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Endlich M, Gozdzik S, Néel N, da Rosa AL, Frauenheim T, Wehling TO, Kröger J. Phthalocyanine adsorption to graphene on Ir(111): Evidence for decoupling from vibrational spectroscopy. J Chem Phys 2014; 141:184308. [PMID: 25399148 DOI: 10.1063/1.4901283] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kröger J, Landgraf R, Mattenklodt P, Lüthgens B, Hermanns N, Kulzer B. Diabetes: Unterschiedliche Perspektive von Patienten, Angehörigen und Behandlern. DIABETOL STOFFWECHS 2014. [DOI: 10.1055/s-0034-1375112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Kulzer B, Mattenklodt P, Kröger J, Landgraf R, Lüthgens B, Hermanns N. Diabetesbezogene emotionale und psychische Belastungen bei Menschen mit Diabetes. Deutsche Ergebnisse der globalen DAWN2™ Studie. DIABETOL STOFFWECHS 2014. [DOI: 10.1055/s-0034-1375111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Landgraf R, Kröger J, Hermanns N, Mattenklodt P, Lüthgens B, Kulzer B. Zukunftsaufgaben der Diabetologie. DIABETOL STOFFWECHS 2014. [DOI: 10.1055/s-0034-1375143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Hermanns N, Mattenklodt P, Kröger J, Landgraf R, Lüthgens B, Kulzer B. Prävalenz und psychosoziale Konsequenzen von Hypoglykämien in der deutschen Stichprobe der globalen DAWN2™ Studie. DIABETOL STOFFWECHS 2014. [DOI: 10.1055/s-0034-1375005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Mattenklodt P, Hermanns N, Kröger J, Landgraf R, Lüthgens B, Kulzer B. Psychosoziale Belastungen der Angehörigen von Menschen mit Diabetes. DIABETOL STOFFWECHS 2014. [DOI: 10.1055/s-0034-1375159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Schiller K, Jacobs S, Jansen E, Weikert C, di Giuseppe R, Boeing H, Schulze MB, Kröger J. Associated factors of estimated desaturase activity in the EPIC-Potsdam study. Nutr Metab Cardiovasc Dis 2014; 24:503-510. [PMID: 24370446 DOI: 10.1016/j.numecd.2013.10.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 10/15/2013] [Accepted: 10/17/2013] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND AIMS Altered activity of desaturase enzymes may be involved in the development of metabolic diseases like type 2-diabetes. Desaturase activities might be modifiable by diet and lifestyle-related factors, but no study has systematically investigated such factors so far. We aimed to evaluate the association of demographic, anthropometric, dietary and lifestyle characteristics with estimated Δ5-, Δ6- and Δ9-desaturase activity. METHODS AND RESULTS A subsample (n = 1782) of the EPIC-Potsdam study was used for a cross-sectional analysis, involving men and women, mainly aged 35-65 years. Fatty acid (FA) product-to-precursor ratios, derived from the FA composition of erythrocyte membrane phospholipids, were used to estimate desaturase activities. Multiple linear regression models were used with estimated Δ5-, Δ6- and Δ9-desaturase activity as outcome and demographic (age, sex), anthropometric (BMI, WHR), dietary intake (FAs, carbohydrates) and lifestyle (physical activity, smoking, alcohol consumption) factors as exposure variables. Alcohol intake was positively associated with estimated Δ6- (explained variance in desaturase activity: 1.52%) and estimated Δ9-desaturase activity (explained variance: 5.53%). BMI and WHR showed a weak inverse association with estimated Δ5-desaturase activity (explained variance: BMI: 1.07%; WHR: 1.02%) and weak positive associations with estimated Δ6-(explained variance: BMI: 1.17%; WHR: 1.19%) and estimated Δ9-desaturase activities (explained variance: BMI: 0.70%; WHR: 0.96%). Age, sex, physical activity, smoking and dietary factors were only weakly associated with the estimated desaturase activities. CONCLUSION Our findings suggest that alcohol intake as well as obesity measures are associated with the FA ratios reflecting desaturase activity.
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Néel N, Schröder S, Ruppelt N, Ferriani P, Kröger J, Berndt R, Heinze S. Tunneling anisotropic magnetoresistance at the single-atom limit. PHYSICAL REVIEW LETTERS 2013; 110:037202. [PMID: 23373948 DOI: 10.1103/physrevlett.110.037202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 12/19/2012] [Indexed: 06/01/2023]
Abstract
The tunneling anisotropic magnetoresistance (TAMR) of single Co atoms adsorbed on a double-layer Fe film on W(110) is observed by scanning tunneling spectroscopy. Without applying an external magnetic field the TAMR is found by comparing spectra of atoms that are adsorbed on the domains and domain walls of the Fe film. The TAMR can be as large as 12% and repeatedly changes sign as a function of bias voltage. First-principles calculations show that the hybridization between Co d states of different orbital symmetries depends on the magnetization direction via spin-orbit coupling. This leads to an anisotropy of the density of states and thus induces a TAMR.
