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Shastri SD, Moldovan N. Submicron focusing of high-energy X-rays with silicon saw-tooth refractive lenses - fabrication and aberrations: errata. Opt Express 2021; 29:5644. [PMID: 33726098 DOI: 10.1364/oe.420748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Three (3) items of errata are submitted for our recently published paper [Opt. Express28, 36505 (2020)10.1364/OE.405566]. One is a clarifying extension to the Fig. 3 caption. Two are typographical corrections. The scientific results and conclusions are unaffected.
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Shastri SD, Moldovan N. Submicron focusing of high-energy X-rays with silicon saw-tooth refractive lenses: fabrication and aberrations. Opt Express 2020; 28:36505-36515. [PMID: 33379743 DOI: 10.1364/oe.405566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/14/2020] [Indexed: 06/12/2023]
Abstract
Saw-tooth refractive lenses are extremely well-suited to focus high energy X-rays (>50 keV). These lenses have properties of being continuously tunable (in energy or focal length), effectively parabolic, in-line, and attenuation-free on-axis. Vertical focusing of 60 keV synchrotron X-rays to 690 nm at a focal length f = 1.3 m with silicon saw-tooth lenses at a high-energy undulator radiation beamine is demonstrated, with discussion of relevant fabrication and mounting considerations and of geometrical aberrations unique to these devices. Aberration corrections towards further progress into the diffraction-limited nanofocusing regime are suggested. The versatility of such optics, combined with the attainability of smaller spot sizes at these penetrating photon energies, should continue to enhance material microstructure investigations at increasingly higher spatial resolutions.
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Moldovan N, Wang L, Kidane B, Nugent Z, Qing G, Tan L, Buduhan G, Srinathan S, Aliani M, Ahmed N. Non-Invasive Exploration of Metabolic Profile of Lung Cancer with Nuclear Magnetic Resonance Spectroscopy. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.1198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Moldovan N, Moore J, Rivest R, Ahmed S, Liu J, Bashir B, Lambert P, Guest M, Nashed M. Organ Motion During Neoadjuvant Chemoradiotherapy for Rectal Cancer – A Call to Update the RTOG Contouring Guidelines. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Sumant AV, Auciello O, Krauss AR, Gruen DM, Ersoy D, Tucek J, Jayatissa A, Stach E, Moldovan N, Mancini D, Busmann HG, Meyer EM. Fabrication of MEMS Components Based on Ultrananocrystalline Diamond Thin Films and Characterization of Mechanical Properties. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-657-ee5.33] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe mechanical, thermal, chemical, and tribological properties of diamond make it an ideal material for the fabrication of MEMS components. However, conventional CVD diamond deposition methods result in either a coarse-grained pure diamond structure that prevents high- resolution patterning, or in a fine-grained diamond film with a significant amount of intergranular non-diamond carbon. At Argonne National Laboratory, we are able to produce phase-pure ultrananocrystalline diamond (UNCD) films for the fabrication of MEMS components. UNCD is grown by microwave plasma CVD using C60-Ar or CH4-Ar plasmas, resulting in films that have 3-5 nm grain size, are 10-20 times smoother than conventionally grown diamond films, and can have mechanical properties similar to that of single crystal diamond. We used lithographic patterning, lift-off, and etching, in conjunction with the capability for growing UNCD on SiO2 to fabricate 2-D and 3-D UNCD-MEMS structures. We have performed initial characterization of mechanical properties by using nanoindentation and in-situ TEM indentor techniques. The values of Hardness (∼88 GPa) and Young's modulus (∼ 864 GPa) measured are very close to those of single crystal diamond (100 GPa and 1000 GPa respectively). The results show that UNCD is a promising material for future high performance MEMS devices.
