59 research outputs found

    SEIS: Insight’s Seismic Experiment for Internal Structure of Mars

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    By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars’ surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking’s Mars seismic monitoring by a factor of ∼ 2500 at 1 Hz and ∼ 200 000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars’ surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of Mw ∼ 3 at 40◦ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution

    QRS Complex Based Human Identification

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    International audienceIn the last years, the electrocardiogram signal has become an important biometric modality due essentially to the physiological or/and behavioral characteristics variation of the heart among different individuals. The aim of this paper is to present a human identification approach using some time and frequency features of the QRS complex of the ECG signal. These features are extracted from a fractional order model of the frequency content of the QRS complex besides of its temporal area. The K-Nearest Neighbors (KNN) classifier is used for the human identification through the proposed clustering features. Series of tests have been performed to evaluate the proposed identification algorithm using 20 subjects from the MIT-BIH arrhythmia database

    Prediction - based feedback control of fractional order system

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    Naceri A, Mansouri N, Charef A. Prediction - based feedback control of fractional order system. In: Institute of Electrical and Electronics Engineers, ed. 2008 IEEE International Symposium on Industrial Electronics. Piscataway, NJ: IEEE; 2008: 908-912

    Kinetics of Inhibition of Xanthine Oxidase by Lycium arabicum and its Protective Effect against Oxonate- Induced Hyperuricemia and Renal Dysfunction in Mice

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    Purpose: To evaluate the in-vitro inhibition of xanthine oxidase (purified from bovine milk) by extracts of Lycium arabicum, as well as it is in vivo hypouricemic and renal protective effects.Methods: Four extracts of Lycium arabicum, methanol (CrE), chloroform (ChE), ethyl acetate (EaE) and aqueous (AqE) extracts, were screened for their total phenolics and potential inhibitory effects on purified bovine milk xanthine oxidase (XO) activity by measuring the formation of uric acid or superoxide radical. The mode of inhibition was investigated and compared with the standard drugs, allopurinol, quercitin and catechin. To evaluate their hypouricemic effect, the extracts were administered to potassium oxonate-induced hyperuricemic mice at a dose of 50 mg/kg body weight.Results: The results showed that EaE had the highest content of phenolic compounds and was the most potent inhibitor of uric acid formation (IC50 = 0.017 ± 0.001 mg/mL) and formation of superoxide (IC50 = 0.035 ± 0.001 mg/ml). Lineweaver-Burk analysis showed that CrE and EaE inhibited XO competitively, whereas the inhibitory activities exerted by ChE and AqE were of a mixed type. Intraperetoneal injection of L. arabicum extracts (50 mg/kg) elicited hypouricemic actions in hyperuricemic mice. Hyperuricemic mice presented a serum uric acid concentration of 4.71 ± 0.29 mg/L but this was reduced to 1.78 ± 0.11 mg/L by EaE, which was the most potent hyporuricemic extract.Conclusion: L. arabicum fractions have a strong inhibitory effect on xanthine oxidase and and also have a significantly lowering effect on serum and liver creatinine and urea levels in hyperuricemic mice.Keywords: Lycium arabicum, Uric acid, Creatinine, Superoxide, Phenolic compounds, Flavonoids, Hyperuricemi

    Synthesis, density functional theory studies, and sorption properties toward some divalent heavy metal ions of a new polystyrene-supported 4-(5-mercapto-1,3,4-thiadiazol-2-ylimino) pentan-2-one polymer

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    This work pertains to the synthesis, characterization, DFT, and sorption studies of a novel polystyrene-supported 4-(5-mercapto-1,3,4-thiadiazol-2-ylimino) pentan-2-one Schiff bases from 5-amino-1,3,4-thiadiazole-2-thiol (PSAc5A) and acetylacetone chloromethylated polystyrene (PSAc). This material was characterized by FTIR, elemental analysis, transmission electron microscopy, and thermogravimetric analysis (TGA). The chelating properties of the newly synthesized polymer toward the divalent metal Cu(II), Mn(II), Zn(II), and Ni(II) ions in aqueous solutions was studied by means of batch equilibration technique as a function of contact time, pH, mass of resin, and concentration of metal ions using atomic absorption spectrometry (AAS). Results obtained from this investigation revealed that this polymer can be used to remove heavy metal ions from the aquatic environment. In addition, the molecular structural geometry, the theoretical description of charge distribution, chemical reactivity descriptors, frontier molecular orbitals, molecular electrostatic potential (MEP), and electronic and bonding nature of the monomer structure have been investigated by using the density functional theory (DFT) in order to gain insights into the nature of this compound. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48289