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Wang YF, Néel N, Kröger J, Vázquez H, Brandbyge M, Wang B, Berndt R. Voltage-dependent conductance states of a single-molecule junction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:394012. [PMID: 22964461 DOI: 10.1088/0953-8984/24/39/394012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ag-Sn-phthalocyanine-Ag junctions are shown to exhibit three conductance states. While the junctions are conductive at low bias, their impedance drastically increases above a critical bias. Two-level fluctuations occur at intermediate bias. These characteristics may be used to protect a nanoscale circuit. Further experiments along with calculations reveal that the self-limiting conductance of the junctions is due to reversible changes of the junction geometry.
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Schulze MB, Thorand B, Fritsche A, Häring HU, Schick F, Zierer A, Rathmann W, Kröger J, Peters A, Boeing H, Stefan N. Body adiposity index, body fat content and incidence of type 2 diabetes. Diabetologia 2012; 55:1660-7. [PMID: 22349074 DOI: 10.1007/s00125-012-2499-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 01/16/2012] [Indexed: 10/28/2022]
Abstract
AIMS/HYPOTHESIS The aim of this study was to compare estimates of body fat content, i.e. body adiposity index (BAI), BMI and waist and hip circumferences, with respect to their ability to predict the percentage of body fat (PBF; confirmed by magnetic resonance tomography) and incident type 2 diabetes. METHODS Associations between anthropometric measurements and PBF were evaluated in the Tübingen Lifestyle Intervention Program (TULIP; 138 men, 222 women), and between these measurements and incident type 2 diabetes in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study (9,729 men, 15,438 women) and the Cooperative Health Research in the Region of Augsburg (KORA) study (5,573 men, 5,628 women), using correlation and multivariate Cox regression analyses. RESULTS BMI more strongly correlated with PBF (men: r = 0.81, women: r = 0.84) than BAI (r = 0.68 and 0.81, respectively), while waist circumference among men (r = 0.84) and hip circumference among women (r = 0.88) showed the strongest correlations. BAI overestimated PBF among men (mean difference -3.0%), and this error was dependent on the value of PBF. BAI was more weakly associated with diabetes risk (RRs for 1 SD, EPIC-Potsdam men: 1.62 [95% CI 1.52, 1.72], women: 1.67 [95% CI 1.55, 1.80]; KORA men: 1.62 [95% CI 1.48, 1.78], women: 1.82 [95% CI 1.65, 2.02]) compared with BMI (RRs, EPIC-Potsdam men: 1.95 [95% CI 1.83, 2.09], women 1.88 [95% CI 1.76, 2.02], KORA men 1.75 [95% CI 1.62, 1.89], women 2.00 [95% CI 1.81, 2.22]), while waist circumference showed the strongest associations (RRs: 2.17 [95% CI 2.01, 2.35], 2.33 [95% CI 2.15, 2.53], 1.81 [95% CI 1.66, 1.96] and 2.29 [95% CI 2.05, 2.57] for EPIC-Potsdam men and women and KORA men and women, respectively). CONCLUSIONS/INTERPRETATION Waist circumference in men and hip circumference in women are better predictors of PBF than BAI and BMI. BAI was not as strong a predictor of diabetes as BMI, while waist circumference was the strongest predictor.
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Altenburg SJ, Kröger J, Wehling TO, Sachs B, Lichtenstein AI, Berndt R. Local gating of an Ir(111) surface resonance by graphene islands. PHYSICAL REVIEW LETTERS 2012; 108:206805. [PMID: 23003167 DOI: 10.1103/physrevlett.108.206805] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Indexed: 06/01/2023]
Abstract
The influence of graphene islands on the electronic structure of the Ir(111) surface is investigated. Scanning tunneling spectroscopy (STS) indicates the presence of a two-dimensional electron gas with a binding energy of -160 meV and an effective mass of -0.18me underneath single-layer graphene on the Ir(111) surface. Density functional calculations reveal that the STS features are predominantly due to a holelike surface resonance of the Ir(111) substrate. Nanometer-sized graphene islands act as local gates, which shift and confine the surface resonance.
