Insight into intramolecular chemical structure modifications by on-surface reaction using photoemission tomography

Macroautophagy ensures the clearance of intracellular substrates ranging from single ubiquitinated proteins to large proteotoxic aggregates and defective organelles. The selective autophagy receptor p62 binds these targets and recruits them to double-membrane vesicles, which fuse with lysosomes to degrade their content. We recently uncovered that p62 function is riboregulated by the small non-coding vault RNA1-1. Here, we present detailed insight into the underlying mechanism. We show that the PB1 domain and adjacent linker region of p62 (aa 1-122) are necessary and sufficient for specific vault RNA1-1 binding, and identify lysine 7 and arginine 21 as key hinges for p62 riboregulation. Chemical structure probing of vault RNA1-1 further reveals a central flexible loop within the RNA that mediates the specific p62 interaction. Our data define molecular determinants that govern mammalian autophagy via the p62-vault RNA1-1 riboregulatory pair.

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From Fundamental Properties to Applications of Surface Activity Investigations: The Kinetic and Thermodynamic Aspects

Current Physical Chemistry ◽

10.2174/1877946809666191003160537 ◽

2020 ◽

Vol 10 (1) ◽

pp. 3-9

Author(s):

Hary Razafindralambo

Keyword(s):

Chemical Structure ◽

Fundamental Property ◽

Fluid Interfaces ◽

Colloidal Systems ◽

Fundamental Properties ◽

Amphiphilic Molecules ◽

Boundary Limits ◽

Mixed Systems ◽

Insight Into

Interfaces, or surfaces in particular (fluid-solid interfaces), are the boundary limits of two immiscible phases characterized by the surface free energy. Getting insight into their fundamental property is of great importance for both scientific and industrial activities. Such an approach enables us to control the formation and stabilization of colloidal systems, which consist of producing homogenous dispersions from at least two initially immiscible phases. In this mini-review, the kinetic and thermodynamic aspects of fluid surfaces are overviewed. Successively, the main phenomena occurring at the interfaces and the appropriate methodology of investigations, the role of amphiphilic molecules in modifying surface properties and generating various functionalities as a function of their chemical structure, size, and shape, and the current approaches for characterizing interactions as well as synergism or antagonism within mixed systems are treated. Relevant relationships of dynamic fundamental properties to macroscopic consequences at the solid and fluid interfaces of single and mixed amphiphile systems are illustrated.

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Heterostuctures of 4-(chloromethyl)phenyltrichlorosilane and 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine prepared on Si(111) using particle lithography: Nanoscale characterization of the main steps of nanopatterning

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.9.112 ◽

2018 ◽

Vol 9 ◽

pp. 1211-1219 ◽

Cited By ~ 2

Author(s):

Phillip C Chambers ◽

Jayne C Garno

Keyword(s):

Surface Reaction ◽

The Self ◽

Silica Spheres ◽

Spatial Confinement ◽

Nonspecific Adsorption ◽

Surrounding Matrix ◽

Nanoscale Characterization ◽

Particle Lithography ◽

Insight Into

Nanostructures of 4-(chloromethyl)phenyltrichlorosilane (CMPS) were used as a foundation to attach and grow heterostructures of porphyrins and organosilanes. A protocol was developed with particle lithography using steps of immersion in organosilane solutions to selectively passivate the surface of Si(111) with octadecyltrichlorosilane (OTS). A methyl-terminated matrix was chosen to direct the growth of CMPS nanostructures to fill the uncovered sites of Si(111) to enable spatial confinement of the surface reaction. Silica spheres with a diameter of 500 nm were used as a surface mask to prepare nanoscopic holes within the OTS matrix film. Next, the samples were immersed in solutions of CMPS dissolved in toluene or bicyclohexane. Nanostructures of CMPS formed within the nanoholes, to furnish spatially selective sites for binding porphyrins. The samples were then characterized with AFM to evaluate the height and morphology of the CMPS nanostructures that had formed within the nanoholes of OTS. The samples were then refluxed in a porphyrin solution for selective binding to produce heterostructures. The attachment of porphyrins was evidenced by increases in the height and width of the CMPS nanopatterns. The measurements of size indicate that multiple layers of porphyrins were added. Through each step of the surface reaction the surrounding matrix of OTS showed minimal areas of nonspecific adsorption. The AFM studies provide insight into the mechanism of the self-polymerization of CMPS as a platform for constructing porphyrin heterostructures.

