排序方式: 共有47条查询结果,搜索用时 15 毫秒
21.
Alvaréz RS Cutin EH Della Vedova CO Mews R Haist R Oberhammer H 《Inorganic chemistry》2001,40(20):5188-5191
The vibrational spectra, IR (gas) and Raman (liquid) of N-cyanoimidosulfurous difluoride, NCN=SF2, were recorded, and the molecular structure was determined by gas electron diffraction. The spectra were assigned by comparing the vibrational frequencies with those in related molecules and with calculated (HF, MP2, B3LYP with 6-31G(d) basis sets) values, and a normal coordinate analysis was performed. The molecule possesses a syn conformation (Ctriple bondN syn with respect to the bisector of the SF2 angle). This has been rationalized by orbital interactions of the electron lone pairs of sulfur and nitrogen with the N-C and S-F bonds, respectively, which are antiperiplanar or anticlinal to these lone pairs (anomeric effects). Quantum chemical calculations with the B3LYP and MP2 methods reproduce the experimental structure reasonably well if large basis sets (6-311G(2d,f)) are used. 相似文献
22.
Riccardo Flamini Mirko De Rosso Anna Smaniotto Annarita Panighel Antonio Dalla Vedova Roberta Seraglia Pietro Traldi 《Rapid communications in mass spectrometry : RCM》2009,23(18):2891-2896
In a previous work, direct‐infusion electrospray ionization ion trap tandem mass spectrometry (ESI‐IT‐MS/MS) was applied to the study of anthocyanins in extracts from the skins of Clinton grapes, a non‐Vitis vinifera red grape variety qualitatively and quantitatively rich in anthocyanins. A good characterization of anthocyaninins was obtained, but it was impossible to differentiate some compounds with the same nominal mass but with different elemental composition. In this work, the capabilities of quadrupole time‐of‐flight mass spectrometry (QTOF‐MS) coupled with Chip‐liquid chromatography (LC‐Chip) were applied to the study of Clinton anthocyanins and this method provided the complete sample anthocyanin fingerprint in less than 5 min. Multi‐stage mass spectrometry (MSn; n >2) was not necessary to identify isobaric compounds, nor were deuterium‐exchange experiments necessary to distinguish between compounds containing the same aglycone. The fast separation bypasses the problem of petunidin‐3‐O‐(6‐O‐acetyl)monoglucoside and delphinidin‐3,5‐O‐diglucoside quantification, present in the direct‐infusion ESI‐ITMS approach, due to overlapping with matrix interferences. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
23.
M. De Rosso L. Tonidandel R. Larcher G. Nicolini V. Ruggeri A. Dalla Vedova F. De Marchi M. Gardiman R. Flamini 《Analytica chimica acta》2012
The anthocyanins of 21 hybrid red varieties produced by crossing V. vinifera, V. riparia, V. labrusca, V. lincecumii and V. rupestris species, the profiles for which have not yet been reported, were studied. Profiles were determined by LC/DAD, and identification of single anthocyanins was confirmed by LC/MS precursor-ion analysis. Anthocyanidin precursors (pelargonidin at m/z 271, dephinidin at m/z 303, cyanidin at m/z 287, petunidin at m/z 317, peonidin at m/z 301, and malvidin at m/z 331) and precursors of monoglucoside compounds allowed 24 different compounds to be identified. Analysis of precursor ions of monoglucoside anthocyanins at low capillary voltage revealed the signals of diglucosides only, providing a very selective method for analysis of diglucoside anthocyanins in grape. According to anthocyanin profile, the samples were subdivided into two groups: one characterized by the substantial presence of diglucoside compounds (particularly Seyve Villard 23-399 and Seyve Villard 23-369) and one by the scarce presence or practical absence of diglucosides (Seibel 10878, Burdin 4077, and Galibert 238-35). Particularly interesting for producing anthocyanin for the natural colorant industry were the varieties Siebel 8357, Bacò 30-12 and Terzi 100-31. 相似文献
24.
Marijke WA de Backer Carlos P Fitzsimons Maike AD Brans Mieneke CM Luijendijk Keith M Garner Erno Vreugdenhil Roger AH Adan 《BMC neuroscience》2010,11(1):81
Background
This study compared the transduction efficiencies of an adeno-associated viral (AAV) vector, which was pseudotyped with an AAV1 capsid and encoded the green fluorescent protein (GFP), with a lentiviral (LV) vector, which was pseudotyped with a VSV-G envelop and encoded the discosoma red fluorescent protein (dsRed), to investigate which viral vector transduced the lateral hypothalamus or the amygdala more efficiently. The LV-dsRed and AAV1-GFP vector were mixed and injected into the lateral hypothalamus or into the amygdala of adult rats. The titers that were injected were 1 × 108 or 1 × 109 genomic copies of AAV1-GFP and 1 × 105 transducing units of LV-dsRed. 相似文献25.
