407 research outputs found

    Control of time variable, nonlinear multivariable systems using Liapunov's direct method

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    Controlling time variable nonlinear multivariable systems using Lipunous direct metho

    Synthesis and matrix properties of α-cyano-5-phenyl-2,4-pentadienic acid (CPPA) for intact proteins analysis by matrix-assisted laser desorption/ionization mass spectrometry

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    The effectiveness of a synthesized matrix, α-cyano-5-phenyl-2,4-pentadienic acid (CPPA), for protein analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in complex samples such as foodstuff and bacterial extracts, is demonstrated. Ultraviolet (UV) absorption along with laser desorption/ionization mass spectrometry (LDI-MS) experiments were systematically conducted in positive ion mode under standard Nd:YLF laser excitation with the aim of characterizing the matrix in terms of wavelength absorption and proton affinity. Besides, the results for standard proteins revealed that CPPA significantly enhanced the protein signals, reduced the spot-to-spot variability and increased the spot homogeneity. The CPPA matrix was successful employed to investigate intact microorganisms, milk and seed extracts for protein profiling. Compared to conventional matrices such as sinapinic acid (SA), α-cyano-4-hydroxycinnamic acid (CHCA) and 4-chloro-α-cyanocinnamic acid (CClCA), CPPA exhibited better signal-to-noise (S/N) ratios and a uniform response for most examined proteins occurring in milk, hazelnut and in intact bacterial cells of E. coli. These findings not only provide a reactive proton transfer MALDI matrix with excellent reproducibility and sensitivity, but also contribute to extending the battery of useful matrices for intact protein analysis

    A model of maxilla resection to test new hybrid implants:macroporous titanium and tissue engineering elements

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    Maxillary bone loss in commonly found in humans, due to bone ageing, tooth loos, periodontal disease and, more severely, to trauma, radiotherapy and tumor resection. Masillofacial reconstructive surgery is a still unmet clinical demand, available therapies include grafting of autologous or heterologous bone tissue and/or the implantation of metallic plates, buy these treatments are still unable to resume form and function. The emrgence of 3D-printing technology applied to metal alloys now allows the manufacturing of customized, patient-tailored prosthetic implants. However, poor bone quiality at the implant site due to ageing or disease still hamper proper osseointegration. By combining Electron Beam Melting metal sintering and tissue engineering, we are developing hybrid maxillofacial implants, wher a metal framework of Ti6Al4V alloy confers both and appropiaate shape and mechanical stabilty, while stem cells and osteogenic molecules stimulate bone growth into the metal framework, thus pormoting osseointegration. We hereby present the in vitro work driving to the development of our hybrid maxillofacial prostheses, as well as the setting up of an in vivo model of complete maxilla full resection, created in order to test the prostheses in a preclinical studyUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Dynamic titanium prosthesis based on 3D-printed replica for chest wall resection and reconstruction

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    3D-printing technologies can assist the surgical planning and prosthesis engineering for the management of extended chest wall resection. Different types of prosthesis have been utilized over time, but some concerns remain about their impact on the respiratory function. Here we present a new kind of 3D-printed titanium prosthesis designed to be either strong and flexible. The prosthesis was created on a 1:1 3D-printed anatomic replica of the chest, used to delineate surgical margins and to define the reconstructive requirements

    The ACEF score: a simple but powerful predictor of short-term mortality in patients with ST-elevation myocardial infarction

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    Background: several clinical risk scores are available for the risk stratification of patients with ST-elevation myocardial infarction (STEMI), such as the CADILLAC, GRACE, PAMI, TIMI, and Zwolle, but all are complex to use and there is uncertainty on the best one. The age-creatinine-ejection fraction (ACEF) score, has been recently proven effective and proficient as a risk score in cardiac surgery despite its user-friendliness. We thus aimed to compare the performance of the ACEF score in comparison to the other available risk scores in patient with STEMI. Methods: subjects with STEMI undergoing primary percutaneous coronary intervention at our Institution from 2001 to 2009 were enrolled. The primary end-point was in-hospital all-cause death, whereas long-term all-cause death, long-term cardiac death were appraised as secondary outcomes. ACEF, CADILLAC, GRACE, PAMI, TIMI, and Zwolle risk scores were compared with receiver-operating characteristics (ROC) curves with areas under the curve (AUC), and binary multivariable logistic regression analysis with odds ratios (OR), plus 95% confidence intervals

    Impact of PWM Voltage Waveforms in High-Speed Drives: A Survey on High-Frequency Motor Models and Partial Discharge Phenomenon

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    The insulation system’s dielectric of the electric motor is very often subjected to severe electrical stress generated by the high dv/dt seen at the machine’s terminals. The electrical stress and high reflected wave transient overvoltage are even more evident in case of high-speed machines fed by high-frequency (HF) converters featuring very fast wide-bandgap devices. They are promoting the occurrence of partial discharges and consequently accelerate ageing. As this is serious issue and the main cause of the drive failure, it is important to analyse and characterise the surges at the motor terminals. Several HF models of motors have been proposed in the literature for this purpose. This article presents a survey on HF motor models, which is crucial in understanding and studying the most critical parameter identification and overvoltage mitigation techniques. Moreover, it offers a comparison of the models’ main features as well as a comparison with the experimental voltage waveform at motor terminals. A general overview of the partial discharge (PD) phenomenon is also provided, as it is favoured by HF operation and together with HF motor modelling provides key insights to the insulation ageing issue. In particular, an analysis of the effects of PWM waveform affecting insulation is given, as well as useful methods for developing strategies for the inspection and maintenance of winding insulation

