Early Postoperative Immunothrombosis of Bioprosthetic Mitral Valve and Left Atrium: A Case Report

A 72-year-old female patient with mixed rheumatic mitral valve disease and persistent atrial fibrillation underwent mitral valve replacement and suffered from a combined thrombosis of the bioprosthetic valve and the left atrium as soon as 2 days post operation. The patient immediately underwent repeated valve replacement and left atrial thrombectomy. Yet, four days later the patient died due to the recurrent prosthetic valve and left atrial thrombosis which both resulted in an extremely low cardiac output. In this patient’s case, the thrombosis was notable for the resistance to anticoagulant therapy as well as for aggressive neutrophil infiltration and release of neutrophil extracellular traps (NETs) within the clot, as demonstrated by immunostaining. The reasons behind these phenomena remained unclear, as no signs of sepsis or contamination of the BHV were documented, although the patient was diagnosed with inherited thrombophilia that could impede the fibrinolysis. The described case highlights the hazard of immunothrombosis upon valve replacement and elucidates its mechanisms in this surgical setting.     

Methacrylate hydrogels reinforced with bacterial cellulose

Composite hydrogels consisting of nanofibrous bacterial cellulose (BC) embedded in a biocompatible polymeric matrix of various methacrylates were synthesized by UV polymerization using the ‘ever‐wet’ technique. The effect of monomer(s) type and ratio, system dilution at polymerization, monomer(s) hydrophilicity, crosslink density and cellulose/hydrogel ratio was investigated. The effect of BC reinforcement on equilibrium swelling depends on whether the neat gel swells more when brought into contact with water. The major improvement achieved by introduction of 1%–2% BC concerns mechanical properties. Compared with neat gels, the storage shear modulus G′ increased by a factor 10‐20, and the loss part G″ also rose significantly. The compression modulus ranged from 2 to 5.5 MPa for composites swollen to equilibrium (20‐70 wt% water). The BC‐hydrogel composites are considered for application in the tissue engineering area. Copyright © 2012 Society of Chemical Industry     

Design methodology for barrier‐based two phase flow distributor

The barrier‐based distributor is a multiphase flow distributor for a multichannel microreactor which assures flow uniformity and prevents channeling between the two phases. For N number of reaction channels, the barrier‐based distributor consists of a gas manifold, a liquid manifold, N barrier channels for the gas, N barrier channels for the liquid, and N mixers for mixing the phases before the reaction channels. The flow distribution is studied numerically using a method based on the hydraulic resistive networks (RN). The single phase hydraulic RN model (Commenge et al., 2002;48:345–358) is extended for two phases gas‐liquid Taylor flow. For Re_GL <30, the accuracy for the model was above 90%. The developed‐model was used to study the effects of fabrication tolerance and barrier channel dimensions. A design methodology has been proposed as an algorithm to determine the required hydraulic resistance in the barrier channels and their dimensions. This methodology is demonstrated using a numerical example. © 2012 American Institute of Chemical Engineers AIChE J, 2012     

Calculation of the Thermal Stress-Strain State of Permafrost and Thawing Bases of Buildings in the Presence of Accidental Leaks from Utility Lines

Soil Mechanics and Foundation Engineering - A unified classification of accidental leaks of water from utility lines according to the magnitude of the effect of the permafrost in the base of...     

Factors Influencing Rapid Detection of Bioaerosols by Surface Plasmon Resonance-Based Technique

In bioaerosol monitoring applications, technologies allowing rapid and precise detection of airborne pathogens are highly demanded. One of such technologies, based on the immunoreaction-operating principle in nearly real-time mode without any specific labeling, is known as surface plasmon resonance (SPR). In previous studies, we have shown applicability of the SPR technology for rapid and selective detection of viral and bacterial aerosols where successful combination of the SPR machine with our earlier produced personal bioaerosol sampler opened new prospects in development of portable bioaerosol monitors. The current study is a logical continuation of our previous research dedicated to the technology development for rapid bioaerosol detection. Here, we focus on one of the main factors possibly influencing the SPR-based bioaerosol monitoring; the SPR performance on target bioaerosol detection was evaluated at conditions of substantial air contamination with different nontargeted microorganisms, commonly presented in the air. Besides, different compositions of sampling liquids were tested in regards to the SPR results interference. Our findings clearly verified high specificity of the technology even in cases of highly contaminated air environments with aerosols of biological and mineral origins. It was found that both nontargeted bioaerosols and nanosized aerosols of mineral background do not have significant influence on the specific SPR detection of targeted bioaerosols.

Copyright 2014 American Association for Aerosol Research     

Solid-state reorganization,melting and melt-recrystallization of conformationally disordered crystals (α′-phase) of poly (l-lactic acid)

Conformationally disordered α′-crystals of poly (l-lactic acid) were formed by crystallization of the melt at high supercooling at 95 °C. Analysis of their melting temperature as a function of the crystallinity revealed absence of crystal thickening during isothermal crystallization. Annealing of α′-crystals between the crystallization temperature of 95 °C and their zero-entropy production melting temperature of 150 °C leads to their stabilization, mainly by solid-state reorganization. Heating faster than 30 K s⁻¹ suppresses reorganization and permits superheating of the α′-phase. Consequently, isothermal melting followed by melt-recrystallization becomes accessible. Melting is completed within few hundreds of milliseconds, and melt-recrystallization is about two orders of magnitude faster than crystallization of the isotropic melt at identical temperature. The time required for melting decreases with superheating and increases with the lateral dimension of the lamellar crystals. Laterally extended lamellae require long time for melting of the outer crystal layers, which allows stabilization of the central crystal part. These crystal remnants then serve as seed for immediate recrystallization. In case of complete melting of smaller lamellae, melt-recrystallization is retarded but still distinctly faster than cold- and melt-crystallization, due to incomplete isotropization of the melt.     

THD analysis of compliant journal bearings considering liner deformation

A numerical THD model is developed to investigate the effect of lining compliance on the bearing characteristics. The analysis shows increased load carrying capacity, significantly reduced peak pressures and thicker oil film in the loaded zone compared to a white metal bearing. Slightly thinner oil films are predicted at the bearing edges. Temperature and power loss are found to be similar for some load-speed combinations but higher for other operating conditions. It is also shown that load carrying capacity is more sensitive to thermal expansion while pressure and oil film thickness profiles are more sensitive to elastic deformation.