    Multicenter, Double-Blind, Randomized, Phase 2 Study Evaluating the Novel Antibiotic Cadazolid in Patients with Clostridium difficile Infection

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    Cadazolid, a novel fluoroquinolone-oxazolidinone antibiotic, exhibits potent in vitro activity against Clostridium difficile, including the epidemic BI/NAP1/027 strain. This multicenter, randomized, double-blind, active reference group, phase 2 study evaluated the efficacy and safety of oral cadazolid in treatment of adult patients with C. difficile infection (CDI). Eligible patients with first occurrence/first recurrence of CDI were randomized 1:1:1:1 to 250, 500, or 1,000 mg cadazolid twice daily (BID) or oral 125 mg vancomycin four times daily (QID) for 10 days. The primary endpoint was clinical cure at test of cure (48 +/- 24 h after the end of treatment; modified intent-to-treat population), defined as resolution of diarrhea with no further CDI treatment required. Secondary endpoints included recurrence rate, sustained clinical response (clinical cure without recurrence), and time to diarrhea resolution. Of 84 patients enrolled, 20, 22, 20, and 22 received 250, 500, or 1,000 mg cadazolid BID or 125 mg vancomycin QID, respectively. The primary endpoint was achieved in 76.5% (80% confidence interval [CI], 58.4, 89.3), 80.0% (63.9, 91.0), 68.4% (51.1, 82.5), and 68.2% (52.3, 81.3) of patients, respectively. There was no evidence of a cadazolid dosage-dependent response. Each dosage of cadazolid resulted in a lower recurrence rate than with vancomycin (18.2 to 25.0% versus 50%). Consequently, higher sustained clinical response rates were observed with cadazolid (46.7 to 60.0%) than with vancomycin (33.3%). The times to diarrhea resolution were similar for cadazolid and vancomycin. Cadazolid was well tolerated, with no safety signal observed. The results of this phase 2 study support further clinical development of cadazolid. (This study has been registered in the United States at ClinicalTrials.gov under registration no. NCT01222702 and in Europe with the European Medicines Agency under registration no. EUDRA-CT 2010-020941-29.

    Energy prices and seafood security

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    Fish resources are critical to the food security of many nations. Similar to most contemporary food systems, many fisheries and aquaculture resource supply chains are heavily dependent on fossil fuels. Energy price increases and volatility may hence undermine food security in some contexts. Here, we explore the relationships between energy price changes, fish resource supply chain viability, seafood availability and food security outcomes – both for producers and consumers of fish resources. We begin by characterizing the energy intensities of fish resource supply chains, which are shown to be highly variable. We subsequently assess the comparative magnitude and distribution of potential food security impacts of energy price increases for nation states by scoring and ranking countries against a set of vulnerability criteria including metrics of national exposure, sensitivity and adaptive capacity. Considerable variability in the vulnerability of populations and high levels of exposure for already food-insecure populations are apparent. Developed countries are likely to be most exposed to the effects of energy price increases due to their high rates of fleet motorization and preference for energy-intensive seafood products. However, heavy reliance on seafood as a source of food and income, as well as limited national adaptive capacity, translates into greater overall vulnerability in developing countries. At the level of individual producers, a variety of adaptation options are available that may serve to reduce vulnerability to energy price changes and hence contribute to increased food security for producers and consumers, but uptake capacity depends on numerous situational factors

    Multifunctional PLA blends containing chitosan mediated silver nanoparticles: Thermal, mechanical, antibacterial, and degradation properties

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    Poly(lactic acid) (PLA) is one of the most commonly employed synthetic biopolymers for facing plastic waste problems. Despite its numerous strengths, its inherent brittleness, low toughness, and thermal stability, as well as a relatively slow crystallization rate represent some limiting properties when packaging is its final intended application. In the present work, silver nanoparticles obtained from a facile and green synthesis method, mediated with chitosan as a reducing and stabilizing agent, have been introduced in the oligomeric lactic acid (OLA) plasticized PLA in order to obtain nanocomposites with enhanced properties to find potential application as antibacterial food packaging materials. In this way, the green character of the matrix and plasticizer was preserved by using an eco-friendly synthesis protocol of the nanofiller. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results proved the modification of the crystalline structure as well as the crystallinity of the pristine matrix when chitosan mediated silver nanoparticles (AgCH-NPs) were present. The final effect over the thermal stability, mechanical properties, degradation under composting conditions, and antimicrobial behavior when AgCH-NPs were added to the neat plasticized PLA matrix was also investigated. The obtained results revealed interesting properties of the final nanocomposites to be applied as materials for the targeted application.This research was funded by Spanish Ministry of Science, Innovation and Universities (AEI-MICINN/FEDER); Projects MAT2016-78437-R and MAT2017-88123-P
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