3,866 research outputs found

    Expanding the knowledge related to flavors and fragrances by means of three-dimensional preparative Gas Chromatography and Molecular Spectroscopy

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    As universally known, gas chromatography (GC) coupled with mass spectrometry (MS) allows us to acquire spectra that can be searched in specific databases to attain qualitative information on a peak of interest. When not present in databases, structure elucidation is required before including a new component in a library: from that moment, scientists all around the world will be able to identify the new molecule with analytical confidence after GC-MS analysis. Conversely, if data are not shared in commercial databases, even if a molecule is studied and elucidated, it appears to be unknown or only identifiable on the basis of third-party data taken from the literature, which is a serious limitation. The present paper deals with a case that confirms this assumption. A component of Myrtus communis L. volatile fraction was tentatively identified based on literature data. Despite this, reliable identification could not be achieved due to the lack of a corresponding spectrum in commercial MS databases. Afterwards, the target component was isolated in a reasonable quantity and with a high degree of purity for downstream characterization by spectroscopic techniques. For this purpose, preparative (prep) GC may appear insufficient for the isolation of volatile components from highly complex samples. In this study, a prep-MDGC system was implemented for the isolation of the compound of interest from myrtle oil, consisting of three wide-bore columns of different selectivity coupled by means of Deans switch transfer devices. Based on the NMR and GC-FTIR data acquired, the unknown compound was identified as 2,2,5,5,7,7-hexamethyl-3,7-dihydro-1-benzofuran-4,6(2H,5H)-dione. Noticeably, this is a known molecule, yet its mass spectrum had never been registered into MS databases and thus was not available to the scientific community. Finally, the spectrum was included for the first time in a commercial library, namely the FFNSC 5.0 MS database. The aim of the present study was to highlight the opportunity to make analytical data quickly available in a reliable way by registering them in searchable MS databases to improve the identification means for researchers all over the worl

    A Survey on Audio-Video based Defect Detection through Deep Learning in Railway Maintenance

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    Within Artificial Intelligence, Deep Learning (DL) represents a paradigm that has been showing unprecedented performance in image and audio processing by supporting or even replacing humans in defect and anomaly detection. The Railway sector is expected to benefit from DL applications, especially in predictive maintenance applications, where smart audio and video sensors can be leveraged yet kept distinct from safety-critical functions. Such separation is crucial, as it allows for improving system dependability with no impact on its safety certification. This is further supported by the development of DL in other transportation domains, such as automotive and avionics, opening for knowledge transfer opportunities and highlighting the potential of such a paradigm in railways. In order to summarize the recent state-of-the-art while inquiring about future opportunities, this paper reviews DL approaches for the analysis of data generated by acoustic and visual sensors in railway maintenance applications that have been published until August 31st, 2021. In this paper, the current state of the research is investigated and evaluated using a structured and systematic method, in order to highlight promising approaches and successful applications, as well as to identify available datasets, current limitations, open issues, challenges, and recommendations about future research directions

    Surgical therapy for ischemic heart failure: Single-center experience with surgical anterior ventricular restoration

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    ObjectivesOur objectives were (1) to report operative and long-term mortality in patients submitted to anterior surgical ventricular restoration, (2) to report changes in clinical and cardiac status induced by surgical ventricular restoration, and (3) to report predictors of death in a large cohort of patients operated on at San Donato Hospital, Milan, Italy.MethodsA total of 1161 consecutive patients (83% men, 62 ± 10 years) had anterior surgical ventricular restoration with or without coronary artery bypass grafting and with or without mitral repair/replacement. A complete echocardiographic study was performed in 488 of 1161 patients operated on between January 1998 and October 2005 (study group). The indication for surgery was heart failure in 60% of patients, angina, and/or a combination of the two.ResultsThirty-day cardiac mortality was 4.7% (55/1161) in the overall group and 4.9% (24/488) in the study group. Determinants of hospital mortality were mitral valve regurgitation and need for a mitral valve repair/replacement. Mitral regurgitation (>2+) associated with a New York Heart Association class greater than II and with diastolic dysfunction (early-to-late diastolic filling pressure >2) further increases mortality risk. Global systolic function improved postoperatively: ejection fraction improved from 33% ± 9% to 40% ± 10% (P < .001); end-diastolic and end-systolic volumes decreased from 211 ± 73 to 142 ± 50 and 145 ± 64 to 88 ± 40 mL, respectively (P < .001) early after surgery. New York Heart Association functional class improved from 2.7 ± 0.9 to 1.6 ± 0.7 (P < .001) late after surgery. Long-term survival in the overall population was 63% at 120 months.ConclusionsSurgical ventricular restoration for ischemic heart failure reduces ventricular volumes, improves cardiac function and functional status, carries an acceptable operative mortality, and results in good long-term survival. Predictors of operative mortality are mitral regurgitation of 2+ or more, New York Heart Association class greater than II, and diastolic dysfunction (early-to-late diastolic filling pressure >2)

