Static flux bias of a flux qubit using persistent current trapping

Qubits based on the magnetic flux degree of freedom require a flux bias, whose stability and precision strongly affect the qubit performance, up to a point of forbidding the qubit operation. Moreover, in the perspective of multiqubit systems, it must be possible to flux-bias each qubit independently, hence avoiding the traditional use of externally generated magnetic fields in favour of on-chip techniques that minimize cross-couplings. The solution discussed in this paper exploits a persistent current, trapped in a superconducting circuit integrated on chip that can be inductively coupled with an individual qubit. The circuit does not make use of resistive elements that can be detrimental for the qubit coherence. The trapping procedure allows to control and change stepwise the amount of stored current; after that, the circuit can be completely disconnected from the external sources. We show in a practical case how this works and how to drive the bias circuit at the required value.Comment: 5 figures submitted to Superconductor Science and Technolog

Superconducting tunable flux qubit with direct readout scheme

We describe a simple and efficient scheme for the readout of a tunable flux qubit, and present preliminary experimental tests for the preparation, manipulation and final readout of the qubit state, performed in incoherent regime at liquid Helium temperature. The tunable flux qubit is realized by a double SQUID with an extra Josephson junction inserted in the large superconducting loop, and the readout is performed by applying a current ramp to the junction and recording the value for which there is a voltage response, depending on the qubit state. This preliminary work indicates the feasibility and efficiency of the scheme.Comment: 10 pages, 5 figure

CORAM (COsmic RAy Mission): An outreach program one century after Pacini and Hess works

Abstract CORAM (COsmic RAy Mission) is an outreach program carried out by INFN and the University of Salento in close collaboration with high schools. Students and their teachers are involved in the design, construction, test and operation of detectors for the measurement of several properties of the cosmic ray flux. The results of a set of measurements, made with a first detector prototype at different altitudes and underground, will be described

Effect of 2% chlorhexidine treated coronal dentin on bond strength of two self-adhesives cements

Despite advances in adhesive dentistry, lasting bonds between indirect restorations and dentin remain a challenge. Objective: Therefore, the aim of this study was to evaluate the effect of chlorhexidine on the bond strength of self-adhesive cements to dentin after storage for 24 h and 90 days. Material and methods: Forty-eight human third molars crowns were included in polyvinyl chloride matrices using acrylic resin and worn to expose a flat dentin area. The specimens were randomly distributed into 8 groups (n = 12) in accordance with the self-adhesive cement (Rely X U200 and Smart Cem 2), the dentin treatment (application or not of 2 % chlorhexidine digluconate solution for 1 min) and the storage period (24 h or 90 d). Two cylinders’ cements (1.4 x 1 mm) were constructed on the dentin surfaces of each sample, stored in distilled water for 24 h or 90 days and submitted to a micro-shear test. Subsequently, a failure analysis was performed to classify the failure into adhesive, cohesive, and mixed. Data were subjected to ANOVA and Tukey (0.05) tests. Results: There was a statistically significant difference between the materials (Rely X U200 > Smart Cem 2 – p < 0.05) regardless of the surface treatment and the storage period. Conclusion: The chlorhexidine application did not affect the immediate or delayed bond strength values, regardless of the self-adhesive cement

Botulinum toxin injection for the treatment of chronic anal fissure: uni- and multivariate analysis of the factors that promote healing

Purpose Anal fissure is caused by a pathological contraction of the internal anal sphincter. Lateral internal sphincterotomy remains the gold standard for the treatment of fissure. Botulinum toxin injections have been proposed to treat this condition without any risk of permanent injury of the internal sphincter. We investigate clinical and pathological variables and the effects of different dosage regimens of botulinum toxin to induce healing in patients with idiopathic anal fissure. Methods This is a retrospective study at a single center. The patients underwent a pre-treatment evaluation that included clinical inspection of the fissure and anorectal manometry. We collected and analyzed demographic data, pathological variables, associated pathological conditions, and treatment variables. Success was defined as healing of the fissure, and improvement of symptoms was defined as asymptomatic persistent fissure. Results The findings of 1003 patients treated with botulinum toxin injections were reported. At 2 months evaluation, complete healing was evident in 780 patients (77.7%). Resting anal tone (77.1 +/- 18.9 mmHg) was significantly lower from baseline (P &lt; 0.0001) and from 1-month value (P = 0.0008). Thirty-nine not healed patients underwent lateral internal sphincterotomy, and 184 were re-treated with 50 UI of botulinum toxin. In these patients, the healing rate was 93.9% (171 patients). Dose and injection site of toxin correlates with healing rate. There were no relapses during an average of about 71 months. Conclusion Our data show that injection of botulinum toxin into the internal anal sphincter is a safe and effective alternative to surgery in patients with chronic anal fissure

Retention force of T-bar clasps for titanium and cobalt-chromium removable partial dentures