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Diffraction imaging forin situcharacterization of double-crystal X-ray monochromators

Journal of Applied Crystallography ◽

10.1107/s1600576715017446 ◽

2015 ◽

Vol 48 (6) ◽

pp. 1734-1744 ◽

Cited By ~ 5

Author(s):

Stanislav Stoupin ◽

Zunping Liu ◽

Steve M. Heald ◽

Dale Brewe ◽

Mati Meron

Keyword(s):

Imaging Method ◽

Additional Insight ◽

Element Analysis ◽

Double Crystal ◽

X Ray ◽

Diffraction Imaging ◽

Insight Into ◽

Exit Beam

Imaging of the Bragg-reflected X-ray beam is proposed and validated as anin situmethod for characterization of the performance of double-crystal monochromators under the heat load of intense synchrotron radiation. A sequence of images is collected at different angular positions on the reflectivity curve of the second crystal and analyzed. The method provides rapid evaluation of the wavefront of the exit beam, which relates to local misorientation of the crystal planes along the beam footprint on the thermally distorted first crystal. The measured misorientation can be directly compared with the results of finite element analysis. The imaging method offers an additional insight into the local intrinsic crystal quality over the footprint of the incident X-ray beam.

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Insight into hydrostatic pressure effects on diffusible hydrogen content in wet welding joints using in-situ X-ray imaging method

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2020.01.195 ◽

2020 ◽

Vol 45 (16) ◽

pp. 10219-10226 ◽

Cited By ~ 6

Author(s):

Hao Chen ◽

Ning Guo ◽

Cheng Liu ◽

Xin Zhang ◽

Changsheng Xu ◽

...

Keyword(s):

Hydrostatic Pressure ◽

Hydrogen Content ◽

Pressure Effects ◽

Imaging Method ◽

Diffusible Hydrogen ◽

X Ray ◽

X Ray Imaging ◽

Welding Joints ◽

Insight Into

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Laser Chemical Etching of Conducting and Semiconducting Materials

MRS Proceedings ◽

10.1557/proc-17-45 ◽

1982 ◽

Vol 17 ◽

Cited By ~ 10

Author(s):

T. J. Chuang

Keyword(s):

Material Processing ◽

Laser Radiation ◽

Reaction Mechanisms ◽

Chemical Etching ◽

Surface Reaction ◽

Semiconducting Materials ◽

Laser Method ◽

Experimental Approaches ◽

Product Species ◽

Insight Into

ABSTRACTThe purpose of the paper is to examine the basic processes involved in the laser-enhanced chemical etching of solids. Specifically, the process of chemisorption, the reaction between the adsorbate and substrate atoms and the vaporization of product species affected by the laser radiation are discussed. It is shown that the laser method can provide important insight into the gas-surface reaction mechanisms. In addition, a number of examples are given to demonstrate the potential of the technique for applications to material processing. Some current studies on the laser-induced chemical etching of materials relevant to microelectronics are reviewed. Certain practical experimental approaches are also considered.

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Chemistry at Dalhousie circa 1868

Canadian Journal of Chemistry ◽

10.1139/cjc-2017-0608 ◽

2018 ◽

Vol 96 (7) ◽

pp. 606-613

Author(s):

J. Stuart Grossert ◽

Robert L. White ◽

Louis Ramaley

Keyword(s):

Chemical Structure ◽

Biological Chemistry ◽

Large Section ◽

Complex Molecules ◽

General Chemical ◽

Wide Range ◽

Chemical Concepts ◽

University Archives ◽

Chemical Knowledge ◽

Insight Into

This article describes details of classes at Dalhousie University in 1868–1869, of the life of George Lawson, the first Professor of Chemistry and Mineralogy, and of the wide range of chemical concepts known at that time. A comprehensive set of lecture notes from Lawson’s chemistry course, written by a student, Alexander Russell, and held in the Dalhousie University Archives, offers a wonderful insight into the state of chemical knowledge and how it was taught at that time. Lawson began with general chemical principles followed by a detailed discussion of the nonmetals. The second half of the class covered a range of metals followed by a small section on mineralogy and a large section on organic and biological chemistry. Lawson used an older set of atomic masses in which many, but not all, of the elements had masses one-half of the accepted values today. When corrected for these errors, Lawson’s formulae, even for complex molecules such as morphine, mostly agreed with contemporary usage. Examples of nomenclature, chemical formulae, preparations, processes, and properties are presented. A few examination questions are given also. Even though the concepts involved in understanding chemical structure were just being developed, the breadth and depth of descriptive chemical knowledge at that time was remarkable.

