Bovine pericardial patch repair in infected fields

ObjectiveBovine pericardial patches (BPP) are frequently used for arterial reconstruction, but little data exist regarding their ability to resist infection. We hypothesize that BPP would provide a reasonable alternative to autologous vein patches in infected fields.MethodsWe used BPP to repair 51 arteriotomies (25 brachial, 23 femoral, three popliteal) in 48 consecutive patients (mean age, 68 years; 65% men, 75% diabetic, 67% dialysis dependent) undergoing removal of infected (33 gram-positive, three gram-negative, eight mixed flora, and four culture-negative) polytetrafluoroethylene grafts (35 arteriovenous grafts, nine femoral-distal bypasses, and four femoral patch angioplasties) between January 2007 and January 2011. Patient records were retrospectively reviewed and outcomes, including death, rupture, secondary reconstruction, and infection, were recorded.ResultsOver a mean follow-up of 2.1 years (range, 3-48 months), 50 of 51 patches remained in place without evidence of recurrent infection, rupture, or revision. One patient had acute rupture of a popliteal arteriotomy 1 week postrepair and had subsequent ligation and above-knee amputation. Eight of the 48 patients died from unrelated causes during follow-up (three withdrew from dialysis, three myocardial infarction, and two unknown).ConclusionsBPP provide a durable alternative to saphenous vein for arterial reconstruction following removal of infected arterial grafts

Cube law, condition factor and weight-length relationships: history, meta-analysis and recommendations

This study presents a historical review, a meta-analysis, and recommendations for users about weight–length relationships, condition factors and relative weight equations. The historical review traces the developments of the respective concepts. The meta-analysis explores 3929 weight–length relationships of the type W = aLb for 1773 species of fishes. It shows that 82% of the variance in a plot of log a over b can be explained by allometric versus isometric growth patterns and by different body shapes of the respective species. Across species median b = 3.03 is significantly larger than 3.0, thus indicating a tendency towards slightly positive-allometric growth (increase in relative body thickness or plumpness) in most fishes. The expected range of 2.5 < b < 3.5 is confirmed. Mean estimates of b outside this range are often based on only one or two weight–length relationships per species. However, true cases of strong allometric growth do exist and three examples are given. Within species, a plot of log a vs b can be used to detect outliers in weight–length relationships. An equation to calculate mean condition factors from weight–length relationships is given as Kmean = 100aLb−3. Relative weight Wrm = 100W/(amLbm) can be used for comparing the condition of individuals across populations, where am is the geometric mean of a and bm is the mean of b across all available weight–length relationships for a given species. Twelve recommendations for proper use and presentation of weight–length relationships, condition factors and relative weight are given

A scalable helium gas cooling system for trapped-ion applications

Microfabricated ion-trap devices offer a promising pathway towards scalable quantum computing. Research efforts have begun to focus on the engineering challenges associated with developing large-scale ion-trap arrays and networks. However, increasing the size of the array and integrating on-chip electronics can drastically increase the power dissipation within the ion-trap chips. This leads to an increase in the operating temperature of the ion-trap and limits the device performance. Therefore, effective thermal management is an essential consideration for any large-scale architecture. Presented here is the development of a modular cooling system designed for use with multiple ion-trapping experiments simultaneously. The system includes an extensible cryostat that permits scaling of the cooling power to meet the demands of a large network. Following experimental testing on two independent ion-trap experiments, the cooling system is expected to deliver a net cooling power of 111 W at ∼70 K to up to four experiments. The cooling system is a step towards meeting the practical challenges of operating large-scale quantum computers with many qubits

Expansions of solutions of higher order evolution equations in series of generalized heat polynomials

Upper bound estimates are established on generalized heat polynomials for higher order linear homogeneous evolution equations with coefficients depending on the time variable. These estimates are analogous to well known bounds of Rosenbloom and Widder on the heat polynomials. The bounds lead to further estimates on the width of the strip of convergence of series expansions in terms of these polynomial solutions. An application is given to a Cauchy problem, wherein the solution is expressed as the sum of a series of polynomial solutions

Heat polynomial analogs for higher order evolution equations

Polynomial solutions analogous to the heat polynomials are demonstrated for higher order linear homogeneous evolution equations with coefficients depending on the time variable. Further parallels with the heat polynomials are established when the equation is parabolic with constant coefficients and only highest order terms