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Schill WJ, Armstrong MR, Nguyen JH, Sterbentz DM, White DA, Benedict LX, Rieben RN, Hoff A, Lorenzana HE, Belof JL, La Lone BM, Staska MD. Suppression of Richtmyer-Meshkov Instability via Special Pairs of Shocks and Phase Transitions. Phys Rev Lett 2024; 132:024001. [PMID: 38277580 DOI: 10.1103/physrevlett.132.024001] [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] [Received: 03/23/2023] [Revised: 11/13/2023] [Accepted: 11/28/2023] [Indexed: 01/28/2024]
Abstract
The classical Richtmyer-Meshkov instability (RMI) is a hydrodynamic instability characterizing the evolution of an interface following shock loading. In contrast to other hydrodynamic instabilities such as Rayleigh-Taylor, it is known for being unconditionally unstable: regardless of the direction of shock passage, any deviations from a flat interface will be amplified. In this article, we show that for negative Atwood numbers, there exist special sequences of shocks which result in a nearly perfectly suppressed instability growth. We demonstrate this principle computationally and experimentally with stepped fliers and phase transition materials. A fascinating immediate corollary is that in specific instances, a phase-transitioning material may self-suppress RMI.
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Affiliation(s)
- W J Schill
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - M R Armstrong
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - J H Nguyen
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - D M Sterbentz
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - D A White
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - L X Benedict
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - R N Rieben
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - A Hoff
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - H E Lorenzana
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - J L Belof
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - B M La Lone
- Special Technologies Laboratory, 5520 Ekwill Street, Suite B, Santa Barbara, California 93117, USA
| | - M D Staska
- Special Technologies Laboratory, 5520 Ekwill Street, Suite B, Santa Barbara, California 93117, USA
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Reed BW, Armstrong MR, Browning ND, Campbell GH, Evans JE, LaGrange T, Masiel DJ. The evolution of ultrafast electron microscope instrumentation. Microsc Microanal 2009; 15:272-281. [PMID: 19575828 DOI: 10.1017/s1431927609090394] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Extrapolating from a brief survey of the literature, we outline a vision for the future development of time-resolved electron probe instruments that could offer levels of performance and flexibility that push the limits of physical possibility. This includes a discussion of the electron beam parameters (brightness and emittance) that limit performance, the identification of a dimensionless invariant figure of merit for pulsed electron guns (the number of electrons per lateral coherence area, per pulse), and calculations of how this figure of merit determines the trade-off of spatial against temporal resolution for different imaging modes. Modern photonics' ability to control its fundamental particles at the quantum level, while enjoying extreme flexibility and a very large variety of operating modes, is held up as an example and a goal. We argue that this goal may be approached by combining ideas already in the literature, suggesting the need for large-scale collaborative development of next-generation time-resolved instruments.
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Affiliation(s)
- B W Reed
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA.
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Abstract
BACKGROUND AND OBJECTIVE Few studies have investigated femtosecond (fs) lasers for cutting bone tissue. STUDY DESIGN/MATERIALS AND METHODS A 775 nm, 1 kHz, 200 femtosecond, up to 400 microJ laser system was used to irradiate in vitro calcified cortical bone samples and bone tissue culture samples. RESULTS The ablation threshold in cortical bone was 0.69+/-0.08 J/cm(2) at 775 nm and 0.19+/-0.05 J/cm(2) at 387 nm. Plasma shielding experiments determined that the ablation plume and the plasma significantly affect material removal at high repetition rates and appear to generate thermal transients in calcified tissue. Confocal analysis revealed intact enzymatic activity on the surface of cells immediately adjacent to cells removed by fs laser irradiation. CONCLUSIONS These experiments demonstrate that fs lasers used for bone tissue cutting do not appear to generate significant temperature transients to inactivate proteins and that cellular membrane integrity is disrupted for only a few cell layers.
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Affiliation(s)
- B Girard
- Department of Medical Biophysics, Ontario Cancer Institute, University of Toronto, Ontario, Canada
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Armstrong MR, Ogilvie JP, Cowan ML, Nagy AM, Miller RJD. Observation of the cascaded atomic-to-global length scales driving protein motion. Proc Natl Acad Sci U S A 2003; 100:4990-4. [PMID: 12697894 PMCID: PMC154285 DOI: 10.1073/pnas.0936507100] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [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: 11/18/2022] Open
Abstract
Model studies of the ligand photodissociation process of carboxymyoglobin have been conducted by using amplified few-cycle laser pulses short enough in duration (<10 fs) to capture the phase of the induced nuclear motions. The reaction-driven modes are observed directly in real time and depict the pathway by which energy liberated in the localized reaction site is efficiently channeled to functionally relevant mesoscale motions of the protein.
