Chronic fondaparinux use in a hemodialysis patient with heparin‐induced thrombocytopenia type II and extracorporeal circuit thrombosis—A case report and review of the literature

Heparin‐induced thrombocytopenia (HIT) is a potentially life‐threatening condition that can develop after exposure to unfractionated or low–molecular‐weight heparins. Treatment options appear to be limited in patients on concurrent intermittent hemodialysis. We report the case of an 88‐year‐old man newly initiated on high‐flux hemodialysis who developed HIT and extracorporeal circuit thrombosis after 3 weeks of exposure to unfractionated heparin. Our patient was successfully treated with fondaparinux 2.5 mg subcutaneously three times per week and citrate during dialysis sessions. Antifactor Xa levels were measured on several occasions while receiving fondaparinux.     

Simulation and optimization of retention in ion chromatography using virtual column 2 software

A new software package, Virtual Column 2, is described for the simulation and optimization of the separation of inorganic anions by ion chromatography (IC). The software uses a limited amount of experimental retention data acquired according to a correct experimental design to predict retention times for analytes over a designated search area of eluent compositions. The experimental retention data are used to solve a new retention model, called the linear solvent strength model, empirical approach (LSSM-EA), which then enables prediction of retention times for all eluent compositions in the search area. The theoretical development of LSSM-EA and the processes used for solving the equations are discussed. Virtual Column 2 can be used for eluents containing one or two competing ions, and the software contains retention databases for up to 33 analytes on the Dionex AS9A-HC, AS4A-SC, and AS14A analytical columns with carbonate-bicarbonate eluents and the Dionex AS10, AS15, and AS16 analytical columns with hydroxide eluents (results for the AS10 and AS15 columns are not discussed in the present study). Virtual Column 2 has been evaluated extensively and is shown to give predicted retention times that in most cases agree with experimentally determined data to within 5%. The software has uses in practical IC method development, education and training in IC, and refinement of existing IC methodology. A free version of this program is available by download at www.virtualcolumn.com.     

Self‐Healing of a Confined Phase Change Memory Device with a Metallic Surfactant Layer

Understanding and possibly recovering from the failure mechanisms of phase change memories (PCMs) are critical to improving their cycle life. Extensive electrical testing and postfailure electron microscopy analysis have shown that stuck–set failure can be recovered. Here, self‐healing of novel confined PCM devices is directly shown by controlling the electromigration of the phase change material at the nanoscale. In contrast to the current mushroom PCM, the confined PCM has a metallic surfactant layer, which enables effective Joule heating to control the phase change material even in the presence of a large void. In situ transmission electron microscope movies show that the voltage polarity controls the direction of electromigration of the phase change material, which can be used to fill nanoscale voids that form during programing. Surprisingly, a single voltage pulse can induce dramatic migration of antimony (Sb) due to high current density in the PCM device. Based on the finding, self‐healing of a large void inside a confined PCM device with a metallic liner is demonstrated for the first time.     

Multiscale modeling reveals poisoning mechanisms of MgO-supported Au clusters in CO oxidation

Catalyst deactivation mechanisms on MgO-supported Au(6) clusters are studied for the CO oxidation reaction via first-principle kinetic Monte Carlo simulations and shown to depend on support vacancies. In defect-poor MgO or in the presence of a Mg vacancy, O(2) does not bind to the clusters and the catalyst is poisoned by CO. On Au clusters interacting with O vacancies of the support, O(2) can be chemisorbed and transient activity is observed. In this case, an unexpected catalyst "breathing" mechanism (restructuring) leads to carbonate formation and catalyst deactivation, rationalizing several experimental observations. Our study underscores the importance of the cluster's charge state and dynamics on catalytic activity.     

Biomimetic synthesis and patterning of silver nanoparticles

The creation of nanoscale materials for advanced structures has led to a growing interest in the area of biomineralization. Numerous microorganisms are capable of synthesizing inorganic-based structures. For example, diatoms use amorphous silica as a structural material, bacteria synthesize magnetite (Fe3O4) particles and form silver nanoparticles, and yeast cells synthesize cadmium sulphide nanoparticles. The process of biomineralization and assembly of nanostructured inorganic components into hierarchical structures has led to the development of a variety of approaches that mimic the recognition and nucleation capabilities found in biomolecules for inorganic material synthesis. In this report, we describe the in vitro biosynthesis of silver nanoparticles using silver-binding peptides identified from a combinatorial phage display peptide library.     

Small Molecule-Gold Nanorod Conjugates Selectively Target and Induce Macrophage Cytotoxicity towards Breast Cancer Cells

Gold nanoparticles are known to activate anti-tumor potential in macrophage immune cells; however, the subsequent effects of these cells on others nearby are poorly understood. A novel gold-nanoparticle conjugate that selectively targets and induces cytotoxic activity of tumor-associated macrophages towards breast cancer cells in co-culture is synthesized. These constructs are promising new tools for studying fundamental biological interactions with nanoscale materials and candidates for emerging macrophage-mediated delivery applications.