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Auciello O, Krauss A, Gruen D, Meyer E, Busmann H, Tucek J, Sumant A, Jayatissa A, Moldovan N, Mancini DC, Gardos MN. Two- and Three-Dimensional Ultrananocrystalline Diamond (UNCD) Structures for a High Resolution Diamond-Based MEMS Technology. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-605-73] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractSilicon is currently the most commonly used material for the fabrication of microelectromechanical systems (MEMS). However, silicon-based MEMS will not be suitable for long-endurance devices involving components rotating at high speed, where friction and wear need to be minimized, components such as 2-D cantilevers that may be subjected to very large flexural displacements, where stiction is a problem, or components that will be exposed to corrosive environments. The mechanical, thermal, chemical, and tribological properties of diamond make it an ideal material for the fabrication of long-endurance MEMS components. Cost-effective fabrication of these components could in principle be achieved by coating Si with diamond films and using conventional lithographic patterning methods in conjunction with e. g. sacrificial Ti or SiO2 layers. However, diamond coatings grown by conventional chemical vapor deposition (CVD) methods exhibit a coarse-grained structure that prevents high-resolution patterning, or a fine-grained microstructure with a significant amount of intergranular non-diamond carbon. We demonstrate here the fabrication of 2-D and 3-D phase-pure ultrananocrystalline diamond (UNCD) MEMS components by coating Si with UNCD films, coupled with lithographic patterning methods involving sacrificial release layers. UNCD films are grown by microwave plasma CVD using C60-Ar or CH4-Ar gas mixtures, which result in films that have 3-5 nm grain size, are 10-20 times smoother than conventionally grown diamond films, are extremely resistant to corrosive environments, and are predicted to have a brittle fracture strength similar to that of single crystal diamond.
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Stutman D, Finkenthal M, Moldovan N. Development of optics for x-ray phase-contrast imaging of high energy density plasmas. Rev Sci Instrum 2010; 81:10E504. [PMID: 21034032 DOI: 10.1063/1.3479116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Phase-contrast or refraction-enhanced x-ray radiography can be useful for the diagnostic of low-Z high energy density plasmas, such as imploding inertial confinement fusion (ICF) pellets, due to its sensitivity to density gradients. To separate and quantify the absorption and refraction contributions to x-ray images, methods based on microperiodic optics, such as shearing interferometry, can be used. To enable applying such methods with the energetic x rays needed for ICF radiography, we investigate a new type of optics consisting of grazing incidence microperiodic mirrors. Using such mirrors, efficient phase-contrast imaging systems could be built for energies up to ∼100 keV. In addition, a simple lithographic method is proposed for the production of the microperiodic x-ray mirrors based on the difference in the total reflection between a low-Z substrate and a high-Z film. Prototype mirrors fabricated with this method show promising characteristics in laboratory tests.
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Affiliation(s)
- D Stutman
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
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Liu J, Grierson DS, Moldovan N, Notbohm J, Li S, Jaroenapibal P, O'Connor SD, Sumant AV, Neelakantan N, Carlisle JA, Turner KT, Carpick RW. Preventing nanoscale wear of atomic force microscopy tips through the use of monolithic ultrananocrystalline diamond probes. Small 2010; 6:1140-1149. [PMID: 20486220 DOI: 10.1002/smll.200901673] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Nanoscale wear is a key limitation of conventional atomic force microscopy (AFM) probes that results in decreased resolution, accuracy, and reproducibility in probe-based imaging, writing, measurement, and nanomanufacturing applications. Diamond is potentially an ideal probe material due to its unrivaled hardness and stiffness, its low friction and wear, and its chemical inertness. However, the manufacture of monolithic diamond probes with consistently shaped small-radius tips has not been previously achieved. The first wafer-level fabrication of monolithic ultrananocrystalline diamond (UNCD) probes with <5-nm grain sizes and smooth tips with radii of 30-40 nm is reported, which are obtained through a combination of microfabrication and hot-filament chemical vapor deposition. Their nanoscale wear resistance under contact-mode scanning conditions is compared with that of conventional silicon nitride (SiN(x)) probes of similar geometry at two different relative humidity levels (approximately 15 and approximately 70%). While SiN(x) probes exhibit significant wear that further increases with humidity, UNCD probes show little measurable wear. The only significant degradation of the UNCD probes observed in one case is associated with removal of the initial seed layer of the UNCD film. The results show the potential of a new material for AFM probes and demonstrate a systematic approach to studying wear at the nanoscale.
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Affiliation(s)
- J Liu
- University of Wisconsin-Madison Madison, WI 53706, USA
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Lin JJA, Paterson D, Peele AG, McMahon PJ, Chantler CT, Nugent KA, Lai B, Moldovan N, Cai Z, Mancini DC, McNulty I. Measurement of the spatial coherence function of undulator radiation using a phase mask. Phys Rev Lett 2003; 90:074801. [PMID: 12633233 DOI: 10.1103/physrevlett.90.074801] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2002] [Indexed: 05/24/2023]
Abstract
A measurement of the horizontal coherence function of 7.9 keV radiation from an undulator beam line at the Advanced Photon Source is reported. X-ray diffraction from a phase-shifting mask was used, and the coherence function was measured as a function of the width of beam-conditioning slits in the beam line. The coherence distribution is found to be best described by a Lorentzian function.
