361 research outputs found

    Experimental L-band SST satellite communications/surveillance terminal study. Volume 3 - Communications/surveillance analysis

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    Analysis of surveillance and communications functions of L band air traffic control satellite syste

    Identification of proteases employed by dendritic cells in the processing of protein purified derivative (PPD)

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    Dendritic cells (DC) are known to present exogenous protein Ag effectively to T cells. In this study we sought to identify the proteases that DC employ during antigen processing. The murine epidermal-derived DC line Xs52, when pulsed with PPD, optimally activated the PPD-reactive Th1 clone LNC.2F1 as well as the Th2 clone LNC.4k1, and this activation was completely blocked by chloroquine pretreatment. These results validate the capacity of XS52 DC to digest PPD into immunogenic peptides inducing antigen specific T cell immune responses. XS52 DC, as well as splenic DC and DCs derived from bone marrow degraded standard substrates for cathepsins B, C, D/E, H, J, and L, tryptase, and chymases, indicating that DC express a variety of protease activities. Treatment of XS52 DC with pepstatin A, an inhibitor of aspartic acid proteases, completely abrogated their capacity to present native PPD, but not trypsin-digested PPD fragments to Th1 and Th2 cell clones. Pepstatin A also inhibited cathepsin D/E activity selectively among the XS52 DC-associated protease activities. On the other hand, inhibitors of serine proteases (dichloroisocoumarin, DCI) or of cystein proteases (E-64) did not impair XS52 DC presentation of PPD, nor did they inhibit cathepsin D/E activity. Finally, all tested DC populations (XS52 DC, splenic DC, and bone marrow-derived DC) constitutively expressed cathepsin D mRNA. These results suggest that DC primarily employ cathepsin D (and perhaps E) to digest PPD into antigenic peptides

    Preliminary evaluation of spectral, normal and meteorological crop stage estimation approaches

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    Several of the projects in the AgRISTARS program require crop phenology information, including classification, acreage and yield estimation, and detection of episodal events. This study evaluates several crop calendar estimation techniques for their potential use in the program. The techniques, although generic in approach, were developed and tested on spring wheat data collected in 1978. There are three basic approaches to crop stage estimation: historical averages for an area (normal crop calendars), agrometeorological modeling of known crop-weather relationships agrometeorological (agromet) crop calendars, and interpretation of spectral signatures (spectral crop calendars). In all, 10 combinations of planting and biostage estimation models were evaluated. Dates of stage occurrence are estimated with biases between -4 and +4 days while root mean square errors range from 10 to 15 days. Results are inconclusive as to the superiority of any of the models and further evaluation of the models with the 1979 data set is recommended

    Argon, krypton, and xenon abundances in the solar wind measured in silicon from the genesis mission

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    Up to now solar wind (SW) abundances of Kr and Xe have been exclusively determined using SW irradiated regolith [1]. Hence, one of Genesis’s major objectives is to obtain the heavy noble gas composition of the present-day SW using artificial targets exposed to the SW for 2.5 years. SW abundances will allow to study fractionation processes upon SW formation, e.g., due to the first ionization potential (FIP-effect) [2]. This is of importance to deduce solar abundances of noble gases and other elements from SW data. Solar, i.e., photospheric, abundances of noble gases are indirectly determined due to the lack of suitable lines in the spectrum. Recently, solar abundance estimates for Ne and Ar were strongly reduced whereas Kr and Xe changed only slightly [3]. This led to a dramatic decrease of the solar Ar/Kr ratio by a factor of ~3 from the earlier value [4] of 2140. If true, this change would invalidate theories of heavy noble gas fractionation in the SW identified with regolith data [1, 5]. The Kr and Xe composition in present-day SW will enable us to reassess solar abundances and fractionation theories. Thus, we concentrate here on abundances of Ar, Kr and Xe in the bulk SW

    Integration of Clinical Variables for the Prediction of Late Distant Recurrence in Patients With Estrogen Receptor-Positive Breast Cancer Treated With 5 Years of Endocrine Therapy: CTS5.

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    Purpose Estimating risk of late distant recurrence (DR) is an important goal for managing women with hormone receptor-positive breast cancer after 5 years of endocrine treatment without recurrence. We developed and validated a simple clinicopathologic tool (Clinical Treatment Score post-5 years [CTS5]) to estimate residual risk of DR after 5 years of endocrine treatment. Patients and Methods The ATAC (Arimidex, Tamoxifen, Alone or in Combination) data set (N = 4,735) was used to create a prognostic score for post-5-year risk of DR. Validity of CTS5 (ATAC) was tested in the BIG 1-98 data set (N = 6,711). Time to late DR, 5 years after finishing scheduled endocrine therapy, was the primary end point. Cox regression models estimated the prognostic performance of CTS5 (ATAC). Results CTS5 (ATAC) was significantly prognostic for late DR in the ATAC cohort (hazard ratio, 2.47; 95% CI, 2.24 to 2.73; P 10%) identified 43% of the validation cohort as low risk, with an observed DR rate of 3.6% (95% CI, 2.7% to 4.9%) during years 5 to 10. From years 5 to 10, 63% of node-negative patients were low risk, with a DR rate of 3.9% (95% CI, 2.9% to 5.3%), and 24% with one to three positive nodes were low risk, with a DR rate of 1.5% (95% CI, 0.5% to 3.8%). A final CTS5 for future use was derived from pooled data from ATAC and BIG 1-98. Conclusion CTS5 is a simple tool based on information that is readily available to all clinicians. CTS5 was validated as highly prognostic for late DR in the independent BIG 1-98 study. The final CTS5 algorithm identified 42% of women with < 1% per-year risk of DR who could be advised of the limited potential value of extended endocrine therapy
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