Effect of doping and oxygen vacancies on the octahedral tilt transitions in the BaCeO3 perovskite

We present a systematic study of the effect of Y doping and hydration level on the structural transformations of BaCeO3 based on anelastic spectroscopy experiments. The temperature of the intermediate transformation between rhombohedral and orthorhombic Imma phases rises with increasing the molar fraction x of Y roughly as (500 K)x in the hydrated state, and is depressed of more than twice that amount after complete dehydration. This is explained in terms of the effect of doping on the average (Ce/Y)-O and Ba-O bond lengths, and of lattice relaxation from O vacancies. The different behavior of the transition to the lower temperature Pnma orthorhombic phase is tentatively explained in terms of progressive flattening of the effective shape of the OH ion and ordering of the O vacancies during cooling.Comment: 8 pages, 5 figure

Oral cavity reconstruction with the masseter flap.

The purpose of this report is to highlight how an unusual, outdated, unpopular and overlooked reconstructive method such as the masseter flap can be a reliable, straightforward and effective solution for oral reconstruction in selected cases. We report the transposition of the masseter crossover flap in two previously pre-treated patients presenting a second primary oral squamous cell carcinoma; excellent functional results with satisfactory cosmetic appearance were obtained in both cases. In the literature, only 60 cases of oral cavity and oropharyngeal reconstructions using the masseter flap have been reported. The possible clinical utility of this flap, even in modern head and neck reconstructive surgery, is presented and discussed. We believe that the masseter flap should enter in the armamentarium of every head and neck surgeon and be kept in mind as a possible solution since it provides an elegant and extremely simple procedure in suboptimal cases for microvascular reconstruction

Hydrogen tunneling in the perovskite ionic conductor BaCe(1-x)Y(x)O(3-d)

We present low-temperature anelastic and dielectric spectroscopy measurements on the perovskite ionic conductor BaCe(1-x)Y(x)O(3-x/2) in the protonated, deuterated and outgassed states. Three main relaxation processes are ascribed to proton migration, reorientation about an Y dopant and tunneling around a same O atom. An additional relaxation maximum appears only in the dielectric spectrum around 60 K, and does not involve H motion, but may be of electronic origin, e.g. small polaron hopping. The peak at the lowest temperature, assigned to H tunneling, has been fitted with a relaxation rate presenting crossovers from one-phonon transitions, nearly independent of temperature, to two-phonon processes, varying as T^7, to Arrhenius-like. Substituting H with D lowers the overall rate by 8 times. The corresponding peak in the dielectric loss has an intensity nearly 40 times smaller than expected from the classical reorientation of the electric dipole associated with the OH complex. This fact is discussed in terms of coherent tunneling states of H in a cubic and orthorhombically distorted lattice, possibly indicating that only H in the symmetric regions of twin boundaries exhibit tunneling, and in terms of reduction of the effective dipole due to lattice polarization.Comment: submitted to Phys. Rev.

Role of contrast-enhanced ultrasound (CEUS) in paediatric practice: an EFSUMB position statement

The use of contrast-enhanced ultrasound (CEUS) in adults is well established in many different areas, with a number of current applications deemed off-label, but the use supported by clinical experience and evidence. Paediatric CEUS is also an off-label application until recently with approval specifically for assessment of focal liver lesions. Nevertheless there is mounting evidence of the usefulness of CEUS in children in many areas, primarily as an imaging technique that reduces exposure to radiation, iodinated contrast medium and the patient-friendly circumstances of ultrasonography. This position statement of the European Federation of Societies in Ultrasound and Medicine (EFSUMB) assesses the current status of CEUS applications in children and makes suggestions for further development of this technique

Designing a High-Power Sodium-Ion Battery by in Situ Metal Plating

Sodium ion batteries represent a drop-in technology and a more sustainable alternative to Li-ion, but higher energies and power levels are required to meet the demands required by a greener electrification. Here, the design of an anode-free sodium-ion battery is presented and its performances discussed in terms of reduced mass and high power capabilities. The cell consists of an Iron Hexacyanoferrate - reduced Graphene Oxide composite as cathode material whose synthesis is tailored to achieve minimal structural defects (3%) and water content. Its high-potential redox couple FeLS(C) is stabilized at high rates, granting the full cell with high discharge voltage and power. As negative substrate, a carbon coated aluminum foil was adopted for in situ plating/stripping of Na metal, showing very small voltage hysteresis up to an applied current of 2 mA/cm2. Overall, this simplified full cell architecture can deliver up to 340 Wh/kg and 500 W/kg at nominal 1C retaining 80% in 250 cycles, with the possibility of delivering 9000 W/kg at 20C. Bridging the boundaries between batteries and supercapacitors, this research aims to expand the range of possible applications for Na-ion technology

