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  • 1
    Electronic Resource
    Electronic Resource
    Direct, high throughput LIGA for commercial applications: a progress report (2000)
    Springer
    Microsystem technologies 6 (2000), S. 103-105 
    Details
    ISSN: 1432-1858
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Technology
    Notes: Abstract Direct LIGA; LIGA without injection molding; has the potential to become a cost effective, high throughput form of LIGA. The process requires high energy photons; near 20,000 eV; which are best produced in facilities such as the X-ray ring at Brookhaven National Laboratory. The increased absorption lengths over lower energy photons eliminates the need for a membrane type X-ray mask. This in turn facilitates very large area X-ray masks fabricated from standard silicon wafers with 20 μm gold absorbers. The absorption length increase in PMMA to 2 cm is used to implement stacked PMMA exposures in which 1 mm thick PMMA layers are used to produce exposed PMMA sheets. These sheets are eventually solvent bonded to working substrates with plating bases. New high energy X-ray masks have been developed. Two exposure stations at Brookhaven are operational. The recently commissioned manufacturing exposure station which uses a 22 inch scanner which can expose four separate PMMA-mask combination is in the testing phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005420050007
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  • 2
    Electronic Resource
    Electronic Resource
    Ionization potentials and radii of neutral and ionized species of elements 107 (bohrium) and 108 (hassium) from extended multiconfiguration Dirac–Fock calculations (2002)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 116 (2002), S. 1862-1868 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Large multiconfiguration Dirac–Fock calculations were performed for all neutral and up to 7 and 8 times ionized species of elements 107 and 108, respectively, as well as all the homologous elements Mn, Tc, Re, Fe, Ru, and Os for a number of different total angular momenta. Comparison of the resulting ionization potentials to the known values of the homologues allow an extrapolation and thus a prediction of the chemically important seven or eight ionization potentials of elements 107 or 108 as well as a prediction of some ionic radii. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1430256
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  • 3
    Electronic Resource
    Electronic Resource
    THE CHLOROPLAST ATP SYNTHASE: A Rotary Enzyme? (2000)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Plant Physiology and Plant Molecular Biology 51 (2000), S. 83-109 
    Details
    ISSN: 1040-2519
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Notes: Abstract The chloroplast adenosine triphosphate (ATP) synthase is located in the thylakoid membrane and synthesizes ATP from adenosine diphosphate and inorganic phosphate at the expense of the electrochemical proton gradient formed by light-dependent electron flow. The structure, activities, and mechanism of the chloroplast ATP synthase are discussed. Emphasis is given to the inherent structural asymmetry of the ATP synthase and to the implication of this asymmetry to the mechanism of ATP synthesis and hydrolysis. A critical evaluation of the evidence in support of and against the notion that one part of the enzyme rotates with respect to other parts during catalytic turnover is presented. It is concluded that although rotation can occur, whether it is required for activity of the ATP synthase has not been established unequivocally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.arplant.51.1.83
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  • 4
    Electronic Resource
    Electronic Resource
    Prior exposure to a behaviorally sensitizing regimen of d-methamphetamine does not alter the striatal dopaminergic damage induced by a neurotoxic regimen (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Addiction biology 5 (2000), S. 0 
    Details
    ISSN: 1369-1600
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Repeated exposure to psychostimulant drugs such as d-methamphetamine (d-METH) and cocaine can be associated with extremely long-lived changes in dopamine systems at the behavioral, cellular and molecular level. Sensitization or an enhanced response to drug exposure is one such change. Investigations of these phenomena at the cellular and molecular levels are being conducted in the hope that this will aid in understanding how such adaptations might contribute to drug addition. Repeated exposure to certain amphetamines can also result in damage to dopaminergic pathways. Although some of the same molecular adaptations and mechanisms are suspected to occur or play a role in the neurotoxic sequelae associated with psychostimulant exposure, there has been little attempt to examine the relationship among these phenomena. Here we utilized C57BL/6J female mice to examine whether exposure to a sensitizing regimen of d-METH would impact the degree of neural injury induced by a subsequent exposure to a neurotoxic regimen of the same psychostimulant. Every other day exposure to d-METH (1.0 or 2.0 mg/kg) for 11 days produced a behavioral sensitization, as evidenced by a significant increase in the degree of locomotor activity induced by each subsequent exposure to d-METH. Following a 5-day period of no drug exposure sensitized mice were given a neurotoxic regiment of d-METH (a total of four injections of 10.0 mg/kg, one every 2 hours) and striatal tissue examined 72 hours later. All groups, whether drug-naive or sensitized previously to d-METH, showed exactly the same degree of dopaminergic striatal damage induced by a neurotoxic regimen. This was evidenced by equivalent reductions in dopamine and elevations in GFAP protein, a marker of astrocytic response to injury, GFAP. The inability of a sensitizing regimen to either exacerbate or lessen the neurotoxic actions of the same compound suggests that the molecular and cellular control of these two aspects of psychostimulant exposure may differ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1369-1600.2000.tb00203.x
