| 71. |
- Zhaunerchyk, Vitali, et al.
(författare)
-
Sequential formation of the CH3+H+H channel in the dissociative recombination of CH5
- 2009
-
Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 79:3, s. 30701-
-
Tidskriftsartikel (refereegranskat)abstract
- The fragmentation dynamics in the CH3+H+H channel arising from the dissociative recombination of protonated methane, CH5+, has been investigated with an imaging detector at the CRYRING storage ring. The experimental results imply that this channel proceeds via two-step break-up in which the intermediate CH4 molecule is sufficiently internally excited to further fragment. These observations could go some way to explaining the discrepancy in results reported from ion storage rings and FALP apparatus.
|
|
| 72. |
- Al-Khalili, A, et al.
(författare)
-
Dissociative recombination cross section and branching ratios of protonated dimethyl disulfide and N-methylacetamide
- 2004
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 121:12, s. 5700-5708
-
Tidskriftsartikel (refereegranskat)abstract
- Dimethyl disulfide (DMDS) and N-methylacetamide are two first choice model systems that represent the disulfide bridge bonding and the peptide bonding in proteins. These molecules are therefore suitable for investigation of the mechanisms involved when proteins fragment under electron capture dissociation (ECD). The dissociative recombination cross sections for both protonated DMDS and protonated N-methylacetamide were determined at electron energies ranging from 0.001 to 0.3 eV. Also, the branching ratios at 0 eV center-of-mass collision energy were determined. The present results give support for the indirect mechanism of ECD, where free hydrogen atoms produced in the initial fragmentation step induce further decomposition. We suggest that both indirect and direct dissociations play a role in ECD.
|
|
| 73. |
- Alim, MA, et al.
(författare)
-
Pleckstrin Levels Are Increased in Patients with Chronic Periodontitis and Regulated via the MAP Kinase-p38α Signaling Pathway in Gingival Fibroblasts
- 2022
-
Ingår i: Frontiers in immunology. - : Frontiers Media SA. - 1664-3224. ; 12, s. 801096-
-
Tidskriftsartikel (refereegranskat)abstract
- Chronic periodontitis (CP) is a bacteria-driven inflammatory disease characterized by the breakdown of gingival tissue, the periodontal ligament, and alveolar bone, leading ultimately to tooth loss. We previously reported the pleckstrin gene (PLEK) to be highly upregulated in gingival tissue of patients with CP and the only gene concurrently upregulated in other inflammatory diseases including rheumatoid arthritis and cardiovascular diseases. Using saliva from 169 individuals diagnosed with CP and healthy controls, we investigated whether pleckstrin could serve as a novel biomarker of periodontitis. Additionally, we explored signal pathways involved in the regulation of PLEK using human gingival fibroblasts (HGFs). Pleckstrin levels were significantly higher (p < 0.001) in the saliva samples of patients with CP compared to controls and closely associated with CP severity. Immunohistochemical analysis revealed the expression of pleckstrin in inflammatory cells and gingival fibroblasts of CP patients. To explore the signal pathways involved in pleckstrin regulation, we stimulated HGFs with either interleukin-1β (IL-1β) or lipopolysaccharides (LPS) alone, or in combination with inhibitors targeting c-Jun N-terminal kinase, tyrosine kinase, protein kinase C, or p38 MAP kinase. Results showed that IL-1β and LPS significantly increased PLEK mRNA and pleckstrin protein levels. VX-745, the p38 MAP kinase inhibitor significantly decreased IL-1β- and LPS-induced pleckstrin levels at both the mRNA and the protein level. Together, these findings show that pleckstrin could serve as a salivary biomarker for the chronic inflammatory disease periodontitis and a regulator of inflammation via the p38 MAP kinase pathway.
|
|
| 74. |
- Bäckström, Erik, 1983-, et al.
(författare)
-
Storing keV negative ions for an hour : The lifetime of the metastable 2P1/2 level in 32S−
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 114:14
-
Tidskriftsartikel (refereegranskat)abstract
- We use a novel electrostatic ion storage ring to measure the radiative lifetime of the upper level in the 3p 5 P 2 o 1/2 →3p 5 P 2 o 3/2 spontaneous radiative decay in S − 32 to be 503±54 sec . This is by orders of magnitude the longest lifetime ever measured in a negatively charged ion. Cryogenic cooling of the storage ring gives a residual-gas pressure of a few times 10 −14 mbar at 13 K and storage of 10 keV sulfur anions for more than an hour. Our experimental results differ by 1.3σ from the only available theoretical prediction.
|
|
| 75. |
- Chartkunchand, C, et al.