Partial pharyngolaryngectomy with infrahyoid flap: Our experience

Aim: We evaluated a cohort of advanced hypopharyngeal squamous cell carcinoma, treated with conservative surgery, reconstruction with infrahyoid flap and radio-chemotherapy. Methods: We used partial pharyngo-laryngectomy and radio-chemotherapy to treat fifty-seven patients with stage III–IV hypopharyngeal SCC from November 1994 to December 2011. Clinical examination and speech therapy evaluation were used for estimation of laryngeal function. Results: All patients received a partial pharyngo-laryngectomy. All patients underwent neck dissection; 56 patients received bilateral neck dissection. Reconstruction was achieved by infra-hyoid flap. Five-year overall and disease-specific survival rates were 54.4% and 61.4%, respectively. Successful laryngeal function preservation with complete five-year remission was achieved in 44% of the patients. Conclusion: Selected even if advanced carcinomas of the hypopharynx maybe treated with partial pharyngo-laryngectomy with reconstruction with pedicled flap. Both oncological and functional results showed a good outcome

Reconstruction microchirurgicale et prise en charge globale des patients porteurs de cancer ORL : l’importance d’une approche qualité et d’un circuit protocolisé [Microsurgical reconstruction and full management of patients with head and neck cancer: Importance of a quality approach and a circuit protocolisation]

Main of study: Management and surgical reconstruction of head and neck cancers remain a challenge. From the first consultation to surgery and radiotherapy, it is necessary to save time to ensure optimum treatment and better survival rates. Objectif: To establish a kind of quality approach to the management of patients with head and neck cancers. 54 patients who had microsurgical reconstruction after head and neck cancer were included in this study between 1997 and 2006. Results : Multiple data were considered: body mass index (BMI), ASA stage, age, existence of a pre-or postoperative radiotherapy, the surgeon's experience and the number of veins drainage. The success rate is superior when more than one draining vein is sutured to the flap for patients with a BMI > 20. Radiotherapy does not seem to affect the survival of the flap. Conclusion: According to current literature, the survival rate of these patients is better when the overall time care is less than 100 days. That period is possible with a perfect organization of the medical and paramedical team. Therefore, we propose to include these patients in a circuit protocolisation care, which saves time, to better inform patients and improve survival rates. Buts: la prise en charge et la reconstruction chirurgicale des cancers ORL restent un challenge. De la première consultation à la chirurgie et la radiothérapie, il est nécessaire de gagner du temps afin d’assurer une traitement optimum et un meilleur taux de survie. Objectif : établir une sorte d’approche qualité de la prise en charge des patients porteurs de cancers ORL. 54 patients qui ont bénéficié d’une reconstruction microchirurgicale suite à un cancer ORL ont été inclus dans cette étude entre 1997 et 2006. Résultats : plusieurs données ont été étudiées : l’index de masse corporelle (IMC), le stade ASA, l’âge, l’existence d’une radiothérapie pré ou post opératoire, l’expérience du chirurgien ainsi que le nombre de veines de drainage. Le taux de succès se révèle supérieur lorsque plus d’une veine de drainage est suturée au lambeau, pour des patients ayant un IMC > 20. La radiothérapie ne semble pas avoir de répercussion sur la survie du lambeau. Conclusion : conformément à la littérature actuelle, le taux de survie de ces patients est meilleur lorsque le temps global de prise en charge est inférieur à 100 jours. Ce délai court n’est possible qu’avec une parfaite organisation de l’équipe médicale et paramédicale. De ce fait, nous proposons d’inclure ces patients dans un circuit de prise en charge protocolisé, ce qui permet de gagner du temps, de mieux informer le patient et d’améliorer le taux de survie

UV photodecomposition of zinc acetate for the growth of ZnO nanowires

The thermal annealing of zinc precursors to form suitable seed layers for the growth of ZnO nanowires is common. However, the process is relatively long and involves high temperatures which limit substrate choice. In this study the use of a low temperature, ultra-violet (UV) exposure is demonstrated for photodecomposition of zinc acetate precursors to form suitable seed layers. Comparisons are made between ZnO nanowire growth performed on seed layers produced through thermal annealing and exposure to UV. The dependence of growth density and nanowire diameter on UV exposure time is investigated. Growth quality is confirmed with energy dispersive x-ray (EDX) and x-ray diffraction analyses. The chemical composition of the exposed layers is investigated with EDX and x-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) is utilized to investigate morphological changes with respect to UV exposure. The diameter and density of the resultant growth was found to be strongly dependent on the UV exposure time. UV exposure times of only 25–30 s led to maximum density of growth and minimum diameter, significantly faster than thermal annealing. EDX, XPS and AFM analyses of the seed layers confirmed decomposition of the zinc precursor and morphological changes which influenced the growth