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ABSTRACT: Functional studies have shown altered cholinergic mechanisms in the inflamed bladder, which partly depend on muscarinic receptor-induced release of nitric oxide (NO). The current study aimed to characterize which muscarinic receptor subtypes that are involved in the regulation of the nitrergic effects in the bladder cholinergic response during cystitis. For this purpose, in vitro examinations of carbachol-evoked contractions of inflamed and normal bladder preparations were performed. The effects of antagonists with different selectivity for the receptor subtypes were assessed on intact and urothelium-denuded bladder preparations. In preparations from cyclophosphamide (CYP; in order to induce cystitis) pre-treated rats, the response to carbachol was about 75% of that of normal preparations. Removal of the urothelium or administration of a nitric oxide synthase inhibitor re-established the responses in the inflamed preparations. Administration of 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) inhibited the carbachol-induced contractile responses of preparations from CYP pre-treated rats less potently than controls. Pirenzepine and p-fluoro-hexahydro-sila-diphenidol (pFHHSiD) affected the carbachol-induced contractile responses to similar extents in preparations of CYP pre-treated and control rats. However, the Schild slopes for the three antagonists were all significantly different from unity in the preparations from CYP pre-treated rats. Again, L-NNA or removal of the urothelium eliminated any difference compared to normal preparations. This study confirms that muscarinic receptor stimulation in the inflamed rat urinary bladder induces urothelial release of NO, which counteracts detrusor contraction.
Autonomic neuroscience: basic & clinical 07/2012; 170(1-2):5-11. · 1.82 Impact Factor
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ABSTRACT: Regulation of bladder function involves both divisions of the autonomic nervous system. However, in addition to the classical autonomic transmitters, noradrenaline and acetylcholine, other autonomic transmitters and other signalling components play important roles in physiology and pathophysiology of the lower urinary tract. Several substances of neuronal non-adrenergic, non-cholinergic (NANC) systems have already proven to considerably influence functional responses in the inflamed urinary bladder. Interstitial cystitis (IC) or painful bladder syndrome (PBS) is a chronic inflammatory bladder disease, characterized by urinary frequency, urgency and pelvic pain. IC/PBS is difficult to diagnose, especially because the etiology of the condition is largely unknown. Despite the unclear nature of the cause and manifestation of IC/PBS, it has been shown that the disease involves a significant NANC component. Here, we review the possible roles of ATP, adenosine, nitric oxide, vasoactive intestinal polypeptide, substance P, and pituitary adenylate cyclase-activating peptide in the contribution to IC/PBS development and manifestation of IC/PBS symptoms.
Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 06/2012; 63(3):209-16. · 2.27 Impact Factor
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ABSTRACT: Highly abrasion and erosive resistance materials are an important group of materials and has very wide applications in many industrial areas. The characteristic properties for this material include the castability and the superior wear resistance. The material, however, is in the group of hard-to-machine materials due to its abrasion to cutting tool and low thermal conductivity. In this article, the experimental results were reported on machinability of a N-AR cast iron with use of PCBN cutting tool, mainly focusing on the determination of machining conditions, possible tool life and tool wear. Cutting forces and chip morphology of the N-AR iron material were also examined during the investigation to clarify the reason of high tool wear rate in the machining.
Materials and Manufacturing Processes 05/2008; 23(5):506-512. · 1.06 Impact Factor
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ABSTRACT: Colloidal polymer particles are widely used in a variety of applications ranging from chromatography to surface modified bioreactors in protein arrays. In the present study, surface attachment of polystyrene particles to a polystyrene substrate has been performed using oligonucleotide hybridization. Thiolated complementary oligomers of cytosine and guanine have been covalently coupled to a pyridyl disulphide (PDS) modified polyethyleneglycol tether, forming part of a triblock copolymer which is adsorbed to the polystyrene surfaces via hydrophobic polypropylene oxide center blocks. The ability to withstand shear forces was studied using a laminar flow cell and the uptake of oligomers on the particles was quantified using two complementary techniques: UV-spectroscopy and sedimentation field flow fractionation. The possibility to tether particles in a flow cell suitable for practical use in e.g. a FIA-system is demonstrated.
