Extended multiplicative signal correction (EMSC) is a widely used preprocessing technique in infrared spectroscopy. EMSC is a model-based method favored for its flexibility and versatility. The model can be extended by adding constituent spectra to explicitly model-known analytes or interferents. This paper addresses the use of constituent spectra and demonstrates common pitfalls. It clarifies the difference between analyte and interferent spectra, and the importance of orthogonality between model spectra. Different normalization approaches are discussed, and the importance of weighting in the EMSC is demonstrated. The paper illustrates how constituent analyte spectra can be estimated, and how they can be used to extract additional information from spectral features. It is shown that the EMSC parameters can be used in both regression tasks and segmentation tasks. 相似文献
Apple industrial by-products are a promising source of bioactive compounds with direct implications on human health. The main goal of the present work was to characterize the Jonathan and Golden Delicious by-products from their fatty acid, amino acid, and volatile aroma compounds’ point of view. GC-MS (gas chromatography-mass spectrometry) and ITEX/GC-MS methods were used for the by-products characterization. Linoleic and oleic were the main fatty acids identified in all samples, while palmitic and stearic acid were the representant of saturated ones. With respect to amino acids, from the essential group, isoleucine was the majority compound identified in JS (Jonathan skin) and GS (Golden skin) samples, lysine was the representant of JP (Jonathan pomace), and valine was mainly identified in GP (Golden pomace). A total number of 47 aroma volatile compounds were quantified in all samples, from which the esters groups ranged from 41.55–53.29%, aldehydes 29.75–43.99%, alcohols from 4.15 to 6.37%, ketones 4.14–5.72%, and the terpenes and terpenoids group reached values between 2.27% and 4.61%. Moreover, the by-products were valorized in biscuits manufacturing, highlighting their importance in enhancing the volatile aroma compounds, color, and sensorial analysis of the final baked goods. 相似文献
Ferroptosis is a recently described programmed cell death mechanism that is characterized by the buildup of iron (Fe)-dependent lipid peroxides in cells and is morphologically, biochemically, and genetically distinct from other forms of cell death, having emerged to play an important role in cancer biology. Ferroptosis has significant importance during cancer treatment because of the combination of factors, including suppression of the glutathione peroxidase 4 (Gpx4), cysteine deficiency, and arachidonoyl (AA) peroxidation, which cause cells to undergo ferroptosis. However, the physiological significance of ferroptosis throughout development is still not fully understood. This current review is focused on the factors and molecular mechanisms with the diagrammatic illustrations of ferroptosis that have a role in the initiation and sensitivity of ferroptosis in various malignancies. This knowledge will open a new road for research in oncology and cancer management. 相似文献
The behaviour of masonry constructions results to be very far from the one characterizing ductile structures. In masonry constructions, the seismic action activates a rocking motion rather than a dissipating mechanism. A strength resource of masonry structures, properly reinforced in order to avoid early local failures, consists in exhibiting rocking behaviour, until a failure condition is attained. Aim of the paper is to investigate the dynamic behaviour of masonry single storey walls, according to Housner’s studies and innovatively introducing the effect of diagonal cracks developing from the toes of the piers and shown by typical post-earthquake cracking patterns. The proposed procedure can be easily applied to the case of multi-storey regular masonry walls with openings representing the main resistant structural components of a masonry building. Starting from the evaluation of the incipient rocking acceleration of the system, the free and forced motions of the wall are examined. In the paper, according to the classical Housner’s approach, the energy dissipation occurring during the impact is modelled. Finally, a numerical application, considering a simple constant horizontal acceleration impulse of given duration has been carried out.
