Fluctuation relation for heat exchange in Markovian open quantum systems.

A fluctuation relation for the heat exchange of an open quantum system under a thermalizing Markovian dynamics is derived. We show that the probability that the system absorbs an amount of heat from its bath, at a given time interval, divided by the probability of the reverse process (releasing the same amount of heat to the bath) is given by an exponential factor which depends on the amount of heat and the difference between the temperatures of the system and the bath. Interestingly, this relation is akin to the standard form of the fluctuation relation (for forward-backward dynamics). We also argue that the probability of the violation of the second law of thermodynamics in the form of the Clausius statement (i.e., net heat transfer from a cold system to its hot bath) drops exponentially with both the amount of heat and the temperature differences of the baths.

Impact of loss on the wave dynamics in photonic waveguide lattices.

We analyze the impact of loss in lattices of coupled optical waveguides and find that, in such a case, the hopping between adjacent waveguides is necessarily complex. This results not only in a transition of the light spreading from ballistic to diffusive, but also in a new kind of diffraction that is caused by loss dispersion. We prove our theoretical results with experimental observations.

The S-lift facelift featuring the U-suture and O-suture combined with skin resurfacing.

BACKGROUND: A short-flap S-lift may be helpful for minor jowling or submental laxity in cases of early facial ptosis, revision facelifts, or where skin resurfacing is combined with neck lifting. OBJECTIVE: To develop a safe and effective method to lift the jowl either as a single procedure or combined with other rejuvenation methods. METHODS: After the induction of monitored anesthesia care the skin resurfacing is completed, if necessary, and the submental and lateral S-lift incisions are marked next to the tragus. The submental area is hydrodissected with modified tumescent solution. After a 15-minute waiting period, the submental area is debulked with small spatula cannulas using reduced pressure liposuction. Often the platysma bands are tied together with a running locked suture. The right cheek area is hydrodissected and debulked in a similar fashion. A 3-4 cm flap is elevated. If necessary, further blunt dissection is passed through the anterior mandible ligament and the nasolabial fold. Care is taken to keep the skin trabeculae intact. The SMAS is plicated with a U-shaped and O-shaped purse-string suture. Following this tightening of the subcutaneous tissue, the skin is closed with a double-layer closure. The face is dressed in two layers of tube gauze. Sutures are removed in 7-9 days. RESULTS: This S-lift gives a pleasing rejuvenation of the jowl and submental area. It is also possible to combine this procedure with other procedures such as corset platysmaplasty, skin resurfacing, fat augmentation, a browlift, or blepharoplasty. CONCLUSION: The S-lift provides a safe and effective method for rejuvenation of the early sagging face or for revision facelift.

Calcein fluorophotometry in streptozocin-induced diabetic rats.

Calcein was used in vitreous fluorophotometry (VF) to study the blood-retinal barrier (BRB) in rats with streptozocin-induced diabetes. Calcein was injected intravenously in 18 diabetic rats and sodium fluorescein (NaF) in 12 diabetic rats. VF was performed at 1, 2, 4, 6, 9, and 21 hours following the single injection in these diabetic rats; it was also performed at these times in 24 normal (control) rats. On another day, the same experiment was performed using NaF. There was no significant difference between the two dyes in the diabetic and nondiabetic rats at 1 hour. However, at 4 hours and at later measurement points, there was dye leakage into the vitreous, peaking at 9 hours; the leakage was significantly greater in the diabetic rats. Also, the leakage was significantly greater with calcein than it was with NaF. The data demonstrate that calcein circulates longer and at higher levels than NaF and thus is probably more useful for BRB integrity studies.

Microwave-induced retinal destruction with sparing of sclera and choriocapillaris.

We studied the effect of short-term hyperthermia on sclera, choroid, and retina by delivering microwave radiation (2.45 GHz) for 1 minute to 12 eyes of Dutch belted pigmented rabbits. Four eyes each were treated with 43 degrees C, 45 degrees C, and 47 degrees C and followed for 4 weeks. The 43 degrees C group showed minimal disruption of retinal pigment epithelium and outer retina, with pigment migration; the 45 degrees C and 47 degrees C groups showed complete retinal and RPE damage, pigment migration, and glial proliferation. At the same time, the sclera and choroid in all of the eyes remained essentially unchanged. We conclude that microwave-induced hyperthermia can create retinal scarring without significant damage to sclera and choriocapillaris. The next experimental step will be to refine the microwave delivery system to ensure predictable and reproducible lesions.

Calcein: a new dye for evaluation of the blood-retinal barrier by fluorophotometry.

A vitreous fluorophotometry study was performed on rabbits to compare the characteristics of carboxyfluorescein and calcein with those of sodium fluorescein. Our results demonstrated that carboxyfluorescein and calcein attained midvitreous concentrations similar in magnitude to fluorescein approximately one hour after injection of the dye. As long as three to four hours after injection of the dye, the mean fluorescence levels of calcein in the chorioretina were much higher than those of sodium fluorescein and carboxyfluorescein. These results point out that calcein has potential experimental and clinical use as a probe of the blood-ocular barrier as well as in experimental and clinical angiography of the fundus.