370 research outputs found
Retrospective analysis of the cholesterol levels in a european mid-latitude population between 2007 and 2018: Controversies and therapeutic implications
Background and aim of the work: Coronary heart disease is the leading cause of morbidity and mortality in developed countries and its association with LDL-cholesterol has been well established. During the last decades statin therapy, and an healthy lifestyle, has proven highly effective in reducing cardiovascular event rates. Yet, there is still controversy among national guidelines and clinical practice with regard to LDL-cholesterol measurements. The aim of this study was to verify whether significant changes in cholesterol levels were observed over a relatively long (12 years) period. We also compared the Friedewald-calculated with directly-measured LDL cholesterol in order to verify whether the two methods were equivalent. Meth-ods: We retrospectively analyzed 288000 data (total cholesterol, HDL, LDL both directly-measured and Friedewald-calculated, and triglycerides), from 57600 individuals, collected at the San Raffaele Hospital in Milan between 2007 and 2018. Data were statistically analyzed using a linear regression over the 12 years long period of time. Results: We observed a general decreasing trend in total cholesterol (and an increasing trend in HDL) and a decrease in triglycerides only in the male group. Directly-measured LDL did not cor-relate well with calculated LDL. Conclusion: The total cholesterol decrease and the corresponding increment in HDL was attributed to either an increased use of statin and/or an improvement of the general population dietary habits. The latter was further confirmed by the decrease in triglycerides observed in the male group. Based on our data, an alternative method for assessing atherogenics lipoproteins level has been proposed. (www.actabiomedica.it)
trans-Resveratrol, Quercetin, (+)-Catechin, and (-)-Epicatechin Content in South Italian Monovarietal Wines: Relantionship with Maceration Time and Marc Pressing during Winemaking
The concentrations of trans-resveratrol, (+)-catechin, (-)-epicatechin, and quercetin were evaluated by means of high-performance liquid chromatography-diode array detection in red wines obtained from Aglianico, Piedirosso, and Nerello Mascalese grapes. The trans-resveratrol and epicatechin
concentrations did not differ significantly between experimental wines. The concentration of quercetin in Nerello Mascalese wines was more than twice that observed in Aglianico and Piedirosso wines.
Nerello Mascalese wines also significantly differed from other wines in the (+)-catechin content, which was significantly higher than those found in the other two wines. During maceration, the maximum extraction of trans-resveratrol was reached after 12 days for Aglianico and Piedirosso, after which a decline was observed. On the contrary, in the case of Nerello Mascalese, the concentration of trans-resveratrol increased steadily throughout the whole maceration process. After 2 days of maceration,
the maximum concentration of quercetin was observed in Aglianico must, whereas the maximum quercetin extraction was reached after 12 days for Piedirosso and 17 days for Nerello Mascalese.
The maximum levels of (+)-catechin and (-)-epicatechin were generally observed after 12 days of maceration for all wines, although a decline of (-)-epicatechin occurred after maximum extraction in Aglianico and Piedirosso wines. Following marc pressing, a significant increase in the concentration of trans-resveratrol for Aglianico, (+)-catechin and (-)-epicatechin for Piedirosso, and (-)-epicatechin for Nerello Mascalese was observed
Suitability of short-period sensors for retrieving reliable H/V peaks for frequencies less than 1 Hz
Using three different short-period electromagnetic sensors with resonant frequencies of 1 Hz (Mark L4C-3D), 2 Hz (Mark L-22D), and 4.5 Hz (I/O SM-6), coupled with three digital acquisition system, the PDAS Teledyne Geotech, the REFTEK 72A, and the Earth Data Logger PR6-24 (EDL), the effect of the seismic instruments on the horizontal-to-vertical spectral ratio (H/V) using seismic noise for frequencies less than 1 Hz has been evaluated. For all possible sensors - acquisition system pairs, the background seismic signal and instrumental self-noise power spectral densities have been calculated and compared. The results obtained when coupling the short-period sensors with different acquisition systems show that the performance of the considered instruments at frequencies < 1 Hz strongly depends upon the sensor-acquisition system combination and the gain used, with the best performance obtained for sensors with the lowest resonance frequency. For all acquisition systems, it was possible to retrieve correctly the H/V peak down to 0.1-0.2 Hz by using a high gain and a 1 Hz sensor. In contrast, biased H/V spectral ratios were retrieved when low-gain values were considered. Particular care is required when using 4.5 Hz sensors since they may not even allow the fundamental resonance frequency peak to be reproduce
Routine blood analysis greatly reduces the false-negative rate of RT-PCR testing for COVID-19
Background: The COVID-19 outbreak is now a pandemic disease reaching as much as 210 countries worldwide with more than 2.5 million infected people and nearly 200.000 deaths. Amplification of viral RNA by RT-PCR represents the gold standard for confirmation of infection, yet it showed false-negative rates as large as 15-20% which may jeopardize the effect of the restrictive measures taken by governments. We previously showed that several hematological parameters were significantly different between COVID-19 positive and negative patients. Among them aspartate aminotransferase and lactate dehydrogenase had pre-dictive values as large as 90%. Thus a combination of RT-PCR and blood tests could reduce the false-negative rate of the genetic test. Methods: We retrospectively analyzed 24 patients showing multiple and inconsistent RT-PCR, test during their first hospitalization period, and compared the genetic tests results with their AST and LDH levels. Results: We showed that when considering the hematological parameters, the RT-PCR false-negative rates were reduced by almost 4-fold. Conclusions: The study represents a preliminary work aiming at the development of strategies that, by combining RT-PCR tests with routine blood tests, will lower or even abolish the rate of RT-PCR false-negative results and thus will identify, with high accuracy, patients infected by COVID-19. (www.actabiomedica.it)
Determination of shallow S-wave attenuation by down-hole waveform deconvolution: a case study in Istanbul (Turkey)
The estimation of shear-wave velocity and attenuation in near-surface geology is of primary importance in engineering seismology. In fact, their knowledge is essential for site response studies when preparing improved seismic hazard scenarios. In this study, we propose two approaches for estimating the average shear-wave quality factor Qs by using recordings of a vertical array of accelerometers. The methods are mainly based on the deconvolution of the wavefield recorded in a borehole with that recorded at the surface.