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Affiliation(s)
- M R Armstrong
- Department of Physics and Astronomy, University of Rochester, Bausch & Lomb Hall, Rochester, NY 14627-0171, USA
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Armstrong MR, Plachta P, Ponomarev EA, Miller RJ. Versatile 7-fs optical parametric pulse generation and compression by use of adaptive optics. Opt Lett 2001; 26:1152-1154. [PMID: 18049546 DOI: 10.1364/ol.26.001152] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We have compressed the output from a beta-barium borate noncollinear optical parametric amplifier to ~7-fs pulse durations, using a micromachined deformable mirror with an efficient search algorithm. This compression method allows phase compensation of both material and gain dispersion, which produces an optimized wavelength-tunable pulse shape for ultrahigh-resolution time-domain spectroscopy.
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Runge VM, Armstrong MR, Barr RG, Berger BL, Czervionke LF, Gonzalez CF, Halford HH, Kanal E, Kuhn MJ, Levin JM, Low RN, Tanenbaum LN, Wang AM, Wong W, Yuh WT, Zoarski GH. A clinical comparison of the safety and efficacy of MultiHance (gadobenate dimeglumine) and Omniscan (Gadodiamide) in magnetic resonance imaging in patients with central nervous system pathology. Invest Radiol 2001; 36:65-71. [PMID: 11224753 DOI: 10.1097/00004424-200102000-00001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [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: 11/26/2022]
Abstract
RATIONALE AND OBJECTIVES The safety and diagnostic efficacy of MultiHance (gadobenate dimeglumine) in the central nervous system (CNS) were evaluated in a double-blind, multicenter, phase III clinical trial. METHODS Two hundred five patients highly suspected of having a CNS lesion (by previous imaging exam) were enrolled at 16 sites in the United States. Patients were randomized to one of three incremental dosing regimens. Magnetic resonance imaging with Omniscan (gadodiamide) at doses of 0.1 and 0.3 mmol/kg was compared with MultiHance (gadobenate dimeglumine) at doses of 0.05 and 0.15 mmol/kg and at 0.1 and 0.2 mmol/kg. RESULTS Compared with predose images alone, efficacy was demonstrated in each of the gadobenate dimeglumine and gadodiamide groups (single and cumulative doses) as indicated by the level of diagnostic information, number of lesions detected, and contrast-to-noise ratio measurements. The level of diagnostic information from gadobenate dimeglumine at 0.1 mmol/kg was equivalent to that with gadodiamide at the same dose. One of the two blinded reviewers found equivalence between the gadobenate dimeglumine 0.05 mmol/kg dose and gadodiamide at 0.1 mmol/kg. Both reviewers found the level of diagnostic information to be equivalent after the second dose of contrast for all three dosing regimens. The cumulative doses of gadobenate dimeglumine were well tolerated and as safe as gadodiamide. CONCLUSIONS Gadobenate dimeglumine is comparable to gadodiamide in terms of safety and efficacy for imaging of CNS lesions, with a possible advantage in imaging applications owing to enhanced T1 relaxivity.
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Affiliation(s)
- V M Runge
- University of Kentucky, Department of Diagnostic Radiology, Lexington 40536, USA.
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Abstract
The mitochondrial genome (mtDNA) of the plant parasitic nematode Globodera pallida exists as a population of small, circular DNAs that, taken individually, are of insufficient length to encode the typical metazoan mitochondrial gene complement. As far as we are aware, this unusual structural organization is unique among higher metazoans, although interesting comparisons can be made with the multipartite mitochondrial genome organizations of plants and fungi. The variation in frequency between populations displayed by some components of the mtDNA is likely to have major implications for the way in which mtDNA can be used in population and evolutionary genetic studies of G. pallida.
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Affiliation(s)
- M R Armstrong
- Department of Nematology, Scottish Crop Research Institute, Dundee, Scotland DD2 5DA.
