Digital Radiography for Determination of Primary Tooth Length: In Vivo

Background. Methods for determining the root canal length of the primary tooth should yield accurate and reproducible results. In vitro studies show some limitations, which do not allow their findings to be directly transferred to a clinical situation. Aim. To compare the accuracy of radiographic tooth length obtained from in vivo digital radiograph with that obtained from ex vivo digital radiograph. Method. Direct digital radiographs of 20 upper primary incisors were performed in teeth (2/3 radicular resorption) that were radiographed by an intraoral sensor, according to the long-cone technique. Teeth were extracted, measured, and mounted in a resin block, and then radiographic template was used to standardise the sensor-target distance (30 cm). The apparent tooth length (APTL) was obtained from the computer screen by means of an electronic ruler accompanying the digital radiography software (CDR 2.0), whereas the actual tooth length (ACTL) was obtained by means of a digital calliper following extraction. Data were compared to the ACTL by variance analysis and Pearson’s correlation test. Results. The values for APTL obtained from in vivo radiography were slightly underestimated, whereas those values obtained from ex vivo were slightly overestimated. No significance was observed (P≤0.48) between APTL and ACTL. Conclusion. The length of primary teeth estimated by in vivo and ex vivo comparisons using digital radiography was found to be similar to the actual tooth length

Beyond Chandra (towards the X-ray Surveyor mission): possible solutions for the implementation of very high angular resolution X-ray telescopes in the new millennium based on fused silica segments

An important challenge for the X-ray astronomy of the new millennium is represented by the implementation of an X-ray telescope able to maintain the exquisite angular resolution of Chandra (with a sub-arcsec HEW, on-axis) but, at the same time, being characterized by a much larger throughput and grasp. A mission with similar characteristics is represented by the X-ray Surveyor Mission. The project has been recently proposed in USA and is being currently studied by NASA. It will host an X-ray telescope with an effective area of more than 2 square meters at 1 keV (i.e. 30 times greater than Chandra) and a 15-arcminutes field-of-view, with 1-arcsecond or better half-power diameter (versus the 4 arcmin diameter of Chandra). While the scientific reasons for implementing a similar mission are clear, being related to compelling problems like e.g. the formation and subsequent growth of black hole seeds at very high redshift or the identification of the first galaxy groups and proto-clusters, the realization of a grazing-angle optics system able to fulfil these specs remain highly challenging. Different technologies are being envisaged, like e.g. the use of adjustable segmented mirrors (with use of piezoelectric or magneto-restrictive film actuators on the back surface) or the direct polishing of a variety of thin substrates or the use of innovative correction methods like e.g. differential deposition, ionfiguring or the correction of the profile via controlled stress films. In this paper we present a possible approach based on the direct polishing (with final ion figuring correction of the profile) of thin SiO2 segmented substrates (typically 2 mm thick), discussing different aspects of the technology under implementation and presenting some preliminary results

Isolated Hepatocyte Transplantation for Crigler-Najjar Syndrome Type 1:

Crigler-Najjar syndrome type 1 (CN1) is an inherited disorder characterized by the absence of hepatic uridine diphosphoglucuronate glucuronosyltransferase (UDPGT), the enzyme responsible for the conjugation and excretion of bilirubin. We performed allogenic hepatocyte transplantation (AHT) in a child with CN1, aiming to improve bilirubin glucuronidation in this condition. A 9-year-old boy with CN1 was prepared with plasmapheresis and immunosuppression with prednisolone and tacrolimus. When a graft was made available, 7.5 × 10 9 hepatocytes were isolated and infused into the portal vein percutaneously. After 2 weeks phenobarbitone was added to promote the enzymatic activity of UDPGT of the transplanted hepatocytes. Nocturnal phototherapy was continued throughout the studied period. Total bilirubin was considered a reliable marker of allogenic cell function. There was no significant variation of vital signs nor complications during the infusion. Mean ± SD bilirubin level was 530 ± 38 µmol/L before and 359 ± 46 µmol/L after AHT (t-test, p < 0.001). However, the introduction of phenobarbitone was followed by a drop of tacrolimus level with increase of alanine aminotransferase (ALT) and increase of bilirubin. After standard treatment of cellular rejection bilirubin fell again but from then on it was maintained at a greater level. After discharge the patient experienced a further increase of bilirubin that returned to predischarge levels after readmission to the hospital. This was interpreted as poor compliance with phototherapy. Only partial correction of clinical jaundice and the poor tolerability to nocturnal phototherapy led the parents to refuse further hepatocyte infusions and request an orthotopic liver transplant. After 24 months the child is well, with good liver function on tacrolimus and prednisolone-based immunosuppression. Isolated AHT, though effective and safe, is not sufficient to correct CN1. Maintenance of adequate immunosuppression and family compliance are the main factors hampering the success of this procedure

Green synthesis of carbon nanotubes impregnated with metallic nanoparticles: Characterization and application in glyphosate adsorption