    Functional features defining the efficacy of cholesterol-conjugated, self-deliverable, chemically modified siRNAs

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    Progress in oligonucleotide chemistry has produced a shift in the nature of siRNA used, from formulated, minimally modified siRNAs, to unformulated, heavily modified siRNA conjugates. The introduction of extensive chemical modifications is essential for conjugate-mediated delivery. Modifications have a significant impact on siRNA efficacy through interference with recognition and processing by RNAi enzymatic machinery, severely restricting the sequence space available for siRNA design. Many algorithms available publicly can successfully predict the activity of non-modified siRNAs, but the efficiency of the algorithms for designing heavily modified siRNAs has never been systematically evaluated experimentally. Here we screened 356 cholesterol-conjugated siRNAs with extensive modifications and developed a linear regression-based algorithm that effectively predicts siRNA activity using two independent datasets. We further demonstrate that predictive determinants for modified and non-modified siRNAs differ substantially. The algorithm developed from the non-modified siRNAs dataset has no predictive power for modified siRNAs and vice versa. In the context of heavily modified siRNAs, the introduction of chemical asymmetry fully eliminates the requirement for thermodynamic bias, the major determinant for non-modified siRNA efficacy. Finally, we demonstrate that in addition to the sequence of the target site, the accessibility of the neighboring 3\u27 region significantly contributes to siRNA efficacy

    Randomized clinical trial on short-time compression with Kaolin-filled pad: a new strategy to avoid early bleeding and subacute radial artery occlusion after percutaneous coronary intervention.

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    BACKGROUND: Despite the increasing use of transradial techniques for cardiac percutaneous procedures, none of the strategies commonly utilized for hemostasis has been able to reduce the occurrence of radial artery occlusion (RAO). The aim of this study was to evaluate the occurrence of 24-hour RAO and the rate of bleeding of a novel hemostatic device for radial closure after percutaneous interventions, in adjunct to short-time compression.METHODS: Once the radial access was obtained, patients were randomized to 3 different strategies of radial closure: a short compression with the QuikClot® Interventional™ pad (Z-Medica Corporation, Wallingford, CT, USA) (15 minutes, group 1), a short compression (15 minutes, group 2), and a conventional prolonged compression (2 hours, group 3) both without QuikClot® utilization.RESULTS: Fifty patients in group 1, 20 in group 2, and 50 in group 3 were enrolled. The three groups were homogenous for baseline and procedural characteristics. None of patients in group 1 developed RAO, 1 (5%) occurred in group 2, and 5 (10%) in group 3 (P = 0.05). Active bleeding after compression removal occurred in 10 patients (20%) in group 1, 18 (90%) in group 2, and 1 (2%) in group 3 (P < 0.001). Among patients in group 1, at univariate analysis, the predictors of acute bleeding resulted in chronic therapy with clopidogrel (Odds Ratio 28.78, 95% Confidence Intervals 4.79-172.82, P < 0.001) and high levels of activated clotting time (ACT) at the time of sheath removal (OR 1.02, 95% CI 1.00-1.03, P = 0.009). At ROC analysis, the cutoff value of ACT for the risk of bleeding with a sensitivity of 80% and specificity of 75% was 287 seconds.CONCLUSIONS: Early sheet removal and short-time compression with QuikClot® Interventional™ can reduce the rate of RAO after diagnostic or interventional procedures especially in patients not on double antiplatelet therapy

    Percutaneous pericardiocentesis for pericardial effusion: predictors of mortality and outcomes

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    Pericardial effusion can dangerously precipitate patient’s hemodynamic stability and requires prompt intervention in case of tamponade. We investigated potential predictors of in-hospital mortality, a composite outcome of in-hospital mortality, pericardiocentesis-related complications, and the need for emergency cardiac surgery and all-cause mortality in patients undergoing percutaneous pericardiocentesis. This is an observational, retrospective, single-center study on patients undergoing percutaneous pericardiocentesis (2010–2019). We enrolled 81 consecutive patients. Median age was 71.4&nbsp;years (interquartile range [IQR] 58.1–78.1&nbsp;years) and 51 (63%) were male. Most of the pericardiocentesis were performed in an urgency setting (76.5%) for cardiac tamponade (77.8%). The most common etiology was idiopathic (33.3%) followed by neoplastic (22.2%). In-hospital mortality was 14.8% while mortality during follow-up (mean 17.1&nbsp;months) was 44.4%. Only hemodynamic instability (i.e., cardiogenic shock, hypotension refractory to fluid challenge therapy and inotropes) was associated with in-hospital mortality at the univariate analysis (odds ratio [OR] 7.2; 95% confidence interval [CI] 1.76–29.4). Non-neoplastic/non-idiopathic etiology and hemodynamic instability were associated with the composite outcome of in-hospital mortality, need for emergency cardiac surgery, or pericardiocentesis-related complications (OR 5.75, 95% CI 1.65–20.01, and OR 5.81, 95% CI 2.11–15.97, respectively). Multivariate Cox regression analysis adjusted for possible confounding variables (age, coronary artery disease, and hemodynamic instability) showed that neoplastic etiology was independently associated with medium-term mortality (hazard ratio [HR] 4.05, 95% CI 1.45–11.36). In a real-world population treated with pericardiocentesis for pericardial effusion, in-hospital adverse outcomes and medium-term mortality are consistent, in particular for patients presenting with hemodynamic instability or neoplastic pericardial effusion
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