| 1. |
- Guang-Jun, Tian, et al.
(författare)
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Two Possible Configurations for Silver-C-60-Silver Molecular Devices and Their Conductance Characteristics
- 2009
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Ingår i: Chinese Physics Letters. - 0256-307X .- 1741-3540. ; 26:6, s. 068501-
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Tidskriftsartikel (refereegranskat)abstract
- Coherent electronic transport properties of silver-C-60-silver molecular junctions in different configurations are studied using hybrid density function theory. The experimentally measured current flows of C-60 molecules adsorbed on the silver surface are well reproduced by theoretical calculations. It is found that the current-voltage characteristics of the molecular junctions depend strongly on the configurations of the junctions. Transmission spectra combined with density of states can help us to understand in depth the transport properties. Different kinds of electrode construction are also discussed. With the help of the calculation, two possible configurations of silver-C-60-silver molecular junctions are suggested.
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| 2. |
- Sjöberg, Beatrice G., et al.
(författare)
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Low levels of IgM antibodies against phosphorylcholine : a potential risk marker for ischemic stroke in men
- 2009
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Ingår i: Atherosclerosis. - : Elsevier BV. - 0021-9150 .- 1879-1484. ; 203:2, s. 528-532
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Natural antibodies specific for phosphorylcholine (anti-PC) have been implicated as protective factors in atherosclerosis. We herein determined the relationship between IgM anti-PC and incidence of cardiovascular disease (CVD). METHODS: We studied 349 incident cases (200 men) of first events of CVD (coronary heart disease (CHD; n=203 or ischemic stroke; n=146) and 693 age- and sex-matched controls identified through 12 years of follow-up (1991-2003) of subjects from the cardiovascular cohort within the Malmö Diet and Cancer Study. Relative risks (RR) of CVD with 95% confidence intervals (CI) of incident CVD with adjustments for age, smoking, total cholesterol and blood pressure were determined. Anti-PC-levels were measured using ELISA (Athera CVDefine). RESULTS: As determined using Athera CVDefine, significant associations were attained with values of anti-PC below 17U/ml (corresponding to the lowest 9th percentile), which remained after taking confounders into account (RR: 1.79, 95% CI: 1.09-2.94, p=0.021). If men were studied separately, significance was evident at values below 17U/ml (RR: 2.01, 95% CI: 1.11-3.67, p=0.022), which was not the case among women. Furthermore, values below 17U/ml were also associated with ischemic stroke (RR=3.67, 95% CI: 1.34-10.1, p=0.01), but not with CHD. CONCLUSION: Low IgM anti-PC could be a novel risk marker for development of ischemic stroke in men. Further studies are needed to establish gender and subgroup differences.
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| 3. |
- Su, Jun, et al.
(författare)
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Antibodies of IgM subclass to phosphorylcholine and oxidized LDL are protective factors for atherosclerosis in patients with hypertension
- 2006
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Ingår i: Atherosclerosis. - : Elsevier BV. - 1879-1484 .- 0021-9150. ; 188:1, s. 160-166
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To determine the importance of antibodies against phosphorylcholine (PC) and oxidized low density lipoprotein (OxLDL) for development of atherosclerosis. Methods and results: Two hundred and twenty six individuals with established hypertension (diastolic pressure > 95 mmHg) were from European Lacidipine Study on Atherosclerosis. Antibodies of IgG and IgM subclass were tested by ELISA against PC (aPC), cupper-oxidized (ox)- or malondialdehyde (MDA)-modified LDL. High-sensitivity C-reactive protein was measured by nephelometry. As a surrogate measure of atherosclerosis, we used the mean of the maximum intima-media thicknesses (IMT) in the far walls of common carotids and bifurcations was determined by ultrasonography at the time of enrolment, and 4 years following enrolment. aPC could be competed out by PC and OxLDL, while cardiolipin (CL) and beta 2-glycoprotein I (beta 2GPI) were less effective and phosphatidylserine (PS) not at all. Increases in IMT at follow-up were less common in subjects which at the time of enrolment had high IgM aPC (both 75th and 90th; odds ratios: 0.46; Cl: 0.25-0.85; 0.36; Cl: 0.15-0.87) and high IgM aOxLDL and aMDA-LDL (90th; odds ratios 0.27; p = 0.01; Cl: 0.11-0.69 and 0.27; p = 0.01; Cl: 0.11-0.69). CRP was unrelated to IMT-changes. The relationship between IgM aPC, aOxLDL and aMDA-LDL and changes in IMT was independent of age, treatment with atenolol or lacidipine, smoking and lipids. Women had higher levels of IgM antibodies tested (p < 0.05). Conclusions: High levels of IgM-antibodies against PC and OxLDL predict a favourable outcome in the development of carotid atherosclerosis in hypertensive subjects. Whether these antibodies could be used therapeutically deserves further study. (c) 2005 Elsevier Ireland Ltd. All rights reserved.