(författare)
-
Measuring the 2D3/2 Ni− excited state lifetime in DESIREE
- 2015
-
Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 635
-
Konferensbidrag (refereegranskat)abstract
- Experimental studies of the radiative lifetime of the sole excited state in the nickel anion are presented. Beams of Ni− stored in DESIREE at cryogenic temperatures were subject to photodetachment at different photon energies and the resulting neutrals collected. Preliminary analysis of the decay in neutral production yields a radiative lifetime of approximately 15 seconds for the 3d94s2 2D3/2 excited state.
|
|
| 76. |
- Chartkunchand, Kiattichart C., et al.
(författare)
-
Radiative lifetimes of the bound excited states of Pt-
- 2016
-
Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 94:3
-
Tidskriftsartikel (refereegranskat)abstract
- © 2016 American Physical Society.The intrinsic radiative lifetimes of the 5d106sS1/22 and 5d96s2 D3/22 bound excited states in the platinum anion Pt- have been studied at cryogenic temperatures at the Double ElectroStatic Ion Ring Experiment (DESIREE) facility at Stockholm University. The intrinsic lifetime of the higher-lying 5d106s S1/22 state was measured to be 2.54±0.10s, while only a lifetime in the range of 50-200 ms could be estimated for the 5d96s2 D3/22 fine-structure level. The storage lifetime of the Pt- ion beam was measured to be a little over 15 min at a ring temperature of 13K. The present study reports the lifetime of an atomic negative ion in an excited bound state with an electron configuration different from that of the ground state.
|
|
| 77. |
- de Mello, Vanessa D., et al.
(författare)
-
Serum aromatic and branched-chain amino acids associated with NASH demonstrate divergent associations with serum lipids
- 2021
-
Ingår i: Liver International. - : Wiley. - 1478-3223 .- 1478-3231. ; 41:4, s. 754-763
-
Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Non-alcoholic fatty liver disease (NAFLD) has been associated with multiple metabolic abnormalities. By applying a non-targeted metabolomics approach, we aimed at investigating whether serum metabolite profile that associates with NAFLD would differ in its association with NAFLD-related metabolic risk factors. Methods & Results: A total of 233 subjects (mean ± SD: 48.3 ± 9.3 years old; BMI: 43.1 ± 5.4 kg/m2; 64 male) undergoing bariatric surgery were studied. Of these participants, 164 with liver histology could be classified as normal liver (n = 79), simple steatosis (SS, n = 40) or non-alcoholic steatohepatitis (NASH, n = 45). Among the identified fasting serum metabolites with higher levels in those with NASH when compared to those with normal phenotype were the aromatic amino acids (AAAs: tryptophan, tyrosine and phenylalanine), the branched-chain amino acids (BCAAs: leucine and isoleucine), a phosphatidylcholine (PC(16:0/16:1)) and uridine (all FDRp < 0.05). Only tryptophan was significantly higher in those with NASH compared to those with SS (FDRp < 0.05). Only the AAAs tryptophan and tyrosine correlated positively with serum total and LDL cholesterol (FDRp < 0.1), and accordingly, with liver LDLR at mRNA expression level. In addition, tryptophan was the single AA associated with liver DNA methylation of CpG sites known to be differentially methylated in those with NASH. Conclusions: We found that serum levels of the NASH-related AAAs and BCAAs demonstrate divergent associations with serum lipids. The specific correlation of tryptophan with LDL-c may result from the molecular events affecting LDLR mRNA expression and NASH-associated methylation of genes in the liver.
|
|
| 78. |
- Dongiovanni, P., et al.
