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  • 1
    Electronic Resource
    Electronic Resource
    New sonographic imaging observations in focal pancreatitis (1999)
    Springer
    European radiology 9 (1999), S. 862-867 
    Details
    ISSN: 1432-1084
    Keywords: Key words: Pancreatitis ; Ultrasound ; Pancreatic tumour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The imaging findings that ultrasonographically differentiate focal acute pancreatitis (FAP) from a malignant lesion of the pancreas are described. Focal acute pancreatitis is ultrasonographically (US) characterized as a hypoechoic, homogeneous, localized, subsegmental, non-expansive and diffusely demarcated lesion located mostly in the head of the pancreas. It could not be visualized using CT. Endoscopic retrograde cholangiopancreatography (ERCP) performed in 13 of the 32 patients, showed chronic pancreatitis. Focal acute pancreatitis disappeared in 1–6 months at US follow-up. The clinical diagnoses were acute pancreatitis in 11 patients, chronic pancreatitis in 12 patients, biliary disease in 5 patients, hepatopathia in 1 patient while the diagnosis was unknown in 2 patients. No patient developed any pancreatic cancer during a median of 85 months of follow-up. In conclusion, the present data indicate that patients with FAP at US, without any focal lesion seen on either CT or ERCP, have a benign pancreatic lesion, which resolves in 1–6 months; thus, such patients probably do not need any further investigation or follow-up at all.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003300050756
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  • 2
    Electronic Resource
    Electronic Resource
    New final state in the autoionization decay detected for N2/(2×2)K/graphite: Relevance for the affinity level of NO on a K monolayer (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 1209-1211 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have observed a new type of charge transfer state in the autoionization spectrum for N2/(2×2)K/graphite. It can be viewed as a consequence of an important covalent component to the bonding with the surface in the core hole excited state for N2/(2×2)K/graphite or equivalently for the Z+1 system, "NO"/(2×2)K/graphite. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.476671
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  • 3
    Electronic Resource
    Electronic Resource
    Ammonia adsorbed on Cu(110): An angle resolved x-ray spectroscopic and ab initio study (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 4880-4890 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present a study of a monolayer of ammonia (NH3) adsorbed on Cu(110) using core level spectroscopies in combination with ab initio calculations based on density functional theory. In particular, x-ray emission spectroscopy has been applied, providing an unsurpassed view of the electronic structure of NH3 upon adsorption. The saturated NH3 monolayer, aitch-theta∼0.4 ML, is found to induce strong adsorbate–adsorbate interaction, causing the molecules to tilt on the surface. Based on the angular distribution of the x-ray emission (XE) spectra, we have been able to estimate a mean tilt angle from the surface normal of 40°–45° for the saturated monolayer; the accompanying theoretical calculations for up to three NH3 molecules on a Cu21 all-electron cluster model support a tilted structure due to adsorbate–adsorbate dipole, and possibly hydrogen bonding, interactions. Since the creation of a core hole on the nitrogen atom site in the intermediate state of the XE process does not affect the symmetry of the molecule, a separation of valence electronic states having mainly e symmetry (N 2pxy) and a1 symmetry (N 2pz) has been achieved using angle resolved XE measurements. In addition to the electronic states of free NH3, evidence of new, substrate induced, states has been found, interpreted as ammonia 3a1/4a1-Cu 3d valence band hybrids. It is found that back donation into the previously unoccupied ammonia 4a1 orbital, and a simultaneous 3a1 donation into the substrate plays an important role in the surface chemical bond. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478374
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  • 4
    Electronic Resource
    Electronic Resource
    Redox signalling and the structural basis of regulation of photosynthesis by protein phosphorylation (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 100 (1997), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In photosynthesis in chloroplasts and cyanobacteria, redox control of thylakoid protein phosphorylation regulates distribution of absorbed excitation energy between the two photosystems. When electron transfer through chloroplast photosystem II (PSII) proceeds at a rate higher than that through photosystem I (PSI), chemical reduction of a redox sensor activates a thylakoid protein kinase that catalyses phosphorylation of light-harvesting complex II (LHCII). Phosphorylation of LHCII increases its affinity for PSI and thus redistributes light-harvesting chlorophyll to PSI at the expense of PSII. This short-term redox signalling pathway acts by means of reversible, post-translational modification of pre-existing proteins. A long-term equalisation of the rates of light utilisation by PSI and PSII also occurs: by means of adjustment of the stoichiometry of PSI and PSII. It is likely that the same redox sensor controls both state transitions and photosystem stoichiometry. A specific mechanism for integration of these short- and long-term adaptations is proposed. Recent evidence shows that phosphorylation of LHCII causes a change in its 3-D structure, which implies that the mechanism of state transitions in chloroplasts involves control of recognition of PSI and PSII by LHCII. The distribution of LHCII between PSII and PSI is therefore determined by the higher relative affinity of phospho-LHCII for PSI, with lateral movement of the two forms of the LHCII being simply a result of their diffusion within the membrane plane. Phosphorylation-induced dissociation of LHCII trimers may induce lateral movement of monomeric phospho-LHCII, which binds preferentially to PSI. After dephosphorylation, monomeric, unphosphorylated LHCII may trimerize at the periphery of PSII.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1997.tb00012.x
