Quantifying excitations of quasinormal mode systems

Computations of the strong field generation of gravitational waves by black hole processes produce waveforms that are dominated by quasinormal (QN) ringing, a damped oscillation characteristic of the black hole. We describe here the mathematical problem of quantifying the QN content of the waveforms generated. This is done in several steps: (i) We develop the mathematics of QN systems that are complete (in a sense to be defined) and show that there is a quantity, the ``excitation coefficient,'' that appears to have the properties needed to quantify QN content. (ii) We show that incomplete systems can (at least sometimes) be converted to physically equivalent complete systems. Most notably, we give a rigorous proof of completeness for a specific modified model problem. (iii) We evaluate the excitation coefficient for the model problem, and demonstrate that the excitation coefficient is of limited utility. We finish by discussing the general question of quantification of QN excitations, and offer a few speculations about unavoidable differences between normal mode and QN systems.Comment: 27 pages, 14 figures. To be published in: J. Math. Phys. (1999

Inspiralling black holes: the close limit

Using several approximations, we calculate an estimate of the gravitational radiation emitted when two equal mass black holes coalesce at the end of their binary inspiral. We find that about 1% of the mass energy of the pair will emerge as gravitational waves during the final ringdown and a negligible fraction of the angular momentum will be radiated.Comment: 4 pages, RevTeX, 2 figure

Gene polymorphisms in APOE, NOS3, and LIPC genes may be risk factors for cardiac adverse events after primary CABG

<p>Abstract</p> <p>Introduction</p> <p>Coronary artery disease progression after primary coronary artery bypass grafting may, beside classical atherosclerosis risk factors, be depending on genetic predisposition.</p> <p>Methods</p> <p>We investigated 192 CABG patients (18% female, age: 60.9 ± 7.4 years). Clinically cardiac adverse events were defined as need for reoperation (n = 88; 46%), reintervention (n = 58; 30%), or angina (n = 89; 46%). Mean follow-up time measured 10.1 ± 5.1 years. Gene polymorphisms (<b><it>ApoE, NOS3, LIPC, CETP, SERPINE-1, Prothrombin</it></b>) were investigated separately and combined (gene risk profile).</p> <p>Results</p> <p>Among classical risk factors, arterial hypertension and hypercholesterinemia significantly influenced CAD progression. Single <b><it>ApoE, NOS3 </it></b>and <b><it>LIPC </it></b>polymorphisms provided limited information. Patients missing the most common <b><it>ApoE </it></b>ε3 allele (5,2%), showed recurrent symptoms (p = 0,077) and had more frequently reintervention (p = 0,001). <b><it>NOS3 </it></b>a allele was associated with a significant increase for reintervention (p = 0,041) and recurrent symptoms (p = 0,042).</p> <p>Homozygous <b><it>LIPC </it></b>patients had a higher reoperation rate (p = 0.049).</p> <p>A gene risk profile enabled us to discriminate between faster and slower occurrence of cardiac adverse events (p = 0.0012).</p> <p>Conclusion</p> <p>Single <b><it>APOE, LIPC </it></b>and <b><it>NOS3 </it></b>polymorphisms permitted limited prognosis of cardiac adverse events in patients after CABG. Risk profile, in contrast, allowed for risk stratification.</p

A Plug-Based Microfluidic System for Dispensing Lipidic Cubic Phase (LCP) Material Validated by Crystallizing Membrane Proteins in Lipidic Mesophases

This article presents a plug-based microfluidic system to dispense nanoliter-volume plugs of lipidic cubic phase (LCP) material and subsequently merge the LCP plugs with aqueous plugs. This system was validated by crystallizing membrane proteins in lipidic mesophases, including LCP. This system allows for accurate dispensing of LCP material in nanoliter volumes, prevents inadvertent phase transitions that may occur due to dehydration by enclosing LCP in plugs, and is compatible with the traditional method of forming LCP material using a membrane protein sample, as shown by the successful crystallization of bacteriorhodopsin from Halobacterium salinarum. Conditions for the formation of LCP plugs were characterized and presented in a phase diagram. This system was also implemented using two different methods of introducing the membrane protein: (1) the traditional method of generating the LCP material using a membrane protein sample and (2) post LCP-formation incorporation (PLI), which involves making LCP material without protein, adding the membrane protein sample externally to the LCP material, and allowing the protein to diffuse into the LCP material or into other lipidic mesophases that may result from phase transitions. Crystals of bacterial photosynthetic reaction centers from Rhodobacter sphaeroides and Blastochloris viridis were obtained using PLI. The plug-based, LCP-assisted microfluidic system, combined with the PLI method for introducing membrane protein into LCP, should be useful for minimizing consumption of samples and broadening the screening of parameter space in membrane protein crystallization

The plug-based nanovolume Microcapillary Protein Crystallization System (MPCS)

The Microcapillary Protein Crystallization System (MPCS) is a new protein-crystallization technology used to generate nanolitre-sized crystallization experiments for crystal screening and optimization. Using the MPCS, diffraction-ready crystals were grown in the plastic MPCS CrystalCard and were used to solve the structure of methionine-R-sulfoxide reductase

The plug-based nanovolume Microcapillary Protein Crystallization System (MPCS)

This is the published version. Copyright International Union of CrystallographyThe Microcapillary Protein Crystallization System (MPCS) embodies a new semi-automated plug-based crystallization technology which enables nanolitre-volume screening of crystallization conditions in a plasticware format that allows crystals to be easily removed for traditional cryoprotection and X-ray diffraction data collection. Protein crystals grown in these plastic devices can be directly subjected to in situ X-ray diffraction studies. The MPCS integrates the formulation of crystallization cocktails with the preparation of the crystallization experiments. Within microfluidic Teflon tubing or the microfluidic circuitry of a plastic CrystalCard, ~10-20 nl volume droplets are generated, each representing a microbatch-style crystallization experiment with a different chemical composition. The entire protein sample is utilized in crystallization experiments. Sparse-matrix screening and chemical gradient screening can be combined in one com­prehensive `hybrid' crystallization trial. The technology lends itself well to optimization by high-granularity gradient screening using optimization reagents such as precipitation agents, ligands or cryoprotectants