Colloids and Surfaces B Biointerfaces 05/2004; 34(3):165-71. · 3.46 Impact Factor
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R. Feifel,
A. Baev,
F. Gel’mukhanov,
H. Ågren,
M. N. Piancastelli, M. Andersson,
G. Öhrwall,
C. Miron,
M. Meyer,
S. L. Sorensen,
A. Naves de Brito,
O. Björneholm,
L. Karlsson,
S. Svensson
[show abstract]
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ABSTRACT: The duration-time concept, vastly successful for interpreting the frequency dependence of resonant radiative and nonradiative x-ray scattering spectra, is tested for fine-scale features that can be obtained with state of the art high-resolution spectroscopy. For that purpose resonant photoelectron (RPE) spectra of the first three outermost singly ionized valence states X2Σg+, A2Πu, and B2Σu+, are measured for selective excitations to different vibrational levels (up to n=13) of the N 1s⃗π* photoabsorption resonance in N2 and for negative photon frequency detuning relative to the adiabatic 0-0 transition of this resonance. It is found that different parts of the RPE spectrum converge to the spectral profile of direct photoionization (fast scattering) for different detunings, and that the RPE profiles are asymmetrical as a function of frequency detuning. The observed asymmetry contradicts the picture based on the simplified notation of a common scattering duration time, but is shown to agree with the here elaborated concept of partial and mean duration times. Results of the measurements and the simulations show that the duration time of the scattering process varies for different final electronic and different final vibrational states. This owes to two physical reasons: one is the competition between the fast “vertical” and the slow “resonant” scattering channels and the other is the slowing down of the scattering process near the zeros of the real part of the scattering amplitude.
Phys. Rev. A. 02/2004; 69(2).
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ABSTRACT: In precision hard turning, tool flank wear is one of the major factors contributing to the geometric error and thermal damage in a machined workpiece. Tool wear not only directly reduces the part geometry accuracy but also increases the cutting forces drastically. The change in cutting forces causes instability in the tool motion, and in turn, more inaccuracy. There are demands for reliably monitoring the progress of tool wear during a machining process to provide information for both correction of geometric errors and to guarantee the surface integrity of the workpiece. A new method for tool wear monitoring in precision hard turning is presented in this paper. The flank wear of a CBN tool is monitored by feature parameters extracted from the measured passive force, by the use of a force dynamometer. The feature parameters include the passive force level, the frequency energy and the accumulated cutting time. An ANN model was used to integrate these feature parameters in order to obtain more reliable and robust flank wear monitoring. Finally, the results from validation tests indicate that the developed monitoring system is robust and consistent for tool wear monitoring in precision hard turning.
International Journal of Advanced Manufacturing Technology 10/2003; 22(9):697-702. · 1.10 Impact Factor
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ABSTRACT: +½ O2→H2O on polycrystalline Pt foils has been studied by detection of desorbing OH radicals using the Resonance Enhanced Multiphoton
Ionization, REMPI, technique. The measurements were performed at catalyst temperatures of 1000–1400K and atotal pressure
below 10-4mbar. The studies of OH desorption by REMPI were achieved using atwo-photon excitation D2Σ-–X2Π (1–0), followed by one-photon ionization. The ions were detected in atime-of-flight mass spectrometer, TOF-MS, in order
to avoid interference from non-resonantly ionized molecules. By applying TOF-MS, asimultaneous non-resonant ionization and
detection of H2, O2 and H2O was achieved. Recorded REMPI spectra were compared with spectra simulated using known molecular constants. The kinetics
of the reaction derived from the measurements were compared with what was obtained in earlier LIF detection of OH, performed
at higher total reactant pressure using the A–X transition. REMPI TOF-MS is shown to be acomplement to LIF for reaction studies
below 5×10-4mbar total pressure, where LIF is too insensitive for quantification. The reaction kinetics was found to be in agreement
with atheoretic model and previous LIF studies.
Applied Physics B 04/1997; 64(5):573-578. · 2.19 Impact Factor
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ABSTRACT: A new experiment for measuring the reactivity of neutral metal clusters is presented. A low pressure reaction cell is used to measure the sticking ofO
2 andD
2 gas on small transition metal clusters ofCu, Fe, Co andNi. The experiment yields absolute values for the sticking, at a controlled number of cluster/gas collisions, facilitating comparison with theoretical calculations and other experiments. The most striking result of these preliminary measurements is the difference between oxygen sticking onCo
N
and onCu
N
, with the sticking onCu
N
showing a clear correlation to the electronic shell model, while the sticking onCo
N
only exhibits a sharp increase with size, reaching sticking probability=1.0 forN>25.
Zeitschrift für Physik D 01/1993; 26(1):334-336.
