UV-laser photochemistry of the azoalkane 1-phenyl-2,3-diazabicyclo[2.2.2]oct-2-ene: detection and lifetime determination of the triplet diradical 1-phenyl-1,4-cyclohexadiyl by time-resolved UV-spectroscopy (flash photolysis) and by trapping with molecular oxygen

1987 ◽  
Vol 109 (24) ◽  
pp. 7572-7573 ◽  
Author(s):  
Waldemar Adam ◽  
Sven Grabowski ◽  
R. Marshall Wilson ◽  
Klaus Hannemann ◽  
Jakob Wirz
Keyword(s):  
Molecular Oxygen ◽  
Flash Photolysis ◽  
Uv Spectroscopy ◽  
Uv Laser ◽  
Time Resolved

Environmental photodegradation of pyrimidine fungicides — Kinetics of the visible-light-promoted interactions between riboflavin and 2-amino-4-hydroxy-6-methylpyrimidine

2002 ◽  
Vol 80 (1) ◽  
pp. 62-67 ◽  
Author(s):  
E Haggi ◽  
S Bertolotti ◽  
S Miskoski ◽  
F Amat-Guerri ◽  
N A García
Keyword(s):  
Visible Light ◽  
Molecular Oxygen ◽  
Superoxide Anion ◽  
Flash Photolysis ◽  
Triplet States ◽  
Excited Singlet ◽  
Singlet Molecular Oxygen ◽  
Time Resolved ◽  
Singlet And Triplet States ◽  
Kinetics Of

To clarify the evolution of pyrimidine fungicides under natural aquatic environmental conditions, the visible-light-promoted degradation of the model fungicide 2-amino-4-hydroxy-6-methylpyrimidine (AHMPD) has been studied in air-equilibrated pH 6 aqueous solutions in the presence of riboflavin (Rf), employing time-resolved and stationary kinetic–spectroscopic methods. AHMPD, a compound practically inert towards the attack of singlet molecular oxygen (O2(1Δg)), quenches excited singlet and triplet states of Rf with rate constants of 2.7 × 109 M–1 s–1 and 2.7 × 107 M–1 s–1, respectively. In the presence of AHMPD, the photodecomposition of Rf, which occurs from the excited triplet state of the pigment, depends on the concentration of the fungicide: at [Formula: see text]40–50 mM a limited photochemistry occurs due to the quenching of excited singlet Rf, while at ca. 5–10 mM triplet Rf is largely photogenerated and subsequently quenched either by oxygen, giving rise to O2(1Δg), or by AHMPD, yielding semireduced Rf through an electron transfer process. Flash photolysis experiments and indirect auxiliary tests confirm the presence of superoxide anion generated by the reaction of Rf anion radical with the dissolved oxygen. The neat result of this intricate scheme of competitive reactions is the photodegradation of both AHMPD and Rf, mainly through a superoxide anion-mediated oxidation, although some contribution of O2(1Δg)-mediated photooxidations cannot be disregarded.Key words: photooxidation, pyrimidine derivatives, riboflavin, singlet molecular oxygen, superoxide anion.

Urinary gonadotropin measurements by enhanced luminometric assays (LIA) for the evaluation of pubertal development

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
And Demir ◽  
Adem Aydın ◽  
Atilla Büyükgebiz ◽  
Ulf-Håkan Stenman ◽  
Matti Hero
Keyword(s):  
Healthy Subjects ◽  
Reliable Method ◽  
Pubertal Development ◽  
High Sensitivity ◽  
Tanner Stage ◽  
Time Resolved ◽  
Stage 1 ◽  
Sensitive Detection Technique ◽  
Serum And Urine

