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A leucemia mielóide aguda (LMA) é um grupo heterogêneo de doenças clonais do tecido hematopoiético, que é caracterizada pela proliferação anormal de células progenitoras da linhagem mielóide, resultando na produção insuficiente de células sanguíneas maduras normais, com a consequente substituição do tecido normal. O diagnóstico de LMA inicia-se a partir de uma suspeita clínica e se baseia na avaliação do sangue periférico e da medula óssea. O objetivo desta revisão é informar aos profissionais da saúde, que embora a morfologia continue sendo o fundamento para o diagnóstico, técnicas adicionais, incluindo imunofenotipagem, avaliação citogenética e estudos de genética molecular, tornaram-se essenciais e, em alguns casos específicos, são ferramentas complementares obrigatórias no auxílio ao diagnóstico.

Since its incorporation in 1998, Acsion Industries Inc. has been working with clients to develop industrial uses of electron processing for improving products and manufacturing processes. Acsion has promoted this technology for sterilizing medical devices and pharmaceuticals, for treating wood pulp in the viscose/rayon process, for reducing pathogens in food and animal feed, and for curing advanced composites for the aerospace industry. As a result of significant developments in its composite curing programs, Acsion has recently made major modifications to its facility to increase its production and R&D capabilities. These modifications are described in this paper.

A self-aligned fabrication process for small emitter contact area (2×4 μm2) GaN/AlGaN heterojunction bipolar transistor is described. The process features dielectric-spacer sidewalls, low damage dry etching, and selected-area regrowth of GaAs(C) on the base contact. The junction current–voltage (I–V) characteristics were evaluated at various stages of the process sequence and provided an excellent diagnostic for monitoring the effect of plasma processes such as chemical vapor deposition or etching. A comparison is given with large emitter-area (1.96×103 μm2) devices fabricated on the same material. The small-area devices are attractive for microwave power switching applications provided a high-yield process can be developed.

Acsion is exploiting several emerging electron beam EB applications ranging from composite curing and repair to viscose manufacturing. EB curing of composite structures offers several advantages: significantly reduced curing times; improvements in part quality and performance; reduced environmental and health concerns; improvements in material handling; and reduced overall manufacturing costs compared to thermal curing. The aerospace industry is developing EB technology in all of their market sectors, including military aviation and space products. Some specific products include cryogenic fuel tanks, improved canopy frames for jet aircraft, and the all-composite military aircraft. This paper discusses each of these opportunities.

Advanced composites, such as carbon-fibre-reinforced epoxies, are used in the aircraft, aerospace, sporting goods, and transportation industries. Though thermal curing is the dominant industrial process for advanced composites, electron curing of similar composites containing acrylated epoxy matrices has been demonstrated by our work. The main attraction of electron processing technology over thermal technology is the advantages it offers which include ambient temperature curing, reduced curing times, reduced volatile emissions, better material handling, and reduced costs. Electron curing technology allows for the curing of many types of products, such as complex shaped, those containing different types of fibres, and up to 15 cm thick. Our work has been done principally with the AECL's 10 MeV, 1 kW electron accelerator; we have also done some comparative work with an AECL Gammacell 220. In this paper we briefly review our work on the various aspects of electron curing of advanced composites and their properties.

InP, InAlP and InGaP can be etched at rates of 0.5–0.8 μm min−1 in pure BCl3 discharges at high microwave powers (1000 W). The etch rates are strong functions of focusing magnet current, microwave power, sample temperature and to the nature of additive gases. For example, InGaP etch rates a factor of two to three faster than for BCl3 alone are obtained when small additions (25% by flow) of N2 or O2 are added to enhance dissociation of the BCl3. As microwave power is increased the surface morphology of InP is degraded, while that of InGaP improves, InAlP is relatively resistant to surface changes between 250 and 1000 W of microwave power. The sidewalls of etched features are extremely smooth and suitable for a variety of photonic devices.

Research to develop products and processes tor the electron curing of fibre-reinforced composites is rapidly progressing at several industrial and government laboratories, including AECL Research. Electron curing uses high-energy electrons or X-rays generated from these electrons, rather than thermal energy, to cure selected composite matrix polymers and to enhance their physical and chemical properties. Our recent programs have focussed on resin development, economics and process design. This paper summarizes the recent advances in electron curing technology.

The use of carbon tetrachloride was examined as a means of suppressing deposition on the dielectric mask during the selective regrowth of III–V epitaxial layers by organometallic vapor phase epitaxy. Highly anisotropic dry etching was used to form narrow (∼1 μm wide) trenches and mesas. Reentrant mesas were formed by wet chemical etching. Under conventional growth conditions, polycrystalline GaAs was deposited over the mask adjacent to the trenches. By adding CCl4, selectivity could be greatly enhanced; however the growth rate in the trenches was significantly increased due to lateral diffusion of the reactants upon desorption from the mask thereby making acceptable control of the growth rate difficult. Addition of CCl4 during the growth of InP and AlGaAs significantly improved the selectivity in the case of growth around etched mesas.

We use electric field singularities in biased metal semiconductor microstructures to enhance the generation of terahertz (THz) radiation from semiconductors. We find that, regardless of the mechanism that is responsible for enhanced THz emission near the anode, singular electric fields near sharp anode features will enhance this emission by as much as an order of magnitude. We show scanning THz measurements of several of these structures and discuss the physical mechanism responsible for this enhanced emission. A new family of more efficient terahertz emitters based on these effects can be designed that will improve the dynamic range of THz imaging and spectroscopy systems.