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ABSTRACT: Spectral measurements of the thermoluminescence from a polymineralic sand and its component minerals are reported. The signals from density-separated and chemically separated fractions of the sand are compared in an attempt to select wavelength regions characteristic of the quartz and feldspar mineral components. The data clearly demonstrate that for these materials the uses of conventional broad band optical filters and a blue sensitive photomultiplier tube fail to separate the mineral fractions, despite earlier claims. However, measurements in the near infra-red are characteristic of the feldspar components. Whilst density separations lead to clearly distinguishable spectral features for light, medium and heavy mineral fractions, subsequent HF etching and alpha irradiation emphasized that the TL of the density separated quartz fraction was dominated by the traces of feldspar contamination. Indeed, at the sensitivity level available, all the signal from the quartz fraction arose from traces of feldspar contaminants. The temperatures of the glow peaks are so similar in all mineral fractions that these values are a totally inadequate basis for mineral separation. The X-ray excited luminescence spectra differ from those of thermoluminescence but the blue/green radioluminescence is very similar for all the mineral fractions separated in this study. The similarity of radioluminescence and the glow peak temperatures are attributed to the role of the silicate groups, exciton decay paths and point defects in the silicate networks which are common to all the component minerals of feldspars, quartz, silica, zircon and silicates.
International Journal of Radiation Applications and Instrumentation. Part D. Nuclear Tracks and Radiation Measurements.
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ABSTRACT: The N 1s→π* photoabsorption profile of N2 is quantitatively analysed. New spectroscopical constants for the N 1s−1π* core-excited state are determined from NEXAFS spectra and compared to previously published data. The accuracy of the new spectroscopical constants is discussed and error bars are given for the present data analysis. The goodness of the new spectroscopical constants is demonstrated by lifetime vibrational interference (LVI) simulations of the resonant Auger decay from the N 1s−1π* core-excited state to the A2Πu singly ionized final state of N2. These new values give a much better agreement with recently obtained experimental data compared to the previously published ones.
Chemical Physics Letters.
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ABSTRACT: The initial oxidation of gas phase metal clusters is studied in a new experimental configuration. A beam of neutral metal clusters is produced in a laser vaporization source, and after skimming the beam passes a reaction cell where the clusters undergo one or a few collisions with oxygen molecules. The reaction products are detected with laser ionization and mass spectrometry. We have determined the sticking probability, S, of O2 on FeN, CoN and CuN clusters, with Nκ 10–60. FeN and CoN show a similar size dependence with low sticking probability, S < 0.2, for the smallest sizes, then increasing almost monotonically to Nκ 25, where S levels out at a constant value of 0.7 (FeN) or 1.0 (CoN). CuN shows a different size behavior with reactivity minima for clusters with closed electronic shells.
Nanostructured Materials.
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ABSTRACT: During past 10 years, the availability of polycrystalline cubic boron nitride (PCBN) tools has made application of hard turning increase remarkably in a range of industrial areas, especially in automotive, roller bearing and hydraulic industry. Among the applications of CBN cutting tools, precision hard turning attracts great interests since its environmentally friendly and flexibility, which ultimately has potential to replace grinding. Using today’s high precision hard turning with high precision motion control, high static and dynamic stiffness and thermal stability CNC machine, the dimensional accuracy can reach IT5. However, this accuracy still does not meet the demands from most industries. In addition, precision hard turning has been hampered by uncertainties with respect to part quality and process reliability. Many factors affect the machining accuracy and process stability. The presented work analysis the possible error driver factor and error sources in a precision hard turning and the strategy of on-line compensation of the dimensional errors in the process, based on the monitoring of tool wear and prediction of thermal expansion. Test results indicate that within the certain range of flank wear the developed method can improve the geometric accuracy significantly.
Journal of Materials Processing Technology.
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A. A. Abdo,
M. Ackermann,
M. Ajello, M. Andersson,
W B Atwood,
M. Axelsson,
L Baldini,
J. Ballet,
G. Barbiellini,
D. Bastieri, [......],
T. L. Usher,
V. Vasileiou,
N. Vilchez,
V Vitale,
A P Waite,
P Wang,
B. L. Winer,
K. S. Wood,
T. Ylinen,
M Ziegler
Physical Review Letters, v.103 (2009).
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K Wiesner,
R.F Fink,
S.L Sorensen, M Andersson,
R Feifel,
I Hjelte,
C Miron,
A Naves de Brito,
L Rosenqvist,
H Wang,
S Svensson,
O Björneholm
[show abstract]
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ABSTRACT: Resonant Auger electron spectra of core excited O3 (1s−12b11) are presented for the first time. The photoionization valence spectrum with sample purity and resolution superior to those published is presented. The first direct experimental evidence for the C̃2 B1 state of O3+ is found. Ab initio calculations of the resonant Auger electron (RAE) spectrum have been performed supporting the assignment of the C̃-state.
Chemical Physics Letters.