The objective of this study was to evaluate the retention force of T-bar clasps made from commercially pure titanium (CP Ti) and cobalt-chromium (Co-Cr) alloy by the insertion/removal test simulating 5 years use. Thirty-six frameworks were cast from CP Ti (n=18) and Co-Cr alloy (n=18) with identical prefabricated patterns on refractory casts from a distal extension mandibular hemi-arch segment. The castings were made on a vacuum-pressure machine, under vacuum and argon atmosphere. Each group was subdivided in three, corresponding to 0.25 mm, 0.50 mm and 0.75 mm undercuts, respectively. No polishing procedures were performed to ensure uniformity. The specimens were subjected to an insertion/removal test and data was analyzed statistically to compare CP Ti and Co-Cr alloy in the same undercut (Student's t-test for independent samples) and each material in different undercuts (one-way ANOVA) (p=0.05). Comparisons between materials revealed significant differences (p=0.017) only for the 0.50-mm undercut. No significant differences (p>0.05) were found when comparing the same material for the undercuts. It may be concluded that for different undercuts, both Co-Cr alloy and CP Ti had no significant differences for T-bar clasps; CP Ti showed the lowest retention force values when compared to Co-Cr alloy in each undercut, but with significant difference only for the 0.50-mm undercut; and both materials maintained the retentive capacity during the simulation test.O objetivo deste estudo foi avaliar a força de retenção de grampos tipo barra T confeccionados em titânio cp e liga de Co-Cr, através do ensaio de simulação de uso de estruturas metálicas por um período de 5 anos. Sobre modelos de revestimento que simulavam uma extremidade livre unilateral, foram fundidas 36 estruturas em titânio cp (n=18) e em Co-Cr (n=18) utilizando padrões pré-fabricados. As fundições foram feitas em máquina de vácuo-pressão sob vácuo e atmosfera inerte de argônio. Cada grupo foi subdividido em três correspondendo às retenções de 0,25 mm, 0,50 mm e 0,75 mm, respectivamente. Para manter a uniformidade dos grampos, não foram realizados procedimentos de polimento. Os corpos-de-prova foram submetidos ao teste de inserção e remoção e os dados foram analisados estatisticamente (p=0,05) para comparar Ti cp e Co-Cr na mesma retenção (teste T de Student para amostras independentes) e cada material nas diferentes retenções (análise de variância a um fator). A comparação entre os materiais revelou diferença significativa apenas para retenção de 0,50 (p=0,017). Não foram encontradas diferenças quando se comparou o mesmo material nas diferentes retenções (p>0,05). Pode-se concluir que para as diferentes retenções, grampos barra T confeccionados em liga de Co-Cr e titânio não apresentaram diferença estatisticamente significante; o titânio apresentou menores valores de retenção quando comparado à liga de Co-Cr em cada uma das retenções, mas diferença estatisticamente significante só foi encontrada para a retenção 0,50-mm; e ambos materiais mantiveram a capacidade retentiva durante o teste de simulação de uso.FAPES

Effect of laser welding on the titanium ceramic tensile bond strength

Titanium reacts strongly with elements, mainly oxygen at high temperature. The high temperature of titanium laser welding modifies the surface, and may interfere on the metal-ceramic tensile bond strength. OBJECTIVE: The influence of laser welding on the titanium-ceramic bonding has not yet been established. The purpose of this in vitro study was to analyze the influence of laser welding applied to commercially pure titanium (CpTi) substructure on the bond strength of commercial ceramic. The influence of airborne particle abrasion (Al2O3) conditions was also studied. MATERIAL AND METHODS: Forty CpTi cylindrical rods (3 mm x 60 mm) were cast and divided into 2 groups: with laser welding (L) and without laser welding (WL). Each group was divided in 4 subgroups, according to the size of the particles used in airborne particle abrasion: A - Al2O3 (250 µm); B - Al2O3 (180 µm); C - Al2O3 (110 µm); D - Al2O3 (50 µm). Ceramic rings were fused around the CpTi rods. Specimens were invested and their tensile strength was measured at fracture with a universal testing machine at a crosshead speed of 2.0 mm/min and 200 kgf load cell. Statistical analysis was carried out with analysis of variance and compared using the independent t test (

Effect of laser welding on the titanium composite tensile bond strength

The aim of this study was to analyze the shear bond strength between commercially pure titanium, with and without laser welding, after airbone-particle abrasion (Al2O3) and 2 indirect composites. Sixty-four specimens were cast and divided into 2 groups with and without laser welding. Each group was divided in 4 subgroups, related to Al2O3 grain size: A - 250 µm; B - 180 µm; C- 110 µm; and D - 50 µm. Composite rings were formed around the rods and light polymerized using UniXS unit. Specimens were invested and their shear bond strength at failure was measured with a universal testing machine at a crosshead speed of 2.0 mm/min. Statistical analysis was carried out with ANOVA and Tukey's test (&#945;=0.05). The highest bond strength means were recorded in 250 µm group without laser welding. The lowest shear bond strength means were recorded in 50 µm group with laser welding. Statistically significant differences (p<0.05) were found between all groups. In conclusion, airborne particle abrasion yielded significantly lower bond strength as the Al2O3 particle size decreased. Shear bond strength decreased in the laser welded specimens.O objetivo deste estudo foi analisar a força de união entre o titânio comercialmente puro com solda e sem solda modificado por partículas de óxido de alumínio (Al2O3) e duas resinas indiretas. Um total de 64 espécimes foram fundidas e divididas em dois grupos sem solda e com solda a laser. Cada grupo foi novamente divididos em 4 subgrupos, de acordo com o tamanho de partículas de óxido de alumínio utilizado: A - Al2O3 (250 µm); B - Al2O3 (180 µm); C- Al2O3 (110 µm); D - Al2O3 (50 µm). Anéis de resina foram polimerizados ao redor das hastes de titânio no equipamento UniXS. Os espécimes foram embutidos em gesso e a força de união foi mensurada com auxílio da máquina de ensaios universais. ANOVA e teste de Tukey (p<0,05) foram utilizados para análise estatística. Os maiores valores de força de união foram registrados no grupo de 250 µm sem solda a laser. Os menores valores foram registrados para o grupo de 50 µm com solda a laser. Alterações estatisticamente significantes foram observadas entre todos os grupos (p<0,05). As forças de união diminuíram significantemente com a diminuição dos tamanhos das partículas de óxido de alumínio. A força de união diminuiu nas amostras que receberam a solda a laser.CNP