The Beam Expander Testing X-ray facility (BEaTriX) is a unique X-ray apparatus now operated at the Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Brera (OAB), in Merate, Italy. ...It has been specifically designed to measure the point spread function (PSF) and the effective area (EA) of the X-ray mirror modules (MMs) of the Advanced Telescope for High-ENergy Astrophysics (ATHENA), based on silicon pore optics (SPO) technology, for verification before integration into the mirror assembly. To this end, BEaTriX generates a broad, uniform, monochromatic, and collimated X-ray beam at 4.51 keV. ... In BEaTriX, a micro-focus X-ray source with a titanium anode is placed in the focus of a paraboloidal mirror, which generates a parallel beam. A crystal monochromator selects the 4.51 keV line, which is expanded to the final size by a crystal asymmetrically cut with respect to the crystalline planes. ... After characterization, the BEaTriX beam has the nominal dimensions of 170 mm x 60 mm, with a vertical divergence of 1.65 arcsec and a horizontal divergence varying between 2.7 and 3.45 arcsec, depending on the monochromator setting: either high collimation or high intensity. The flux per area unit varies from 10 to 50 photons/s/cm2 from one configuration to the other. The BEaTriX beam performance was tested using an SPO MM, whose entrance pupil was fully illuminated by the expanded beam, and its focus was directly imaged onto the camera. The first light test returned a PSF and an EA in full agreement with expectations. As of today, the 4.51 keV beamline of BEaTriX is operational and can characterize modular X-ray optics, measuring their PSF and EA with a typical exposure of 30 minutes. ... We expect BEaTriX to be a crucial facility for the functional test of modular X-ray optics, such as the SPO MMs for ATHENA.
The Windjana drill sample, a sandstone of the Dillinger member (Kimberley formation, Gale Crater, Mars), was analyzed by CheMin X-ray diffraction (XRD) in the MSL Curiosity rover. From Rietveld ...refinements of its XRD pattern, Windjana contains the following: sanidine (21% weight, ~Or95); augite (20%); magnetite (12%); pigeonite; olivine; plagioclase; amorphous and smectitic material (~25%); and percent levels of others including ilmenite, fluorapatite, and bassanite. From mass balance on the Alpha Proton X-ray Spectrometer (APXS) chemical analysis, the amorphous material is Fe rich with nearly no other cations—like ferrihydrite. The Windjana sample shows little alteration and was likely cemented by its magnetite and ferrihydrite. From ChemCam Laser-Induced Breakdown Spectrometer (LIBS) chemical analyses, Windjana is representative of the Dillinger and Mount Remarkable members of the Kimberley formation. LIBS data suggest that the Kimberley sediments include at least three chemical components. The most K-rich targets have 5.6% K2O, ~1.8 times that of Windjana, implying a sediment component with >40% sanidine, e.g., a trachyte. A second component is rich in mafic minerals, with little feldspar (like a shergottite). A third component is richer in plagioclase and in Na2O, and is likely to be basaltic. The K-rich sediment component is consistent with APXS and ChemCam observations of K-rich rocks elsewhere in Gale Crater. The source of this sediment component was likely volcanic. Finally, the presence of sediment from many igneous sources, in concert with Curiosity's identifications of other igneous materials (e.g., mugearite), implies that the northern rim of Gale Crater exposes a diverse igneous complex, at least as diverse as that found in similar-age terranes on Earth.
The incidence and prevalence of human immunodeficiency virus (HIV) infection among injection drug users, prostitutes, and other women seeking confidential testing in the Orange County Women's Jail ...were assessed from 1985 to 1991. A total of 4616 voluntary tests were completed on 3051 women, and 865 women were tested repeatedly. Eighty-two women tested positively, a ratio of 1.8 positives per 100 tests or 2.7% of all persons tested. Cumulative HIV prevalence increased from 2.5% to 2.7% between 1985 and 1991, increased by age, and showed racial differences. Of women with multiple tests, 29 seroconverted. Incidence declined from 5.7 to 1.4 cases per 100 person-years of observation between 1985 and 1991. The overall rate of seroconversion was 1.6 per 100 person-years of observation.
An outbreak of acute gastroenteritis (AGE) occurred in a 201-bed geriatric convalescent facility in Los Angeles County during December 1988 through January 1989. The attack rate was 55% among ...residents and 25% among employees. Illnesses were characterized by vomiting and diarrhea to a lesser extent, and the absence of fever. Bacterial and parasitic tests in a sample of patients were negative. A 27 nm small round structured virus (SRSV) was identified in one of 30 stools studied by immune electron microscopy (IEM). While rotavirus and influenza A and B were found in three, one and three cases, respectively, no alternative etiologic agent could be demonstrated for most cases. The outbreak met Centers for Disease Control (CDC) clinical and epidemiologic criteria for Norwalk-like gastroenteritis. The death rate of residents was not elevated beyond baseline during the outbreak; however, one healthy employee had diarrhea and dehydration and died after developing an arrhythmia. An autopsy showed moderate, diffuse lymphocytic and neutrophilic myocarditis, and viral studies found influenza A in left ventricular tissue. Fourteen (25%) of 57 employee cases worked in occupations without routine stool or patient contact. At least nine of these employees lacked evidence of direct fecal contact, and transmission of infection in these cases may have been airborne.