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Gas-Surface Reaction Studies Relevant to SiC Chemical Vapor Deposition

MRS Proceedings ◽

10.1557/proc-131-227 ◽

1988 ◽

Vol 131 ◽

Author(s):

C. D. Stinespring ◽

A. Freedman ◽

J. C. Wormhoudt

Keyword(s):

Solid State ◽

Vapor Deposition ◽

Photoelectron Spectroscopy ◽

Transport Process ◽

Surface Reaction ◽

Chemical Vapor ◽

Nucleation Mechanism ◽

Reaction Products ◽

X Ray ◽

Insight Into

ABSTRACTReactions of C2H4, C3H8, and CH4 on Si(111) and C2H4 on Si(100) have been investigated for surface temperatures in the range of 1062 K to 1495 K. These studies used x-ray photoelectron spectroscopy to identify the reaction products, characterize the solid state transport process, determine the nucleation mechanism and growth kinetics, and assess orienta-tion effects. The results are used to provide insight into the mechanisms of SiC CVD processes.

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Considerations on Structure of Natural Rubber Vulcanizates

Rubber Chemistry and Technology ◽

10.5254/1.3547206 ◽

1968 ◽

Vol 41 (3) ◽

pp. 659-668 ◽

Cited By ~ 3

Author(s):

H. Westlinning ◽

S. Wolff

Keyword(s):

Chain Length ◽

Crosslink Density ◽

Chemical Structure ◽

Structural Features ◽

Polymer Modification ◽

Kinetic Measurements ◽

Secondary Reactions ◽

Ring Structures ◽

Natural Rubber Vulcanizates ◽

Insight Into

Abstract Deep insight into the chemistry of vulcanization, its kinetics, and network structures have been provided by the elucidation of reactions of mono and diolefins with sulfur and accelerators, primarily at NRPRA, and the kinetic measurements of transformation of vulcanizing agents with 1,5-polyenes by Scheele and co-workers at the Kautschuk Institute der Technischen Hochschule, Hannover. It is now established that both accelerated and unaccelerated vulcanization of 1,5-polyenes with sulfur begins with formation of polysulfide crosslinks. As sulfur disappearance and formation of polysulfide proceed, secondary reactions participate increasingly. These involve a series of transformations of the crosslinks originally formed. This leads to a continual change in chain length of crosslinks, in their chemical constitution, and in structural features of the polymer. Figure 1 shows schematically the results of sulfur vulcanization. Crosslinks consist of mono, di, or polysulfide structures, depending on vulcanization time and temperature. As polysulfide bonds disappear, the polymer is modified by the appearance of monosulfidic ring structures and conjugated double bonds in the chain. Secondary reactions may change the crosslink density of the vulcanizate. There are three possibilities: shortening of the crosslink chain length can proceed (a) without change in, (b) with decreasing, or (c) with increasing, crosslink density. Which occurs must be determined for each system. For each polymer the density of crosslinking, its chemical structure, and the extent of polymer modification determine physical, chemical, and technological properties of the vulcanizate.

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Computing Vertex Degree-Based Multiplicative Version of Topological Indices for Tungsten Trioxide Nano Multilayer Structure in Nanotherapeutic Anti-Cancer Activity

Biointerface Research in Applied Chemistry ◽

10.33263/briac122.22752284 ◽

2021 ◽

Vol 12 (2) ◽

pp. 2275-2284

Keyword(s):

Chemical Structure ◽

Chemical Compounds ◽

Topological Indices ◽

Vertex Degree ◽

Anti Cancer ◽

Cancerous Cells ◽

Insight Into ◽

Cancer Activity ◽

Mcf 7 ◽

Chemical Materials

Several research reports suggest that there is a strong interdependence among the molecular structure of chemical compounds and their physicochemical properties. The computation of the topological index of such a chemical structure facilitates researchers to gain more insight into the physical and bio-activity of chemical materials. In this article, we focus on WO3, which is a widely studied nanomaterial and is recently employed as an excellent cytotoxic agent towards the liver (Hep–2) and the breast (MCF–7) cancerous cells. Various vertex degree-based multiplicative versions of topological indices for WO3 nano multilayer were computed using the edge partition technique. We also compared all of the indices graphically. The obtained results redress the lack of medical and chemical experiments, thus constructing the theoretical framework for the pharmacological field.

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