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31.
Seraglia R Molin L Tonidandel L Pucciarelli S Agostini M Urso ED Bedin C Quaia M Nitti D Traldi P 《Journal of mass spectrometry : JMS》2007,42(12):1606-1612
In an investigation devoted to the search for plasma markers for colorectal cancer (CRC), carried out by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, a series of overexpressed peptides were identified in the plasma of patients. Among them the peptide with molecular weight 903 Da was the most abundant one, with a mean +/- (SD) relative abundance of 37 +/- 17% and a frequency over 60%. Interestingly, also in plasma samples of ten subjects affected by familial adenomatous polyposis (FAP), the peptide with molecular weight 903 was overexpressed. In this investigation, MALDI/MS/MS experiments were carried out on the ion at m/z 904 detected in the MALDI mass spectra of CRC and FAP patients. The data analysis by SwissProt.2007.01.09 indicates that this peptide is due to the sequence RPPGFSPF, found in the kininogen-1 precursor, which is an alpha-2-thiol proteinase inhibitor. In the case of subjects affected by a particular FAP syndrome, the MALDI/MS/MS spectra were quite different from those obtained from CRC and FAP patients. In fact, two sequences have been evidenced: RPPGFSPF belonging to kininogen-1 precursor, and PRKSSSSR belonging to Forkhead box protein 01A. 相似文献
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33.
A chemometric approach based on Principal Component Analysis (PCA) has been proposed, in order to study chemical features (major and minor ions, total alkalinity, dissolved silica) of surface and deep waters of Lake Como (Northern Italy). The method allowed us to investigate the correlations between the analyzed ions in an easy-to-see way, using bi-dimensional graphs. In wintertime, the ionic composition of Lake Como waters seems to be mainly related to the geological composition of the lake basin, with a crystalline bedrock on the northern side and a sedimentary cover in the southern part. The presence of contaminants such as bromide and nitrite in water columns is also evidenced and discussed. 相似文献
34.
Marcella Niglio Cosimo Damiano Vitale 《Methodology and Computing in Applied Probability》2012,14(1):17-34
In this paper the (strict and weak) stationarity of threshold autoregressive moving average models is discussed. After examining
the strict stationarity, mainly based on the random coefficient autoregressive representation of the model, we provide sufficient
conditions for its weak stationarity that allow to obtain a wider stationarity region with respect to some previous results
given in the literature. These conditions are discussed to distinguish between global and local stationarity, whose relation has been considered in detail. The threshold process has been further evaluated to face the
problem related to the so called existence of a threshold structure in the data generating process that is strictly related to the stationarity and has significant
relevance when the parameters of the model have to be estimated. 相似文献
35.
36.
Marianna Portaccio Daniela Durante Andrea Viggiano Silvana Di Martino Paola De Luca Daniela Di Tuoro Umberto Bencivenga Sergio Rossi Paolo Canciglia Bruno De Luca Damiano Gustavo Mita 《Electroanalysis》2007,19(17):1787-1793
Glucose microelectrodes were prepared by immobilizing glucose oxidase onto a cellulose acetate film coating a platinum wire. Hexamethylenediamine (HMDA) and Glutaraldehyde (GA) were employed as spacer and coupling agent, respectively. Sensitivities and linear response ranges were studied as a function of the relative amounts of HMDA and GA. The best sensitivity was found when HMDA and GA were 5% and 2.5% in aqueous solutions, respectively. Taking as a reference the functioning of this biosensor, the roles of HMDA and GA percentages appear to be opposed when the extension of the linear response range is considered. Indeed, an increase of one unit in HMDA percentage (from 5 to 6 %) induces an increase in the extension of the linear response range equal to that obtained with a decrease of one unit of GA percentage (from 2.5 to 1.5%). 相似文献
37.
Heavy metal biosorption by bacterial cells 总被引:9,自引:0,他引:9
A. Vecchio Carlo Finoli Damiano Di Simine Vincenza Andreoni 《Analytical and bioanalytical chemistry》1998,361(4):338-342
Microbial biomass provides available ligand groups on which metal ions bind by different mechanisms. Biosorption of these
elements from aqueous solutions represents a remediation technology suitable for the treatment of metal-contaminated effluents.
