Conceptual comparison of metabolic pathways with electronic circuits

2004 ◽  
Vol 1 (4) ◽  
pp. 175-182 ◽  
Author(s):  
S. Balaji ◽  
S. Lakshminarayanan
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.


2010 ◽  
Author(s):  
Sohan Lal ◽  
Kolin Paul ◽  
James Gomes
Keyword(s):  

Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
E Vikeved ◽  
R Buonfiglio ◽  
T Kogej ◽  
A Backlund

1965 ◽  
Vol 49 (3) ◽  
pp. 427-435 ◽  
Author(s):  
K. D. Voigt ◽  
J. Tamm ◽  
U. Volkwein ◽  
H. Schedewie

ABSTRACT Pregnenolone-sulphate (400 mg) was perfused through isolated dog livers. The following steroids were isolated in the perfusate: pregnenolone, progesterone, dehydroepiandrosterone, androst-5-ene-diol and the two steroid conjugates, i. e. pregnenolone-sulphate and dehydroepiandrosterone-sulphate. Two »free« steroids and one steroid conjugate could not be characterized. A tentative scheme for the metabolic pathways of pregnenolone-sulphate is presented.


Author(s):  
Kamila B. Muchowska ◽  
Sreejith Jayasree VARMA ◽  
Joseph Moran

How core biological metabolism initiated and why it uses the intermediates, reactions and pathways that it does remains unclear. Life builds its molecules from CO<sub>2 </sub>and breaks them down to CO<sub>2 </sub>again through the intermediacy of just five metabolites that act as the hubs of biochemistry. Here, we describe a purely chemical reaction network promoted by Fe<sup>2+ </sup>in which aqueous pyruvate and glyoxylate, two products of abiotic CO<sub>2 </sub>reduction, build up nine of the eleven TCA cycle intermediates, including all five universal metabolic precursors. The intermediates simultaneously break down to CO<sub>2 </sub>in a life-like regime resembling biological anabolism and catabolism. Introduction of hydroxylamine and Fe<sup>0 </sup>produces four biological amino acids. The network significantly overlaps the TCA/rTCA and glyoxylate cycles and may represent a prebiotic precursor to these core metabolic pathways.


2020 ◽  
Vol 38 (3A) ◽  
pp. 446-456
Author(s):  
Bashar F. Midhat

Step down DC-DC converters are power electronic circuits, which mainly used to convert voltage from a level to a lower level. In this paper, a discontinuous controller is proposed as a control method in order to control Step-Down DC-DC converters. A Lyapunov stability criterion is used to mathematically prove the ability of the proposed controller to give the desired voltage. Simulationsl1 are performedl1 in MATLABl1 software. The simulationl1 resultsl1 are presentedl1 for changesl1 in referencel1 voltagel1 and inputl1 voltagel1 as well as stepl1 loadl1 variations. The resultsl1 showl1 the goodl1 performancel1 of the proposedl1 discontinuousl1 controller.


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