A comprehensive approach to the treatment of popliteal artery aneurysms--personal experience]

During a five-year retrospective follow-up period the authors treated a group of 46 patients with the diagnosis of aneurysm of the popliteal artery (AAP). The group comprised 42 men (91%) and 4 women (9%). The mean age was 62 years. In 32 patients (69%) AAP was on both lower extremities, in the remaining 14 (31%) it was unilateral. Forty-one patients (90%) had surgery and a total of 48 AAP were operated. The remainder was treated by conservative methods (10%). The first symptoms of AAP in the investigated group were: claudication in 17%, thromboembolic complications in 46%, rupture of the AAP in 4%. An asymptomatic aneurysm was detected in 33%. RESULTS: The authors did not record any death or occlusion of the reconstruction during hospitalization. When using a vein the primary patency is 100%. When a prosthesis (PTFE) is used the results are worse but still satisfactory and the five-year secondary patency is 85%. Five patients with thromboembolic complications of AAP were successfully treated by i.a. fibrinolysis. In all exclusion of the aneurysm and revascularization of the extremity followed. In the conclusion the authors emphasize the necessity of early surgical treatment as soon as the condition is detected, before the development of thromboembolic complications of AAP. If they develop it is essential to attempt local fibrinolysis and in the second stage revascularization of the extremity, if possible by a vein.     

Peroperative transluminal angioplasty as a supplementary procedure to arterial reconstruction surgery

Patients with affections of the vascular system of the lower extremities at several levels present a complicated problem for vascular surgery. The authors submit their experience with a combination of vascular reconstruction and peroperative transluminal angioplasty. In 25 patients, mean age 64 years, they performed 29 of these combined operations, 10 times on account of claudications, 11 times on account of pain at rest, 8 times on account of trophic defects. The pelvic vessels were dilated 6 times; the dilated vessels as well as the reconstruction remained patent. Peroperative angioplasty of the superficial femoral artery was performed 6 times, occlusion occurred once. Twelve times they dilated the distal portion of the popliteal artery or the vessels of the leg, 3 times the dilated portion became occluded. None of the patients lost the limb, one patient died from acute myocardial infarction shortly after operation. The authors describe the technique of peroperative transluminal angioplasty, evaluate the results and discuss the advantages and disadvantages of this method.     

Plasma concentrations of phenobarbital in mother and child after combined prenatal and postnatal administration for prophylaxis of hyperbilirubinemia

Phenobarbital is known to reduce serum bilirubin concentration in the newborn infant, but optimal dosage is unknown. Ten pregnant women and their infants were given a standard regimen including prenatal maternal administration and postnatal administration to the infant during the first week of life. The plasma levels of phenobarbital in the infants were found to increase during the period of administration, and to remain high for many days beyond the period of hyperbilirubinemia. Optimal dose schedules for phenobarbital should be based both upon pharmacologic effects (including those other than bilirubin disposition) and upon the pharmacokinetic profile of the drug in the newborn infant.     

Review of current strategies to induce self-healing behaviour in fibre reinforced polymer based composites

Abstract

This paper addresses the various strategies to induce self-healing behaviour in fibre reinforced polymer based composites. A distinction is made between the extrinsic and intrinsic healing strategies. These strategies can be applied at the level of the fibre, the fibre/matrix interface or at the level of the matrix. It is shown that the degree of healing depends on the type of damage and the testing mode used and examples are given both for extrinsic and for intrinsic healing systems. The conclusion is drawn that self-healing in fibre reinforced composites is possible yet unlikely to become a commercial reality in the near future.     

ELB-Q: a new method for improving the robustness in DNA microarray image quantification.

Reliable and robust quantification of signal intensities is a critical step in microarray-based biomedical studies. However, traditional techniques for microarray image processing would face significant challenges if the number of pixels used for the quantification of the local background and the foreground decreases dramatically. We have developed a new method, ELB-Q, which, by design, is well suited for the image quantification of microarrays with very high density of spot layout (large number of spots arranged in unit area). In ELB-Q, a large extended local background (ELB) interspot region excluding those "noise of the background" pixels is used for estimating the local background, and the quantification of spot intensities (mean and median) in the putative target spot regions is performed after further excluding background pixels in these areas based on the cutoff values established during the ELB calculation. ELB-Q takes advantage of the abundant spatial information around each spot of interest, makes no assumption of the shape and size of the spots, and needs no sophisticated adjustment. We show results of image processing using ELB-Q on both the simulated data and real DNA microarrays, which compare favorably in robustness and accuracy against those obtained with GenePix Pro 6.0 (Axon Instruments, 1999) and the Markov random field (MRF) modeling approach. The ELB-Q software is developed in Matlab, and is available upon request.     