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  • 5
    Electronic Resource
    Electronic Resource
    The interaction of two vortices on a beta-plane (2001)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 13 (2001), S. 884-893 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Two motion of two interacting vortices in the presence of a background gradient of potential vorticity due to the β-effect is considered. The vortices, and their interaction, are modeled using a two-layer, quasigeostrophic model. The paper extends that of McDonald [Philos. Trans. R. Soc. London, Ser. A 456, 1029 (2000)] who, using a similar model, considered only steady configurations of zonally aligned vortices, i.e., lying along the same parallel of latitude. Here Green's function techniques are used to calculate the velocity of one vortex due to the presence of the Rossby wave wake of the other. This enables consideration of the more general case of vortices having arbitrary relative location, the only requirement being that the vortices are well-separated (i.e., several Rossby radii apart). An additional quasisteady approximation enables the time evolution of vortices to be studied. Of particular interest is the existence of equilibrium configurations in which the vortices do not move relative to each other and maintain their orientation with respect to the direction defined by the gradient of the background potential vorticity field. It is shown that necessary conditions for equilibrium are that the vortices are (a) of equal strength, or (b) aligned zonally. The stability of equilibria to small perturbations in the relative location of the vortices is investigated and the equilibria found to be weakly unstable in that the vortex trajectories drift slowly (but not exponentially fast) from their equilibrium paths. This is verified by numerical computation of the trajectories near equilibrium. For equal strength vortices not in equilibrium the distance between the vortices remains constant, but the line joining the two vortices rotates with constant angular velocity. For this case, examples of the trajectories of the individual vortices and the center of mass are given. For vortices of differing strength and arbitrary initial configurations, the motion is, in general, complicated. Some examples are presented. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1351858
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  • 6
    Electronic Resource
    Electronic Resource
    X-ray transmission through a plasma window (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 1677-1679 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Traditional solid window materials used for x-ray synchrotron beamlines may introduce undesirably high attenuation, or are subject to failure under high heat loads. A plasma window can in principle obviate these problems over a wide range of energies. Experiments were performed at the Brookhaven National Laboratory National Synchrotron Light Source on beamline X6A to study the transmission characteristics of a plasma window using argon as the arc gas. Measurements were made around the Ar K edge and far from resonance. The "white-line" absorption at the K edge was actually suppressed during arc operation as compared to room temperature gas at the same pressure. This is attributed to the high degree of ionization in the plasma. The relative strength of the white line to the edge jump does not seem to be a strong function of arc current at the argon K edge. Away from resonance (∼3 times the edge energy) x-ray attenuation was negligible. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1344598
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  • 7
    Electronic Resource
    Electronic Resource
    Is your patient taking the medicine? A simple assay to measure compliance with 5-aminosalicylic acid-containing compounds (2002)
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 16 (2002), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background : Poor compliance with 5-aminosalicylic acid therapy has been reported amongst patients with inflammatory bowel disease. Currently, there is no easy method to monitor 5-aminosalicylic acid; however, the chemical similarity between 5-aminosalicylic acid and salicylate might provide a solution.Aim : To determine the feasibility of using salicylate levels to monitor compliance with 5-aminosalicylic acid medication.Methods : Thirty-six patients with inflammatory bowel disease, taking maintenance 5-aminosalicylic acid, provided either a paired serum and urine sample or an intestinal biopsy. Samples were split into two: half were sent to the hospital biochemistry department for salicylate measurement, and half were analysed for 5-aminosalicylic acid and its metabolite, N-acetyl-5-aminosalicylic acid, using high performance liquid chromatography. Correlation between the results was calculated.Results : Serum and urine were available for 25 patients. Serum salicylate was undetectable, but urinary salicylate ranged from 31 to 3254 µg/mL. The correlations between urinary salicylate and 5-aminosalicylic acid and N-acetyl-5-aminosalicylic acid were 0.96 (95% confidence interval, 0.91–0.98) and 0.9 (95% confidence interval, 0.77–0.96), respectively. Sixteen biopsies were available from 13 patients. The 5-aminosalicylic acid and N-acetyl-5-aminosalicylic acid concentrations were 0.2–657 ng/mg and 1.6–1598 ng/mg, respectively; there was no correlation with bowel salicylate.Conclusions : The close correlation between 5-aminosalicylic acid and salicylate levels offers a simple method to assess compliance with 5-aminosalicylic acid therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.2002.01375.x
