Non-Fermi liquid behavior and scaling of low frequency suppression in optical conductivity spectra of CaRuO3_3

Optical conductivity spectra $\sigma_1(\omega)$ of paramagnetic CaRuO$_3$ are investigated at various temperatures. At T=10 K, it shows a non-Fermi liquid behavior of $\sigma_1(\omega)\sim 1/{\omega}^{\frac 12}$, similar to the case of a ferromagnet SrRuO$_3$. As the temperature ($T$) is increased, on the other hand, $\sigma_1(\omega)$ in the low frequency region is progressively suppressed, deviating from the 1/{\omega}^{\frac 12%}-dependence. Interestingly, the suppression of $\sigma_1(\omega)$ is found to scale with $\omega /T$ at all temperatures. The origin of the $$ scaling behavior coupled with the non-Fermi liquid behavior is discussed.Comment: 4 pages, 3 figure

Pairing symmetry of superconducting graphene

The possibility of intrinsic superconductivity in alkali-coated graphene monolayers has been recently suggested theoretically. Here, we derive the possible pairing symmetries of a carbon honeycomb lattice and discuss their phase diagram. We also evaluate the superconducting local density of states (LDOS) around an isolated impurity. This is directly related to scanning tunneling microscopy experiments, and may evidence the occurrence of unconventional superconductivity in graphene.Comment: Eur. Phys. J. B, to appea

Pseudogap formation of four-layer BaRuO3_3 and its electrodynamic response changes

We investiaged the optical properties of four-layer BaRuO$_{3}$, which shows a fermi-liquid-like behavior at low temperature. Its optical conductivity spectra clearly displayed the formation of a pseudogap and the development of a coherent peak with decreasing temperature. Temperature-dependences of the density $n$ and the scattering rate $1/\tau$ of the coherent component were also derived. As the temperature decreases, both $n$ and $1/\tau$ decrease for four-layer BaRuO$_{3}$. These electrodynamic responses were compared with those of nine-layer BaRuO$_{3}$, which also shows a pseudogap formation but has an insulator-like state at low temperature. It was found that the relative rates of change of both $n$ and $1/\tau$ determine either metallic or insulator-like responses in the ruthenates. The optical properties of the four-layer ruthenate were also compared with those of other pseudogap systems, such as high $T_{c}$ cuprates and heavy electron systems.Comment: 7 figures. submitted to Phys. Rev.

Videochirurgia

La nascita e lo sviluppo della chirurgia laparoscopica e mini-invasiva \ue8 il cambiamento pi\uf9 importante avvenuto in chirurgia pediatrica negli ultimi 30 anni. Questo volume permette una rapida consultazione grazie alla praticit\ue0 della struttura: per ogni patologia sono riportate le indicazioni e le note essenziali di tecnica chirurgica, arricchite da schemi e figure che mostrano le posizioni del paziente, le posizioni dei trocars oltre agli step principali della tecnica chirurgica, ed \ue8 completato da un mini DVD che propone filmati delle principali tecniche descritte nel testo. La trattazione degli argomenti - tra i quali laparoscopia, toracoscopia, retroperitoneoscopia, robotica, realt\ue0 virtuale e problematiche medico legali - \ue8 stata affidata a un team di esperti italiani e internazionali sul campo. Il volume \ue8 dedicato primariamente ai chirurghi pediatri, ma pu\uf2 essere valido aiuto anche per i chirurghi generali, gli urologi e i chirurghi delle altre specialit\ue0 che si trovano ad operare pazienti pediatrici

Congenital seminal vesicle cyst: prenatal diagnosis and postnatal laparoscopic excision with an attempt to preserve fertility

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Transvesicoscopic Cohen ureteric reimplantation for vesicoureteral reflux in children: A single-centre 5-year experience

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Is the appendix graft suitable for routine biliary surgery in children?

BACKGROUND/PURPOSE: The appendix graft (AG) is used widely for urinary tract replacement in children. Biliary tract replacement is less common. The purpose of this retrospective multicentric study was to evaluate the safety of appendix grafting for biliary reconstruction. METHODS: The files of 33 patients treated at 7 European pediatric centers were reviewed. Indications included choledochal cyst (CC) in 5 cases, biliary trauma (BT) in 1, and biliary atresia (BA) in 27. In CC and BT patients, the graft was inserted isoperistaltically between the proximal biliary duct and second duodenum. In all but one of the BA patients, the graft was placed antiperistaltically by patching its cecal end onto the porta hepatis. RESULTS: Postoperatively, all CC and BT patients initially became asymptomatic but developed laboratory evidence of anicteric cholestasis within 1 year. The most common manifestation was increased gamma-glutamyl-transpeptidase level (GGT), whereas histologic findings showed liver damage (mainly fibrosis). Reoperation has been carried out in 4 CC and 1 BT patients within a mean period of 19 months after appendix grafting. The graft procedure was converted to hepaticojejunostomy (HJ) in 4 and to choledocoduodenostomy in 1. Surgical exploration showed kinking in 1 patient and stenosis in 1. In the remaining 3 cases, there was no discernible cause of cholestasis, and appendix histology findings were normal. In all 5 reoperated patients, liver function findings returned to normal within 1 month. Reoperation is scheduled for the remaining CC patient who currently requires ursodesoxycholic medication to maintain normal liver function and presents histologic evidence of "de novo" sclerosing cholangitis. Results of appendix grafting also were poor in the 27 BA patients. Procedure-related perioperative complications occurred in 4 (15%) including 1 early death from graft necrosis. Another early death resulted from intestinal hemorrhage. Jaundice cleared in only 8 (28%). CONCLUSIONS: The findings of this study suggest that the AG is unsuitable for routine biliary repair in children. It should be used only as a salvage technique when conventional HJ repair is contraindicated. Because of the high risk of graft dysfunction, we recommend screening tests to detect biochemical or histologic cholestasis in any patient previously treated with appendix grafting

Retroperitoneoscopic vs open dismembered pyeloplasty for ureteropelvic junction obstruction in children

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