Excited-Band Coherent Delocalization for Improved Optical Lattice Clock Performance.

We implement coherent delocalization as a tool for improving the two primary metrics of atomic clock performance: systematic uncertainty and instability. By decreasing atomic density with coherent delocalization, we suppress cold-collision shifts and two-body losses. Atom loss attributed to Landau-Zener tunneling in the ground lattice band would compromise coherent delocalization at low trap depths for our ^{171}Yb atoms; hence, we implement for the first time delocalization in excited lattice bands. Doing so increases the spatial distribution of atoms trapped in the vertically oriented optical lattice by ∼7 times. At the same time, we observe a reduction of the cold-collision shift by 6.5(8) times, while also making inelastic two-body loss negligible. With these advantages, we measure the trap-light-induced quenching rate and natural lifetime of the ^{3}P_{0} excited state as 5.7(7)×10^{-4} E_{r}^{-1} s^{-1} and 19(2) s, respectively.

Role of perforator flaps in leg and foot reconstruction.

INTRODUCTION: Lower extremity wounds have always been a challenge for the reconstructive surgeons. Free perforator flaps are considered to be the best option for this problem but require the complexity of microsurgery. So, pedicled perforator flaps have emerged as an alternative option. PATIENTS AND METHODS: Prospective study was conducted in 40 patients with traumatic soft tissue defects in the leg and foot. The free flaps included the anterolateral thigh flap (ALT) and medial sural artery perforator flap (MSAP). In pedicled perforator flaps group, 10 cases were designed as propeller flaps while the other 10 flaps were designed as perforator plus flaps. RESULTS: Free flaps were mainly used for large-sized defects; we had one case of partial flap loss and one case of complete flap necrosis.  MSAP flap was the first option for coverage of large-sized defects on foot and ankle as it is a thin and pliable flap, while ALT flap was used for coverage of larger defects on the leg. Pedicled perforator flaps were used mainly for small to medium-sized defects, especially in the lower third of the leg; we had three cases of flap loss in propeller flap design while we had no cases of flap loss in perforator plus flap. CONCLUSION: Perforator flaps have become a reasonable solution for soft tissue defects of the lower extremity. Careful assessment of the dimensions, location, patient comorbidities, availability of surrounding soft tissue and presence of adequate perforators are mandatory for proper perforator flap selection.

Subrecoil Clock-Transition Laser Cooling Enabling Shallow Optical Lattice Clocks.

Laser cooling is a key ingredient for quantum control of atomic systems in a variety of settings. In divalent atoms, two-stage Doppler cooling is typically used to bring atoms to the µK regime. Here, we implement a pulsed radial cooling scheme using the ultranarrow ^{1}S_{0}-^{3}P_{0} clock transition in ytterbium to realize subrecoil temperatures, down to tens of nK. Together with sideband cooling along the one-dimensional lattice axis, we efficiently prepare atoms in shallow lattices at an energy of 6 lattice recoils. Under these conditions key limits on lattice clock accuracy and instability are reduced, opening the door to dramatic improvements. Furthermore, tunneling shifts in the shallow lattice do not compromise clock accuracy at the 10^{-19} level.

New concept in urethral advancement for anterior hypospadias.

OBJECTIVE: We report on our experience with urethral mobilization and advancement as a treatment for anterior hypospadias. PATIENTS AND METHODS: From January 2004 to March 2007, 55 out of 160 children with anterior hypospadias were managed by urethral mobilization and advancement; 46 had a mean follow-up period of 25 months (range 6-38) and are the subjects of this report. Their ages ranged from 2.5 to 12 years with mean age 4.5 years. The dissection began proximally in the avascular plane above the tunica albuginea covering each corpus cavernosum medially until reaching beneath the corpus spongiosum up to the hypospadiac meatus. Tension-free urethral anastomosis was achieved. The ventral glans was incised deeply at the interballanitic groove. The two glans wings and ventral glanular mucosal flaps were mobilized laterally. Interrupted sutures were placed through the tunica albuginea of corpus spongiosum to the corpora cavernosa. The mobilized urethra was wrapped by dartos fascia. The urethral stent was removed 24h postoperatively. RESULTS: Three-fold urethral mobilization was sufficient to achieve tension-free urethral anastomosis. A slit-like orthotopic meatus, with conically shaped glans and straight penis, was achieved in all but one subcoronal case with mid-glans meatal retraction during our early experience. Postoperative urethral fistula was not recorded in any patient. Satisfactory urinary stream for parents and child was reported in 42/46. Peak flow rate was within normal range (upper 50% percentile) in all. CONCLUSION: Urethral mobilization should begin proximally. Three-fold penile urethral mobilization, deep interballanitic incision and wide dissection of the glans can provide a slit-like orthotopic meatus with conical glans and straight penis in cases of anterior hypospadias without hypoplastic distal urethra and persistent ventral curvature after penile skin degloving, regardless of the presence of unhealthy, narrow urethral plate, shallow glanular groove, and flat or small glans.