Effect of particle bombardment on the orientation and the residual stress of sputtered AlN films for SAW devices

We present a study of the effect of particle bombardment on the preferred orientation and the residual stress of polycrystalline aluminum nitride (AlN) thin films for surface acoustic wave (SAW) applications. Films were deposited on silicon (100) substrates by radio frequency (RF) sputtering of an aluminum target in an argon and nitrogen gas mixture. The main deposition parameters were changed as follows: the total pressure from 4 mTorr to 11 mTorr, the N2 content in the gas mixture from 20% to 80%, and the substrate self-bias voltage from -10 V to -30 V. If a sufficiently high negative substrate self-bias voltage is induced, (00.2)-oriented films are obtained over the full ranges of pressure and N2 content. Such films have values of residual stress ranging from -3 GPa to +1 GPa, depending on the deposition conditions. Our results suggest that the energy of the Ar ions colliding with the substrate controls the preferred orientation of the films, whereas the directionality of the ions (for the same energy) is the main factor determining the residual stress. To demonstrate the suitability of our material for the intended application, SAW filters with good electroacoustic response have been fabricated using AlN thin films with optimized (00.2) orientation and controlled residual stress.     

In-flight measured and predicted ambient dose equivalent and latitude differences on effective dose estimates

The results from 2 years (2001-2002) of experimental measurements of in-board radiation doses received at IBERIA commercial flights are presented. The routes studied cover the most significant destinations and provide a good estimate of the route doses as required by the new Spanish regulations on air crew radiation protection. Details on the experimental procedures and calibration methods are given. The experimental measurements from the different instruments (Tissue Equivalent Proportional Counter and the combination of a high pressure ion chamber and a high-energy neutron compensated rem-counter) and their comparison with the predictions from some route-dose codes (CARI-6, EPCARD 3.2) are discussed. In contrast with the already published data, which are mainly focused on North latitudes over parallel 50, many of the data presented in this work have been obtained for routes from Spain to Central and South America.     

Polymerase chain reaction for the direct detection of Brucella spp. in milk and cheese

A polymerase chain reaction test was developed to detect Brucella spp. directly in milk and cheese and optimized using primers for the BSCP-31 gene. A total of 46 cheese samples produced with sheep and goats milk were assayed, and Brucella spp. was detected in 46% of them, especially in cheese made from sheep milk. This method is of remarkable epidemiologic interest because it is an indirect test indicating the sanitary quality of milk used in dairy industries. The method showed good sensitivity and specificity. It is faster and less expensive than the conventional bacteriological assays.     

A novel calcium-activated apamin-insensitive potassium current in pituitary gonadotrophs

In cultured rat pituitary gonadotrophs, GnRH-induced oscillations in cytosolic calcium concentration ([Ca2+]i) are associated with periodic membrane hyperpolarization. The hyperpolarizing waves are secondary to the activation of apamin-sensitive Ca2+-activated K+ channels that account for a single class of 125I-apamin binding sites present in these cells. In a substantial fraction of gonadotrophs, however, we observed a Ca2+-controlled oscillatory current that was resistant to apamin, even at concentrations five orders of magnitude higher than the dissociation constant (Kd) observed in the binding experiments. With the K+ in the pipette, the apamin-resistant current showed a reversal potential of -42 mV, nearly 40 mV more positive than that of the apamin-sensitive current. With Cs+ in place of K+ in the pipette solution, both the size of the apamin-insensitive current and its reversal potential remained unchanged. Ion substitution studies further revealed that the reversal potential was independent of Cl-. In contrast, an 11 mV hyperpolarizing shift in the reversal potential occurred when extracellular Na+ was reduced to 80 mM. In cells expressing apamin-resistant conductances, addition of apamin evoked a marked increase in the duration of the action potentials and reduction in the frequency of spontaneous spiking. In the presence of GnRH, gonadotrophs exhibit the typical burst pattern of electrical activity. Further exposure of the cells to apamin depolarized the membrane from a silent phase bursting level of about -80 mV to a new level of about -40 mV. These observations indicate that, in addition to apamin-sensitive current, a subpopulation of pituitary gonadotrophs also expresses a cationic component of the Ca2+-activated membrane conductance that has the potential to remodulate spontaneous and agonist-induced electrical activity.     