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| 4. |
- Su, Jun
(författare)
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Natural antibodies against phosphorylcholine as potential protective factors in atherosclerosis, cardiovascular disease and systemic lupus erythematosus
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Atherosclerosis is the most important contributor to cardiovascular disease (CVD). Although it was initially considered as a bland lipid storage disease, processes of inflammation and autoimmunity are now considered to play a major role in atherosclerosis. Oxidation of low density lipoprotein (OxLDL) has been implicated in atherogenesis and much of the lipid content in the atherosclerotic lesions consists of OxLDL. OxLDL binds to and is taken up by macrophages through scavenger receptors (SRs) and subsequently these macrophages develop into foam cells, which marks the initiation of atherosclerosis. The important role of autoimmunity and inflammation in atherosclerosis and CVD is illustrated by Systemic lupus erythematosus (SLE), an autoimmune disease, where the risk of CVD is very high and the prevalence of atherosclerotic plaques is increased. This association is only partially linked to the traditional risk factors for CVD. In addition to these, systemic inflammation and autoantibodies against phospholipids among others can be considered SLE-related risk factors to CVD. CVD in SLE is not only an important clinical problem, but may also shed light on the role of immunity in atherosclerosis. The purpose of this thesis was 1) to develop an assay for anti-phosphorylcholine (anti-PC) antibodies and define the correlation between anti-PC levels and atherosclerosis, CVD and SLE, 2) to determine whether PC-epitopes on OxLDL are involved in the uptake of OxLDL by human macrophages, and 3) to investigate if anti-PC antibodies have any anti-inflammatory role in CVD. An ELISA-based method was developed to measure anti-PC antibodies levels in clinical cohorts. We used sepharose columns to purify anti-PC antibodies from human IgM and IgG. Next, we determined the affinity and specificity of such purified anti-PC antibodies by competition experiments. We established a method to study different properties of anti-PC, including macrophage uptake of OxLDL and effects of anti-PC on inflammatory reactions relevant in atherosclerosis, by use of flow cytometry and confocal microscopy. In the first study, we developed an assay for and determined anti-PC levels in hypertensive subjects. We found that high levels of IgM anti-PC antibodies and IgM anti-OxLDL antibodies predict a favorable outcome in the development of carotid atherosclerosis. In the second study on SLE and SLE related CVD, we determined, surprisingly, that low levels of IgG and IgM anti-PC are more prevalent in SLE and SLE-related CVD and that levels of IgG anti-PC are decreased in these groups. Further, we found that anti-PC antibodies have anti-inflammatory effects on adhesion molecule expression stimulated by an inflammatory phospholipid. In the third, prospective study, we found that low levels of IgM anti-PC antibodies predict CVD in 60-year old men, and determined that human IgM anti-PC antibodies block the uptake of OxLDL in macrophages which may be one explanation as to why anti-PC may protect against atherosclerosis development in humans. In the fourth paper, which is a follow-up study of the 60-year old cohort, we determined, that in contrast to IgM anti-PC, IgG anti-PC did not predict risk for CVD. Specific IgG anti-PC antibodies extracted from total IgG only had minimal effects in preventing uptake of OxLDL. Howerer, upon pre-incubation with antibodies against FC-receptors, IgG anti-PC were able to induce a reduction in uptake of OxLDL, indicating that FC-receptors may contribute to OxLDL uptake in macrophages. In conclusion, we report for the first time that high levels of IgM anti-PC antibodies is a novel protective factor for atherosclerosis, and low IgM anti-PC antibodies is an independent risk marker for development of CVD in humans. Further, we demonstrate that anti-PC can inhibit the uptake of OxLDL in macrophages and exert anti-inflammatory effects relevant in the atherosclerotic lesions. It is thus conceivable that raising anti-PC levels through active immunization or passive transfer of anti-PC could be a novel therapeutic possibility.
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| 5. |
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| 6. |
- Su, Wenyong, et al.
(författare)
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First-principles study of electrochemical gate-controlled conductance in molecular junctions
- 2006
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 6:9, s. 2091-2094
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Tidskriftsartikel (refereegranskat)abstract
- A first-principles computational method is developed to study the electrochemical gate-controlled conductance in molecular junctions. It has been applied to a single molecular field-effect transistor made by a perylene tetracaboxylic diimide molecule connected to gold electrodes and has successfully reproduced the experimentally observed huge gate voltage effect on the current. It is found that such a significant gain is a result of the large polarization of the molecule induced by the huge local electrical field generated by the electrochemical gate. The resonant electron tunneling through unoccupied molecular orbitals is shown to be the dominant transport process.
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| 7. |
- Su, Wenyong, et al.
(författare)
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Quantum chemical study of coherent electron transport in oligophenylene molecular junctions of different lengths
- 2005
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 412:4-6, s. 406-410
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Tidskriftsartikel (refereegranskat)abstract
- The coherent electron transportation properties of the gold-oligophenylene-gold junctions of different lengths have been studied by means of a generalized quantum chemical approach. The experimentally measured length dependence of current flow in the junctions has been well reproduced by the hybrid density functional theory calculations. It is found that the current-voltage characteristics of the junctions depend strongly on the metal-molecule bonding distances. With the help of the calculations, the possible gold-molecule bonding distances in the experimental devices are identified.
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| 8. |
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