(författare)
-
Transmembrane 6 Superfamily Member 2 Gene Variant Disentangles Nonalcoholic Steatohepatitis From Cardiovascular Disease
- 2015
-
Ingår i: Hepatology. - : Ovid Technologies (Wolters Kluwer Health). - 0270-9139 .- 1527-3350. ; 61:2, s. 506-514
-
Tidskriftsartikel (refereegranskat)abstract
- Excess hepatic storage of triglycerides is considered a benign condition, but nonalcoholic steatohepatitis (NASH) may progress to fibrosis and promote atherosclerosis. Carriers of the TM6SF2 E167K variant have fatty liver as a result of reduced secretion of very-low-density lipoproteins (VLDLs). As a result, they have lower circulating lipids and reduced risk of myocardial infarction. In this study, we aimed to assess whether TM6SF2 E167K affects liver damage and cardiovascular outcomes in subjects at risk of NASH. Liver damage was evaluated in 1,201 patients who underwent liver biopsy for suspected NASH; 427 were evaluated for carotid atherosclerosis. Cardiovascular outcomes were assessed in 1,819 controls from the Swedish Obese Subjects (SOS) cohort. Presence of the inherited TM6SF2 E167K variant was determined by TaqMan assays. In the liver biopsy cohort, 188 subjects (13%) were carriers of the E167K variant. They had lower serum lipid levels than noncarriers (P<0.05), had more-severe steatosis, necroinflammation, ballooning, and fibrosis (P<0.05), and were more likely to have NASH (odds ratio [OR]: 1.84; 95% confidence interval [CI]: 1.23-2.79) and advanced fibrosis (OR, 2.08; 95% CI: 1.20-3.55), after adjustment for age, sex, body mass index, fasting hyperglycemia, and the I148M PNPLA3 risk variant. However, E167K carriers had lower risk of developing carotid plaques (OR, 0.49; 95% CI: 0.25-0.94). In the SOS cohort, E167K carriers had higher alanine aminotransferase ALT and lower lipid levels (P<0.05), as well as a lower incidence of cardiovascular events (hazard ratio: 0.61; 95% CI: 0.39-0.95). Conclusions: Carriers of the TM6SF2 E167K variant are more susceptible to progressive NASH, but are protected against cardiovascular disease. Our findings suggest that reduced ability to export VLDLs is deleterious for the liver. (Hepatology 2015;61:506-514)
|
|
| 79. |
- Fattibene, P, et al.
(författare)
-
The 4th international comparison on EPR dosimetry with tooth enamel Part 1: Report on the results
- 2011
-
Ingår i: Radiation Measurements. - : Elsevier. - 1350-4487 .- 1879-0925. ; 46:9, s. 765-771
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Munchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated sample was kept as control. The doses delivered to the individual samples were unknown to the participants, who were asked to measure each sample nine times, and to report the EPR signal response, the mass of aliquots measured, and the parameters of EPR signal acquisition and signal evaluation. Critical dose and detection limit were calculated by the organizers on the basis of the calibration-curve parameters obtained at every laboratory. For calibration curves obtained by measuring every calibration sample three times, the mean value of the detection limit was 205 mGy, ranging from 56 to 649 mGy. The participants were also invited to provide the signal response and the nominal dose of their current dose calibration curve (wherever available), the critical dose and detection limit of which were also calculated by the organizers.
|
|
| 80. |
- Geppert, W D, et al.
(författare)
-
Dissociative recombination of nitrile ions : DCCCN+ and DCCCND
- 2004
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 613:2, s. 1302-1309
-
Tidskriftsartikel (refereegranskat)abstract
- Branching ratios and absolute cross sections have been measured for the dissociative recombination of DCCCN+ and DCCCND+ using the CRYRING ion storage ring. In the case of DCCCN+ the dissociation yielding D + C3N and those leading to two fragments containing a pair of heavy atoms dominate, whereas pathways producing a fragment with three heavy atoms play only a minor role. Conversely, for DCCCND+, only those channels preserving the carbon chain or producing two fragments with a pair of heavy atoms each are detected. The cross sections of the reactions are very similar and can be fitted to the expressions sigma = (2.9 +/- 0.5) x 10(-15)E(eV)(-1.05 +/- 0.02) cm(2) and sigma = (2.3 +/- 0.4) x 10(-15)E(eV)(-1.10 +/- 0.02) cm(2) for DCCCN+ and DCCCND+, respectively. From these data, thermal reaction rates of k(T) = (1.5 +/- 0.3) x 10(-6)(T/300 K)(-0.60 +/- 0.02) cm(3) s(-1) and k(T) = (1.5 +/- 0.3) x 10(-6)(T/300 K)(-0.58 +/- 0.02) cm(3) s(-1) were calculated for DCCCN+ and DCCCND+, respectively. These rates and branching ratios are compared with those hitherto used in astrophysical models.
|
|
