Ariel - Volume 8 Number 5

Executive Editor James W. Lockard. Jr. Business Manager Neeraj K. Kanwal University News Martin Trichtinger World News Doug Hiller Opinions Elizabeth A. McGuire Features Patrick P. Sokas Sports Desk Shahab S. Minassian Managing Editor Edward H. Jasper Managing Associate Brenda Peterson Photography Editor Robert D. Lehman, Jr. Graphics Christine M. Kuhnl

Neighborhoods of trees in circular orderings

In phylogenetics, a common strategy used to construct an evolutionary tree for a set of species X is to search in the space of all such trees for one that optimizes some given score function (such as the minimum evolution, parsimony or likelihood score). As this can be computationally intensive, it was recently proposed to restrict such searches to the set of all those trees that are compatible with some circular ordering of the set X. To inform the design of efficient algorithms to perform such searches, it is therefore of interest to find bounds for the number of trees compatible with a fixed ordering in the neighborhood of a tree that is determined by certain tree operations commonly used to search for trees: the nearest neighbor interchange (nni), the subtree prune and regraft (spr) and the tree bisection and reconnection (tbr) operations. We show that the size of such a neighborhood of a binary tree associated with the nni operation is independent of the tree’s topology, but that this is not the case for the spr and tbr operations. We also give tight upper and lower bounds for the size of the neighborhood of a binary tree for the spr and tbr operations and characterize those trees for which these bounds are attained

Selection of the best proper DC-SQUIDs in a multi-SQUID configuration

We have carried out experimental investigation of multi-DC-SQUID magnetometer configuration fabricated on YBa2Cu30 7-δ thin films onto 24 degree SrTiO3 bicrystal substrates by directly coupling the pick-up loop to DC-SQUIDs. The layout of the magnetometer pick-up loop was chosen as a square washer configuration by maximizing loop effective area and minimizing loop inductance. We have used De-Magnetron Sputtering technique for deposition of the films and chemical etching process for patterning the Josephson junctions having 4 μm widths. The use of multi-SQUID configuration is related to the selection of the best proper junctions for SQUID to improve the chip sensitivity with selectivity option of choosing the squid junctions rather than multichannel operation. Selection of the best junctions compared to each other depending on the junction critical currents and noise levels caused by the fabrication process and placements of the junctions on the grain boundary enable having an increased output signal of the DC-SQUID. © 2007 IEEE

Mortality Not Correlated With Paclitaxel Exposure

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Delivery Site of Perivascular Endothelial Cell Matrices Determines Control of Stenosis in a Porcine Femoral Stent Model

PURPOSE: High restenosis rates are a major limitation of peripheral interventions. Endothelial cells, grown within gelatin matrices and implanted onto the adventitia of injured vessels, inhibit stenosis in experimental models. To determine if this technology could be adapted for minimally invasive procedures, we compared the effects of cells in an implantable sponge to an injectable formulation and investigated the importance of delivery site in a stent model. MATERIALS AND METHODS: Stents were implanted in the femoral arteries of 30 pigs followed by perivascular implantation of sponges or injection of particles containing allogeneic endothelial cells. Controls received acellular matrices or nothing. The effects of delivery site were assessed by injecting cellular matrices into or adjacent to the perivascular tissue, or into the neighboring muscle. Animals were sacrificed after 28 days. Pre-sacrifice angiograms and tissue sections were evaluated for stenosis. RESULTS: Arteries treated with cellular matrices had a 55 – 63% decrease in angiographic stenosis (P<0.05) and a 38 – 43% reduction (P<0.05) in histologic stenoses compared to controls. Intimal area was greatest when cellular matrices were delivered into the muscle (6.35 ± 0.95 mm2) compared to into or adjacent to the perivascular tissue (4.05 ± 0.56 mm2 and 4.73 ± 0.53 mm2, respectively, P < 0.05). CONCLUSIONS: Perivascular endothelial-cell matrices reduced stenosis after stent-induced injury. The effects were not dependent on the formulation but appeared to be dependent upon delivery site. Minimally invasive injections of endothelial-cell matrices to the adventitia of arteries following peripheral interventions may decrease restenosis rates.National Institutes of Health (U.S.) (Grant GM 49039

Dependence of Josephson junction critical current on the deposition rate of YBa2Cu3O7-δ thin films

We have reported the effect of YBa2Cu3O 7-δ (YBCO) thin film deposition rate on the 24 and 30 degree STO bicrystal Josephson junctions critical currents by fabricating series of junctions with different deposition rates. Dependence of YBCO thin film structures on the deposition rate was investigated. We have observed that the critical currents of junctions are strongly affected by the thin film deposition rate. © 2007 American Institute of Physics

Durability of Treatment Effect Using a Drug-Coated Balloon for Femoropopliteal Lesions

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Three-year sustained clinical efficacy of drug-coated balloon angioplasty in a real-world femoropopliteal cohort

