scholarly journals Spin‐inversion mechanisms in O 2 binding to a model heme compound: A perspective from nonadiabatic wave packet calculations

2020 ◽  
Vol 41 (29) ◽  
pp. 2527-2537
Author(s):  
Kohei Saito ◽  
Yuya Watabe ◽  
Takaaki Miyazaki ◽  
Toshiyuki Takayanagi ◽  
Jun‐ya Hasegawa
Keyword(s):  
Wave Packet ◽  
Compound A ◽  
Spin Inversion

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (03) ◽  
pp. 100-103 ◽  
Author(s):  
C. Schümichen ◽  
J. Waiden ◽  
G. Hoffmann
Keyword(s):  
Glomerular Filtration ◽  
Renal Clearance ◽  
Plasma Protein ◽  
Kinetic Data ◽  
Adult Rats ◽  
Compound A ◽  
Extravascular Space ◽  
Tubular Cells ◽  
Glomerular Filtrate ◽  
Kinetics Of

SummaryThe kinetic data of two different 99mTc-Sn-pyrophosphate compounds (compound A and B) were evaluated in non-adult rats. Only compound A concentrated in bone. Both compounds dispersed rapidly in the intravascular as well as the extravascular space. The plasma protein bond of both compounds increased with time after injection and impaired both the renal clearance of both compounds and the bone clearance of compound A. The renal clearance of both compounds was somewhat above that of 5 1Cr-EDTA. It is concluded that compound A and B is mainly excreted by glomerular filtration. About one fourth of the glomerular filtrate of compound B is reabsorbed and accumulated by the tubular cells.

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

2020 ◽  
Author(s):  
Nathan O'Brien ◽  
Naokazu Kano ◽  
Nizam Havare ◽  
Ryohei Uematsu ◽  
Romain Ramozzi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ring Expansion ◽  
Bicyclic Compound ◽  
Compound A ◽  
Ligand System ◽  
Large Bulk ◽  
Rearrangement Reaction ◽  
Hydride Abstraction ◽  
Pentacoordinated Phosphorus ◽  
Acids And Bases

<div>The isolation and reactivities of two pentacoordinated phosphorus–tetracoordinated boron bonded compounds were</div><div>explored. A strong Lewis acidic boron reagent and electron-withdrawing ligand system were required to form the</div><div>pentacoordinated phosphorus state of the P–B bond. The first compound, a phosphoranyl-trihydroborate, gave a THF</div><div>stabilised phosphoranyl-borane intermediate upon a single hydride abstraction in THF. This compound could undergo a</div><div>unique rearrangement reaction, that involved a two-fold ring expansion, to give an unusual fused bicyclic compound or it</div><div>could act as a mono-hydroboration reagent. The hydroboration reactivity of the intermediate was found to be more reactive</div><div>towards alkynes over alkenes with good to moderate regioselectivity towards the terminal carbon. The second compound,</div><div>a phosphoranyl-triarylborate, was found to have a vastly different reactivity to the trihydroborate as it was highly stable</div><div>towards acids and bases. This is thought to be due to the large bulk around the P–B bond as shown in the crystal structure</div>

Extraction, isolation and characterization of Bauhinia variegata flower

2020 ◽  
pp. 9-12
Author(s):  
Akanksha Gupta ◽  
Abhishek K Tripathi ◽  
Pushpraj S Gupta
Keyword(s):  
Biological Activities ◽  
Molecular Formula ◽  
Native Plant ◽  
Compound A ◽  
Active Constituents ◽  
Chromatographic Techniques ◽  
Isolation And Characterization ◽  
Soxhlet Apparatus ◽  
Bauhinia Variegata

Background: Bauhinia variegata Linn. is a native plant of Asia and China. B. variegata is found in tropical regions of the world. It belongs to family Leguminosae. It is used for diarrhea, hemorrhoids, constipation, piles, edema, leprosy, wounds, tumors, etc.  Objective: The objective of the present study was to perform extraction of B. variegata flower and isolation of active constituents from the extract. Materials and Methods: The ethanolic extraction of B. variegata flower was performed using the Soxhlet apparatus. The isolation of active constituents from the extract was performed using chromatographic techniques. In column chromatographic studies, n-hexane- [dichloromethane (DCM)] (2:8) was used as an eluting system and further purified through thin layer chromatography (TLC). Compound A and B were isolated through chromatographic techniques, then the molecular formula and characterization of these compounds were carried out with mass and infrared (IR) spectral analysis. Results and Discussion: The percentage yield of B. variegata ethanolic extract (BVE) was found to be 20.8% w/w. The different fractions were F1 having 12.5 grams with n-hexane, F2 (17.1 grams) with CH2Cl2, F3 (21.2 grams) with EtOAc, and F4 (13.4 grams) with EtOH. Compound A and B were isolated from the solvent fractions of n-hexane-DCM (2:8) and EtOAc-DCM (1:9), respectively. The compound A was characterized as 3-hydroxy-6-methoxy-2-phenyl-4H-chromen-4-one. The compound B was characterized as 3-hydroxy-6-methyl-2-phenyl-4H-chromen-4-one. Conclusion: Thus, B. variegata flowers possess active components that need to identify their biological activities.

