Blinking dynamics

Ito, S., Toitani, N., Pan, L., Tamai, N. and Miyasaka, H. (2007) Fluorescence correlation spectroscopic study on water-soluble cadmium telluride nanocrystals fast blinking dynamics in the ps-ms region. J. Phys. Condens. Matter, 19, 486208. 

Here we present results of video-microscopy observations of the emission from silver nanoparticles (NPs) adsorbed on a glass substrate upon continuous-wave laser excitation and report what we believe to be the first experimental observation of memory in blinking dynamics of metal nanoparticles. 

A further insight into the mechanisms governing the blinking dynamics can be gained by studying the on- and oflF-times as a function of the on-off (off-on) switching event number n. Interestingly, both toJn) and foj(n) do not behave completely randomly, but show correlated patterns (Fig. 2a,b). Additionally, anticorrelation between to n) and tgj n) can be observed. 

Lin H, Tabaei SR, Thomsson D, Mirzov O, Larsson P-O, Scheblykin IG (2008) Fluorescence blinking, exciton dynamics, and energy transfer domains in single conjugated polymer chains. J Am Chem Soc 130 7042-7051... 

Confocal fluorescence microscopy images in a polymer film of a second-generation polyphenylene dendrimer with eight perylenemonoimide functions at the periphery 49 and a model compound bearing one single perylenemonoimide 50 reveal that the dendrimer exhibits a three- to fourfold intensity and an obvious blinking in comparison to the model compound which shows only uniform spots with less dynamics (Scheme 19) [69]. 

The tear film leaves the surface of the globe and eyelids, enters the upper and the lower punctum at the medial aspect of the lid margin, and enters the lacrimal sac before drainage to the nasolacrimal duct and the nasal cavity. However, much of the tear film is eliminated by direct evaporation or by absorption at the level of the lacrimal sac. The lacrimal outflow system is based on an active and dynamic pumping mechanism. Blinking cycle leads to changes in the drainage canaliculi that activate a pump mechanism that drains tears even with the head held in an inverted position. When the palpebral blink mechanism is impaired, tears accumulation leads to spillover to the skin of the lids and cheek [4],... 

Semiconducting nanocrystals, usually CdSe-ZnS crystals a few nanometers in diameter, called quantum dots, can be useful for in vivo imaging of biochemical dynamics but still suffer from three limitations.51 The most severe problem is that quantum dots blink at probability distributions that lead to loss of continuity in keeping track of individual molecules, limiting the ability to measure the dynamics and mechanisms of biophysical chemistry in vivo and ex vivo. Some significant fraction of fabricated quantum dots appear to be totally dark, reducing... 

Under normal conditions the various components of the tear film are continually produced in sufficient quantity, not only to cover the ocular surfece but also to supply a reservoir of tears that is stored at the margin of the upper and lower eyelids. The movement of the upper eyelid distributes this reservoir, called the tear river or tear meniscus, during blinking or voluntary lid closure. As the tear film thins and breaks up, the blink reflex is stimulated. The down-phase of each blink compresses the superficial lipid layer, and the up-phase redistributes the lipid layer, which remains in a fairly dynamic state well after the completion of the blink. Each time the eyelid reopens, a new tear film layer is spread across the ocular surfece. The blink itself may also augment meibomian gland expression. 

PL quenching rate scales inversely with the QD diameter and can be understood in terms of a tunnelling of the electron (of the excited electron-hole pair) followed by a (self-) localization of the electron or formation of trap states. These observations are in line with the microscopic understanding of blinking phenomena of single QD. Our findings show also that single functionalized molecules can be considered as one of the probes for the complex interface physics and dynamics of colloidal semiconductor QD. 

Figure 2.15 Instantaneous view of the chaotic saddle (a), stable (b) and unstable (c) manifolds for the advection dynamics in the blinking vortex-sink flow. The vortex-sinks are at (x,y) = ( — 1,0) and (0,1) (from Karolyi and Tel (1997)).

Figure 7.11 Total concentration (C ) in the stationary state vs Da for the FitzHugh-Nagumo dynamics in the open blinking vortex-sink flow showing two discontinuous transitions.

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