    Wetting Properties of Graphene Aerogels

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    Graphene hydrophobic coatings paved the way towards a new generation of optoelectronic and fluidic devices. Nevertheless, such hydrophobic thin films rely only on graphene non-polar surface, rather than taking advantage of its surface roughness. Furthermore, graphene is typically not self-standing. Differently, carbon aerogels have high porosity, large effective surface area due to their surface roughness, and very low mass density, which make them a promising candidate as a super-hydrophobic material for novel technological applications. However, despite a few works reporting the general super-hydrophobic and lipophilic behavior of the carbon aerogels, a detailed characterization of their wetting properties is still missing, to date. Here, the wetting properties of graphene aerogels are demonstrated in detail. Without any chemical functionalization or patterning of their surface, the samples exhibit a super-lipophilic state and a stationary super-hydrophobic state with a contact angle up to 150 ± 15° and low contact angle hysteresis ≈ 15°, owing to the fakir effect. In addition, the adhesion force of the graphene aerogels in contact with the water droplets and their surface tension are evaluated. For instance, the unique wettability and enhanced liquid absorption of the graphene aerogels can be exploited for reducing contamination from oil spills and chemical leakage accidents

    Cationic poly(amidoamine) promotes cytosolic delivery of bovine RNase A in melanoma cells, while maintaining its cellular toxicity

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    Ribonucleases are known to cleave ribonucleic acids, inducing cell death. RNase A, a member of the ribonuclease family, generally displayed poor in vitro activity. This has been attributed to factors such as low intracellular delivery. Poly(amidoamine)s have been used to promote the translocation of non-permeant proteins to the cytosol. Our objective was to demonstrate that poly(amidoamine)s could potentially promote the delivery of RNase A to selected cell line. Interactions of three cationic poly(amidoamine)s (P1, P2 and ISA1) with wild-type bovine RNase A were investigated using gel retardation assays, DLS and microcalorimetry. Although the polymers and the protein are essentially cationic at physiological pH, complexation between the PAAs and RNase A was observed. The high sensitivity differential scanning calorimetry (HSDSC) thermograms demonstrated that the thermal stability of the protein was reduced when complexed with ISA1 (Tmax decreased by 6.5 °C) but was not affected by P1 and P2. All the polymers displayed low cytotoxicity towards non-cancerous cells (IC50 > 3.5 mg mL?1). While RNase A alone was not toxic to mouse melanoma cells (B16F1), P1 was able to promote cytosolic delivery of biologically active RNase A, increasing cell death (IC50 = 0.09 mg mL?1)

    Testis Sparing Surgery of Small Testicular Masses: Retrospective Analysis of a Multicenter Cohort

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    PURPOSE: We evaluated possible factors predicting testicular cancer in patients undergoing testis sparing surgery. MATERIALS AND METHODS: We retrospectively analyzed the records of all patients who underwent testis sparing surgery for a small testicular mass at a total of 5 centers. All patients with 1 solitary lesion 2 cm or less on preoperative ultrasound were enrolled in the study. Testis sparing surgery consisted of tumor enucleation for frozen section examination. Immediate radical orchiectomy was performed in all cases of malignancy at frozen section examination but otherwise the testes were spared. Univariate and multivariate analysis were performed and ROC curves were produced to evaluate preoperative factors predicting testicular cancer. RESULTS: Overall 147 patients were included in the study. No patient had elevated serum tumor markers. Overall 21 of the 147 men (14%) presented with testicular cancer. On multivariate analysis the preoperative ultrasound diameter of the lesion was a predictor of malignancy (OR 6.62, 95% CI 2.26-19.39, p=0.01). On ROC analysis lesion diameter had an AUC of 0.75 (95% CI 0.63-0.86, p=0.01) to predict testicular cancer. At the best cutoff of 0.85 the diameter of the lesion had 81% sensitivity, 58% specificity, 24% positive predictive value and 95% negative predictive value. CONCLUSIONS: Our study confirms that small testicular masses are often benign and do not always require radical orchiectomy. Preoperative ultrasound can assess lesion size and the smaller the nodule, the less likely that it is malignant. Therefore, we suggest a stepwise approach to small testicular masses, including tumorectomy, frozen section examination and radical orchiectomy or testis sparing surgery according to frozen section examination results

    Extended LCDM: generalized non-minimal coupling for dark matter fluids

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    In this paper we discuss a class of models that address the issue of explaining the gravitational dynamics at the galactic scale starting from a geometric point of view. Instead of claiming the existence of some hidden coupling between dark matter and baryons, or abandoning the existence of dark matter itself, we consider the possibility that dark matter and gravity have some non trivial interaction able to modify the dynamics at astrophysical scales. This interaction is implemented assuming that dark matter gets non--minimally coupled with gravity at suitably small scales and late times. After showing the predictions of the model in the Newtonian limit we also discuss the possible origin of it non-minimal coupling. This investigation seems to suggest that phenomenological mechanisms envisaged for the dark matter dynamics, such as the Bose--Einstein condensation of dark matter halos, could be connected to this class of models.Comment: 15 pages, more references added, minor changes, accepted for publication on JCA

    Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

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    The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E>Eth=5.5×1019E>E_{th}=5.5\times 10^{19} eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E>EthE>E_{th} are heavy nuclei with charge ZZ, the proton component of the sources should lead to excesses in the same regions at energies E/ZE/Z. We here report the lack of anisotropies in these directions at energies above Eth/ZE_{th}/Z (for illustrative values of Z=6, 13, 26Z=6,\ 13,\ 26). If the anisotropies above EthE_{th} are due to nuclei with charge ZZ, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies
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