The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform

Alexis Shackleford - One of the best experts on this subject based on the ideXlab platform.

Xia Ma - One of the best experts on this subject based on the ideXlab platform.

  • In–situ synthesis of an Al composite reinforced with multi–scale Al12Mo, (Al, Zr, Si) and Al2O3 particles through a multi–stage Reaction
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019
    Co-Authors: Yihan Bian, Zengqiang Li, Xia Ma
    Abstract:

    Abstract Heterogeneous strengthening effect has been a more and more attractive theory for designing metal matrix composites in recent years. In this paper, a new multiphase reinforced Al composite (Al12Mo+(Al,Zr,Si)+Al2O3)/Al has been prepared through a multi–stage Reaction of Al–10ZrO2–5MoSi2 alloy on the basis of Al–10ZrO2, i.e. (ZrAl3+Al2O3)/Al composite, by introducing MoSi2. The strengthening phases, including micro–sized Al12Mo, sub–micron (Al,Zr,Si) and nano–sized Al2O3, are in–situ synthesized, performing attractive strengthening effect. The in–situ synthesized sub–micron (Al,Zr,Si) and nano–sized Al2O3 particles exhibit a net–work distribution, while micron Al12Mo particles act as the node of particle network. Compared with Al–10ZrO2, the Al–10ZrO2–5MoSi2 composite exhibits improved tensile strength at both room temperature (25 °C) and elevated temperature (350 °C). The Reaction mechanism and phase evolution procedure have been discussed. This work can be referred in designing new multifarious particles reinforced composites to achieve promotion at material properties.

P J Chivers - One of the best experts on this subject based on the ideXlab platform.

  • 60 – Rates of chemical Reaction
    Newnes Engineering and Physical Science Pocket Book, 1993
    Co-Authors: John Bird, P J Chivers
    Abstract:

    Publisher Summary This chapter discusses that the rate of a chemical Reaction can be obtained by either measuring the amount of products formed or by measuring the amount of reagents used up in a given time. Chemical Reactions can be considered as a rearrangement of elements, or groups of elements, into new patterns. Each particular chemical Reaction takes place at an individual rate which can be very slow or very rapid. Because of this large variation in Reaction time, it is apparent that under a set of conditions one Reaction might not take place while another takes place with ease. Chemical Reactions do not all take place in the same way. Some chemical Reactions take place by a one step mechanism while others take place as a result of a number of steps each equivalent to the formation of an intermediate product before further Reaction occurs. When a Multi-Stage Reaction occurs, the rate of the Reaction is taken to be that of the slowest step in the Reaction mechanism. The rate of a Reaction has been found experimentally to depend upon certain factors such as temperature (all Reactions); concentration (nongaseous systems); pressure (gaseous systems); catalysts (all Reactions); and particle size.

Anastassios Economou - One of the best experts on this subject based on the ideXlab platform.

  • Bacterial secretome: the assembly manual and operating instructions (Review)
    Molecular Membrane Biology, 2020
    Co-Authors: Anastassios Economou
    Abstract:

    Bacterial protein secretion is a complex Multi-Stage Reaction that is central to membrane and cell wall biosynthesis and essential for cell viability. An impressive array of experimental tools have been used to dissect this Reaction into discreet sub-Reactions. Synthesis of these data reveals a fascinating cascade of inter- and intra-molecular interactions that select, sort and target secretory polypeptides to the membrane and then spend metabolic energy to bias their vectorial movement across the membrane plane through a lipid-inaccessible proteinaceous environment. Transmembrane crossing is catalyzed by protein translocase, an astonishingly dynamic molecular machine. The unusual molecular features of the Sec pathway components allows a handful of proteins to catalyze the export of hundreds of secretory polypeptide substrates with astonishing fidelity. Knowledge of the molecular details of the secretion pathway allows us to rationally exploit these features in heterologous protein production biotechnolog...

  • Bacterial protein secretion through the translocase nanomachine
    Nature Reviews Microbiology, 2007
    Co-Authors: Effrosyni Papanikou, Spyridoula Karamanou, Anastassios Economou
    Abstract:

    The Sec pathway, which transports proteins across membranes, is ubiquitous and essential for viability in all three domains of life. At the core of the pathway is the translocase, a dynamic nanomachine that catalyses transmembrane crossing. This Review considers the latest data on the structure and function of the bacterial Sec translocase. All cells must traffic proteins across their membranes. This essential process is responsible for the biogenesis of membranes and cell walls, motility and nutrient scavenging and uptake, and is also involved in pathogenesis and symbiosis. The translocase is an impressively dynamic nanomachine that is the central component which catalyses transmembrane crossing. This complex, Multi-Stage Reaction involves a cascade of inter- and intramolecular interactions that select, sort and target polypeptides to the membrane, and use energy to promote the movement of these polypeptides across — or their lateral escape and integration into — the phospholipid bilayer, with high fidelity and efficiency. Here, we review the most recent data on the structure and function of the translocase nanomachine. The Sec machinery is essential for life. All cells need to assemble phospholipid bilayer membranes, which have embedded proteins. In bacteria, the Sec pathway catalyses most of the load of protein secretion and acts as the front end for several subsequent protein-sorting and sub-cellular-targeting machines. A combination of membrane-embedded and soluble factors that contribute to pre-protein targeting and translocation are described. A membrane-embedded pre-protein-conducting channel and an ATPase motor lie at its core. Atomic resolution structures of the pre-protein-conducting channel, its ATPase motor and targeting chaperones are available. The protein-conducting channel is composed of several tilted and straight helices of varying lengths and is gated by a periplasmic plug. It has a well-characterized closed state and an anticipated open state that is expected to result from dilation. Metabolic energy in the form of both ATP and the proton motive force is used to power pre-protein movement through the translocase machine. The available data allow for a synthesis of multiple sub-Reactions into a coherent model. This model describes how the translocase recognizes secretory proteins at specific sites and how it subsequently promotes protein export by a series of distinct energy-driven conformational states.

Joesph Mclean - One of the best experts on this subject based on the ideXlab platform.