The purpose of the present investigation was the assessment of the capability of Brevibacterium sp. cells to remove bivalent ions, when present alone or in pairs, from aqueous solutions, using immobilized polyacrylamide
cells of the microorganism in a flow-through system. The biosorption capacity of Brevibacterium cells was studied for lead, cadmium and copper. The metal cell binding capacity followed the order Cu > Pb > Cd, based on
estimated qmax. These values, expressed as mmol metal/g dry weight cells, were 0.54 for Cu, 0.36 for Pb and 0.14 for Cd. Polyacrylamide-gel
immobilized cells were effective in Pb, Cu and Cd removal. Lead removal was not affected by the presence of Cd and Cu; lead
instead inhibited Cd and Cu removal. The desorption of the metal, by fluxing a chelating solution, restored the metal binding
capacity of the cells, thus affording the multiple use of the same biomass in the remediation treatment.
Received: 31 July 1997 / Revised: 22 December 1997 / Accepted: 30 December 1997 相似文献
38.
Phenol, catechol, and hydroquinone, are urinary end-products of the metabolism of benzene, nutrients, drugs, and endogenous substances. Recent research demonstrated that phenol, catechol, and hydroquinone, may have themselves a role in the carcinogenicity of benzene and in mechanisms that lead to leukemia. In this respect there is the need of rapid, low-cost, and possibly direct methods to quantitate these phenolic metabolites. Three single-residue coupled-column HPLC methods with fluorimetric detection (LC-LC-FLD) are described for the direct quantitation of phenol, catechol, and hydroquinone, in human urine. After enzymatic hydrolysis of the corresponding beta-glucuronoconjugates and sulfates, urine was directly injected into the LC-LC analyzer. The LC-LC-FLD procedure allowed base-to-base separation of the target compounds from urine interferents and good linearity (r2 = 0.998) within the ranges studied (0.5–50 mg L−1 for phenol, 0.35–35 mg L−1 for catechol and 0.2–10 mg L−1 for hydroquinone). Despite the high background levels of these metabolites in human urine, within- and inter-session precision expressed as RSD% was better than 20% on spiked and on authentic urine samples obtained from benzene-exposed workers. Accuracy expressed as the recovery ratio between measured and nominal concentration in spiked urine was comprised between 93% and 115% for the three metabolites. The column switching system was fully automated and computer-controlled, and was applied to the determination of phenol, catechol, and hydroquinone in urine samples showing a sample throughput of at least 20–30 samples per day.Revised: 21 February and 7 April 2005 相似文献
39.
Dr. Caterina Viglianisi Kristian Vasa Dr. Damiano Tanini Prof. Antonella Capperucci Dr. Riccardo Amorati Prof. Luca Valgimigli Dr. Andrea Baschieri Prof. Stefano Menichetti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(38):9108-9116
Symmetrical ditocopheryl disulfides ( Toc ) 2 S2 and symmetrical and unsymmetrical ditocopheryl sulfides ( Toc )2 S were simply prepared under remarkably mild conditions with complete control of the regiochemistry by using δ-, γ-, and β-tocopheryl-N-thiophthalimides ( Toc-NSPht ) as common starting materials. The roles of sulfur atom(s), H-bond and aryl ring substitution pattern on the antioxidant profile of these new compounds, which were assembled by linking together two tocopheryl units, are also discussed. 相似文献
40.
The common fallacy in risk measurement throughout a long investment horizon is to handle only the terminal risk. This pathology affects Value-at-Risk, hence a recent contribution in the literature has proposed the concept of within-horizon risk as a solution to the problem. The quantification of this type of risk leads to the so called MaxVaR measure, but the assumption of Gaussian distributed returns biases this model. This study analyzes the consequences of non-Gaussian returns to the MaxVaR inference. An example of application to long-term risk management is provided. 相似文献