The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. CitationAaltonen, T. et al. "Measurement of particle production and inclusive differential cross sections in pp-bar collisions at s=1. Terms of UseArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. We report a set of measurements of particle production in inelastic p " p collisions collected with a minimum-bias trigger at the Tevatron Collider with the CDF II experiment. The inclusive charged particle transverse momentum differential cross section is measured, with improved precision, over a range about ten times wider than in previous measurements. The former modeling of the spectrum appears to be incompatible with the high particle momenta observed. The dependence of the charged particle transverse momentum on the event particle multiplicity is analyzed to study the various components of hadron interactions. This is one of the observable variables most poorly reproduced by the available Monte Carlo generators. A first measurement of the event transverse energy sum differential cross section is also reported. A comparison with a PYTHIA prediction at the hadron level is performed. The inclusive chargedparticle differential production cross section is fairly well reproduced only in the transverse momentum range available from previous measurements. At higher momentum the agreement is poor. The transverse energy sum is poorly reproduced over the whole spectrum. The dependence of the charged particle transverse momentum on the particle multiplicity needs the introduction of more sophisticated particle production mechanisms, such as multiple parton interactions, in order to be better explained. Measurement of particle production and inclusive differential cross sections inp p collisions at ffiffi ffi s p ¼ 1
Marine cyanobacteria (blue-green algae) have been shown to possess an enormous capacity to produce structurally diverse natural products that exhibit a broad spectrum of potent biological activities, including cytotoxic, antifungal, antiparasitic, antiviral and antibacterial activities. Using mass spectrometry-guided fractionation together with molecular networking, cyanobacterial field collections from American Samoa and Palmyra Atoll yielded three new cyclic peptides, tutuilamides A-C. Their structures were established by spectroscopic techniques including 1D and 2D NMR, HR-MS, and chemical derivatization. Structure elucidation was facilitated by employing advanced NMR techniques including non-uniform sampling in combination with the 1,1-ADEQUATE experiment. These cyclic peptides are characterized by the presence of several unusual residues including 3-amino-6-hydroxy-2-piperidone and 2-amino-2-butenoic acid, together with a novel vinyl chloride-containing residue. Tutuilamides A-C show potent elastase inhibitory activity together with moderate potency in H-460 lung cancer cell cytotoxicity assays. The binding mode to elastase was analyzed by X-ray crystallography revealing a reversible binding mode similar to the natural product lyngbyastatin 7. The presence of an additional hydrogen bond with the amino acid backbone of the flexible side chain of tutuilamide A, compared to lyngbyastatin 7, facilitates its stabilization in the elastase binding pocket and possibly explains its enhanced inhibitory potency.
Peripheral neuropathy is a major complication associated with diabetes and central neuropathy characterized by Alzheimer’s disease-like features in the brain is associated with increased dementia risk for patients with diabetes. Although glucose uptake into the cells of the nervous system is insulin-independent, contribution of impaired insulin support is clearly recognized to play a role, however not yet fully understood, in the development of neuropathy. In this study, we assessed the direct role of insulin on the PNS and CNS of insulin-dependent type 1 diabetic rats. Fresh sciatic nerve and hippocampus from control and diabetic rats were incubated with varied ex vivo concentrations of insulin and phosphorylation levels of insulin receptor and GSK3β were assessed by Western blot analysis. Both sciatic nerve and hippocampus from type 1 diabetic rats were highly responsive to exogenous insulin with a significantly increased phosphorylation of insulin receptor and GSK3 compared to tissues from control rats. Further, sustained in vivo insulin delivery, not sufficient to restore normal blood glucose, normalized the activation of both insulin receptor and GSK3 in both PNS and CNS tissues. These results suggest that the insulin-signaling pathway is responsive to exogenous insulin in the nervous system of insulin-deficient type 1 diabetic rats and that constant insulin delivery restore normal nerve function and may protect peripheral and central nervous system from damage.
We report on the analysis of experiments on a neodymium-doped yttrium aluminum garnet laser with an intracavity frequency-doubling crystal. Three modes of the laser were excited in differing polarization configurations. The total intensity of infrared light was observed and then analyzed using methods of nonlineartime-series analysis. We present clear evidence using global false nearest neighbors that when all polarizations are parallel, the intensity is chaotic with two positive Lyapunov exponents and the system can be embedded in dimension 7. The noise level in this operating condition, which we call type I chaos, is small. When one of the polarizations is perpendicular to the others, the intensity is again chaotic with positive Lyapunov exponents, but there is substantial noise in the signal of high dimensional origin, and no finite embedding dimension appears possible. We call this type II chaos. We suggest that the origin of this phenomenon is the intrinsic quantum noise associated with the generation of green light, which is 25 times more intense in the type II operating configuration than in the first. In past experiments with this system we have found that the type I chaos can be controlled to unstable periodic orbits while type II cannot. In each type of chaotic laser operation we use local false nearest neighbors to demonstrate that the local dimension of the dynamics is 7. This means seven differential equations can capture the full dynamics of these regimes of the laser. We evaluate local and global false nearest neighbors to support our conclusions and determine the Lyapunov spectrum of each type of chaotic behavior. The predictability of type II chaos is shown to be much less than that of type I, and we make local polynomial models in reconstructed-state space to demonstrate that we can predict rather well for type I chaos. Finally we suggest a fairly standard model for the interaction of the infrared light with the nonlinear frequency doubling medium and with a two-level of the active medium.
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