A Tail of a Quark in N=4 SYM

We study the dynamics of a `composite' or `dressed' quark in strongly-coupled large-N_c N=4 super-Yang-Mills, making use of the AdS/CFT correspondence. We show that the standard string dynamics nicely captures the physics of the quark and its surrounding non-Abelian field configuration, making it possible to derive a relativistic equation of motion that incorporates the effects of radiation damping. From this equation one can deduce a non-standard dispersion relation for the composite quark, as well as a Lorentz covariant formula for its rate of radiation. We explore the consequences of the equation in a few simple examples.Comment: 26 pages, no figures. v2: added brief clarification on string boundary conditions, version to be published in JHE

The correlation of dative bond length and parameter n in adducts Me3N-AlMe3-nCln (n

Complexes of the general formula Me3N-AlMe3-nCln (Me = CH3; n = 0, 1, 2, 3) 1-4 have been synthesized and structurally characterized by X-ray crystallography and NMR spectroscopy. The shape of the molecules is trigonal-antiprismatic with the nitrogen and aluminium atoms being tetrahedrally surrounded. The length of the dative bond N-Al is correlated with the parameter n due to inductive effects of the electronegative chlorine substituents, resulting in a difference in N-Al between 1 and 4 of 0.1 Angstrom (2.045, 2.010, 1.971, and 1.949 Angstrom). This shortening with increasing n, however, is not linear

. By John D. Sutton (ed.) (Boulder and London, Lynne Rienner Publisher, 1988, pp. 247, £ 23.95 hardback)

Background: Emerging data indicate that gut-derived endotoxin may contribute to low-grade systemic inflammation in insulin resistant states. This study aimed to examine the importance of serum endotoxin and inflammatory markers in non-alcoholic fatty liver disease (NAFLD) patients, with and without type 2 diabetes mellitus (T2DM), and to explore the effect of treatment with a lipase inhibitor, Orlistat, on their inflammatory status. Methods: Fasted serum from 155 patients with biopsy proven NAFLD and 23 control subjects were analysed for endotoxin, soluble CD14 (sCD14), soluble tumour necrosis factor receptor II (sTNFRII) and various metabolic parameters. A subgroup of NAFLD patients were re-assessed 6 and 12 months after treatment with diet alone (n = 6) or diet plus Orlistat (n = 8). Results: Endotoxin levels were significantly higher in patients with NAFLD compared with controls (NAFLD: 10.6(7.8, 14.8) EU/mL; controls: 3.9(3.2, 5.2) EU/mL, p < 0.001); NAFLD alone produced comparable endotoxin levels to T2DM (NAFLD: T2DM: 10.6(5.6, 14.2) EU/mL; non-diabetic: 10.6(8.5, 15.2) EU/mL), whilst a significant correlation between insulin resistance and serum endotoxin was observed (r = 0.27, p = 0.008). Both sCD14 (p < 0.01) and sTNFRII (p < 0.001) increased with severity of fibrosis. A positive correlation was also noted between sTNFRII and sCD14 in the NAFLD subjects (r = 0.29, p = 0.004). Sub-cohort treatment with Orlistat in patients with NAFLD showed significant decreases in ALT (p = 0.006), weight (p = 0.005) and endotoxin (p = 0.004) compared with the NAFLD, non-Orlistat treated control cohort at 6 and 12 months post therapy, respectively. Conclusions: Endotoxin levels were considerably increased in NAFLD patients, with marked increases noted in early stage fibrosis compared with controls. These results suggest elevated endotoxin may serve as an early indicator of potential liver damage, perhaps negating the need for invasive liver biopsy. As endotoxin may promote insulin resistance and inflammation, interventions aimed at reducing endotoxin levels in NAFLD patients may prove beneficial in reducing inflammatory burden