Superfluidity and Superconductivity

2018 ◽  
Author(s):  
Norman J. Morgenstern Horing
Keyword(s):  
Magnetic Field ◽  
Wave Function ◽  
Wave Packet ◽  
Long Range ◽  
Cooper Pair ◽  
Bose Condensation ◽  
Range Order ◽  
Condensed State ◽  
Long Range Order ◽  
Coherent Wave

Chapter 13 addresses Bose condensation in superfluids (and superconductors), which involves the field operator ψ‎ having a c-number component (<ψ(x,t)>≠0), challenging number conservation. The nonlinear Gross-Pitaevskii equation is derived for this condensate wave function<ψ>=ψ−ψ˜, facilitating identification of the coherence length and the core region of vortex motion. The noncondensate Green’s function G˜1(1,1′)=−i<(ψ˜(1)ψ˜+(1′))+> and the nonvanishing anomalous correlation function F˜∗(2,1′)=−i<(ψ˜+(2)ψ˜+(1′))+> describe the dynamics and elementary excitations of the non-condensate states and are discussed in conjunction with Landau’s criterion for viscosity. Associated concepts of off-diagonal long-range order and the interpretation of <ψ> as a superfluid order parameter are also introduced. Anderson’s Bose-condensed state, as a phase-coherent wave packet superposition of number states, resolves issues of number conservation. Superconductivity involves bound Cooper pairs of electrons capable of Bose condensation and superfluid behavior. Correspondingly, the two-particle Green’s function has a term involving a product of anomalous bound-Cooper-pair condensate wave functions of the type F(1,2)=−i<(ψ(1)ψ(2))+>≠0, such that G2(1,2;1′,2′)=F(1,2)F+(1′,2′)+G˜2(1,2;1′,2′). Here, G˜2 describes the dynamics/excitations of the non-superfluid-condensate states, while nonvanishing F,F+ represent a phase-coherent wave packet superposition of Cooper-pair number states and off-diagonal long range order. Employing this form of G2 in the G1-equation couples the condensed state with the non-condensate excitations. Taken jointly with the dynamical equation for F(1,2), this leads to the Gorkov equations, encompassing the Bardeen–Cooper–Schrieffer (BCS) energy gap, critical temperature, and Bogoliubov-de Gennes eigenfunction Bogoliubons. Superconductor thermodynamics and critical magnetic field are discussed. For a weak magnetic field, the Gorkov-equations lead to Ginzburg–Landau theory and a nonlinear Schrödinger-like equation for the pair wave function and the associated supercurrent, along with identification of the Cooper pair density. Furthermore, Chapter 13 addresses the apparent lack of gauge invariance of London theory with an elegant variational analysis involving re-gauging the potentials, yielding a manifestly gauge invariant generalization of the London equation. Consistency with the equation of continuity implies the existence of Anderson’s acoustic normal mode, which is supplanted by the plasmon for Coulomb interaction. Type II superconductors and the penetration (and interaction) of quantized magnetic flux lines are also discussed. Finally, Chapter 13 addresses Josephson tunneling between superconductors.

scholarly journals Wave packet dynamics in Yang-Mills theory

1995 ◽  
Vol 52 (4) ◽  
pp. 2402-2411 ◽  
Author(s):  
C. R. Hu ◽  
S. G. Matinyan ◽  
B. Müller ◽  
A. Trayanov ◽  
T. M. Gould ◽  
...  
Keyword(s):  
Wave Packet ◽  
Yang Mills ◽  
Wave Packet Dynamics

scholarly journals IMPLICATIONS OF A QUANTUM MECHANICAL TREATMENT OF THE UNIVERSE

1998 ◽  
Vol 13 (05) ◽  
pp. 347-351 ◽  
Author(s):  
MURAT ÖZER
Keyword(s):  
Quantum Mechanics ◽  
Wave Packet ◽  
Early Universe ◽  
Mechanical Treatment ◽  
Correspondence Principle ◽  
Scale Factor ◽  
Quantum Mechanical ◽  
Quantum Mechanical Treatment ◽  
The Standard Model ◽  
The Universe

We attempt to treat the very early Universe according to quantum mechanics. Identifying the scale factor of the Universe with the width of the wave packet associated with it, we show that there cannot be an initial singularity and that the Universe expands. Invoking the correspondence principle, we obtain the scale factor of the Universe and demonstrate that the causality problem of the standard model is solved.

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