Reports of plumes or patches of methane in the martian atmosphere that vary over monthly time scales have defied explanation to date. From in situ measurements made over a 20-month period by the ...tunable laser spectrometer of the Sample Analysis at Mars instrument suite on Curiosity at Gale crater, we report detection of background levels of atmospheric methane of mean value 0.69 ± 0.25 parts per billion by volume (ppbv) at the 95% confidence interval (CI). This abundance is lower than model estimates of ultraviolet degradation of accreted interplanetary dust particles or carbonaceous chondrite material. Additionally, in four sequential measurements spanning a 60-sol period (where 1 sol is a martian day), we observed elevated levels of methane of 7.2 ± 2.1 ppbv (95% CI), implying that Mars is episodically producing methane from an additional unknown source.
There is a high incidence of asthma, rhinitis, conjunctivitis and contact urticaria in workers of precious metal refineries. Symptoms are closely associated with sensitization to halogenated platinum ...compounds, as assessed by skin-prick test. The aim of the present study was to examine the molecular mechanisms involved by describing the T-cell receptor (TCR) repertoire distribution of peripheral blood mononuclear cells (PBMCs) without and after in vitro stimulation with sodium hexachloroplatinate. PBMCs of 17 sensitized subjects with work-related asthma and a positive skin-prick test result to sodium hexachloroplatinate and of 15 nonexposed subjects were isolated and TCR expression determined by flow cytometry. Furthermore, the sodium hexachloroplatinate-mediated in vitro effects on the frequency of Vbeta-expressing T-cells, the proliferation response and the expression of cell surface molecules like CD71, CD25, CD95 and HLA-DR were studied. CD3-positive lymphocytes of platinum salt-sensitized workers had a significantly higher frequency of Valpha2a+, Vbeta11+ and Vbeta21.3+ T-cells than controls (p<0.01, p<0.01 and p<0.001 respectively). In vitro stimulation of PBMCs from platinum salt-sensitized as well as control subjects with sodium hexachloroplatinate increased the percentage of CD3-positive cells bearing specific TCRs, especially Vbeta5.3, Vbeta6.7, Vbeta8a, Vbeta20 and Vbeta21.3. This effect was time- and dose-dependent. The present results indicate that the frequencies of Valpha2a-, V11 and Vbeta21.3-bearing blood T-cells and platinum salt-induced lymphocyte proliferation are strongly enhanced in subjects who suffer from asthma due to platinum salt. In addition, in vitro stimulation with sodium hexachloroplatinate modulates the frequencies of certain T-cell receptor-bearing T-cells.
Telomerase as a therapeutic target in cancer Gellert, Ginelle C.; Jackson, Shalmica R.; Dikmen, Z. Gunnur ...
Drug discovery today. Disease mechanisms,
2005, Letnik:
2, Številka:
2
Journal Article
Recenzirano
Advances in chromosome dynamics have increased our understanding of the significant role of telomeres and telomerase in cancer. Telomerase is expressed in almost all cancer cells but is inactive in ...most normal somatic cells. Therefore, telomerase is an important target for the design of therapeutic agents that might have minimal side effects. Herein, we evaluate current approaches to telomerase-targeted therapy, discuss the benefits and disadvantages, and speculate on the future direction of telomerase inhibitors as cancer therapeutics.
David Fisher – Departments of Medical Oncology and Pediatric Oncology, Dana-Farber Cancer Institute, USA
To estimate the prevalence of elevated lead levels among children in Orange County, California, and to evaluate the appropriateness of a universal pediatric blood lead screening policy in this ...community.
Venous blood lead testing was conducted and results were analyzed according to seven blood lead strata ranging from less than 0.50 mumol/L (10 micrograms/dL) to 3.35 mumol/L (70 micrograms/dL) or higher. A cost analysis of the lead-testing program in Orange County was conducted.
Children meeting poverty eligibility criteria and attending the Child Health and Disability Prevention Program, the state's implementation of the federal Early and Periodic Screening, Diagnosis and Treatment (EPSDT) services program.
A total of 5115 Orange County children between 12 and 72 months of age using EPSDT services from March through December 1992.
Blood lead levels and associated costs of the testing program stratified by level of blood lead elevation.
Blood lead levels of 0.50 mumol/L (10 micrograms/dL) or higher were found in 371 children (7.25%; 95% confidence interval, 6.66% to 7.85%), but only six children (0.12%; 95% confidence interval, 0.04% to 0.20%) had elevations greater than 1.20 mumol/L (25 micrograms/dL). Five children (83.3%) had histories of lead consumption unrelated to ingestion of lead-containing paint but related to the use of lead-containing folk remedies and cooking utensils. Costs for detection of children with blood levels elevated to 0.50 mumol/L (10 micrograms/dL) or higher was $310 per child and for levels of 1.20 mumol/L (25 micrograms/dL) or higher was $19,139 per child.
These data suggest that lead poisoning is not a major public health problem among Orange County children and detection of infrequent cases would involve a high cost per child. In jurisdictions with newer housing, initial screening for a history of possible lead exposure alone may offer reasonable efficacy that is cost-effective. The scope of lead-testing programs should be determined according to local needs and conditions.
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