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81.
Maria Nieddu Antonio Carta Lucia Burrai Maria Cristina Porcu Nicola Culeddu Maria Antonietta Pirisi Gianpiero Boatto 《Applied magnetic resonance》2014,45(2):135-144
In the recent years the so-called designer drugs have been diffused dramatically worldwide. Amphetamine psychostimulants are one of the major classes of illicit drugs consumed for recreational purposes in the world. The detection of the illegal substances is important both in the management of their misuse and in the forensic field. Urine matrix is a reliable biological matrix for verifying amphetamines intake in the short and medium term because the excretion of these drugs mainly occurs in urine, where substantial amounts of unchanged drug are present. In response to a growing demand for reliable evidence of amphetamine use, a method for identification and quantitation of amphetamine, methamphetamine, 3,4-methylenedioxy-N-methylamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxy-N-ethylamphetamine in urine has been developed by nuclear magnetic resonance spectroscopy, using electronic reference to access in vivo concentration method. The method showed good linearity. The limits of detection and quantitation of amphetamines analyzed ranging from 1.9–7.9 to 5.8–23.8 μg mL?1, respectively. These data demonstrate that the present method is suitable for detection of these drugs in urine samples, allowing to quantitate the target analytes without any purification step of the matrix. 相似文献
82.
Prof. Gianpiero Cera Gabriele Giovanardi Prof. Andrea Secchi Prof. Arturo Arduini 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(40):10261-10266
We report the synthesis and characterization of novel triphosphine calix[6]arene ligands. These supramolecular wheels, with recognition features governed by the hydrogen-bonding domain, were employed to synthesize multitasking trinuclear gold(I) complexes as a new platform for the synthesis of interwoven (pseudo)rotaxane species. In parallel, the multivalent, metal-bonded upper rim displayed catalytic features promoting highly selective gold-catalyzed cycloisomerization reactions of 1,6-enynes. 相似文献
83.
Numerical assessment of friction damping at turbine blade root joints by simultaneous calculation of the static and dynamic contact loads 总被引:1,自引:0,他引:1
In turbomachinery, the perfect detuning of turbine blades in order to avoid high cycle fatigue damage due to resonant vibration
is often unfeasible due to the high modal density of bladed disks. 相似文献
84.
Luisa Sciortino Fabrizio Messina Gianpiero Buscarino Simonpietro Agnello Marco Cannas Franco M. Gelardi 《Journal of nanoparticle research》2017,19(6):228
We describe the simple fabrication of SiO2 sol-gel monoliths embedding highly luminescent carbon nanodots (CDs) sensitive to metal ions. The pristine CDs we synthesize display an intense dual emission consisting in two fluorescence bands in the green and violet region, and we demonstrate that this photoluminescence is substantially unchanged when the dots are incorporated in the SiO2 matrix. The emission of these CDs is quenched by interactions with Cu2+ ions, which can be used to detect these ions with a detection limit of 1 μM. The chromophores remain accessible to diffusing Cu2+ ions even after embedding CDs in the sol-gel monolith, where their detection capabilities are preserved. Such a result provides the proof-of-principle of a new sensing scheme, where CDs are exploited as active sensing centers of metal transition ions within a solid-state device. The different interaction mechanisms of CDs with copper, in liquid and solid phase, are analyzed in detail and discussed in terms of different accessibility of their chromophores when the dots are incorporated in the SiO2 matrix. 相似文献
85.
Ferrous glycine sulfate pentahydrate [Fe(glycine)(SO4)·5H2O with glycine = C2H5NO2], contained in the supplement for treating iron deficiency anaemia, commercially known as ferro sanol duodenal®, was characterized by laboratory X‐ray powder diffraction (XRPD), scanning electron microscope (SEM), and infrared spectroscopy (IR). The thermal behavior was investigated by thermal analysis (TGA and DTA) and temperature‐dependent in situ XRPD measurements. Furthermore, the phase transitions to a less hydrated form [Fe(glycine)(SO4)·3H2O] and successively to the anhydrous form were demonstrated to occur in the crystalline solid state. Compared to the crystal structure of the pentahydrate, the trihydrate exhibits a different coordination environment of the iron sites where glycine ligands bridge iron forming a 1D polymeric chain structure. From detailed structural comparison, the mechanism of the phase transitions can be concluded. 相似文献
86.
C. Giori G. Schianchi G. Erriu S. Onnis P. Randaccio N. Zucca 《Il Nuovo Cimento D》1991,13(3):401-404
Summary Nonbilayer structures, as lysophospholipid micelles, can be produced in membranes by gamma irradiation. Interesting information
on the gamma-ray effect on the lysophospholipid organization can be obtained by spin-label techniques. Variations of the TEMPO
partition are appreciable, particularly in the range of the lipid thermotropic transition, even from relatively low doses.
With increasing dose this transition becomes more and more complex and wider, according to the previous thermodinamic analysis. 相似文献
87.
Gianpiero Cattaneo Carlo Dalla Pozza Claudio Garola Giuseppe Nisticò 《International Journal of Theoretical Physics》1988,27(11):1313-1349
We make a critical analysis of the basic concepts of the Jauch-Piron (JP) approach to quantum physics. Then, we exhibit a formalized presentation of the mathematical structure of the JP theory by introducing it as a completely formalized syntactic system, i.e., we construct a formalized languageL
e
and formally state the logical-deductive structure of the JP theory by means ofL
e
. Finally, we show that the JP syntactic system can be endowed with an intended interpretation, which yields a physical model of the system. A mathematical model endowed with a physical interpretation is given which establishes (in the usual sense of the model theory) the coherence of the JP syntactic system. 相似文献
88.