Using metal organic chemical vapor deposition, we have fabricated self-organized quantum dots that emit efficiently at 1.3 μm at room temperature. They are grown on GaAs and consist of InAs covered with an InGaAs cap layer. Their density is 2×1010 cm−2 as determined by transmission electron microscopy. Room-temperature photoluminescence shows a 36 meV broad line at 1.3 μm, corresponding to the quantum-dot ground state, with excellent uniformity across the wafer. The efficiency of this emission is reduced only by a factor of 4 with respect to low temperature showing the high quality of the sample.

We describe the first results of hybrid mode locking combining both active and passive mode locking of a semiconductor laser. These functions are integrated into a monolithic device with a 1.3 μm GaInAsP gain region, an active waveguide, and a saturable absorber. The devices have low threshold currents, and exhibit hysteresis in their light/current characteristics. The long integrated waveguides allow mode locking at a repetition rate of 15 GHz without the need for an external cavity. Pulse widths as short as 1.4 ps have been demonstrated using the combined effects of active and passive mode locking.

This is a report on work in progress on microelectrical and mechanical systems (MEMS)-based gas turbine engines, turbogenerators, and rocket engines currently under development at MIT. Fabricated in large numbers in parallel using semiconductor manufacturing techniques, these engines are based on micro-high speed rotating machinery with the same power density as that achieved in their more familiar, full-sized brethren. The micro-gas turbine is a 1 cm diameter by 3 mm thick SiC heat engine designed to produce 10-20 W of electric power or 0.050.1 Nt of thrust while consuming under 10 grams/hr of H 2 . Later versions may produce up to 100 W using hydrocarbon fuels. A liquid fuel, bi-propellant rocket motor of similar size could develop over 3 lb of thrust. The rocket motor would be complete with turbopumps and control valves on the same chip. These devices may enable new concepts in propulsion, fluid control, and por table power generation.

Some published results on mode locked monolithic lasers are reviewed. Optical spectra of a typical hybrid mode-locked monolithic device for different levels of RF power and frequency are shown and discussed, as are effects of detuning the modulation frequency. Design considerations are examined. These include the length of the device, the use of hybrid mode locking, and the choice of active or passive waveguides. >

Etch rates for InP, InAlP, and InGaP can be controlled between ∼1500 A/min and ≳1 μm/min by varying the microwave power, rf power, or N2 composition in BCl3N2 discharges under electron cyclotron resonance conditions. The surface morphology of InGaP is poor at low microwave power (250 W), but becomes very smooth at high powers (1000 W). InP has exactly the opposite dependence on microwave power, while InAlP shows little change in morphology over a wide range of powers. The high ion current under electron cyclotron resonance conditions enables etching of In‐based semiconductors without the need for high sample temperatures to enhance desorption of InClX species.

The capped-mesa buried-heterostructure distributed-feedback (CMBH-DFB) laser structure requires three epitaxial growths and is designed to allow good control of the width of the active layer using straightforward chemical etching techniques. The base structure, which contains the active layer, was fabricated using a variety of epitaxial techniques: liquid-phase epitaxy, hydride vapor-phase epitaxy (VPE) and metalorganic vapor-phase epitaxy (MOVPE). The final cap growth was done using hydride VPE. High yields of low-threshold high-power DFB lasers were produced from a number of wafers at emission wavelengths of 1.3 and 1.55 mu m. >

The first results for hybrid mode locking of semiconductor lasers are reported. Hybrid mode locking combines both active and passive mode locking to produce shorter mode-locked pulses. These functions are integrated into monolithic devices with a 1.3-μm GaInAsP gain region, an active waveguide, and a saturable absorber. The monolithic mode locked lasers are fabricated as arrays of six devices. These devices have low threshold currents and exhibit hysteresis in their light/current characteristics. The uniformity of threshold currents over an array of devices is very good. The long integrated waveguides allow mode locking at a repetition rate of 15 GHz without the need for an external cavity, with pulse widths as short as 1.4 ps being demonstrated.

Summary form only given. 1.3 mu m GaInAsP lasers were integrated with active waveguides and satirable absorbers to form arrays of monolithic devices. These devices have low threshold currents, and long integrated waveguides have led to picosecond pulse widths at a 15-GHz repetition rate. The integrated active waveguides decrease the effective coupling losses from laser to integrated cavity, and the saturable absorber provides pulse shortening by both active and passive mode locking. Arrays of six monolithic devices were fabricated from semi-insulating channeled substrate buried heterostructure 1.3 mu m GaInAsP laser material. Microwave measurements of the frequency response of these devices show a very large peak at 15 GHz which is one over the round trip time of the device. This peak at 15 GHz was measured to be 12 dB below the response at 50 MHz, while away from the peak the response falls by over 27 dB. This indicates a strong feedback from the integrated cavity, a characteristic of active waveguides. >

Plasma‐enhanced CVD requires close control of the plasma power density for reproducibility of both deposition rate and spatial uniformity in a radial‐flow reactor. Frequently the low rf power levels needed are not adequately controlled by the output power control of the relatively high power rf generator found in most commercial multipurpose plasma etch/deposition systems. This paper describes very simple and inexpensive broadband optical monitoring of the plasma emission for improved control sensitivity. The technique has the advantage of directly monitoring the plasma intensity, avoiding effects of variable power transmission losses between the rf generator and the plasma. Application to the control of low power plasma‐enhanced CVD of ‘‘SiO2’’ from Ar:SiH4:N2O plasmas, where the monitor signal is almost entirely due to near infrared Ar emission, is described.