This paper deals with the analysis of leakage current and phase angle characteristics of porcelain and silicone rubber insulator in order to develop a better diagnostic tool to identify the pollution ...severity of outdoor insulators. In this work, laboratory based pollution performance tests are carried out on porcelain and silicone rubber insulator under ac voltage at different pollution levels and relative humidity conditions with sodium chloride as a contaminant. Multi resolution signal decomposition (MRSD) using discrete wavelet transform (DWT) is employed to understand the time-frequency characteristics of the leakage current signal. Fast Fourier transform (FFT) spectral analysis is adopted to calculate the phase angle values of the applied voltage and leakage current signals. Reported results on porcelain and silicone rubber insulators show that the pollution severity of outdoor insulators could be identified from the DWT STD-MRA (standard deviation multi resolution analysis) distortion ratio pattern analysis of leakage current signals.
This paper reports the characterization of an electrochemical biosensor for the continuous monitoring of Naproxen based on cytochrome P450. The electrochemical biosensor is based on the drop-casting ...of multi-walled carbon-nanotubes (MWCNTs) and microsomal cytochrome P4501A2 (msCYP1A2) on a graphite screen-printed electrode (SPE). The proposed biosensor was employed to monitor Naproxen (NAP), a well-known anti-inflammatory compound, through cyclic voltammetry. The dynamic linear range for the amperometric detection of NAP had an upper limit of 300 µM with a corresponding limit of detection (LOD) of 16 ± 1 µM (S/N=3), which is included in NAP physiological range (9-300 µM). The MWCNT/msCYP1A2-SPE sensor was also calibrated for NAP detection in mouse serum that was previously extracted from mice, showing a slightly higher LOD (33 ± 18 µM). The stability of the msCYP1A2-based biosensor was assessed by longtime continuous cyclic voltammetric measurements. The ability of the sensor to monitor drug delivery was investigated by using a commercial micro-osmotic pump. Results show that the MWCNT/msCYP1A2-SPE sensor is capable of precisely monitoring the real-time delivery of NAP for 16 h. This work proves that the proposed electrochemical sensor might represent an innovative point-of-care solution for the personalization of drug therapies, as well as for pharmacokinetic studies in both animals and humans.
Background and purpose
Multiple studies have suggested an immunomodulatory role of cholesterol. We investigated whether cholesterol levels are associated with the risk of infectious complications ...(ICs) in acute ischemic stroke patients.
Methods
A single‐center prospective cohort was analyzed. Total (TOTc), low‐density lipoprotein cholesterol and high‐density lipoprotein cholesterol levels were measured within 24 h from admission. The outcome of interest was the occurrence of any IC (pneumonia, urinary tract infection, sepsis, other infection) during hospitalization. Predictors of ICs were investigated with multivariable logistic regression.
Results
A total of 603 patients were included (median age 78 years, 49.3% males), of whom 134 (22.2%) developed an IC. Subjects with ICs had lower TOTc compared with patients without ICs (median 157 vs. 173 mg/dL; P < 0.001). When TOTc was stratified in quartiles, we observed a linear decrease in the prevalence of ICs with higher TOTc levels (Q1, <144 mg/dL, 32.7%; Q2, 145–168 mg/dL, 24.7%; Q3, 169–197 mg/dL, 17.8%; Q4, >197 mg/dL, 13.3% P < 0.001). The inverse relationship between TOTc and ICs remained significant after adjustment for confounders in logistic regression odds ratio (OR) for 10 mg/dL increase, 0.92; 95% confidence intervals (CI), 0.87–0.97; P = 0.001. This association was also confirmed for low‐density lipoprotein cholesterol (OR, 0.93; 95% CI, 0.88–0.99; P = 0.013) and high‐density lipoprotein cholesterol (OR, 0.85; 95% CI, 0.73–0.98; P = 0.026) and was not mediated by statin treatment.
Conclusion
Higher cholesterol levels are independently associated with lower risk of ICs in ischemic stroke patients. Further studies are needed to confirm our findings and characterize the biological mechanisms underlying this association.
