RESUMO
The Utah Department of Health currently groups African-born blacks with U.S.-born blacks when reporting HIV/AIDS surveillance data. Studies suggest that categorizing HIV/AIDS cases in this manner may mask important epidemiological trends, and the distinct differences between these two populations warrant disaggregating data prior to reporting. The purpose of this study was to characterize the HIV/AIDS positive populations in U.S. and African-born blacks in Utah and evaluate the need for disaggregating the two groups. A total of 1,111 cases were identified through the statewide electronic HIV/AIDS Reporting System from 2000 - 2009. Data were analyzed for prevalence of HIV diagnosis for African-born blacks, U.S.-born blacks, and U.S.-born whites. Secondary analysis included HIV diagnosis by age, sex, African region of nativity, transmission risk factors, and differences in late diagnosis of HIV infection. U.S.-born whites accounted for 914 (82.3%) cases, and had the lowest annual prevalence (4/100,000). Conversely, African-born and U.S.- born blacks had the highest prevalence, 162/100,000 and 24/100,000 respectively. African-born blacks made up 0.25% of the total population, but accounted for 7.9% of all HIV/AIDS cases. African-born black males were more likely to report "no reported risk" for HIV transmission than U.S.-born black males. Of African-born blacks, 55.7% reported East-African nativity. These results demonstrate the importance of stratifying the black/African American racial category by African-born and U.S.-born blacks when collecting and reporting HIV/AIDS state surveillance data even in a low-incidence state,which will better inform prevention and linkage-to-care efforts in Utah.
RESUMO
The design of an electromagnetic acoustic transducer (EMAT) array device for the inspection of large areas of metallic plate-like structures using the S0 guided wave mode is described. The reasons for using the S0 mode are discussed and it is shown how the choice of mode determines the nature of the EMAT array elements. A novel array construction technique is shown to be necessary whereby the EMAT coils for adjacent elements are overlapped in order to achieve the required element density. Results are presented that illustrate the operation of the device on steel and aluminum plate specimens in the thickness range from 5 to 10 mm. An area of at least 10 m2 can be inspected from a single location. Spurious signals in the results are caused both by the unwanted A0 mode and by S0 sidelobes, the latter occurring at the same radial distance from the array as the genuine S0 signal from a reflector, but in the wrong direction. The signal-to-coherent noise performance of the complete system is determined by the amplitude ratio of the largest genuine S0 signal to the largest spurious signal. This is typically around 30 dB. The sensitivity of the device to artificial defects and genuine corrosion patches is demonstrated and the limitations of its operation are discussed. The feasibility of using the device with the S1 guided wave mode to inspect a 20 mm thick plate is also demonstrated.
RESUMO
The aim of this paper is threefold: to describe the physical phenomenon of the excitation of modal waves such as Lamb waves, in anisotropic multilayered media, by a monochromatic incident beam, using an asymptotic approach; to present a three-dimensional model using the decomposition of the incident beam into monochromatic plane waves (the formalism is applied to the particle displacement vector); to illustrate the phenomenon both numerically and experimentally. Numerical and experimental maps of the reflected field of pressure are presented, and the reradiation of the Lamb wave beam in an oblique plane is theoretically and numerically illustrated.
RESUMO
Many plants contain hydroxycinnamic acid conjugates of polyamines that are remarkably similar in general structure to the acylated polyamines found in spider and wasp toxins. In an effort to determine whether these compounds might play a role in the chemical defense of plants against arthropod pests we synthesized a variety of analogues of the coumaric (4-hydroxycinnamic) acid conjugates of di-, tri-, and tetraamines using common protection and acylation strategies. N(1)- and N(8)-coumaroyl spermidine were tested in feeding trials with insect larvae including the European corn borer (Ostrinia nubilalis), the tobacco budworm (Heliothis verescens) and the oblique banded leaf roller (Choristoneura rosaceana). Antifeedant assays with the rice weevil Sitophilus oryzae were also performed. Neither the naturally occurring coumaric acid conjugates of polyamines nor their analogues showed notable toxicity towards insects, despite precautions to maintain these easily oxidized materials in the wet diet. However, more direct bioassays of these compounds on glutamate dependent neuroreceptors including the deep abdominal extensor muscles of crayfish, or mammalian NMDA, delta2, and AMPA receptors, clearly showed that these compounds were inhibitory. N(1)-Coumaoryl spermine, a dodecyl and a cyclohexyl analogue were especially active at NMDA NR1/NR2B receptors. The latter had an IC(50) of 300 microM in the crayfish. N(1)-Coumaroyl spermine had an IC(50) in the crayfish preparation of 70-300 microM and against the mammalian NR1/NR2B receptor of 38 nM. Structure-activity variations show similar trends of length and hydrophobicity as has been seen previously with analogues of spider toxins. We conclude from this work that while the coumaric acid polyamine conjugates are active when directly applied to neuroreceptors, they show no overt toxicity when ingested by insect larvae.