Detection of C-reactive protein based on immunoassay using antibody-conjugated magnetic nanoparticles

We report a detection method for C-reactive protein (CRP) based on competitive immunoassay using magnetic nanoparticles under magnetic fields. Functional magnetic nanoparticles were prepared and conjugated with anti-CRP for immunoassay. Magnetic nanoparticles labeled with anti-CRP were flowed through a separation channel to form depositions for selective capture of CRP under magnetic fields. Free CRP and a fixed number of CRP-labeled particles were used to compete for a limited number of anti-CRP binding sites on the magnetic nanoparticles. The deposited percentages of CRP-labeled particles at various concentrations of free CRP were determined and used as a reference plot. The determination of CRP in the unknown sample was deduced from the reference plot using the deposited percentages. The running time was less than 10 min. The CRP concentration of serum sample was linearly over the range of 1.2-310 microg/mL for deposited percentages of CRP-labeled particles. The detection limit of this method was 0.12 microg/mL which was approximately 8-fold lower than the typical clinical cutoff concentration (1 microug/mL). This method can provide a fast, simple, and sensitive way for protein detection based on competitive immunoassay using magnetic nanoparticles under magnetic fields.     

Use of real-time, label-free analysis in revealing low-affinity binding to blood group antigens by Helicobacter pylori

Infectious diseases are often initiated by microbial adherence that is mediated by the binding of attachment molecules, termed adhesins, to cell surface receptors on host cells. We present an experimental system, oblique-incidence reflectivity difference (OI-RD) microscopy, which allows the detection of novel, low-affinity microbial attachment mechanisms that may be essential for infectious processes. OI-RD microscopy was used to analyze direct binding of the oncopathogen, Helicobacter pylori ( H. pylori ) to immobilized glycoconjugates in real time with no need for labeling tags. The results suggest the presence of additional Lewis b blood group antigen (Le(b)) binding adhesins that have not been detected previously. OI-RD microscopy also confirmed the high-affinity binding of H. pylori outer-membrane protein BabA to Le(b). The OI-RD microscopy method is broadly applicable to real-time characterization of intact microbial binding to host receptors and offers new strategies to elucidate the molecular interactions of infectious agents with human host cells.     

From driving cycle analysis to understanding battery performance in real-life electric hybrid vehicle operation

This paper proposes a methodology and approach to understand battery performance and life through driving cycle and duty cycle analyses from electric and hybrid vehicle (EHV) operation in real-world situations. Conducting driving cycle analysis with trip data collected from EHV operation in real life is very difficult and challenging. In fact, no comprehensive approach has been accepted to date, except those using standard driving cycles on a dynamometer or a track. Similarly, analyzing duty cycle performance of a battery under real-life operation faces the same challenge. A successful driving cycle analysis, however, can significantly enhance our understanding of EHV performance in real-life driving. Likewise, we also expect similar results through duty cycle analysis for batteries. Since 1995, we have been developing tools to analyze EHV and power source performance. In particular, we were able to collect data from a fleet of 15 Hyundai Santa Fe electric sports utility vehicles (e-SUVs) operated on Oahu, Hawaii; from July 2001 to June 2003 to allow driving and duty cycle analyses in order to understand battery pack performance from a variety of EHV operating conditions. We thus developed a comprehensive approach that comprises fuzzy logic pattern recognition (FL-PR) techniques to perform driving and duty cycle analyses. This approach has been successfully applied to EHV performance analysis via the creation of a compositional driving profile called “driving cycle profile” (DrCP) for each trip. The same approach was used to analyze battery performance via the construction of “duty cycle profile” (DuCP) to express battery usage under various operating conditions. The combination of the two analyses enables us to understand both the usage profile of EHV and battery performance in synergetic details and in a systematic manner using a pattern recognition technique.     

Damping in partially delaminated composites

A simple model was developed to predict the material damping in partially delaminated composites. First, we evaluated the damping loss factors experimentally in three kinds of specimens corresponding to various partial delamination areas. Second, the stiffness loss with delamination growth was assumed to result directly in the loss of energy from the oscillatory system because the delamination due to interlaminar stress is accompanied with stiffness loss in numerous laminated composites. By correlating the laminate stiffness reduction and the corresponding delamination area, a model for their basic material damping properties was formulated using the elastic-viscoelastic principle, the rule-of-mixtures law and modified Hashin’s Model. We predicted the damping of any partially delaminated composites with different stacking sequences based on Adams and Ni’s work and their basic damping loss factors. Numerical and experimental results demonstrate that damping is significantly influenced by the size of delamination area in laminated composites. In addition, experimental improvements in making accurate damping measurements are discussed as well.