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  • 8
    Electronic Resource
    Electronic Resource
    Elevated Antibody Responses in Patients with Crohn's Disease against a 14-kDa Secreted Protein Purified from Mycobacterium avium subsp. paratuberculosis (2001)
    Oxford, UK : Blackwell Science Ltd
    Scandinavian journal of immunology 53 (2001), S. 0 
    Details
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Patients with Crohn's disease (CD) (n = 10) and ulcerative colitis (UC) (n = 10) were tested for immune responses against various antigens from Mycobacterium avium subsp. paratuberculosis; alkyl hydroperoxide reductase C (AhpC) and alkyl hydroperoxide reductase D (AhpD), which are constitutively expressed in this species as opposed to other mycobacteria, a 14-kDa secreted antigen and PPD-J. The CD patients had significantly elevated antibody levels against the 14 kDa protein (P 〈 0.05) that were negatively correlated with the duration of the disease (rs = − 0.85). They also seemed to have increased antibody levels against AhpC and AhpD, but the differences between the two groups were not significant. However, taken together, the antibody responses to three individual mycobacterial antigens in CD patients strengthen the possibility that the observed responses are caused by mycobacterial infection. No significant differences in the interferon (IFN)-γ production, the interleukin (IL)-10 production and the ability to proliferate upon stimulation with these antigens were observed. These results show that measuring antibody responses against purified specific antigens is a suitable and simple approach when assessing the connection between CD and mycobacteria in patients with clinical CD. Another important aspect in such studies is to have well defined patient groups tested at the onset of clinical symptoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3083.2001.00857.x
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  • 9
    Electronic Resource
    Electronic Resource
    Ultrastructural Observations on the Platelets of the Arabian Tahr (Hemitragus jayakari) (2002)
    Berlin, Germany : Blackwell Verlag GmbH
    Anatomia, histologia, embryologia 31 (2002), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The ultrastructure of platelets was studied in specimens of peripheral blood from 18 healthy adult Arabian tahrs (Hemitragus jayakari). The platelets were characterized by their extreme polymorphism. The number of alpha granules, typically one to six per cell, was considerably less than that reported for most animal platelets. Similar to humans, the platelets of the Arabian tahr had nucleoids within the alpha granules. However, nucleoids were not a consistent finding. One or more electron-dense granules, most commonly contained within clear vesicles, was commonly observed. A unique feature was the lack of an open canalicular system, which is considered a hallmark feature of this cell type in most mammalian and reptilian platelets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0264.2002.00379.x
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  • 10
    Electronic Resource
    Electronic Resource
    SUMO conjugation and deconjugation (2000)
    Springer
    Molecular genetics and genomics 263 (2000), S. 771-786 
    Details
    ISSN: 1617-4623
    Keywords: Key wordsSaccharomyces cerevisiae ; Ubiquitin-like protein ; ULP ; SUMO/SMT3 ; UBA2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ligation of the ubiquitin-like protein SUMO (Smt3p) to other proteins is essential for viability of the yeast Saccharomyces cerevisiae. Like ubiquitin (Ub), SUMO undergoes ATP-dependent activation by a specific activating enzyme. SUMO-activating enzyme is a heterodimer composed of Uba2p and Aos1p, polypeptides with sequence similarities, respectively, to the C- and N-terminal parts of Ub-activating enzyme. To study the function of SUMO conjugation, we isolated uba2 mutants that were temperature-sensitive for growth. In these mutants conjugation of SUMO to other proteins was drastically reduced, even at the temperature permissive for growth. In a screen for spontaneous suppressors of the temperature-sensitive growth phenotype of the mutant uba2-ts9, we isolated a strain with a null mutation (sut9) in a gene of hitherto unknown function (SUT9/YIL031W/SMT4). This gene encodes a protein with similarities to Ulp1p, a dual-function protease that processes the SUMO precursor and deconjugates SUMO from its substrates. The novel protein was therefore termed Ulp2p. Inactivation of ULP2 in a strain expressing wild-type SUMO-activating enzyme resulted in slow and temperature-sensitive growth, and accumulation of SUMO conjugates. Thus, mutations in SUMO-activating enzyme and mutations in Ulp2p suppress each other, indicating that SUMO conjugation and deconjugation must be in balance for cells to grow normally. Other phenotypes of ulp2 mutants include a defect in cell cycle progression, hypersensitivity to DNA damage, and chromosome mis-segregation. Ulp2p is predominantly located within the nucleus, whereas Ulp1p colocalizes with nuclear pore complex proteins, indicating that the apparently distinct functions of the two SUMO deconjugating enzymes are spatially separated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004380000254
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