Abstract Objectives Determination of LH in urine has proved to be a reliable method for evaluation of pubertal development. The human LH assay based on time-resolved immunofluorometric (IFMA) technology (AutoDELFIA, PerkinElmer, Wallac) has been found to be suitable for this purpose thanks to its high sensitivity but other assays have not been evaluated. We have analyzed our data obtained by another potentially sensitive detection technique, enhanced luminometric assay (LIA) with the objective of finding a viable alternative to IFMA since these may not be available in the future. Methods LIA was used to measure LH and FSH in serum and urine samples from 100 healthy subjects of each Tanner stage and both genders, whose pubertal development has been determined. Results Urinary gonodotropin concentrations measured by LIA correlated well with Tanner stage [(r=0.93 for girls, r=0.81 for boys; p<0.01 for LH) and (r=0.81 for girls, r=0.73 for boys; p<0.01 for FSH)]. LIA determinations revealed the increase in U-LH concentrations during the transition from Tanner stage 1–2 in both girls and boys (p<0.001), whereas U-FSH and S-LH were able to detect the increase from Tanner stage 1–2 only in boys or girls, respectively (both p<0.001). Conclusions Measurement of urinary gonadotropin concentrations by LIA may be useful for the evaluation of overall pubertal development and also in the detection of transition from prepuberty to puberty.

scholarly journals Time-resolved ARPES Determination of a Quasi-Particle Band Gap and Hot Electron Dynamics in Monolayer MoS2

Nano Letters ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 7363-7370
Author(s):  
Woojoo Lee ◽  
Yi Lin ◽  
Li-Syuan Lu ◽  
Wei-Chen Chueh ◽  
Mengke Liu ◽  
...  
Keyword(s):  
Band Gap ◽  
Hot Electron ◽  
Electron Dynamics ◽  
Monolayer Mos2 ◽  
Quasi Particle ◽  
Time Resolved

scholarly journals KD determination from time-resolved experiments on live cells with LigandTracer and reconciliation with end-point flow cytometry measurements

2021 ◽  
Author(s):  
Diana Spiegelberg ◽  
Jonas Stenberg ◽  
Pascale Richalet ◽  
Marc Vanhove
Keyword(s):  
Flow Cytometry ◽  
Live Cells ◽  
Time Resolved ◽  
Surface Receptors ◽  
Full Characterization ◽  
End Point ◽  
Titration Curves ◽  
Kinetics Of

AbstractDesign of next-generation therapeutics comes with new challenges and emulates technology and methods to meet them. Characterizing the binding of either natural ligands or therapeutic proteins to cell-surface receptors, for which relevant recombinant versions may not exist, represents one of these challenges. Here we report the characterization of the interaction of five different antibody therapeutics (Trastuzumab, Rituximab, Panitumumab, Pertuzumab, and Cetuximab) with their cognate target receptors using LigandTracer. The method offers the advantage of being performed on live cells, alleviating the need for a recombinant source of the receptor. Furthermore, time-resolved measurements, in addition to allowing the determination of the affinity of the studied drug to its target, give access to the binding kinetics thereby providing a full characterization of the system. In this study, we also compared time-resolved LigandTracer data with end-point KD determination from flow cytometry experiments and hypothesize that discrepancies between these two approaches, when they exist, generally come from flow cytometry titration curves being acquired prior to full equilibration of the system. Our data, however, show that knowledge of the kinetics of the interaction allows to reconcile the data obtained by flow cytometry and LigandTracer and demonstrate the complementarity of these two methods.

Freezing in Silicon at Large Undercooling

1989 ◽  
Vol 157 ◽  
Author(s):  
P.A. Stolk ◽  
A. Polman ◽  
W.C. Sinke
Keyword(s):  
Interface Temperature ◽  
Limiting Factor ◽  
Time Resolved ◽  
Large Undercooling ◽  
Explosive Crystallization ◽  
Crystallization Speed ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Rate Limiting

ABSTRACTPulsed laser irradiation is used to induce epitaxial explosive crystallization of amorphous silicon layers buried in a (100) oriented crystalline matrix. This process is mediated by a self-propagating liquid layer. Time-resolved determination of the crystallization speed combined with numerical calculation of the interface temperature shows that freezing in silicon saturates at 16 m/s for large undercooling (> 130 K). A comparison between data and different models for melting and freezing indicates that the crystallization behavior at large undercooling can be described correctly if the rate-limiting factor is assumed to be diffusion in liquid Si at the solid/liquid interface.

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