In the present work, multi-walled carbon nanotubes (MWCNTs) were used as support material for the impregnation of metallic nanoparticles (MNPs) produced by green synthesis. The influences of the plant extracts (pomegranate (Punica Granatum), Eucalyptus, and pecan (Carya illinoinensis, leaves), metal species (copper and iron), metallic concentrations, and type of functionalization (OH and COOH) on the characteristics of the obtained materials were studied. The precursor and impregnated MWCNTs were characterized through X-ray diffraction, Fourier transformed infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, point of charge, N2 adsorption/desorption isotherms and, X-ray photoelectron spectroscopy. All the synthesized materials were tested as adsorbents to remove glyphosate (GLY) in an aqueous medium. The MWCNTs were resistant to withstand the synthesis process, preserving its structure and morphological characteristics. The copper and iron on the surface of MWCNTS confirm the successful synthesis and impregnation of the MNPs. The MWCNTs impregnated with high metallic concentrations showed favorable adsorption of GLY. The adsorption capacity and percentage of removal were 21.17 mg g−1 and 84.08%, respectively, for the MWCNTs impregnated with iron MNPs using the pecan leaves as a reducing agent. The results indicated that an advanced adsorbent for GLY could be obtained by green synthesis, using MWCNTs as precursors and pecan leaves as a reducing agent

Direct hot slumping of thin glass foils for future generation x-ray telescopes: current state of the art and future outlooks

To significantly improve the performances of the current X-ray observatories, the next generation of X-ray telescopes has to be characterized by a large effective area (Aeff { 2 m2 at 1 keV) and angular resolution better than 5 arcsec. The large dimension implied by these requirements forces the use of a modular approach, splitting the optics into segments. Moreover, lightweight materials, such as glass, have to be selected for the segmented optics in order to maintain a manageable weight for the optics. Since 2009 we are developing a direct hot slumping technique assisted by pressure, in which the glass optical surface is in contact with the mould and a pressure is applied in order to force the glass to copy the mould shape. A cold slumping step is used then to integrate the mirror segments into the final Wolter-I configuration. We present the state of the art of our hot slumping technology, comparing the results obtained with different glass types and mould materials. We also provide an overview of the possibilities of this technology also in view of future developments

Imaging of programmed cell death in arrhythmogenic right ventricle cardiomyopathy/dysplasia

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a myocardial disease that predominantly affects the right ventricle (RV). Its hallmark feature is fibrofatty replacement of the RV myocardium. Apoptosis in ARVC/D has been proposed as an important process that mediates the slow, ongoing loss of heart muscle cells which is followed by ventricular dysfunction. We aimed to establish whether cardiac apoptosis can be assessed noninvasively in patients with ARVC/D. Six patients fulfilling the ARVC/D criteria were studied. Regional myocardial apoptosis was assessed with (99m)Tc-annexin V scintigraphy. Overall, the RV wall showed a higher (99m)Tc-annexin V signal than the left ventricular wall (p = 0.049) and the interventricular septum (p = 0.026). However, significantly increased uptake of (99m)Tc-annexin V in the RV was present in only three of the six ARVC/D patients (p = 0.001, compared to (99m)Tc-annexin V uptake in the RV wall of the other three patients). Our results are suggestive of a chamber-specific apoptotic process. Although the role of apoptosis in ARVC/D is unsolved, the ability to assess apoptosis noninvasively may aid in the diagnostic course. In addition, the ability to detect apoptosis in vivo with (99m)Tc-annexin V scintigraphy might allow individual monitoring of disease progression and response to diverse treatments aimed at counteracting ARVC/D progressio

CeO2 nanoparticles synthesized by a microwave-assisted hydrothermal method: evolution from nanospheres to nanorods

Ceria (CeO2) plays a vital role in emerging technologies for environmental and energy-related applications. The catalytic efficiency of ceria nanoparticles depends on its morphology. In this study, CeO2 nanoparticles were synthesized by a microwave-assisted hydrothermal method under different synthesis temperatures. The samples were characterized by X-ray diffraction, transmission electron microscopy, Raman scattering spectroscopy, electron paramagnetic resonance spectroscopy and by the Brunauer-Emmett-Teller method. The X-ray diffraction and Raman scattering results indicated that all the synthesized samples had a pure cubic CeO2 structure. Rietveld analysis and Raman scattering also revealed the presence of structural defects due to an associated reduction in the valence of the Ce4+ ions to Ce3+ ions caused by an increasing molar fraction of oxygen vacancies. The morphology of the samples was controlled by varying the synthesis temperature. The TEM images show that samples synthesized at 80 degrees C consisted of spherical particles of about 5 nm, while those synthesized at 120 degrees C presented a mix of spherical and rod-like nanoparticles and the sample synthesized at 160 degrees C consisted of nanorods with 10 nm average diameter and 70 nm length. The microwave-assisted method proved to be highly efficient for the synthesis of CeO2 nanoparticles with different morphologies.FAPESPCNP

Advancements in ion beam figuring of very thin glass plates

The high-quality surface characteristics, both in terms of figure error and of micro-roughness, required on the mirrors of a high angular resolution x-ray telescope are challenging, but in principle well suited with a deterministic and non-contact process like the ion beam figuring. This process has been recently proven to be compatible even with very thin (thickness around 0.4mm) sheet of glasses (like D263 and Eagle). In the last decade, these types of glass have been investigated as substrates for hot slumping, with residual figure errors of hundreds of nanometres. In this view, the mirrors segments fabrication could be envisaged as a simple two phases process: a first replica step based on hot slumping (direct/indirect) followed by an ion beam figuring which can be considered as a post-fabrication correction method. The first ion beam figuring trials, realized on flat samples, showed that the micro-roughness is not damaged but a deeper analysis is necessary to characterize and eventually control/compensate the glass shape variations. In this paper, we present the advancements in the process definition, both on flat and slumped glass samples