The synthesis of a number of 3d transition metal binary pyrazolates in microcrystalline form, thus suitable for a full XRPD characterization, has been pursued. The crystal and molecular structures of the Fe(pz)3, Co(pz)2, Co(pz)3, and Ni(pz)2 polymers, together with the few congeners reported in the recent literature, show that these species tend to afford highly crystalline materials where strictly collinear chains of metal atoms are present. Depending on the synthetic strategy used, Ni(pz)2 has been found to crystallize as two different alpha (orthorhombic) and beta (monoclinic) phases, possessing nearly identical intramolecular features. Data for each compound follow. Fe(pz)3: C9H9FeN6, hexagonal, P63/m, a = 9.1745(3) A, c = 7.2191(4) A, Z = 2. Co(pz)2: C6H6CoN4, orthorhombic, Ibam, a = 7.5239(5) A, b = 14.3461(9) A, c = 7.4331(5) A, Z = 4. Co(pz)3: C9H9CoN6, hexagonal, P63/m, a = 9.1966(3) A, c = 7.1051(3) A, Z = 2. Alpha-Ni(pz)2: C6H6N4Ni, orthorhombic, Cmcm, a = 16.6758(11) A, b = 6.4872(4) A, c = 6.9423(6) A, Z = 4. Beta-Ni(pz)2: C6H6N4Ni, monoclinic, P21/m, a = 9.967(2) A, b = 6.975(1) A, c = 6.016(1), A, beta = 98.50(1)degrees, Z = 2. The thermal stability and the detailed structural properties of these model compounds have been evaluated, in the light of the technologically relevant crystal phases (the well-known metal-diazolates showing reversible spin-crossover or spin-transition behavior) obtainable upon doping, magnetic dilution, and ring substitution (in the 4-position). 相似文献
A new, one-step preparation of 1,4-di(2,2':6',2' '-terpyridin-4'-yl)benzene was employed in the synthesis of a linear trinuclear Ru(II) complex, which was compared to mononuclear and dinuclear analogues using UV-vis spectrometry, cyclic voltammetry, and ability to sensitize the photogeneration of methyl viologen radical cation. The chain length-dependent increase in sensitization ability was consistent with an increasing molar absorbance and with an end-on approach of the photoreactants mitigating the increasing charge. 相似文献
The acid properties of pure and modified silica surfaces were studied by 2-phenylethylamine (PEA) desorption in a thermogravimetric (TGA) apparatus, carrying out the experiments at different heating rates (5 < beta/(degrees C.min(-1)) < 30). The samples, containing about 13 wt % alumina, titania, and zirconia, were prepared by the sol-gel route from molecular precursors. The textural, structural, and surface properties of the materials were studied by complementary techniques (ICP, XRD, N(2) physisorption, SEM-EDS, and XPS). The chemical modification of the silica surface by enrichment with Al, Ti, or Zr, in amounts of about 90, 50, and 60% of that introduced in the preparation as determined by XPS, justified the increase of acidity of the modified silica surfaces compared with that of pure silica. The total number of strong acid sites was found to be in the order of SZ > SA > ST > S. Two different kinetic approaches were applied to the thermogravimetric data to kinetically interpret the PEA desorption from the different types of acid sites. The classical differential Kissinger model was found to be inadequate in representing the very complex situation of the acid surfaces. A more complex model is proposed by simultaneously taking into account PEA desorption from the different acid sites by a set of parallel and independent desorption reactions following Arrhenius's kinetic law. The fraction of each type of acid site on each surface and the relevant activation parameters were optimized through a computational procedure. Very good fitting of the experimental-calculated desorption profiles corroborated the validity of the model. For each surface, the acid-site energy distribution is presented and discussed in relationship to the surface composition of the oxides. 相似文献
This feature article highlights work from the authors' laboratories on the synthesis, assembly, reactivity, and optical applications of metallic nanoparticles of nonspherical shape, especially nanorods. The synthesis is a seed-mediated growth procedure, in which metal salts are reduced initially with a strong reducing agent, in water, to produce approximately 4 nm seed particles. Subsequent reduction of more metal salt with a weak reducing agent, in the presence of structure-directing additives, leads to the controlled formation of nanorods of specified aspect ratio and can also yield other shapes of nanoparticles (stars, tetrapods, blocks, cubes, etc.). Variations in reaction conditions and crystallographic analysis of gold nanorods have led to insight into the growth mechanism of these materials. Assembly of nanorods can be driven by simple evaporation from solution or by rational design with molecular-scale connectors. Short nanorods appear to be more chemically reactive than long nanorods. Finally, optical applications in sensing and imaging, which take advantage of the visible light absorption and scattering properties of the nanorods, are discussed. 相似文献
** Email: giorgio.vittadini{at}unimib.it*** Email: simona.minotti{at}unicatt.it In this paper we propose a methodology for measuring the relativeeffectiveness of healthcare services (i.e. the effectof hospital care on patients) under general conditions, in which:) a healthcare outcome underlies qualitative and quantitativeobservable indicators; ß) we are interested in studyingthe simultaneous dependency of multiple outcomes on covariates(where the outcomes can also be correlated to each other); )the relative effectiveness is adjusted for hospital-specificcovariates; ) we hypothesise a general distribution for randomdisturbances and the random parameters of relative effectiveness.For this topic, a generalisation of the SURE (seemingly unrelatedregression equations) multilevel model is proposed. The solutionsare obtained by means of Bayesian inference methods. Since thereis currently no software available to estimate this model, anSAS procedure based on Markov Chain Monte Carlo methods hasbeen developed by the authors, in line with Goldstein &Spiegelhalter (1996, J. R. Stat. Soc. Ser. A, 159, 385443),Spiegelhalter et al. (1996, Bayesian Using Gibbs Sampling Manual.Cambridge: MRC Biostatistic Unit, Institute of Public Health)and Albert & Chib (1997, J. Am. Stat. Assoc., 92, 916925).In addition, a new theoretical result regarding the joint posteriordistribution for the parameters is provided. The model proposedhas been implemented for an effectiveness study of a selectionof Lombard hospitals. 相似文献