Selective catalytic reduction of nitric oxide with ammonia on Mn‐promoted carbonized used silica–alumina sorbents

Deactivated (waste) silica–alumina sorbents were carbonized and used as supports. The introduction of manganese led to active and selective SCR catalysts at low temperatures. Two methods of Mn promoting were compared: wet impregnation and adsorption. They influenced the distribution of Mn and N₂O production. The catalysts behaved similarly to Mn‐promoted active carbon. This revised version was published online in July 2006 with corrections to the Cover Date.     

FTIR study of hydration of dodecatungstosilicic acid

The isomerization of 2‐methyl‐2‐pentene has been studied on boron phosphate (BP) catalysts with P/B ratios from 0.8 to 1.6 and at various reaction temperatures and contact times. Double‐bond shift occurs on the compositions with P/B of 1.0 and less, while methyl shifts occur on samples with P/B of 1.2–1.6, demonstrating the presence of strong acidity on the latter solids. Ammonia chemisorption and proton MAS NMR is employed to provide supplementary evidence of the variation in acidity with composition. Although BP of P/B < 1 contains predominantly Lewis acid sites, 2‐methyl‐2‐pentene isomerizes through carbocations, which are formed on the strong Brønsted acid sites on BP with P/B > 1.     

Catalytic reduction of no over the modified MFI metallosilicalites

The metallosilicalites (MFI) containing copper ([Cu,Si]), zinc ([Zn,Si]) or both elements ([Cu,Zn,Si]) were prepared and modified as potential catalysts for the NO reduction with propene. The H-[Cu,Si] samples showed the highest activity, which was initially comparable to that of Cu-ZSM-5, but contrary to the latter, it increased with time. The framework Cu or Cu released from the framework probably act as active sites.     

Discrete distributions for which the regression of the first record on the second is linear

The linearity of regression of the first record on the second is examined for discrete random variables. Both ordinary and weak records are considered. The analysis involves the determination of all possible linear relationships and all possible probability distributions. Several characterizations of geometric distributions are also shown.     

Effects of blackcurrant seeds and rosemary extracts on oxidative stability of bulk and emulsified lipid substrates

The effects of blackcurrant seeds extract and commercially available rosemary extracts on rapeseed oil and rapeseed oil triacylglycerol oxidative stability were evaluated. The antioxidant activity of plant extracts was investigated, both in bulk and emulsified lipid substrates, and compared with those of α-tocopherol and BHT. The investigation showed that blackcurrant seeds and rosemary extracts are the source of active antioxidants and are appropriate for food lipid stabilization. The extracts performed better in stripped substrates as they may interfere with native tocopherols present in rapeseed oil and show different activity according to the presence of water. α-Tocopherol, a 200 ppm, was inactive in bulk and emulsified rapeseed oil but was an effective antioxidant in triacylglycerols. BHT showed the best performance of all used additives in emulsified substrates.     

A fourth-order accurate, three-point compact approximation of the boundary gradient, for electrochemical kinetic simulations by the extended Numerov method

The fourth-order accurate, three-point compact (extended Numerov) finite-difference scheme of Chawla [J. Inst. Math. Appl. 22 (1978) 89] has been recently found superior (in terms of accuracy and efficiency) to the conventional second-order accurate spatial discretisation commonly used in electrochemical kinetic simulations. However, the two-point compact boundary gradient approximation, accompanying the scheme, is difficult to apply in the case of time-dependent kinetic partial differential equations, because it introduces unwanted second temporal derivatives into calculations. The conventional five-point gradient formula is free from this drawback, but it is also not very convenient, owing to the locally increased bandwidth of the matrix of linear equations arising from the spatio-temporal discretisation. A new three-point compact boundary gradient approximation derived in this work, avoids the above inconveniences and economically re-uses expressions utilised by the extended Numerov discretisation. The fourth-order accuracy of the new approximation is proven theoretically and verified in computational experiments performed for examples of kinetic models.     

MIR spectroscopy and partial least-squares regression for determination of phospholipids in rapeseed oils at various stages of technological process

Fourier transform-mid infrared spectroscopy (FT-MIR) and partial least-square (PLS) regression were used for determination of phospholipids (PL) in rapeseed oils at various stages of technological process. The standard error of calibration (SEC) and the standard error of prediction (SEP) were calculated for evaluation of the calibration models. The chemometric calibration model was prepared in spectral region 1760–860 cm⁻¹ for standard PL solutions (1.5–120 mg/mL). Obtained mean concentrations of PL in rapeseed oils at different stages of conventional technological operations varied from 22,710 to 224.6 mg/kg. Satisfactory values of precision (RSD = 0.23–0.73%) and accuracy (recovery – 96.1–101.9%), demonstrate the benefit of the proposed MIR-PLS method in the routine analysis of PL in vegetable oils.     

Lexicon randomization for near-duplicate detection with I-Match

Detection of near duplicate documents is an important problem in many data mining and information filtering applications. When faced with massive quantities of data, traditional techniques relying on direct inter-document similarity computation are often not feasible given the time and memory performance constraints. On the other hand, fingerprint-based methods, such as I-Match, while very attractive computationally, can be unstable even to small perturbations of document content, which causes signature fragmentation. We focus on I-Match and present a randomization-based technique of increasing its signature stability, with the proposed method consistently outperforming traditional I-Match by as high as 40–60% in terms of the relative improvement in near-duplicate recall. Importantly, the large gains in detection accuracy are offset by only small increases in computational requirements. We also address the complimentary problem of spurious matches, which is particularly important for I-Match when fingerprinting long documents. Our discussion is supported by experiments involving large web-page and email datasets.     

The Influence of Bisphenol A (BPA) on the Occurrence of Selected Active Substances in Neuregulin 1 (NRG1)-Positive Enteric Neurons in the Porcine Large Intestine

Bisphenol A (BPA) is a substance used in the manufacture of plastics which shows multidirectional adverse effects on living organisms. Since the main path of intoxication with BPA is via the gastrointestinal (GI) tract, the stomach and intestine are especially vulnerable to the impact of this substance. One of the main factors participating in the regulation of intestinal functions is the enteric nervous system (ENS), which is characterized by high neurochemical diversity. Neuregulin 1 (NRG1) is one of the lesser-known active substances in the ENS. During the present study (performed using the double immunofluorescence method), the co-localization of NRG1 with other neuronal substances in the ENS of the caecum and the ascending and descending colon has been investigated under physiological conditions and after the administration of BPA. The obtained results indicate that NRG1-positive neurons also contain substance P, vasoactive intestinal polypeptide, a neuronal isoform of nitric oxide synthase and galanin and the degree of each co-localization depend on the type of enteric plexus and the particular fragment of the intestine. Moreover, it has been shown that BPA generally increases the degree of co-localization of NRG1 with other substances.