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Abstract
A new concept is introduced whereby thermal stresses generated through the pumping process are canceled by an applied force. By use of a Nd:YVO(4) disk laser as a model system, significant reduction of thermal lensing and deformation is demonstrated as a function of applied pressure, and the output power (19 W TEM(00)) is limited only by the available pump power.
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Stone LA, Albert PS, Smith ME, DeCarli C, Armstrong MR, McFarlin DE, Frank JA, McFarland HF. Changes in the amount of diseased white matter over time in patients with relapsing-remitting multiple sclerosis. Neurology 1995; 45:1808-14. [PMID: 7477973 DOI: 10.1212/wnl.45.10.1808] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [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: 01/25/2023] Open
Abstract
MRI is a sensitive technique for assessing disease activity in MS. Diseased white matter (WM) can be identified on T2-weighted images, and active disease is reflected by abnormalities in the blood-brain barrier (BBB) shown on T1-weighted images after administration of paramagnetic contrast agents. Active disease may be demonstrated by contrast-enhanced MRI in patients with early, mild relapsing-remitting (RR) MS even during periods of clinical stability, which indicates that MS is an active process even during the early phase of the illness. To examine the amount of abnormal WM at frequent intervals over time, we studied seven mildly affected RRMS patients, all of whom had frequent contrast-enhancing lesions. These RRMS patients were imaged monthly for 26 to 36 months at 1.5 tesla; the area of abnormal increased WM signal was calculated by image-processing software that utilizes both the T2- and T1-weighted images. All patients showed fluctuations over time in amount of abnormal WM signal, which reflected factors such as the amount of BBB breakdown (measured by number or area of enhancing lesions) and measurement error. All seven RRMS patients, however, showed an overall increase in abnormal WM. Because of the fluctuations between individual measurements, the increase was most accurately reflected when the mean of the first 6 months' measurements was compared with the mean of the final 6 months' measurements, or when a linear regression model was applied.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L A Stone
- Neuroimmunology Branch, NINDS, NIH, Bethesda, MD 20892, USA
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Heier LA, Armstrong MR. What are the optimal MR pulse sequences for the detection of intramedullary spinal cord lesions? AJR Am J Roentgenol 1995; 164:1020. [PMID: 7726017 DOI: 10.2214/ajr.164.4.7726017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- L A Heier
- Cornell Medical Center, New York Hospital, New York 10021, USA
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Affiliation(s)
- T E Hubbert
- Department of Radiology (Henry M. Jackson Foundation), Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892
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Alger JR, Symko SC, Bizzi A, Posse S, DesPres DJ, Armstrong MR. Absolute quantitation of short TE brain 1H-MR spectra and spectroscopic imaging data. J Comput Assist Tomogr 1993; 17:191-9. [PMID: 8454744 DOI: 10.1097/00004728-199303000-00006] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.1] [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: 01/30/2023]
Abstract
A method for determining the concentrations of the materials that produce the well-resolved singlet signals in short TE brain 1H MR spectroscopic examinations is presented. Concentration determination is achieved by a water-referencing procedure. The ratios of the areas of the choline, total creatine, and N-acetyl signals to that of the water signal from the same volume of interest (VOI) are determined using acquisitions with and without water suppression. The tissue concentrations of the molecules producing the three signals can then be determined if the water concentration in the VOI can be found. This is done with a density-weighted MR study. The MR study provides the ratio of the mean MR signal amplitude from the VOI to that from an external standard containing a known water concentration. The method's flexibility is illustrated by using it with two different single-volume localization schemes and spectroscopic imaging. Preliminary evaluations of accuracy and reproducibility are made in phantom, animal, and limited human studies. The method's advantages and limitations are discussed.
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Affiliation(s)
- J R Alger
- Neuroimaging Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
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Abstract
We present a case of a patient with apoplexy due to infarction of a large pituitary macroadenoma. Conservative treatment with steroids resulted in reversal of symptoms and the adenoma involuted. This suggests that medical management may be sufficient therapy in some patients with this complication.
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Affiliation(s)
- M R Armstrong
- Department of Radiology, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892
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Armstrong MR, Marar H. Herniation of a duodenal diverticulum into the ascending colon. AJR Am J Roentgenol 1988; 151:1056-7. [PMID: 3140623 DOI: 10.2214/ajr.151.5.1056-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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