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  • 5
    Electronic Resource
    Electronic Resource
    Coherent and incoherent processes in resonant photoemission (1997)
    Springer
    Applied physics 65 (1997), S. 159-167 
    Details
    ISSN: 1432-0630
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 3 threshold. At threshold, the emission feature changes character and after a rather narrow transition region it appears at constant emission energy instead. Clear signatures of interference between the direct photoemission and autoionization channels are identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003390050559
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  • 6
    Electronic Resource
    Electronic Resource
    Local probing of the surface chemical bond using X-ray emission spectroscopy (1997)
    Springer
    Applied physics 65 (1997), S. 147-154 
    Details
    ISSN: 1432-0630
    Keywords: PACS: 78.70.En; 73.20.Hb; 85.65.Pa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 2 and CO on Ni(100), benzene on Ni(100) and Cu(110), and glycine adsorbed on Cu(110). New types of molecular states are observed which are directly related to the surface chemical bond. The long-accepted Blyholder model which is based on a frontier orbital concept cannot explain our results for N2 and CO chemisorption. We find it necessary to offer a new picture where changes in the whole molecular orbital framework have to be considered. We show that both π and σ type interactions are important in describing the bonding in benzene to metal surfaces. The future prospect is illustrated by the adsorption of the simplest amino acid, glycine, on Cu(110). The adsorbate has four different atomic centers where X-ray emission spectra are obtained, providing a unique view of the local electronic structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003390050557
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of Ursodeoxycholate and Other Bile Salts on Levels of Rat Intestinal Alkaline Sphingomyelinase (A Potential Implication in Tumorigenesis) (1998)
    Springer
    Digestive diseases and sciences 43 (1998), S. 26-32 
    Details
    ISSN: 1573-2568
    Keywords: ALKALINE SPHINGOMYELINASE ; URSODEOXYCHOLATE ; BILE SALTS ; BILE ; COLON CANCER
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies showed that bile salts had apromoting effect on colon cancer development and thiseffect was inhibited by ursodeoxycholate (UDC). Werecently found that both human colorectal adenomas and carcinomas were associated with a specificdecrease in alkaline sphingomyelinase activity. In thiswork, we compared the effects of ursodeoxycholate andother bile salts on the levels of rat intestinal alkaline sphingomyelinase both in theintestinal loops and after oral administration. Bilesalts at different concentrations were injected intointestinal loops and the dissociation of alkalinesphingomyelinase from the mucosa was assayed. We found that bilesalts, including taurocholate, taurodeoxycholate,glycocholate, glycochenodeoxycholate, and3-(3-cholamidopropyl dimethylammonio)-1-propanesulonate(CHAPS), dose dependently dissociated alkalinesphingomyelinase from the intestinal mucosa. UDC alonedid not dissociate the enzyme but significantlyinhibited the dissociation caused by other bile saltsand CHAPS. Feeding rats with 0.3% (w/w) taurocholate forfour days decreased peak activity of intestinal alkalinesphingomyelinase by 39% and total activity in theintestine by 20% and increased the output of the enzyme in the feces. In contrast, feeding 0.3%(w/w) UDC for four days increased the peak activity ofalkaline sphingomyelinase in the small intestine by 87%and the activity in the colon by 187% . The total activity of alkaline sphingomyelinase wasincreased by 80% and the output of the enzyme in thefeceswas only slightly increased by UDC administration.The changes in alkaline phosphatase after feeding taurocholate and UDC were much smaller. Ourresults indicate that UDC and other bile salts havedifferent effects on the levels of alkalinesphingomyelinase, which may be implicated in theirdifferent influences on cancer development reportedpreviously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018807600683
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  • 8
    Electronic Resource
    Electronic Resource
    Distribution of alkaline sphingomyelinase activity in human beings and animals (1996)
    Springer
    Digestive diseases and sciences 41 (1996), S. 1801-1806 
    Details
    ISSN: 1573-2568
    Keywords: alkaline sphingomyelinase ; intestine ; bile ; human beings ; species differences
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The alkaline sphingomyelinase (SMase) was first found in rat intestinal brush border. The important roles of this enzyme in digestion of sphingomyelin and in mucosal cell proliferation have been suggested. In the present work, the distribution of the alkaline SMase in the tissues of human beings and animals have been studied. By assaying the enzyme activity in human biopsy samples, we found that the alkaline SMase activity was absent in the stomach, increased in the duodenum, present at high levels in the small intestine, and slightly declined in the colon and rectum. High activities were found similarly in the intestinal contents of the healthy adults and infants. The activities were also found in the intestinal mucosa of rats, normal and germ-free mice, and hamsters with the same distribution pattern as in humans, but not in the intestinal mucosa of guinea pigs. Apart from the intestinal tract, a SMase activity preferring alkaline pH was identified in human and guinea pig bile, but not in the bile of rat, pig, sheep, and cow. No activity was found in either pancreatic tissue or pancreatic juice in all species tested, and none was detected in human urine and milk. In conclusion, alkaline SMase exists predominantly in the digestive system with considerable tissue and species differences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02088748
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