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Schmidt W, Kröger J, Lankers H. Neue „missense“-Mutation im HNF1α-Gen als Ursache für Maturity Onset Diabetes of the Young (MODY 3). DIABETOL STOFFWECHS 2012. [DOI: 10.1055/s-0032-1314524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Néel N, Kröger J, Berndt R. Two-level conductance fluctuations of a single-molecule junction. NANO LETTERS 2011; 11:3593-3596. [PMID: 21854026 DOI: 10.1021/nl201327c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The conductance of a single-molecule junction in a low-temperature scanning tunneling microscope has been measured at nanosecond time resolution. In a transition region between tunneling and contact the conductance exhibits rapid two-level fluctuations which are attributed to different geometries of the junction. The voltage dependence of the fluctuations indicates that electrons injected into the lowest unoccupied molecular orbital may efficiently couple to molecular vibrations.
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Néel N, Berndt R, Kröger J, Wehling TO, Lichtenstein AI, Katsnelson MI. Two-site Kondo effect in atomic chains. PHYSICAL REVIEW LETTERS 2011; 107:106804. [PMID: 21981521 DOI: 10.1103/physrevlett.107.106804] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Indexed: 05/31/2023]
Abstract
Linear CoCu(n)Co clusters on Cu(111) fabricated by atomic manipulation represent a two-site Kondo system with tunable interaction. Scanning tunneling spectroscopy reveals oscillations of the Kondo temperature T(K) with the number n of Cu atoms for n≥3. Density functional calculations show that the Ruderman-Kittel-Kasuya-Yosida interaction mediated by the Cu chains causes the oscillations. Calculations find ferromagnetic and antiferromagnetic interaction for n=1 and 2, respectively. Both interactions lead to a decrease of T(K) as experimentally observed.
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Altenburg SJ, Kröger J, Wang B, Bocquet ML, Lorente N, Berndt R. Graphene on Ru(0001): contact formation and chemical reactivity on the atomic scale. PHYSICAL REVIEW LETTERS 2010; 105:236101. [PMID: 21231481 DOI: 10.1103/physrevlett.105.236101] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Indexed: 05/30/2023]
Abstract
Graphene on Ru(0001) is contacted with Au tips of a cryogenic scanning tunneling microscope. The formation and conductance of single-atom contacts vary within the moiré unit cell. Density functional calculations reveal that elastic distortions of the graphene lattice occur at contact due to a selectively enhanced chemical reactivity of C atoms at hollow sites of Ru(0001). Concomitant quantum transport calculations indicate that the graphene-Ru distance determines the conductance variations.
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Wang YF, Kröger J, Berndt R, Vázquez H, Brandbyge M, Paulsson M. Atomic-scale control of electron transport through single molecules. PHYSICAL REVIEW LETTERS 2010; 104:176802. [PMID: 20482125 DOI: 10.1103/physrevlett.104.176802] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Indexed: 05/29/2023]
Abstract
Tin-phthalocyanine molecules adsorbed on Ag(111) were contacted with the tip of a cryogenic scanning tunneling microscope. Orders-of-magnitude variations of the single-molecule junction conductance were achieved by controllably dehydrogenating the molecule and by modifying the atomic structure of the surface electrode. Nonequilibrium Green's function calculations reproduce the trend of the conductance and visualize the current flow through the junction, which is guided through molecule-electrode chemical bonds.
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Pischon N, Pischon T, Gülmez E, Kröger J, Purucker P, Kleber BM, Landau H, Jost-Brinkmann PG, Schlattmann P, Zernicke J, Burmester GR, Bernimoulin JP, Buttgereit F, Detert J. Periodontal disease in patients with ankylosing spondylitis. Ann Rheum Dis 2010; 69:34-8. [PMID: 19126560 DOI: 10.1136/ard.2008.097212] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE Ankylosing spondylitis (AS) and periodontal disease (PD) are characterised by dysregulation of the host inflammatory response, resulting in soft and hard connective tissue destruction. AS has been related to other inflammatory diseases, however, there is a paucity of data on whether AS is associated with inflammatory PD. METHODS The association between AS and PD was examined in 48 patients with AS and 48 healthy controls, matched for age and gender. AS was diagnosed according to the modified New York criteria. Periodontal examination included probing pocket depth (PPD), clinical attachment loss (CAL), plaque index (PI) and bleeding on probing (BOP). Potential risk factors of PD such as smoking, low education, alcohol consumption, body mass index (BMI), as well as chronic diseases associated with PD and AS were assessed through questionnaires. RESULTS In stepwise logistic regression, including AS status, age, gender, education, smoking, alcohol consumption and BMI, only AS status, age and education remained significant predictors of PD. Patients with AS had significant 6.81-fold increased odds (95% CI 1.96 to 23.67) of PD (defined as mean attachment loss >3 mm) compared to controls. The strength of the association was attenuated but remained statistically significant after further adjustment for plaque accumulation (odds ratio (OR) 5.48, 95% CI 1.37 to 22.00). CONCLUSIONS The present study shows that patients with AS have a significantly higher risk of PD, strongly suggesting the need for close collaboration between rheumatologists, periodontists and dental hygienists when treating patients with AS.