Purpose:To report the 36-month outcomes from the prospective, multicenter, single-arm IN.PACT Global Study (ClinicalTrials.govidentifier NCT01609296) evaluating the performance of the IN.PACT Admiral drug-coated balloon (DCB) in real-world patients with femoropopliteal occlusive disease.Materials and Methods:The IN.PACT Global Study was conducted at 64 international sites and enrolled 1535 patients with complex lesions, which included bilateral disease, multiple lesions, de novo in-stent restenosis, long lesions, and chronic total occlusions. The predefined full clinical cohort included 1406 patients (mean age 68.6 years; 67.8% men) with claudication or rest pain treated with the study DCB. Mean lesion length was 12.09 +/- 9.54 cm; 18.0% had in-stent restenosis, 35.5% were totally occluded, and 68.7% were calcified. Freedom from clinically-driven target lesion revascularization (CD-TLR) was evaluated through 36 months. The safety composite endpoint was freedom from device- and procedure-related death through 30 days and freedom from major target limb amputation and clinically-driven target vessel revascularization within 36 months. All safety and revascularization events were reviewed by an independent clinical events committee.Results:The Kaplan-Meier estimate of freedom from CD-TLR through 36 months was 76.9%. The composite safety endpoint was achieved in 75.6% of patients. The 36-month all-cause mortality rate was 11.6%, and the major target limb amputation rate was 1.0%. The Kaplan-Meier estimate of freedom from CD-TLR through 36 months was significantly lower in patients with chronic limb-threatening ischemia (CLTI) compared with claudicants (67.6% vs 78.0%; p=0.003). Lesions affecting both the superficial femoral artery (SFA) and popliteal artery had lower Kaplan-Meier freedom from CD-TLR through 36 months (69.2%) than either isolated SFA (79.7%) or popliteal artery lesions (76.5%; log- rank p<0.001). Predictors of CD-TLR through 36 months included increased lesion length, reference vessel diameter <= 4.5 mm, in-stent restenosis, bilateral disease, CLTI, and hyperlipidemia.Conclusion:DCB angioplasty with the IN.PACT Admiral DCB for femoropopliteal disease in a diverse and complex real-world population is associated with sustained clinical efficacy and low rates of reinterventions at 3 years after the initial procedure

Influence of confinement on the orientational phase transitions in the lamellar phase of a block copolymer melt under shear flow

In this work we incorporate some real-system effects into the theory of orientational phase transitions under shear flow (M. E. Cates and S. T. Milner, Phys. Rev. Lett. v.62, p.1856 (1989) and G. H. Fredrickson, J. Rheol. v.38, p.1045 (1994)). In particular, we study the influence of the shear-cell boundaries on the orientation of the lamellar phase. We predict that at low shear rates the parallel orientation appears to be stable. We show that there is a critical value of the shear rate at which the parallel orientation loses its stability and the perpendicular one appears immediately below the spinodal. We associate this transition with a crossover from the fluctuation to the mean-field behaviour. At lower temperatures the stability of the parallel orientation is restored. We find that the region of stability of the perpendicular orientation rapidly decreases as shear rate increases. This behaviour might be misinterpreted as an additional perpendicular to parallel transition recently discussed in literature.Comment: 25 pages, 4 figures, submitted to Phys. Rev.

AMS INSIGHT—Absorbable Metal Stent Implantation for Treatment of Below-the-Knee Critical Limb Ischemia: 6-Month Analysis

Endoluminal treatment of infrapopliteal artery lesions is a matter of controversy. Bioabsorbable stents are discussed as a means to combine mechanical prevention of vessel recoil with the advantages of long-term perspectives. The possibility of not having a permanent metallic implant could permit the occurrence of positive remodeling with lumen enlargement to compensate for the development of new lesions. The present study was designed to investigate the safety of absorbable metal stents (AMSs) in the infrapopliteal arteries based on 1- and 6-month clinical follow-up and efficacy based on 6-month angiographic patency. One hundred seventeen patients with 149 lesions with chronic limb ischemia (CLI) were randomized to implantation of an AMS (60 patients, 74 lesions) or stand-alone percutaneous transluminal angioplasty (PTA; 57 patients, 75 lesions). Seven PTA-group patients “crossed over” to AMS stenting. The study population consisted of patients with symptomatic CLI (Rutherford categories 4 and 5) and de novo stenotic (>50%) or occlusive atherosclerotic disease of the infrapopliteal arteries who presented with a reference diameter of between 3.0 and 3.5 mm and a lesion length of <15 mm. The primary safety endpoint was defined as absence of major amputation and/or death within 30 days after index intervention and the primary efficacy endpoint was the 6-month angiographic patency rate as confirmed by core-lab quantitative vessel analysis. The 30-day complication rate was 5.3% (3/57) and 5.0% (3/60) in patients randomized for PTA alone and PTA followed by AMS implantation, respectively. On an intention-to-treat basis, the 6-month angiographic patency rate for lesions treated with AMS (31.8%) was significantly lower (p = 0.013) than the rate for those treated with PTA (58.0%). Although the present study indicates that the AMS technology can be safely applied, it did not demonstrate efficacy in long-term patency over standard PTA in the infrapopliteal vessels