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ABSTRACT: The size-dependent reactivity of neutral Ni and Nb clusters towards CO has been investigated. A beam of clusters is let through a low-pressure reaction cell containing CO and the clusters experience only a few collisions with CO molecules. The reaction products are detected with laser ionisation and time-of-flight mass spectrometry. Absolute sticking probabilities (S) of the first CO molecule on Ni9Ni40 and Nb4Nb47 have been determined. For NinS exhibits a smooth size dependence with a broad maximum of S = 0.8–0.85 for cluster sizes n = 12–18. For larger clusters S seems to level off at a constant value of ∼ 0.5. For Nbn the CO reactivity shows a strong size dependence for n < 13 with a distinct minimum in reactivity for n = 10. For cluster sizes Nb13Nb20S increases smoothly and for n > 20 S is almost constant close to 1.0. We compare our results with previous investigations on CO reactivity of transition-metal clusters as well as with the reactivity of corresponding bulk surfaces.
Surface Science.
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R. Feifel,
A. Baev,
F. Gel’mukhanov,
H. Ågren, M. Andersson,
G. Öhrwall,
M.N. Piancastelli,
C. Miron,
S.L. Sorensen,
A. Naves de Brito,
O. Björneholm,
L. Karlsson,
S. Svensson
[show abstract]
[hide abstract]
ABSTRACT: We show that the undular stray light, diffusely scattered by the optical system of a synchrotron beamline, can play an important role in the formation of high-resolution resonant photoelectron (RPE) spectra. The influence of the stray light is mediated through the Stokes doubling effect, with the Lorentzian tail of the spectral function being replaced by a more complicated form. This effect is shown to appear in the high-resolution resonant photoelectron spectrum of the N2 molecule in which the spectral shape of the “non-Raman (NR) bands” differs qualitatively for the A2Πu and X2Σ+g final states. A particularly large enhancement of the non-Raman Stokes line is observed for the A-state while the picture is inverted for the X-state where the non-Raman band is suppressed. It is shown that the resonant photoemission profile is affected by two qualitatively different detunings, the detuning of the monochromatized line relative to the photoabsorption line and the detuning of the undulator harmonic relative to the same reference line. The experimental data show that the relative intensity of the non-Raman line strongly depends on the tuning of the undulator harmonic with respect to the selected monochromator bandpass, leading to a strong decrease of the Stokes line intensity for certain undulator detunings. A clear red-shift asymmetry for the decrease in the Stokes line intensity is observed when the monochromator line is detuned towards negative photon frequencies, whereas the picture is reverted for the situation of a positively detuned monochromator line. The results show the necessity to control the stray light and to investigate both the Raman and non-Raman contributions to the spectral profiles in order to avoid misinterpretation and in order to make full use of the information available in resonant photoemission spectra of molecules.
Journal of Electron Spectroscopy and Related Phenomena 134(1):49-65. · 1.96 Impact Factor
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ABSTRACT: The purpose of this paper is to present a developed cutting force model for multi-toothed cutting processes, including a complete set of parameters influencing the cutting force variation that has been shown to occur in face milling, and to analyse to what extent these parameters influence the total cutting force variation for a selected tool geometry. The scope is to model and analyse the cutting forces for each individual tooth on the tool, to be able to draw conclusions about how the cutting action for an individual tooth is affected by its neighbours.A previously developed cutting force model for multi-toothed cutting processes is supplemented with three new parameters; eccentricity of the spindle, continuous cutting edge deterioration and load inflicted tool deflection influencing the cutting force variation. A previously developed milling force sensor is used to experimentally analyse the cutting force variation, and to give input to the cutting force simulation performed with the developed cutting force model.The experimental results from the case studied in this paper show that there are mainly three factors influencing the cutting force variation for a tool with new inserts. Radial and axial cutting edge position causes approximately 50% of the force variation for the case studied in this paper. Approximately 40% arises from eccentricity and the remaining 10% is the result of spindle deflection during machining. The experimental results presented in this paper show a new type of cutting force diagrams where the force variation for each individual tooth when two cutting edges are engaged in the workpiece at the same time. The wear studies performed shows a redistribution of the individual main cutting forces dependent on the wear propagation for each tooth.
International Journal of Machine Tools and Manufacture 51(1):67-76. · 2.17 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Colloidal polymer particles are widely used in a variety of applications ranging from chromatography to surface modified bioreactors in protein arrays. In the present study, surface attachment of polystyrene particles to a polystyrene substrate has been performed using oligonucleotide hybridization. Thiolated complementary oligomers of cytosine and guanine have been covalently coupled to a pyridyl disulphide (PDS) modified polyethyleneglycol tether, forming part of a triblock copolymer which is adsorbed to the polystyrene surfaces via hydrophobic polypropylene oxide center blocks. The ability to withstand shear forces was studied using a laminar flow cell and the uptake of oligomers on the particles was quantified using two complementary techniques: UV-spectroscopy and sedimentation field flow fractionation. The possibility to tether particles in a flow cell suitable for practical use in e.g. a FIA-system is demonstrated.
Colloids and Surfaces B: Biointerfaces.
