Positivity of the weights of interpolatory quadrature formulae with Bernstein–Szegö abscissae

We consider interpolatory quadrature formulae, relative to the Legendre weight function w(t)?=?1 on [???1,1], having as nodes the zeros of any one of the nth degree orthogonal polynomials relative to the Bernstein–Szegö weight functions $$w_{\gamma}^{\left(\pm 1/2\right)}(t)=\frac{\left(1-t^{2}\right)^{\pm 1/2}} {1-\displaystyle\frac{4\gamma}{(1+\gamma)^{2}}t^{2}},\ \ -1<t<1, \ \ -1<\gamma<1.$$ We derive semiexplicit formulae for the quadrature weights and show that the weights are almost all positive; exceptions occur only for the weight corresponding to the node at 0 when n is odd and are carefully identified.     

Development and validation of a method for the determination of buprenorphine and norbuprenorphine in breast milk by gas chromatography-mass spectrometry

Buprenorphine (BUP) is used for the maintenance of opioid‐addicted pregnant women. Because BUP and its main metabolite nor‐BUP are excreted into breast milk, a sensitive and specific GC/MS method has been developed, optimized and validated for their determination in breast milk. BUP‐d4 was used as internal standard. The sample preparation includes combination of protein precipitation with solid‐phase extraction and derivatization (acetylation). The absolute recovery for both analytes was found to be higher than 87.3%. The limits of detection and quantification were 0.07 and 0.20 µg/L, respectively. The calibration curves were linear within the dynamic range 0.20–20.0 µg/L, with a correlation coefficient higher than 0.996. Intra‐ and inter‐day accuracies were ranged from ?7.06 to 4.50 and from ?5.88 to 7.00%, respectively, while intra‐ and inter‐day precision were less than 5.7 and 6.1%. The analytes were found to be stable in breast milk at 4°C for one week, at ?20°C for one month, and after three freeze–thaw cycles. The method can be used for the determination of BUP and nor‐BUP in breast milk of BUP‐maintained mothers, in order to calculate the amount of drug that could pass to the newborn via breast milk and to avoid toxic consequences of breastfeeding. Copyright © 2011 John Wiley & Sons, Ltd.     

A Review of the Health Protective Effects of Phenolic Acids against a Range of Severe Pathologic Conditions (Including Coronavirus-Based Infections)

Phenolic acids comprise a class of phytochemical compounds that can be extracted from various plant sources and are well known for their antioxidant and anti-inflammatory properties. A few of the most common naturally occurring phenolic acids (i.e., caffeic, carnosic, ferulic, gallic, p-coumaric, rosmarinic, vanillic) have been identified as ingredients of edible botanicals (thyme, oregano, rosemary, sage, mint, etc.). Over the last decade, clinical research has focused on a number of in vitro (in human cells) and in vivo (animal) studies aimed at exploring the health protective effects of phenolic acids against the most severe human diseases. In this review paper, the authors first report on the main structural features of phenolic acids, their most important natural sources and their extraction techniques. Subsequently, the main target of this analysis is to provide an overview of the most recent clinical studies on phenolic acids that investigate their health effects against a range of severe pathologic conditions (e.g., cancer, cardiovascular diseases, hepatotoxicity, neurotoxicity, and viral infections—including coronaviruses-based ones).     

Exact Results and Bounds for the Joint Tail and Moments of the Recurrence Times in a Renewal Process

Methodology and Computing in Applied Probability - The best known result about the joint distribution of the backward and forward recurrence times in a renewal process concerns the asymptotic...     

Asymptotic behaviour of the stochastic Lotka-Volterra model

This paper examines the asymptotic behaviour of the stochastic extension of a fundamentally important population process, namely the Lotka-Volterra model. The stochastic version of this process appears to have far more intriguing properties than its deterministic counterpart. Indeed, the fact that a potential deterministic population explosion can be prevented by the presence of even a tiny amount of environmental noise shows the high level of difference which exists between these two representations.     

Budgeting fuel consumption in a cruise liner

An equation to be used to budget fuel consumption in a cruise liner is developed. The model building process is described in detail to explain the way in which the results were obtained.     

Eine einfache Methode zur Bestimmung von Cadmium in Harn

Zusammenfassung Cadmium bildet negativ geladene Jodidkomplexe, die eine Abtrennung dieses Elementes aus dem Harn mit Hilfe eines Anionen-austauschers ermöglichen. Elution vom Austauscher ergibt eine Cadmiumlösung mit nur wenigen Begleitstoffen bzw. einer einheitlichen Matrix, die für eine weitgehend störungsfreie Endbestimmung durch flammenlose Atomabsorptionsspektrometrie verwendet werden kann. Danach beträgt der Normalgehalt an Cadmium im Harn im Mittel 0,78±0,53 ng/ml und liegt im Bereich zwischen 0,22 und 1,7 ng/ml.

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A simple method for determination of cadmium in urine

Summary Cadmium can be isolated from urine by formation of negatively charged iodide complexes bound to an anion exchange resin. Elution from the resin gives a cadmium solution with only a few concomitant substances in an uniform matrix. Thus an undisturbed determination by flameless atomic absorption spectrometry is achieved. The mean of the natural cadmium level found in urine was 0.78±0.53 ng/ml, within the normal range between 0.22 and 1.7 ng/ml.

     

157-nm Laser ablation of polymeric layers for fabrication of biomolecule microarrays

A new methodology for protein microarray fabrication is proposed based on the ablation of polymer film using laser at 157 nm (F₂). The polymer has been selected among others with the criterion of negligible protein adsorption. Improved results have been obtained by pretreatment of the polymer surface with an inert protein. The use of 157-nm laser radiation allowed very good depth control during the polymeric layer ablation process. In addition the importance of laser ablation at 157 nm is based on the fact that irradiated surfaces indicate limited chemical change due to the fact that laser ablation at 157 nm is only photochemical, thus avoiding excessive surface heating and damage. Results of protein microarray fabrication are presented to illustrate the viability of the proposed method.     

The determination of arsenic at ng/g- andμg/g-levels in organic and biological matrices

Summary Three independent decomposition methods for organic matter are compared for use in the determination of arsenic by the hydride-AAS method. Matrix interferences in the arsine evolution cause systematic errors.

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Bestimmung von Arsen im ng/g- und g/g-Bereich in organischem und biologischem Material

Zusammenfassung Drei unabhängige Aufschlußmethoden zwecks Arsenbestimmung nach der Hydrid-Atomabsorptionsmethode wurden verglichen. Störungen seitens der Matrix bei der AsH₃-Entwicklung sind eine der Ursachen für systematische Fehler.