Naturally Occurring Exopolysaccharide Nanoparticles: Formation Process and Their Application in Glutathione Detection

2021 ◽  
Author(s):  
Chengcheng Li ◽  
Xiaodong Zhang ◽  
Yuxin Guo ◽  
Farzad Seidi ◽  
Xiaotong Shi ◽  
...  
Keyword(s):  
Formation Process ◽  
Naturally Occurring

scholarly journals Origin of precious opal revisited: Possible quick formation of precious opal

2021 ◽  
Author(s):  
Hiroki Okudera ◽  
Tetsuyoshi Takeda
Keyword(s):  
Formation Process ◽  
Hot Water ◽  
Silica Spheres ◽  
Naturally Occurring ◽  
Initial Stage ◽  
Stöber Particles ◽  
Diffusive Medium ◽  
Reactive Silica ◽  
Shape And Size ◽  
Precious Opal

Abstract It has been well known that a sedimentary precious opal is composed of closely packed uni-size silica spheres with voids filled by an air or water, and that an interference among reflections from the boundaries of those spheres and filler yields play-of-colour (iridescence). So, occurrence of a play-of-colour means occurrence of natural selection in size of spheres, or suppression of further nucleation after initial outburst of spheres, during its formation process. We had been exploring the possibility if we can regard a Stöber process as an analogue of the formation process of precious opal. The key is the reason why variation in size is rarely found on both precious opal and Stöber colloid. To give a clue, we examined the internal structure of Stöber particles and how those particles were formed at very initial stage of the process. The answers for evenness in shape and size are a quick supersaturation of reactive silica species, consecutive formation of large and loose polymers by fast dehydration, and their quick aggregation as the initial burst of silica spheres in highly diffusive medium. These can be achieved in nature by quick but continuous decrease in temperature on “basic” (high pH) geothermal hot water moving upward through cracks in rocks. Sedimentary precious opal can thus be formed when such naturally occurring colloid is filtered by a permeable bed.

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.

Formation process of periodic non-conservative antiphase boundary structure in L-Pd5Ce

1990 ◽  
Vol 48 (4) ◽  
pp. 162-163
Author(s):  
Masaru Itakura ◽  
Noriyuki Kuwano ◽  
Kensuke Oki
Keyword(s):  
Formation Process ◽  
Domain Size ◽  
Antiphase Boundary ◽  
Boundary Structure ◽  
Temperature Phase ◽  
Arc Melting ◽  
Iced Water ◽  
Antiphase Domains ◽  
Low Temperature Phase ◽  
Degree Of Order

The low temperature phase of Pd5Ce (L-Pd5Ce) has a one-dimensional long period superstructure (1D-LPS) derived from Ll2. The periodic antiphase boundaries (APBs) are parallel to (110) planes and have a shift vector of 1/2[110]. Hereafter, the indices are referred to the basic lattices of Ll2 As insertion of the APB causes a change in composition, such an APB is called “non-conservative”. Then, a domain size M depends upon the Ce concentration in the alloy. It was found that M increases also with temperature. The temperature dependency of M is attributed to a change of the degree of order within the antiphase domains. In this work, morphology of the non-conservative APBs is observed to clarify the formation process of the 1D-LPS.The alloy of Pd-16.7 at%Ce was prepared by arc melting in argon atmosphere. Disc specimens made from the alloy ingot were first held at 985 K for 260 ks and quenched in iced water to obtain the state of M=∞ or Ll2, followed by annealing for various lengths of time. The annealing temperature was 873 K where the equilibrium value for M is about 3 in unit of (110) lattice spacing of Ll2. Observation was carried out using microscopes JEM-2000FX, JEM-4000EX (HVEM Lab., Kyushu Univ.) and JEM-2000EX (Dept. of Mater. Sci. Tech., Kyushu Univ.).

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.

