Comparison of green enhanced fluidity reversed phase liquid chromatography with HPLC

The growing interest in high throughput assays is the result of the increasing numbers and complexity of samples being produced by modern combinatorial synthetic procedures. The low viscosities and high diffusivities of enhanced fluid mixtures allow highly efficient separations to be achieved with analysis time gain as compared to High-performance liquid chromatography (HPLC). In this study, possibilities and limitations of HPLC mobile phases ethanol/water, acetonitrile/water, and methanol/water at higher proportion aqueous content and acetone/ acetonitrile as non-aqueous mobile phases were evaluated to compare liquid chromatography with green enhanced fluidity liquid chromatography (EFLC) separations by adding different concentrations of carbon dioxide as ternary mobile phase. The techniques were evaluated via van Deemter plots on reversed phase columns. EFLC allows reduce analysis time reduction and to obtain improved column efficiencies by effectively increasing the permeability of the system and by ensuing faster diffusion kinetics and further better selectivity. Similarly the impact on retention and separation in reversed phase using C18 and Naphtylethyl (Pi NAP) stationary phases were explored. A mixture of 16 priority PAH pollutants were used to investigate these effects. Next to interesting changes in selectivity improvements in analysis time and shifting Van Deemter curves could be measured in this way demonstrating the potential of this new green variant of HPLC

Venous Congestion and Systemic Hypoperfusion in Cardiorenal Syndrome: Two Sides of the Same Coin

A wide range of comorbidities play a pivotal role in worsening outcomes and increasing mortality risk in patients with heart failure (HF). Among them, renal dysfunction has been recognized as a highly prevalent prognostic variable, with a strong impact on prognosis, length of hospital stay and need for intensive care. In this context, recent evidence has pointed out the relevance of both systemic hypoperfusion and venous congestion on the imbalance of renal function as well as on the conditioning the pathophysiological crosstalk between heart and kidneys through a wide range of haemodynamic and biochemical pathways. This narrative review aims to investigate the intricate interplay between impaired systemic perfusion and venous congestion in cardiorenal syndrome, as well as their haemodynamic and biochemical implications for renal damage in HF

Tribocorrosion Properties of PEO Coatings Produced on AZ91 Magnesium Alloy with Silicate- or Phosphate-Based Electrolytes

In this work, the tribocorrosion behavior of plasma electrolytic oxidation (PEO)-coated AZ91 samples was studied. In particular, two different coatings were produced and compared. One was obtained with an alkaline electrolyte containing sodium phosphate, whereas the other one was produced with an alkaline electrolyte containing sodium silicate. The coatings were characterized with SEM-EDS and XRD techniques, and after the tribocorrosion tests, the wear scars were analyzed with SEM-EDS. The tribocorrosion behavior was evaluated measuring the OCP during a pin on disk test performed in an aggressive environment. Moreover, potentiodynamic polarization and electrochemical impedance spectroscopy tests were performed, to evaluate the corrosion resistance of the different samples in the absence of wear phenomena. The behavior of all the PEO-treated specimens was compared with the one of the untreated sample. A remarkable increase in the tribocorrosion performances after the PEO treatments was observed. Moreover, the samples obtained with the electrolyte containing silicates showed higher tribocorrosion performances

Low-cost wearable multichannel surface EMG acquisition for prosthetic hand control

Prosthetic hand control based on the acquisition and processing of surface electromyography signals (sEMG) is a well-established method that makes use of the electric potentials evoked by the physiological contraction processes of one or more muscles. Furthermore intelligent mobile medical devices are on the brink of introducing safe and highly sophisticated systems to help a broad patient community to regain a considerable amount of life quality. The major challenges which are inherent in such integrated system’s design are mainly to be found in obtaining a compact system with a long mobile autonomy, capable of delivering the required signal requirements for EMG based prosthetic control with up to 32 simultaneous acquisition channels and – with an eye on a possible future exploitation as a medical device – a proper perspective on a low priced system. Therefore, according to these requirements we present a wireless, mobile platform for acquisition and communication of sEMG signals embedded into a complete mobile control system structure. This environment further includes a portable device such as a laptop providing the necessary computational power for the control and a commercially available robotic handprosthesis. Means of communication among those devices are based on the Bluetooth standard. We show, that the developed low cost mobile device can be used for proper prosthesis control and that the device can rely on a continuous operation for the usual daily life usage of a patient

Impairment of myocardial perfusion and function during painless myocardial ischemia

Left ventricular (or pulmonary and systemic arterial) hemodynamics were measured for a mean of 13.6 hours during continuous electrocardiographic monitoring in 14 patients admitted to the coronary care unit because of angina at rest. Of 293 episodes of transient ST segment and T wave changes identified, 247 (84%) were completely asymptomatic. Sixty-three percent of asymptomatic episodes were associated with an elevation of the left ventricular end-diastolic or pulmonary artery diastolic pressure of 5 mm Hg or more; in 15% there were smaller elevations (2 to 4 mm Hg) and in 22% there were no changes or less than a 2 mm Hg elevation of pressure. The peak contraction and relaxation dP/dt (first deriviative of left ventricular pressure) were reduced to 100 mm Hg/s or more in 84 and 81 % of asymptomatic episodes, respectively. Great cardiac vein oxygen saturation measured in three patients showed an increased myocardial oxygen extraction similar to that seen in painful episodes, which preceded and accompanied asymptomatic electrocardiographic changes. These results indicate that asymptomatic electrocardiographic changes represent transient myocardial ischemia.Comparison of asymptomatic and symptomatic episodes revealed that asymptomatic episodes were generally shorter (253 ± 159 versus 674 ± 396 seconds, probability [p] < 0.001) and produced less impairment of left ventricular function: there were smaller elevations of left ventricular end-diastolic or pulmonary artery diastolic pressure (5.9 ± 5.0 versus 16.5 ± 6.9 mm Hg, p < 0.001), and smaller reductions of peak left ventricular contraction dP/dt (252 ± 156 versus 395 ± 199 mm Hg/s, p < 0.001) and relaxation dP/dt (259 ± 191 versus 413 ± 209 mm Hg/s, p < 0.001). In individual patients, however, asymptomatic and symptomatic episodes of similar duration and severity were observed. The duration and severity of ischemia appear important for the genesis of anginal pain, but additional factors must be involved

Sudden death after valve-in-valve procedure due to delayed coronary obstruction: A case report

Background: Valve-in-valve transcatheter aortic valve implantation for degenerated aortic bioprostheses is an effective option for patients at high risk for redo surgery, even if it may be burdened by complications more common in specific settings, such as, coronary artery obstruction. Case presentation: We present the case of a Caucasic 84-year-old woman with degeneration of a previously implanted aortic Mitroflow bioprosthesis. She underwent a valve-in-valve transcatheter aortic valve implantation with a CoreValve\uae bioprosthesis. End-procedure coronary angiography demonstrated maintained perfusion of both coronary arteries. However, few hours later, she experienced sudden cardiac death. An autopsy showed that Mitroflow prosthesis leaflets were higher than the left main coronary ostium, and no other possible cause for the sudden death. Fatality was thus ascribed to left main coronary ostium obstruction due to apposition of the Mitroflow leaflet pushed upward by the late expansion of CoreValve\uae. Conclusions: Coronary artery obstruction is a frequently fatal complication which usually presents just after valve implantation, but, as reported in our case, it may also have a delayed presentation. Accurate patient's selection and intraoperative preventive measures can reduce this eventuality