Microfin tubes are widely used in air cooled and water cooled heat exchangers for heat pump and refrigeration applications during condensation or evaporation of refrigerants. In order to design heat ...exchangers and to optimize heat transfer surfaces, accurate procedures for computing pressure drops and heat transfer coefficients are necessary. This paper presents a new simple model for the prediction of the heat transfer coefficient to be applied to condensation in horizontal microfin tubes of halogenated and natural refrigerants, pure fluids or nearly azeotropic mixtures. The updated model accounts for refrigerant physical properties, two-phase flow patterns in microfin tubes and geometrical characteristics of the tubes. It is validated against a data bank of 3115 experimental heat transfer coefficients measured in different independent laboratories all over the world including diverse inside tube geometries and different condensing refrigerants among which R22, R134a, R123, R410A and CO
2.
Condensation in minichannels is widely used in air-cooled condensers for the automotive and air-conditioning industry, in heat pipes and other applications for system thermal control. The knowledge ...of pressure drops in such small channels is important in order to optimize heat transfer surfaces. This paper presents a model for calculation of the frictional pressure gradient during condensation or adiabatic liquid–gas flow inside minichannels with different surface roughness. In order to account for the effects of surface roughness, new experimental frictional pressure gradient data associated to single-phase flow and adiabatic two-phase flow of R134a inside a single horizontal mini tube with rough wall has been used in the modelling. It is a Friedel (1979) Friedel, L., 1979. Improved friction pressure drop correlations for horizontal and vertical two-phase pipe flow. In: Proceedings of the European Two-Phase Flow Group Meeting, Ispra, Paper E2 based model and it takes into account mass velocity, vapor quality, fluid properties, reduced pressure, tube diameter, entrainment ratio and surface roughness. With respect to the flow pattern prediction capability, it has been built for shear dominated flow regimes inside pipes, thus, annular, annular-mist and mist flow are here predicted. However, the suggested procedure is extended to the intermittent flow in minichannels and it is also applied with success to horizontal macro tubes.
Arbuscular mycorrhizal (AM) fungi (AMF) establish beneficial symbioses with the roots of the majority of land plants, including major food crops. The susceptibility of sunflower (
Helianthus annuus
) ...to AMF was studied in 26 genotypes—nine wild accessions, 11 cultivars and six inbred lines—by assessing mycorrhizal root colonization in individual plants, with the aim of gaining insights into the genetic control of this trait. The analysis of genetic diversity among sunflower wild accessions, cultivars, and inbred lines, performed by retrotransposon display (multilocus fingerprinting), showed large variability among the analysed genotypes, with wild accessions more variable than domesticated genotypes. Wild accessions were also more susceptible to mycorrhizal colonization than cultivars. Nevertheless, analyses of inbred lines revealed a low repeatability value of the mycorrhizal colonization trait, suggesting the absence of a clearcut genetic control; variability should therefore mostly reflect environmental effects.
Background and purpose
Comorbidity of acute ischaemic stroke with Covid‐19 is a challenging condition, potentially influencing the decision of whether to administer intravenous thrombolysis (IVT). We ...aimed to assess the 1‐month outcome in ischaemic stroke patients with Covid‐19 infection who received IVT alone or before thrombectomy (bridging therapy).
Methods
As a collaboration initiative promoted by the Italian Stroke Organization, all Italian stroke units (n = 190) were contacted and invited to participate in data collection on stroke patients with Covid‐19 who received IVT.
Results
Seventy‐five invited centers agreed to participate. Thirty patients received IVT alone and 17 received bridging therapy between 21 February 2020 and 30 April 2020 in 20 centers (n = 18, Northern Italy; n = 2, Central Italy). At 1 month, 14 (30.4%) patients died and 20 (62.5%) survivors had a modified Rankin Scale (mRS) score of 3 to 5. At 24 to 36 hours, asymptomatic intracerebral hemorrhage (ICH) was reported in eight (17.4%) patients and symptomatic ICH (sICH) in two (4.3%) patients. Causes of death were severe ischaemic stroke (n = 8), a new ischaemic stroke (n = 2), acute respiratory failure (n = 1), acute renal failure (n = 1), acute myocardial infarction (n = 1), and endocarditis (n = 1). In survivors with a 1‐month mRS score of 3 to 5, baseline glucose level was higher, whereas endovascular procedure time in cases of bridging therapy was longer. Baseline National Institutes of Health Stroke Scale glucose and creatinine levels were higher in patients who died.
