In vitro biomineralization by osteoblast-like cells. II. Characterization of cellular culture supernatants

The quantification of total calcium, phosphorus, iron, chromium and nickel in cell culture medium by electrochemical or spectroscopic means may require digestion of samples. Nevertheless, when pH adjustment is performed for values higher than about 6.5, the formation of two phases occurs: a white precipitate and a clear solution. Analysing both phases using microelectrodes, atomic absorption spectrometry (AAS), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, X-ray dispersive (XRD) analysis, scanning electron microscopy (SEM) and energy dispersive spectroscopic (EDS) analysis, it was observed that iron, chromium and nickel are not co-precipitating with the white solid phase. If quantification of calcium, phosphorus and magnesium is intended, a ten-fold dilution at least, must be performed to avoid most of these elements going into the precipitate. This knowledge is crucial if a mineralization study is going to be made.     

Impulse response symmetry error for designing phase equalisers

A new approach to designing analogue phase equalisers based on the symmetry of the impulse response is proposed. Phase equalisation techniques based on group delay or phase delay are usually performed on a limited band, the time response of which may not be adequate for the transmission of pulsed signals. The proposed technique is inherently a wideband process, and therefore more adequate for systems that deal with pulsed signals     

New data on phase equilibria in the Nb-rich region of the Nb-B system

The currently accepted Nb-B phase diagram shows Nb_ss (solid solution), Nb₃B₂, NbB, Nb₅B₆, Nb₃B₄, NbB₂, B, and liquid L as the stable phases in this system. There is a general agreement in the literature about the stability of the NbB, Nb₃B₄, and NbB₂ phases. However, the stability of Nb₃B₂, Nb₅B₆, and Nb₂B₃ phases is arguable. The aim of this work was to reevaluate the phase equilibria in the Nb-rich region (0-50at.% B) of the Nb-B system. The alloys were arc melted from high purity materials and heat-treated at 1700 °C under high vacuum. The samples were characterized by scanning electron microscopy/back-scattered electron image (SEM/BSE) and x-ray diffraction (XRD). The most important findings were: (1) no liquid formation was observed during heat-treatments of the alloys at 1700 °C; (2) the eutectic reaction in the Nb-rich region is L ↔ Nb_ss+ NbB with liquid eutectic composition close to 16 at.%B; and (3) the Nb₃B₂-phase is formed through the peritectoid reaction Nb_ss+ NbB ↔ Nb₃B₂. These results support the phase diagram proposed by Rudy [1969 Rud] for the Nb-rich region, which is not in agreement with the currently accepted Nb-B phase diagram.     

Dual-wavelength (1050 nm +1550 nm) pumped thulium-doped fiber amplifier characterization by optical frequency-domain reflectometry

We present experimental results of distributed gain measurements from a dual-pumped (1050 nm +1550 nm) thulium-doped fiber amplifier using optical frequency-domain reflectometry. We show that significant reductions in total pump power and/or fiber length are realized with the addition of a few milliwatts at 1550 nm. For our experimental conditions, the addition of 5 mW of 1550 nm allows for a reduction of 100 mW of pump power at 1050 nm or a reduction of 44% of doped fiber length to reach the same gain as with 1050-nm pumping alone.     

Pixel clustering by adaptive pixel moving and chaotic synchronization

In this paper, a network of coupled chaotic maps for pixel clustering is proposed. Time evolutions of chaotic maps in the network corresponding to a pixel cluster are synchronized with each other. Those synchronized trajectories are desynchronized with respect to the time evolutions of chaotic maps corresponding to other pixel clusters in the same image. A pixel motion mechanism is also introduced, which makes each group of pixels more compact and, consequently, makes the model robust enough to classify ambiguous pixels. Another feature of the proposed model is that the number of pixel clusters does not need to be previously known.     

Langerhans cell histiocytosis in anogenital region]

We compared thoracoscopic surgery (TS) and open thoracotomy for the diagnosis of interstitial pneumonia. Intraoperative blood loss and duration of postoperative chest drainage were significantly less with TS than with thoracotomy. The length of postoperative hospital stay and social insurance costs with TS was significantly less than with thoracotomy. These results show that TS for the diagnosis of interstitial pneumonia is superior to open thoracotomy in terms of surgical stress and cost.     

Gene amplification in bladder tumors

Eight patients with transitional cell bladder carcinoma were analyzed viewing the detection of ras oncogene mutations. This sample was picked out from a preliminary study of 20 cases of transitional cell tumors where complex chromosomal rearrangements were observed in tumors of grade II/III. In this first stage of the study non invasive tumors presented an almost diploid chromosome number while the most infiltrative ones displayed pseudo triploidy, triploidy or tetraploidy. A Subsequent study searched for the mutational frequency of the oncogene n-ras using the knowledge of direct DN sequencing and based on the technology of polymerase chain reaction amplification (PCR) in view to establish a relationship between the mutational frequency and the tumor stage and grade. The wild type allele was present in all the tumors examined. Point mutations were detected in 1/3 of the analyzed samples. These samples displayed a grade II-III histology as opposed to the other tumors. These data appear to indicate that n-ras mutations may be early phenomena in the development and progress of a number of human tumors of the urothelium.     

Electrocatalytic properties of mechanically alloyed Co-20wt%Ni-10wt%Mo and Co-70wt%Ni-10wt%Mo alloy powders

Mechanically alloyed Co-20wt%Ni-10wt%Mo and Co-70wt%Ni-10wt%Mo (nominal compositions) alloy powders were produced by milling of pure elemental powders. Mechanically alloyed powders were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. MA powder specimens were tested electrollitically in a 30% KOH aqueous solution at 298 K. X-ray diffraction analysis and transmission electron microscopy of milled powders showed the presence of two phases, an fcc solid solution and intermetallic compounds of Ni or Co with Mo. These phases showed a nanometric size. The linear sweep voltammograms confirmed also the presence of two phases in both mechanically alloyed alloy powders. The Co-20wt%Ni-10wt%Mo alloy powders showed the best electrocatalytic activity for hydrogen evolution reaction.     

Toxic Shock Syndrome in a neonate?

Toxic Shock Syndrome is an acute multisystemic disease, characterized by high fever, hypotension and involvement of the skin and mucous membrane, associated with multisystem dysfunction. It is a rare condition in the paediatric population. We describe a newborn child with asphyxia and meconium aspiration, who developed a temperature of > or =38.9 degrees C, severe hypotension and rash with desquamation, associated with evidence of coagulopathy and renal and muscular dysfunction. Strict CDC criteria of toxic shock syndrome were fulfilled in our patient, with all major criteria verified. These criteria have never been validated in neonates, but in this case some symptoms favour a diagnosis of toxic shock syndrome since they are not associated with birth asphyxia, viral intrauterine infection or other disease. We believe a probable intrapartum transmission occurred through ingestion or aspiration of contaminated amniotic fluid. The patient described in this report is, to our knowledge, one of the youngest described to fulfil all of the strict CDC criteria for Toxic Shock Syndrome.