Rising incidence of non-Hodgkin''s lymphoma in Spain: analysis of period of diagnosis and cohort effects

INTRODUCTION: Individual annual cosmic radiation doses for fulltime airline crewmembers were calculated for 12 consecutive months using data from flight profiles and previously reported cosmic radiation intensity measurements at various altitudes. METHODS: Every flight of each crewmember was analyzed using block time and aircraft flight profiles. Actual flight time at various flight levels was first calculated, then cumulative total body radiation doses were calculated for each flight phase and altitude. RESULTS: Cabin crewmembers averaged 673 block hours (range 906-273 h) and pilots 568 block hours (range 833-168 h). Average annual cosmic ray dose for cabin crews was 2.27 mSv x a(-1) (range between 3.1 - 0.72 mSv x a(-1)). Long-distance MD11 flight captains received the highest annual doses of 2.19 mSv x a(-1) (2.83 - 1.08 mSv x a(-1)). M.D.80 pilots who also fly long high-altitude sectors in Europe received 1.94 mSv x a(-1) (2.37 - 1.12) and other aircraft type cockpit crews averaged between 1.49 - 1.26 mSv x a(-1). CONCLUSION: The calculated individual doses reflect the type of aircraft flown and the amount of flight time. The calculated doses are lower than those received by simply assuming constant radiation exposure at all altitudes during flight. Annual individual doses are well below the maximum 5 mSv x a(-1) allowed by the national laws.     

Water and dye adsorption properties of cactaceous material

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Catalytic pre-wave of nickel(II) in presence of cocarboxylase (disulfide form) in borate medium

A brief study is made of the nickel(II) polarography in borate medium. The nickel(II) in borate medium gives one or two waves depending on its concentration as well as the medium composition.In a borate medium, cocarboxylase in its disulfide form gives a nickel(II) pre-wave. The effects of the cocarboxylase (disulfide form) concentration, nickel(II) concentration and mercury column height on the pre-wave are described.The effect of neutral salts on the pre-wave is studied and it is seen that an increase in the ionic strength is accompanied by a decrease in pre-wave current, being of decreasing effect in the order K⁺ < Na⁺ < Li⁺. The electrocapillary curves are present, and it is shown that the presence of cocarboxylase (disulfide form) in the solution causes a decrease in the interfacial tension.The results are discussed and a mechanism for the electrode process of the pre-wave is proposed. Using the approximate method for the catalytic currents, nickel(II) and cocarboxylase-thiol are shown to form the catalytic complex in the relationship 1:1.     

Model-driven component adaptation in the context of Web Engineering

Currently, Web-based applications are no longer monolithic and isolated systems but, rather, distributed applications that need to interoperate with third-party systems, such as external Web services, LDAP repositories or legacy applications. When one component provides a service that the Web application requires, it is often not possible to bind the two systems together if they were not programmed to have compatible collaboration specifications. Modeling the adaptation between a Web application and external assets becomes therefore an essential issue in any realistic model-driven development scenario. However, most of the existing Web Engineering proposals do not take this issue into account, or they simply address it at the implementation level (in a platform-specific way). In this work, we discuss the problems involved in dealing with component adaptation within the context of Model-Driven Web Engineering and show how design patterns can help addressing it. We first identify the major interoperability problems that can happen when integrating third-party application or legacy systems into our Web systems, and then propose the mechanisms that need to be put in place at the design level to generate the appropriate specification of adapters that compensate for the possible mismatches and differences. We base our proposal on well-known design patterns as they are established solutions to recurring problems, and the generation of code from them is normally straightforward.