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Affiliation(s)
- J J A Lin
- School of Physics, University of Melbourne, Victoria 3010, Australia
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Wang JH, Goldschmidt-Clermont P, Moldovan N, Yin FC. Leukotrienes and tyrosine phosphorylation mediate stretching-induced actin cytoskeletal remodeling in endothelial cells. Cell Motil Cytoskeleton 2000; 46:137-45. [PMID: 10891859 DOI: 10.1002/1097-0169(200006)46:2<137::aid-cm6>3.0.co;2-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We studied actin cytoskeletal remodeling and the role of leukotrienes and tyrosine phosphorylation in the response of endothelial cells to different types of cyclic mechanical stretching. Human aortic endothelial cells were grown on deformable silicone membranes subjected to either cyclic one-directional (strip) stretching (10%, 0.5 Hz), or biaxial stretching. After 1 min of either type of stretching, actin cytoskeletons of the stretched cells were already disrupted. After stretching for 10 and 30 min, the percentage of the stretched cells that had disrupted actin cytoskeletons were significantly increased, compared with control cells without stretching. Also, at these two time points, biaxial stretching consistently produced higher frequencies of actin cytoskeleton disruption. At 3 h, strip stretching caused the formation of stress fiber bundles, which were oriented nearly perpendicular to the stretching direction. With biaxial stretching, however, actin cytoskeletons in many stretched cells were remodeled into three-dimensional actin structures protruding outside the substrate plane, within which cyclic stretching was applied. In both stretching conditions, actin filaments were formed in the direction without substrate deformation. Moreover, substantially inhibiting either leukotriene production with nordihydroguaiaretic acid or tyrosine phosphorylation with tyrphostin A25 did not block the actin cytoskeletal remodeling. However, inhibiting both leukotriene production and tyrosine phosphorylation completely blocked the actin cytoskeletal remodeling. Thus, the study showed that the remodeling of actin cytoskeletons of the stretched endothelial cells include rapid disruption first and then re-formation. The resulting pattern of the actin cytoskeleton after remodeling depends on the type of cyclic stretching applied, but under either type of cyclic stretching, the actin filaments are formed in the direction without substrate deformation. Finally, leukotrienes and tyrosine phosphorylation are necessary for actin cytoskeletal remodeling of the endothelial cells in response to mechanical stretching.
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Affiliation(s)
- J H Wang
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri, USA.
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Marsh CB, Pomerantz RP, Parker JM, Winnard AV, Mazzaferri EL, Moldovan N, Kelley TW, Beck E, Wewers MD. Regulation of monocyte survival in vitro by deposited IgG: role of macrophage colony-stimulating factor. J Immunol 1999; 162:6217-25. [PMID: 10229867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
IgG deposition at tissue sites characteristically leads to macrophage accumulation and organ injury. Although the mechanism by which deposited IgG induces tissue injury is not known, we have recently demonstrated that deposited IgG stimulates the release of IL-8 and monocyte chemoattractant protein-1 from normal human monocytes, which may drive inflammation. Since IgG also induces macrophage accumulation in these diseases, we hypothesized that deposited IgG protects monocytes from apoptosis. As an in vitro model of the effect of deposited IgG on monocyte survival, monocyte apoptosis was studied after FcgammaR cross-linking. Monocytes cultured on immobilized IgG, which induces FcgammaR cross-linking, were protected from apoptosis, whereas monocytes cultured with equivalent concentrations of F(ab')2 IgG or 50 times higher concentrations of soluble IgG, neither of which induces FcgammaR cross-linking, were not protected. Moreover, this protection was transferable, as supernatants from immobilized IgG-stimulated monocytes protected freshly isolated monocytes from apoptosis and contained functional M-CSF, a known monocyte survival factor. M-CSF mediated the monocyte survival induced by FcgammaR cross-linking, as neutralizing anti-human M-CSF Abs blocked the monocyte protection provided by either immobilized IgG or IgG-stimulated monocyte supernatants. These findings demonstrate a novel mechanism by which deposited IgG targets tissue macrophage accumulation through FcgammaR-mediated M-CSF release. This pathway may play an important role in promoting and potentiating IgG-mediated tissue injury.
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Affiliation(s)
- C B Marsh
- Division of Pulmonary and Critical Care Medicine and The Heart and Lung Institute, Ohio State University College of Medicine and Public Health, Columbus, OH 43210, USA.