Flavonoids in adipose tissue inflammation and atherosclerosis: one arrow, two targets

2020 ◽  
Vol 134 (12) ◽  
pp. 1403-1432 ◽  
Author(s):  
Manal Muin Fardoun ◽  
Dina Maaliki ◽  
Nabil Halabi ◽  
Rabah Iratni ◽  
Alessandra Bitto ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fruits And Vegetables ◽  
Metabolic Diseases ◽  
Therapeutic Agents ◽  
Adipose Tissue Inflammation ◽  
Cellular Mechanisms ◽  
Tissue Inflammation ◽  
Cholesterol Levels ◽  
Naturally Occurring ◽  
Pro Inflammatory Cytokines

Abstract Flavonoids are polyphenolic compounds naturally occurring in fruits and vegetables, in addition to beverages such as tea and coffee. Flavonoids are emerging as potent therapeutic agents for cardiovascular as well as metabolic diseases. Several studies corroborated an inverse relationship between flavonoid consumption and cardiovascular disease (CVD) or adipose tissue inflammation (ATI). Flavonoids exert their anti-atherogenic effects by increasing nitric oxide (NO), reducing reactive oxygen species (ROS), and decreasing pro-inflammatory cytokines. In addition, flavonoids alleviate ATI by decreasing triglyceride and cholesterol levels, as well as by attenuating inflammatory mediators. Furthermore, flavonoids inhibit synthesis of fatty acids and promote their oxidation. In this review, we discuss the effect of the main classes of flavonoids, namely flavones, flavonols, flavanols, flavanones, anthocyanins, and isoflavones, on atherosclerosis and ATI. In addition, we dissect the underlying molecular and cellular mechanisms of action for these flavonoids. We conclude by supporting the potential benefit for flavonoids in the management or treatment of CVD; yet, we call for more robust clinical studies for safety and pharmacokinetic values.

Molecular Mechanism of Apoptosis Induction by Resveratrol, a Natural Cancer Chemopreventive Agent

2008 ◽  
Vol 78 (1) ◽  
pp. 3-8 ◽  
Author(s):  
Fan ◽  
Jiang ◽  
Zhang ◽  
Bai
Keyword(s):  
Cancer Treatment ◽  
Molecular Mechanism ◽  
Apoptosis Induction ◽  
Protective Agents ◽  
Chemopreventive Agent ◽  
Naturally Occurring ◽  
Apoptosis Pathways ◽  
Present Understanding

In efforts to identify naturally occurring compounds that act as protective agents, resveratrol, a phytoalexin existing in wine, has attracted much interest because of its diverse pharmacological characteristics. Considering that apoptosis induction is the most potent defense approach for cancer treatment, we have tried to summarize our present understanding of apoptosis induction by resveratrol based on the two major apoptosis pathways.

An Empirical Analysis of the Obtrusiveness of and Participants' Compliance with the Electronically Activated Recorder (EAR)

2007 ◽  
Vol 23 (4) ◽  
pp. 248-257 ◽  
Author(s):  
Matthias R. Mehl ◽  
Shannon E. Holleran
Keyword(s):  
Empirical Analysis ◽  
Sampling Method ◽  
Daily Life ◽  
Assessment Method ◽  
Data Confidentiality ◽  
Short Term ◽  
Naturally Occurring ◽  
Two Samples ◽  
Audio Recorder ◽  
Term Monitoring

Abstract. In this article, the authors provide an empirical analysis of the obtrusiveness of and participants' compliance with a relatively new psychological ambulatory assessment method, called the electronically activated recorder or EAR. The EAR is a modified portable audio-recorder that periodically records snippets of ambient sounds from participants' daily environments. In tracking moment-to-moment ambient sounds, the EAR yields an acoustic log of a person's day as it unfolds. As a naturalistic observation sampling method, it provides an observer's account of daily life and is optimized for the assessment of audible aspects of participants' naturally-occurring social behaviors and interactions. Measures of self-reported and behaviorally-assessed EAR obtrusiveness and compliance were analyzed in two samples. After an initial 2-h period of relative obtrusiveness, participants habituated to wearing the EAR and perceived it as fairly unobtrusive both in a short-term (2 days, N = 96) and a longer-term (10-11 days, N = 11) monitoring. Compliance with the method was high both during the short-term and longer-term monitoring. Somewhat reduced compliance was identified over the weekend; this effect appears to be specific to student populations. Important privacy and data confidentiality considerations around the EAR method are discussed.

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