The first method requires the Fourier transform of the deconvolved wavefield to be fitted with a theoretical transfer function valid for the vertical or nearly vertical (in the case at hand up to 30° incidence angle) propagation of S-waves. The second method is based on the spectral fitting of the Fourier transform of only the acausal part of the deconvolved wavefield with a theoretical transfer function.
Both methods can be applied without any prior knowledge of the subsoil structure (since they are based on empirical data analysis) and do not require a precise knowledge of the azimuthal orientation of the sensors in the boreholes (which is seldom available). First, we describe the theoretical framework of the proposed methodologies for Qs estimation, which are based on the assumption that the structure in the borehole is weakly heterogeneous in the vertical direction (that is, no large impedance contrast exists between the borehole sensor and the surface). Second, by using synthetic accelerograms, we verify that in a realistic subsoil structure, the assumption of vertical homogeneity can hold and we investigate the robustness and the suitability of the proposed methods. Finally, only the method that was shown to provide the more stable results, based on fitting the borehole-to-surface spectral ratio with a theoretical function, is applied to earthquakes signals recorded by a vertical array of accelerometers installed in Ataköy (western Istanbul). Results show that using borehole data provides a fair and robust estimate of an average Qs (of about 30, 46 and 99 for the 0-50, 0-70, 0-140 m depth ranges, respectively), that can be used for numerical simulations of ground motion
Suitability of short-period sensors for retrieving reliable H/V peaks for frequencies less than 1 Hz
Using three different short-period electromagnetic sensors with resonant frequencies of 1 Hz (Mark L4C-3D), 2 Hz (Mark L-22D), and 4.5 Hz (I/O SM-6), coupled with three digital
acquisition system, the PDAS Teledyne Geotech, the REFTEK 72A, and the Earth Data
Logger PR6-24 (EDL), the effect of the seismic instruments on the horizontal-to-vertical spectral ratio (H/V) using seismic noise for frequencies less than 1 Hz has been evaluated. For all possible sensors - acquisition system pairs, the background seismic signal and instrumental
self-noise power spectral densities have been calculated and compared. The results obtained when coupling the short-period sensors with different acquisition systems show that the performance of the considered instruments at frequencies < 1 Hz strongly depends upon the
sensor-acquisition system combination and the gain used, with the best performance obtained for sensors with the lowest resonance frequency. For all acquisition systems, it was possible to retrieve correctly the H/V peak down to 0.1-0.2 Hz by using a high gain and a 1 Hz sensor.
In contrast, biased H/V spectral ratios were retrieved when low-gain values were considered.
Particular care is required when using 4.5 Hz sensors since they may not even allow the
fundamental resonance frequency peak to be reproduce
Empirical H/V spectral ratios estimated in two deep sedimentary basins using microseisms recorded by short-period seismometers
In this work, we analyse continuous measurements of microseisms to assess the reliability of
the fundamental resonance frequency estimated by means of the horizontal-to-vertical (H/V)
spectral ratio within the 0.1–1 Hz frequency range, using short-period sensors (natural period
of 1 s). We apply the H/V technique to recordings of stations installed in two alluvial basins
with different sedimentary cover thicknesses—the Lower Rhine Embayment (Germany) and
the Gubbio Plain (Central Italy). The spectral ratios are estimated over the time–frequency
domain, and we discuss the reliability of the results considering both the variability of the
microseism activity and the amplitude of the instrumental noise. We show that microseisms
measured by short period sensors allow the retrieval of fundamental resonance frequencies
greater than about 0.1–0.2 Hz, with this lower frequency bound depending on the relative
amplitude of themicroseism signal and the self-noise of the instruments. In particular,we show
an examplewhere the considered short-period sensor is connected to instruments characterized
by an instrumental noise level which allows detecting only fundamental frequencies greater
than about 0.4 Hz. Since the frequency at which the peak of the H/V spectral ratio is biased
depends upon the seismic signal-to-instrument noise ratio, the power spectral amplitude of
instrumental self-noise should be always considered when interpreting the frequency of the
peak as the fundamental resonance frequency of the investigated site
Influence of berry ripening stages over phenolics and volatile compounds in aged aglianicowine
The harvest time of grapes is a major determinant of berry composition and of the wine quality, and it is usually established through empirical testing of main biochemical parameters of the berry. In this work, we studied how the ripening stage of Aglianico grapes modulates key secondary metabolites of wines, phenolics and volatile compounds. Specifically, we analyzed and compared four berry ripening stages corresponding to total soluble solids of 18, 20, 22, and 25 Brix and related aged wines. Wine color intensity, anthocyanins level and total trans-resveratrol (free + glycosidic form) increased with grape maturity degree. Wines obtained from late-harvested grapes significantly differed from the others for a higher content of aliphatic alcohols, esters, acetates, a-terpineol and benzyl alcohol. The content of glycosidic terpene compounds, such as nerol, geraniol and a-terpineol, was higher in wines obtained with grapes harvested at 25 Brix compared to the earlier harvests. Our work indicated that the maturity of the grape is a determining factor in phenolic and volatile compounds of red Aglianico wines. Moreover, extending grape ripening to a sugar concentration higher than 22 Brix improves the biochemical profile of aged wine in terms of aroma compounds and of phytochemicals with known health-related benefits
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