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Berndt R, Kröger J, Néel N, Schull G. Controlled single atom and single molecule contacts. Phys Chem Chem Phys 2010; 12:1022-32. [DOI: 10.1039/b908672m] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gopakumar T, Néel N, Kröger J, Berndt R. Spatial modulation of d states in a nanoscale Co island. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.11.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Lundershausen R, Grüneberg M, Heddaeus H, Kröger J, Schönauer M, Karagiannis E. Effekt einer Kombinationstherapie von Insulin und Pioglitazon bei Typ-2-Diabetikern: Zwischenauswertung einer nicht interventionellen Studie. DIABETOL STOFFWECHS 2009. [DOI: 10.1055/s-0028-1098893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Néel N, Kröger J, Berndt R. Quantized conductance of a single magnetic atom. PHYSICAL REVIEW LETTERS 2009; 102:086805. [PMID: 19257770 DOI: 10.1103/physrevlett.102.086805] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2008] [Revised: 10/31/2008] [Indexed: 05/27/2023]
Abstract
A single Co atom adsorbed on Cu(111) or on ferromagnetic Co islands is contacted with nonmagnetic W or ferromagnetic Ni tips in a scanning tunneling microscope. When the Co atom bridges two nonmagnetic electrodes a conductance of approximately 2e;{2}/h is found. With two ferromagnetic electrodes a conductance of approximately e;{2}/h is observed.
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Néel N, Kröger J, Berndt R, Wehling TO, Lichtenstein AI, Katsnelson MI. Controlling the Kondo effect in CoCu(n) clusters atom by atom. PHYSICAL REVIEW LETTERS 2008; 101:266803. [PMID: 19437660 DOI: 10.1103/physrevlett.101.266803] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Clusters containing a single magnetic impurity were investigated by scanning tunneling microscopy, spectroscopy, and ab initio electronic structure calculations. The Kondo temperature of a Co atom embedded in Cu clusters on Cu(111) exhibits a nonmonotonic variation with the cluster size. Calculations model the experimental observations and demonstrate the importance of the local and anisotropic electronic structure for correlation effects in small clusters.
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Pischon N, Pischon T, Kröger J, Gülmez E, Kleber BM, Bernimoulin JP, Landau H, Brinkmann PG, Schlattmann P, Zernicke J, Buttgereit F, Detert J. Association among rheumatoid arthritis, oral hygiene, and periodontitis. J Periodontol 2008; 79:979-86. [PMID: 18533773 DOI: 10.1902/jop.2008.070501] [Citation(s) in RCA: 265] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND A limited number of studies suggest a higher prevalence of periodontal disease among individuals with rheumatoid arthritis (RA); however, results have been inconsistent. Further, it is unclear to what extent poor oral hygiene among patients with RA may account for this association. METHODS The association between RA and periodontitis was examined in 57 subjects with RA and 52 healthy controls, matched by age and gender. Oral examination included plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment loss (CAL). Potential risk factors for periodontal disease, such as smoking, education, alcohol consumption, and body mass index (BMI), as well as chronic diseases associated with RA and periodontal disease were assessed through questionnaires. RESULTS In a stepwise logistic regression, including RA status, age, gender, education, smoking, alcohol consumption, and BMI, only RA status and age remained significant predictors of periodontal disease. Subjects with RA had a significant 8.05-fold increased odds (95% confidence interval: 2.93 to 22.09) of periodontitis compared to controls. The strength of the association was attenuated but remained statistically significant after further adjustment for PI, GI, or both. PI alone accounted for 12.4%, GI alone accounted for 11.1%, and PI and GI combined accounted for 13.4% of the association between RA and periodontitis. CONCLUSIONS Subjects with RA have significantly increased periodontal attachment loss compared to controls. Oral hygiene may only partially account for this association.
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Schiller F, Ruiz-Osés M, Ortega JE, Segovia P, Martínez-Blanco J, Boyle BP, Pérez-Dieste V, Lobo J, Néel N, Berndt R, Kröger J. Response to “Comment on ‘Electronic structure of C60 on Au(887)’ [J. Chem. Phys. 127, 067101 (2007)]”. J Chem Phys 2008; 128:037101. [DOI: 10.1063/1.2813437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Kröger J, Jensen H, Berndt R, Rurali R, Lorente N. Molecular orbital shift of perylenetetracarboxylic-dianhydride on gold. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.03.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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