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Alvarez RJ, Gips SJ, Moldovan N, Wilhide CC, Milliken EE, Hoang AT, Hruban RH, Silverman HS, Dang CV, Goldschmidt-Clermont PJ. 17beta-estradiol inhibits apoptosis of endothelial cells. Biochem Biophys Res Commun 1997; 237:372-81. [PMID: 9268719 DOI: 10.1006/bbrc.1997.7085] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Endothelial cells provide an antithrombotic and anti-inflammatory barrier for the normal vessel wall. Dysfunction of endothelial cells has been shown to promote atherosclerosis, and normalization of previously dysfunctional endothelial cells can inhibit the genesis of atheroma. In normal arteries, endothelial cells are remarkably quiescent. Acceleration of the turnover rate of endothelial cells can lead to their dysfunction. Apoptosis is a physiological process that contributes to vessel homeostasis, by eliminating damaged cells from the vessel wall. However, increased endothelial cell turnover mediated through accelerated apoptosis may alter the function of the endothelium and therefore, promote atherosclerosis. Apoptotic endothelial cells can be detected on the luminal surface of atherosclerotic coronary vessels, but not in normal vessels. This finding links endothelial cell apoptosis and the process of atherosclerosis, although a causative role for apoptosis in this process remains hypothetical. Estrogen metabolites have been shown to be among the most potent anti-atherogenic agents available to date for post-menopausal women. The mechanism of estrogen's protective effect is currently incompletely characterized. Here we show that 17beta-estradiol, a key estrogen metabolite, inhibits apoptosis in cultured endothelial cells. Our data support the hypothesis that 17beta-estradiol's anti-apoptotic effect may be mediated via improved endothelial cell interaction with the substratum, increased tyrosine phosphorylation of pp125 focal adhesion kinase, and a subsequent reduction in programmed cell death of endothelial cells. Inhibition of apoptosis by estrogens may account for some of the anti-atherogenic properties of these compounds.
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Affiliation(s)
- R J Alvarez
- Department of Medicine, The Johns Hopkins University, Baltimore, Maryland, 21287, USA
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Lupu F, Moldovan N, Ryan J, Stern D, Simionescu N. Intrinsic procoagulant surface induced by hypercholesterolaemia on rabbit aortic endothelium. Blood Coagul Fibrinolysis 1993; 4:743-52. [PMID: 8292724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The effect of hyperlipidaemia on endothelial cell haemostatic properties was examined using ex vivo studies on aortic segments obtained from fat-fed Chinchilla rabbits, mounted in a template device which exposed the luminal surface. Exposure of arterial endothelium to lipids resulted in marked enhancement of externally exposed anionic phospholipids, detected using either fluorescence microscopy with the probe merocyanine 540 or by binding of 125I-polymyxin B and 125I-Annexin V. Consistent with the known procoagulant properties of anionic phospholipid, following the lipid and cholesterol-rich diet intake, intact endothelial cells demonstrated enhanced binding of radioiodinated factors IX/IXa and Xa, and enhanced factor IXa/VIII-dependent factor X activation and factor Xa-factor Va-mediated prothrombin activation. Both factor Xa and thrombin formation were blocked, in large part, by polymyxin B, suggesting dependence of the reaction on anionic phospholipids. Consistent with these results, evidence of increased activation of the coagulation mechanism in vivo was observed in hyperlipidaemic animals, as assessed by a three-fold increase in levels of circulating antithrombin-protease complexes, compared with normolipidaemic controls.
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Affiliation(s)
- F Lupu
- Institute of Cellular Biology and Pathology, Bucharest, Romania
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Abstract
The effect of 4-hydroxynonenal (HNE), a lipid peroxidation product, on junctional communication (JC) among cultured vascular endothelial cells was assessed by both study of the transfer of microinjected 6-carboxyfluorescein between neighboring cells and measurement by a "cut-loading and dye transfer" technique. Both methods indicated that at concentrations higher than 10(-9) M and testing times between 6 and 8 h HNE reduces endothelial cell junctional communication. At 10(-8) M, a gradual development of HNE effect appears during 6-8 h of exposure but is followed by a slow recovery completed at 20 h. The reduction in junctional communication is not produced by the inhibition of protein synthesis, as tested by radiolabeled leucine incorporation. The HNE effect might be relevant to pathological processes in which lipid peroxidation is associated with uncontrolled cell proliferation, as in atherogenesis and promotion of carcinogenesis by chronic inflammation.
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Affiliation(s)
- A Radu
- Institute of Cellular Biology and Pathology, Bucharest, Romania
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