scholarly journals THE ROLE OF PHOSPHOCREATINE AND ADENOSINE-TRIPHOSPHATE IN MUSCULAR CONTRACTION

1953 ◽  
Vol 37 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Emil Bozler
Keyword(s):  
Energy Transfer ◽  
Muscular Contraction ◽  
Energy Transfer Mechanism ◽  
Contracting Muscle ◽  
Low Concentrations ◽  
Strong Contraction ◽  
Autocatalytic Process ◽  
Ca Ions ◽  
Tension Curve

In the presence of 20 mM PC a strong contraction is produced in glycerol-extracted muscle fibers by ATP and AMP in concentrations as low as 10–6 M per liter. At low concentrations of nucleotide tension rises very slowly. This rise is interpreted as being due to absorption of nucleotide by the contractile elements. AMP gives an S-shaped tension curve, indicating that the conversion of AMP into ATP is an autocatalytic process. Tension is maintained in a contracted muscle even in PC solutions free of ATP. PC alone produces a contraction if applied within 5 minutes after ATP has been washed out from a contracting muscle. It is concluded from these results that PC is the substrate for the enzymatic activity of the contractile elements and that this activity depends on the presence of bound nucleotide which acts as an energy transfer mechanism. PC accelerates relaxation which is caused by ATP under certain conditions. In the presence of PC even very low concentrations of ATP can produce relaxation. A strong contraction can be produced under these conditions by the addition of Ca ions. These observations support the conclusion that relaxation depends on the rephosphorylation of nucleotide bound by the contractile elements.

Excitation and DE-Excitation of Yb3+ in Inp and Er3+ in Si: Photoluminescence and Impact Ionization Studies

1996 ◽  
Vol 422 ◽  
Author(s):  
T. Gregorkiewicz ◽  
I. Tsimperidis ◽  
C. A. J. Ammerlaan ◽  
F. P. Widdershoven ◽  
N. A. Sobolev
Keyword(s):  
Energy Transfer ◽  
Impact Ionization ◽  
Crystalline Silicon ◽  
Optical Excitation ◽  
Nonradiative Recombination ◽  
Energy Transfer Mechanism ◽  
Excitation Mechanism ◽  
Conduction Electrons ◽  
The One

AbstractIn the paper the existing information on the optical excitation of the erbium ion in crystalline silicon is critically reviewed. The proposed excitation mechanism is compared to the one which is believed to be responsible for the luminescence of ytterbium in indium phosphide. To this end the influence of constant and microwave electric field on the photoluminescence of both systems is inspected. It is shown that, although both systems show some similarities, their analogy is limited.The particular role of excitons and electrons in both the excitation as well as the de-excitation mechanism is investigated for the Si:Er system. The results of photoluminescence decay studies (T=4.2 K) are presented. It is argued that a nonradiative energy transfer to conduction electrons is responsible for the limitation of the energy transfer to the Er core and for its nonradiative recombination. Also, a prominent role of excitons in the energy transfer mechanism is confirmed. Finally, the origin of the 873 meV photoluminescence band recently reported in Er-implanted Si is discussed in relation to a possible defect-mediated activation of Er.

scholarly journals 1,4-Bis (β-Pyridyl-2-Vinyl) Benzene (P2VB) and 2,5-Distyryl-pyrazine (DSP) as Blue Laser Dyes

1985 ◽  
Vol 5 (4) ◽  
pp. 223-230 ◽  
Author(s):  
E. M. Ebeid ◽  
M. M. F. Sabry ◽  
S. A. El-Daly
Keyword(s):  
Energy Transfer ◽  
Laser Excitation ◽  
Blue Laser ◽  
Quantum Yields ◽  
Nitrogen Laser ◽  
Laser Dyes ◽  
Energy Transfer Mechanism ◽  
Fluorescence Quantum Yields ◽  
Critical Transfer Distance

Solutions of P2VB and DSP in dimethyl-sulphoxide (DMSO) of concentration ca. 10–3 M/l act as laser dyes on pumping with nitrogen laser. P2VB and DSP are lasing in the ranges 390–440 nm (λmax = 416 nm) and 435–465 nm (λmax = 447 nm) respectively. An equimolar mixture of P2VB and DSP behaves as an energy transfer dye laser (ETDL) and is lasing in the range 429–455 nm (λmax = 438 nm). Such ETDL system obeys a long range coulombic energy transfer mechanism with a critical transfer distance R0 = 7.5 nm.The fluorescence quantum yields of both dyes have been measured, and in DMSO φf = 0.46 and 0.35 for P2VB and DSP respectively.Both dyes show a remarkable photostability upon nitrogen laser excitation. This has been attributed to the role of the 337 nm light in inducing a back photo-chemical reaction of the initially formed photoproducts consisting mainly of photo-oligomers and cis-photoisomers.

