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.     

Transparent Plasmonic Nanowire Electrodes via Self‐Organised Ion Beam Nanopatterning

A self‐organised approach for the synthesis of transparent metal nanowire arrays is based on defocused ion beam sputtering. The nanowire arrays, supported on low‐cost dielectric substrates (glass slides), feature a dual functionality: they exhibit anisotropic conductivity, with sheet resistances which are reduced in comparison to those of transparent conductive oxides, and additionally they support localised plasmon resonances. The latter represents an attractive feature in view of plasmon enhanced photon harvesting applications, in which the nanostructured metal electrodes are employed as an alternative to conventional transparent conductive oxides.     

Base effects on electrochemical oxidation of indoline

The electrooxidation of indoline was studied as the first step in exploring its utility as a model liquid hydrogen carrier. Electrochemical oxidation of indoline in the presence of nitrogen-containing bases resulted in a cathodic shift in the onset of the oxidation. A linear correlation was found between the pK_a of the base and the magnitude of the cathodic shift of indoline oxidation. A hydrogen bonding complex model is proposed to account for this effect, and ¹H NMR spectroscopy and cyclic voltammetry experiments were conducted to support this proposed mechanism.     

Model for the final decarburisation of the steel bath through a self-bubbling effect

The decarburisation in the basic oxygen furnace is certainly the chemical process ruling the conversion of pig iron into steel and for the production of high deep drawability steel s. At the end of conversion, the steelmakers have often to blow again to achieve the targeted low values of carbon concentration. This further blowing process implies a productivity loss, even it is not strictly needed because the self-bubbling of the metal bath due to the CO formation can allow setting the carbon concentration within the required chemical range. Actually, due to the high temperatures and oxygen activity at the end of the blowing process, the decarburisation process keeps moving up to the equilibrium. The present study describes and validates a chemical-physical model based on thermodynamic and kinetic aspects that allow the steelmakers to forecast when exploiting the self-bubbling phenomenon avoiding the re-blow, increasing the productivity and the refractories working life.     

Study of Electroless Copper Deposition on Fe Powder

The electrolytic deposition of an electropositive metal is often accompanied by electroless deposition. However, this process is very difficult to control. For that reason, our study has been aimed at the conditions of the electroless deposition of copper coating onto the iron powder particles from sulphate electrolyte. The process consists of two partial reactions; solid iron substrate dissolves into the solution, thus providing the electrons necessary for reduction of copper. The course of the electroless process depends to a large extent on the composition and pH of the electrolyte as well as on the size and concentration of the iron powder particles in the electrolyte. In order to suppress the spontaneous electroless deposition of copper, sodium citrate as complexing agent was used. The following parameters were determined to characterize the reaction course: the heterogeneous rate constant of Fe powder dissolution and degree of Fe conversion as well as thickness of the Cu layer on the Fe powder, both of the latter evaluated upon attaining the stationary state. The main influence exhibited on the reaction course is the efficient surface area available for electroless deposition.     

Functionalization of Si(1 0 0) with ferrocene derivatives via “click” chemistry

We prepared ferrocene-modified silicon surfaces through a three-step procedure consisting of the photochemical anchoring of 11-bromo-1-undecene on H-Si(1 0 0), followed by treatment with NaN₃ and by a reaction with ethynylferrocene via azide-alkyne Huisgen cycloaddition reaction, also known as “click” chemistry. The advantages of this approach are multiple: the synthetic approach is flexible, provided a CC tethering arm is present on the molecule of interest; a self-assembled hydrocarbon chain can guarantee a good coverage and resistance to the further synthetic steps; the redox centers are located at the outer surface, where a good contact with the electrolyte becomes possible. We have monitored the progression of the reaction steps by XPS, and characterized the resulting new hybrid on Si by electrochemical methods. The presence and chemical nature of the redox species covalently attached to the SAM on Si has been evaluated by XPS, while the overall coverage has been calculated by CV measurements. A reversible electrochemical response has been evidenced for the hybrids and the progressive ageing followed at thousands of oxidation-reduction cycles.     

Nucleic acid amplification of individual molecules in a microfluidic device

A microfluidic device was developed that enabled rapid polymerase chain reaction (PCR) analysis of individual DNA molecules. The device combined a means for accessing samples serially from a microtiter plate, channels for assembling eight parallel PCR reactions, and integrated resistive heaters for rapid thermocycling (>5 degrees C/s heating, >7 degrees C/s cooling) of samples as they flowed continuously through PCR channels. Amplification was monitored by fluorescence detection of Taqman probes. The long, narrow channels (10 microm x 180 microm x 40 mm) allowed sufficient separation between neighboring DNA templates to enable amplification of discreet DNA molecules. The functionality of the device was demonstrated by reproducibly amplifying a 2D6.6 CYP450 template and distinguishing between wild-type and mutant sequences using Taqman probes. A comparison of the rate of individual amplification events to the expected Poisson distribution confirmed that the device could reliably analyze individual DNA molecules. This work establishes the feasibility of rapid, single-molecule interrogation of nucleic acids.     

Dynamic infrared study of polyphenylene sulfide using planar array infrared spectroscopy

Planar array infrared (PA-IR) spectroscopy was used to study polyphenylene sulfide (PPS) at room temperature during the application of a sinusoidal elastic deformation. All of the intensity in the dynamic spectra was contained within the in-phase spectrum, which was expected since the measurements were carried out at room temperature, far below the glass transition temperature. The contributions of chain orientation, sample thinning, and stress-induced band shifts were separated in the dynamic spectra. It was found that the effects of chain orientation and sample thinning canceled each other out. Stress-induced band shifts far below the spectral resolution, on the order of 0.01 cm(-1), were quantified and used to calculate the stress optical coefficients and mode Gruneisen parameters for PPS.     

Influence of the crack morphology on the fatigue crack growth rate: A continuously-kinked crack model based on fractals

Threshold condition and rate of fatigue crack growth appear to be significantly affected by the degree of deflection of cracks. In the present paper, the reduction of the fatigue crack growth rate for a so-called ‘periodically-kinked crack’ as compared to that for a straight counterpart is quantified via the Paris–Erdogan law modified according to some simple theoretical arguments. It is shown that such a reduction increases as the value of the kinking angle increases. Then, a so-called ‘continuously-kinked crack’ (the kink length tends to zero) is considered and modelled as a self-similar invasive fractal curve. The sequence of kinking angles in the crack is such that the fatigue crack path is ‘on average’ straight. Using the Richardson’s expression for self-similar fractals, the fractal dimension of the crack is expressed as a function of the kinking angle. It is shown that the fatigue crack growth rate in the Paris range depends not only on the above fractal dimension and in turn on the kinking angle, but also, in an explicit fashion, on the crack length. Some experimental results related to concrete and showing a crack size effect on the fatigue crack growth rate are analysed.