Conclusions
Intravenous thrombolysis for patients with stroke and Covid‐19 was not a rare event in the most affected areas by pandemic, and rates of 1‐month unfavorable outcomes were high compared to previous data from the pre–Covid‐19 literature. However, risk of sICH was not increased.
Seventy‐five centers agreed to participate in the study. Forty‐seven stroke patients with Covid‐19 were treated with thrombolysis alone (n = 30) or bridging therapy (n = 17) in 20 centers (n = 18, Northern Italy; n = 2, Central Italy). During the study period, 283 stroke patients were treated with thrombolysis alone (n = 266, Northern Italy; n = 17, Central Italy) and 167 stroke patients with bridging therapy (n = 156, Northern Italy; n = 11, Central Italy) in the 20 enrolled centers. Rates of 1‐month unfavorable outcomes (death: 30.4%; mRs score 3–5: 62.5%) were high compared to previous data from the pre–Covid‐19 literature. However, risk of sICH (4.3%) was not increased.
This paper reports and discusses qualification and type test procedures for random wound motors as specified in IEC Technical Specification 60034-18-41. Since laboratory tests dealing with off-line ...partial discharges measurements followed by life tests showed that motors qualified as good can fail in very short times, an extensive investigation on the causes of such discrepancy and, in particular, on the differences existing between the stresses applied during off-line tests and in service is described. In addition, the results of partial discharge measurements performed on crossed pairs are presented, highlighting how the differences in the applied voltage waveform can influence the Repetitive Partial Discharge Inception Voltage. Suggestions to improve the off-line test procedure and related equipment are eventually discussed.
Members of CYCLOIDEA (CYC)/TEOSINTE BRANCHED1 (TB1) transcription factor family are essential to control flower symmetry and inflorescence architecture. In the Helianthus annuus genome, ten CYC/TB1 ...genes have been identified. Studies performed on mutants recognised HaCYC2c as one of the key players controlling zygomorphism in sunflower. We identified CYC2c genes in the diploid Helianthus decapetalus (HdCYC2c) and in the interspecific hybrid Helianthus × multiflorus (H × mCYC2cA and H × mCYC2cB), a triploid (2n = 3× = 51), originated from unreduced eggs of H. decapetalus fertilised by reduced H. annuus male gametes. Phylogenetic analysis showed that HdCYC2c and H × mCYC2c were placed within a CYC2 subclade together with HaCYC2c but distinct from it. The present data showed that in H. × multiflorus the allele derived from H. annuus is deleted or highly modified. The H. × multiflorus taxon exists as radiate and ligulate inflorescence types. We analysed CYC2c expression in H. decapetalus and in the cultivar 'Soleil d'Or' of H. × multiflorus, a ligulate inflorescence type with actinomorphic corolla of disk flowers transformed into a zygomorphic ray-like corolla. In H. decapetalus, the HdCYC2c gene showed differential expression between developing flower types, being up-regulated in the corolla of ray flowers in comparison to the disk flower corolla. In H. × multiflorus, an insertion of 865 bp, which is part of a CACTA transposable element, was found in the 5'-untranslated region (5'-UTR) of H × mCYC2cB. This insertion could promote, even with epigenetic mechanisms, ectopic expression of the gene throughout the inflorescence, resulting in the observed loss of actinomorphy and originating a ligulate head.
This paper deals with the effect of supply frequency on partial discharge phenomena. Results of measurements performed on artificial and practical test objects are compared with computer simulations ...based on physical models. This comparative analysis points out and explains the differences in partial discharge phenomena observed in tests performed at different frequencies (from 0.1 to 300 Hz). The consequences associated to the use of different supply frequencies in practical applications are, eventually, outlined.
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