Role of the Spacer in the Singlet−Singlet Energy Transfer Mechanism (Förster vs Dexter) in Cofacial Bisporphyrins

2004 ◽  
Vol 126 (4) ◽  
pp. 1253-1261 ◽  
Author(s):  
Sébastien Faure ◽  
Christine Stern ◽  
Roger Guilard ◽  
Pierre D. Harvey
Keyword(s):  
Energy Transfer ◽  
Transfer Mechanism ◽  
Energy Transfer Mechanism

Testosterone Potentiation of Ionophore and ADP Induced Platelet Aggregation : Relationship to Arachidonic Acid Metabolism

1981 ◽  
Vol 46 (02) ◽  
pp. 538-542 ◽  
Author(s):  
R Pilo ◽  
D Aharony ◽  
A Raz
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Unsaturated Fatty Acids ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Arachidonic Acid Metabolism ◽  
Ionophore A23187 ◽  
Low Concentrations ◽  
Induced Aggregation

SummaryThe role of arachidonic acid oxygenated products in human platelet aggregation induced by the ionophore A23187 was investigated. The ionophore produced an increased release of both saturated and unsaturated fatty acids and a concomitant increased formation of TxA2 and other arachidonate products. TxA2 (and possibly other cyclo oxygenase products) appears to have a significant role in ionophore-induced aggregation only when low concentrations (<1 μM) of the ionophore are employed.Testosterone added to rat or human platelet-rich plasma (PRP) was shown previously to potentiate platelet aggregation induced by ADP, adrenaline, collagen and arachidonic acid (1, 2). We show that testosterone also potentiates ionophore induced aggregation in washed platelets and in PRP. This potentiation was dose and time dependent and resulted from increased lipolysis and concomitant generation of TxA2 and other prostaglandin products. The testosterone potentiating effect was abolished by preincubation of the platelets with indomethacin.

Studies on the Pathogenesis of the Generalized Shwartzman Reaction

1964 ◽  
Vol 12 (02) ◽  
pp. 471-483 ◽  
Author(s):  
F Rodríguez-Erdmann
Keyword(s):  
Clotting Factor ◽  
Factor V ◽  
Clotting System ◽  
Platelet Factor ◽  
Trigger Mechanism ◽  
Haemorrhagic Diathesis ◽  
Shwartzman Reaction ◽  
Ca Ions

SummaryThe rôle of the clotting system in the pathogenesis of the generalized Shwartzman reaction (gSr) has been stressed in recent years. The clotting system is activated ubiquitously and as a result of it, fibrin is deposited intravascularly and a haemorrhagic diathesis develops. Evidence is presented herein, that endotoxin does not activate purified prothrombin, nor does endotoxin influence the convertion of prothrombin when it is activated in the presence of purified platelet-factor 3 (or caephalin) purified Ac-G (factor V) and Ca-ions.The trigger mechanism of the gSr also seems to be in the so-called prephase of clotting mechanism. Data are presented, which show that endotoxin activates the Hageman factor in vitro. The importance of this clotting factor and of platelet-factor 3 is discussed. Also the rôle played by the RES and cardiodynamic and vascular components are taken in consideration in the discussion.

Adiabatic large polarons in anisotropic molecular crystals

2011 ◽  
Vol 35 (1) ◽  
pp. 15-27
Author(s):  
Zoran Ivić ◽  
Željko Pržulj
Keyword(s):  
Energy Transfer ◽  
Effective Mass ◽  
Molecular Crystals ◽  
Single Chain ◽  
Proper Understanding ◽  
One Dimensional ◽  
Interchain Coupling ◽  
Large Polaron ◽  
The One

Adiabatic large polarons in anisotropic molecular crystals We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.

Energy transfer mechanism of supersonic jet noise through rectangular nozzles

2017 ◽  
Vol 65 (2) ◽  
pp. 110-120 ◽  
Author(s):  
Zhe Chen ◽  
Jiu-Hui Wu ◽  
A-Dan Ren ◽  
Xin Chen ◽  
Zhen Huang
Keyword(s):  
Energy Transfer ◽  
Supersonic Jet ◽  
Jet Noise ◽  
Transfer Mechanism ◽  
Energy Transfer Mechanism ◽  
Supersonic Jet Noise

Luminescence Properties and energy transfer mechanism of Eu3+ and Tm3+ Co-doped AlN Thin Films

2021 ◽  
pp. 118082
Author(s):  
Hai Ma ◽  
Xiaodan Wang ◽  
Feifei Chen ◽  
Jiafan Chen ◽  
Xionghui Zeng ◽  
...  
Keyword(s):  
Thin Films ◽  
Energy Transfer ◽  
Transfer Mechanism ◽  
Luminescence Properties ◽  
Energy Transfer Mechanism ◽  
Co Doped
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