Summary A simplified model of gamma-ray-induced damage in lipid membranes has been studied with EPR and DSC techniques. The model
consists of a water dispersion of a lysophospholipid and undergoes a transition from lamellar to micellar structure as temperature
rises. The characteristics of these two structures are discussed on the ground of EPR results. Appreciable and permanent modifications
are evident starting at doses very much lower than those causing clear damage effects in lipid membranes previously studied.
The complex thermotropic transition taking birth in irradiated specimens seems to concern a number of lysophospholipid molecules
that becomes smaller as the dose increases.
Riassunto Viene presentato un modello semplificato, costituito da una dispersione in acqua di lisofosfolipide, per lo studio dei danni da radiazioni gamma su membrane lipidiche. Tecniche EPR e DSC sono state utilizzate per l'analisi della transizione, dalla struttura lamellare a quella micellare, subita da ciascun campione all'aumentare della temperatura. Le caratteristiche delle due strutture vengono discusse sulla base dei risultati ottenuti. Vengono evidenziate modificazioni, apprezzabili e permanenti, prodotte dalle radiazioni gamma fin da dosi molto inferiori a quelle necessarie per avere danni altrettanto evidenti nelle membrane lipidiche precedentemente studiate. La complessa transizione termotropica sembra coinvolgere un numero di molecole lisofosfolipidiche tanto minore quanto più alta è la dose assorbita.
Резюме Используя технику EPR и DSC, исследуется упрощенная модель для описания повреждений в липидных мембранах, индуцированная гамма-лучами. Молель включает дисперию воды и претерпевает переход из ламинарной в мицеллярную структуру при повышении температуры. Обсуждаются характеристики этих двух структур на основе EPR результатов. Обнаружены заметхые и перманентные изменения при дозах, значительно меньших, чем дозы при которых ранее изучались явные радиационные повреждения в липидных мембранах. Комплексный термотропный перешод, возникающий при облучении образцов, повидимомы. связан с числом лисофосфолидных молекул, которое уменьщается при увеличении досы.相似文献
89.
Anna E. Caprifico Elena Polycarpou Peter J. S. Foot Gianpiero Calabrese 《Macromolecular bioscience》2021,21(1)
Chitosan‐based nanocarriers (ChNCs) are considered suitable drug carriers due to their ability to encapsulate a variety of drugs and cross biological barriers to deliver the cargo to their target site. Fluorescein isothiocyanate‐labeled chitosan‐based NCs (FITC@ChNCs) are used extensively in biomedical and pharmacological applications. The main advantage of using FITC@ChNCs consists of the ability to track their fate both intra and extracellularly. This journey is strictly dependent on the physico‐chemical properties of the carrier and the cell types under investigation. Other applications make use of fluorescent ChNCs in cell labeling for the detection of disorders in vivo and controlling of living cells in situ. This review describes the use of FITC@ChNCs in the various applications with a focus on understanding their usefulness in labeled drug‐delivery systems. 相似文献
90.
Rational design, synthesis, and evaluation of key analogues of CC-1065 and the duocarmycins 总被引:2,自引:0,他引:2
Tichenor MS MacMillan KS Stover JS Wolkenberg SE Pavani MG Zanella L Zaid AN Spalluto G Rayl TJ Hwang I Baraldi PG Boger DL 《Journal of the American Chemical Society》2007,129(45):14092-14099
The design, synthesis, and evaluation of a predictably more potent analogue of CC-1065 entailing the substitution replacement of a single skeleton atom in the alkylation subunit are disclosed and were conducted on the basis of design principles that emerged from a fundamental parabolic relationship between chemical reactivity and cytotoxic potency. Consistent with projections, the 7-methyl-1,2,8,8a-tetrahydrocyclopropa[c]thieno[3,2-e]indol-4-one (MeCTI) alkylation subunit and its isomer 6-methyl-1,2,8,8a-tetrahydrocyclopropa[c]thieno[2,3-e]indol-4-one (iso-MeCTI) were found to be 5-6 times more stable than the MeCPI alkylation subunit found in CC-1065 and slightly more stable than even the DSA alkylation subunit found in duocarmycin SA, placing it at the point of optimally balanced stability and reactivity for this class of antitumor agents. Their incorporation into the key analogues of the natural products provided derivatives that surpassed the potency of MeCPI derivatives (3-10-fold), matching or slightly exceeding the potency of the corresponding DSA derivatives, consistent with projections made on the basis of the parabolic relationship. Notable of these, MeCTI-TMI proved to be as potent as or slightly more potent than the natural product duocarmycin SA (DSA-TMI, IC50 = 5 vs 8 pM), and MeCTI-PDE2 proved to be 3-fold more potent than the natural product CC-1065 (MeCPI-PDE2, IC50 = 7 vs 20 pM). Both exhibited efficiencies of DNA alkylation that correlate with this enhanced potency without impacting the intrinsic selectivity characteristic of this class of antitumor agents. 相似文献