solution injection reduces monomer flux, limiting particle growth during synthesis. As predicted by our model, we control the diffusion dynamics by tuning reaction volume, precursor concentration, and injection rate of precursor. Through diffusion-dynamics-control in the continuous process, we synthesize the InAs QDs with a size over 9.0-nm (1Smax of 1600 nm) with a narrow size distribution (12.2%). Diffusion-dynamics-controlled synthesis presented in this study effectively manages the monomer flux and thus overcome monomer-reactivity-originating size limit of nanocrystal growth in solution.

scholarly journals Voltammetric Tracing of Al(III) Using Supramolecular Metal-Polyphenolic Nanofilms Obtained via Electrochemically Assisted Self-Assembly

2020 ◽  
Vol 74 (4) ◽  
pp. 289-292 ◽  
Author(s):  
A. Krywko-Cendrowska
Keyword(s):  
Metal Ions ◽  
Self Assembly ◽  
Metal Ion ◽  
Toxic Metal ◽  
Polyphenolic Compounds ◽  
Colloidal Synthesis ◽  
Naturally Occurring ◽  
Electrical Stimuli ◽  
Molecular Components ◽  
Complexes With Metal Ions

Supramolecular metal-polyphenolic thin sensor films represent a unique class of composite materials. Their properties and sensitivity can be easily modified via controlled self-assembly of their molecular components. Among the different assembly methods, electrochemically triggered processes are extremely powerful because they allow spatial confinement of the film buildup via an electrical stimuli-controlled process. In this article, an approach to employ the electrochemically assisted self-assembly of a multicomponent supramolecular film based on a naturally occurring polyphenol, tannic acid (TA), is featured. Here, the capacity of polyphenolic compounds to form complexes with metal ions, as well as to act both as reducing agents and stabilizers in colloidal synthesis of metal nanoparticles (NPs) is utilized. The electrochemically triggered self-assembly can be coupled with the ion – printing method, in which the targeted metal ion, in this case Al(III), is incorporated into the film during the synthesis and chemically removed afterwards. This procedure results in a template-like structure of the film with openings ready to bind the same metal ion from the probed solution, thus significantly improving the selectivity of the sensor formed and enhancing its applicability for sensing of toxic metal ions in complex aqueous solutions, such as physiological fluids.

Pathology of Bone Cells in Pigs with Experimental Turbinate Osteoporosis (Atrophic Rhinitis)

1971 ◽  
Vol 29 ◽  
pp. 304-305
Author(s):  
A. W. Fetter ◽  
C. C. Capen
Keyword(s):  
Mucous Membrane ◽  
Bone Cells ◽  
Atrophic Rhinitis ◽  
Infectious Agents ◽  
Metabolic Disturbances ◽  
Progressive Reduction ◽  
Naturally Occurring ◽  
Fundamental Cause ◽  
Osteocytic Osteolysis ◽  
Uncertain Etiology

Atrophic rhinitis in swine is a disease of uncertain etiology in which infectious agents, hereditary predisposition, and metabolic disturbances have been reported to be of primary etiologic importance. It shares many similarities, both clinically and pathologically, with ozena in man. The disease is characterized by deformity and reduction in volume of the nasal turbinates. The fundamental cause for the localized lesion of bone in the nasal turbinates has not been established. Reduced osteogenesis, increased resorption related to inflammation of the nasal mucous membrane, and excessive resorption due to osteocytic osteolysis stimulated by hyperparathyroidism have been suggested as possible pathogenetic mechanisms.The objectives of this investigation were to evaluate ultrastructurally bone cells in the nasal turbinates of pigs with experimentally induced atrophic rhinitis, and to compare these findings to those in control pigs of the same age and pigs with the naturally occurring disease, in order to define the fundamental lesion responsible for the progressive reduction in volume of the osseous core.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

SEM study of the morphological effects of kinetin and zeatin on the growth and development of the apical meristem in wheat

1995 ◽  
Vol 53 ◽  
pp. 978-979
Author(s):  
G. M. Hutchins ◽  
J. S. Gardner
Keyword(s):  
Growth And Development ◽  
Furfuryl Alcohol ◽  
Apical Meristem ◽  
Plant Cells ◽  
Triticum Aestivum L ◽  
Morphological Development ◽  
Naturally Occurring ◽  
Chinese Spring Wheat ◽  
Sem Study ◽  
Moist Environment

Cytokinins are plant hormones that play a large and incompletely understood role in the life-cycle of plants. The goal of this study was to determine what roles cytokinins play in the morphological development of wheat. To achieve any real success in altering the development and growth of wheat, the cytokinins must be applied directly to the apical meristem, or spike of the plant. It is in this region that the plant cells are actively undergoing mitosis. Kinetin and Zeatin were the two cytokinins chosen for this experiment. Kinetin is an artificial hormone that was originally extracted from old or heated DNA. Kinetin is easily made from the reaction of adenine and furfuryl alcohol. Zeatin is a naturally occurring hormone found in corn, wheat, and many other plants.Chinese Spring Wheat (Triticum aestivum L.) was used for this experiment. Prior to planting, the seeds were germinated in a moist environment for 72 hours.

Fine structure and properties of defects in naturally occurring silicates and oxides

1990 ◽  
Vol 48 (4) ◽  
pp. 460-461
Author(s):  
David R. Veblen
Keyword(s):  
Chemical Reactions ◽  
High Resolution Electron Microscopy ◽  
Extended Defects ◽  
Single Chain ◽  
Naturally Occurring ◽  
Resolution Electron ◽  
Fine Structures ◽  
Image Simulations ◽  
Similar Crystal Structure

Extended defects and interfaces control many processes in rock-forming minerals, from chemical reactions to rock deformation. In many cases, it is not the average structure of a defect or interface that is most important, but rather the structure of defect terminations or offsets in an interface. One of the major thrusts of high-resolution electron microscopy in the earth sciences has been to identify the role of defect fine structures in reactions and to determine the structures of such features. This paper will review studies using HREM and image simulations to determine the structures of defects in silicate and oxide minerals and present several examples of the role of defects in mineral chemical reactions. In some cases, the geological occurrence can be used to constrain the diffusional properties of defects.The simplest reactions in minerals involve exsolution (precipitation) of one mineral from another with a similar crystal structure, and pyroxenes (single-chain silicates) provide a good example. Although conventional TEM studies have led to a basic understanding of this sort of phase separation in pyroxenes via spinodal decomposition or nucleation and growth, HREM has provided a much more detailed appreciation of the processes involved.

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