N. Mărginean S.M. Lenzi A. Gadea E. Farnea S.J. Freeman D.R. Napoli D. Bazzacco S. Beghini B.R. Behera P.G. Bizzeti A. Bizzeti-Sona D. Bucurescu R. Chapman L. Corradi A.N. Deacon G. de Angelis F. Della Vedova E. Fioretto M. Ionescu-Bujor A. Iordachescu Th. Kröll A. Latina X. Liang S. Lunardi G. Montagnoli R. Mărginean M. Nespolo G. Pollarolo C. Rusu F. Scarlassara J.F. Smith K. Spohr A.M. Stefanini S. Szilner M. Trotta C.A. Ur B.J. Varley W. Zhimin 《Physics letters. [Part B]》2006
26.
Flamini R Vedova AD De Rosso M Panighel A 《Rapid communications in mass spectrometry : RCM》2007,21(22):3737-3742
A new sensitive and selective analytical method for the analysis of ochratoxin A (OTA) in grape and wine was developed by coupling liquid chromatography and surface activated chemical ionization and mass spectrometry with multistage fragmentation (LC/SACI-MS(3)). A high flow gradient was used to strongly reduce the matrix effect phenomenon, and the wine sample was directly injected onto the chromatographic column without sample pre-concentration or purification steps. The amount of OTA was determined for two grape extracts and the amount of OTA, percent accuracy error and percent precision error were analyzed for 15 wine samples. An excellent limit of detection of 0.02 ng/mL was achieved, and the limit of quantification was at least 20-fold lower than the maximum legal limit for OTA (2 ppb). Due to the low limit of quantification, this novel method is a potential tool for official OTA screening purposes. 相似文献
27.
D. Montanari S. Leoni D. Mengoni G. Benzoni N. Blasi G. Bocchi P.F. Bortignon A. Bracco F. Camera G. Colò A. Corsi F.C.L. Crespi B. Million R. Nicolini O. Wieland J.J. Valiente-Dobon L. Corradi G. de Angelis F. Della Vedova E. Fioretto A. Gadea D.R. Napoli R. Orlandi F. Recchia E. Sahin R. Silvestri A.M. Stefanini R.P. Singh S. Szilner D. Bazzacco E. Farnea R. Menegazzo A. Gottardo S.M. Lenzi S. Lunardi G. Montagnoli F. Scarlassara C. Ur G. Lo Bianco A. Zucchiatti M. Kmiecik A. Maj W. Meczynski A. Dewald Th. Pissulla G. Pollarolo 《Physics letters. [Part B]》2011
28.
The objective of this study was to determine if topical anesthesia to the larynx and pharynx affects vocal fold motion during dynamic voice evaluation with transnasal flexible endoscopy. Transnasal dynamic laryngeal examinations of 10 patients with no voice complaints were evaluated by five blinded fellowship-trained laryngologists. Each patient was examined before and after application of topical anesthetic. Reviewers rated briskness of right and left vocal fold movement and longitudinal tension on a visual analogue scale. Statistical comparisons were made between individual subject scores before and after anesthetic application. Inter-rater reliability was also assessed. No statistical difference was observed between subject scores before and after anesthetic application. Average intraclass correlation coefficients were 0.643 and 0.591 for pre- and postanesthesia scores, respectively. Application of topical anesthesia to the larynx and pharynx does not affect vocal fold motion. 相似文献
29.
Annarita Panighel Antonio Dalla Vedova Mirko De Rosso Massimo Gardiman Riccardo Flamini 《Rapid communications in mass spectrometry : RCM》2010,24(14):2023-2029
2′‐Aminoacetophenone (o‐AAP) was identified as the main cause of the aging note called ‘hybrid note’ or ‘foxy smell’ which is typical of non‐Vitis vinifera grapes. Together with methyl anthranilate (MA), this compound contributes to the typical foxy taint of wines made with non‐Vitis vinifera grapes. 3‐Alkyl‐2‐methoxypyrazines in grapes, with their herbaceous note and very low sensory thresholds, contribute to the aroma of several wines. In this study, a solid‐phase microextraction gas chromatography/ion trap tandem mass spectrometry (SPME‐GC/IT‐MS/MS) method for simultaneous detection of o‐AAP, MA and ethyl‐, isopropyl‐, sec‐butyl‐ and isobutylmethoxypyrazine in grape juice was developed. The method was applied to the study of several grape juices: the time required for analysis was less than 24 min, and the method was considered to be suitable for analysis of ‘foxy compounds’ and methoxypyrazines in grape juice. The high levels of MA and o‐AAP found in Clinton and Siebel grapes confirmed the ‘hybrid’ character of these varieties. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
30.
C.O. Della Vedova J.H. Lesk E.L. Varetti P.J. Aymonino O.E. Piro B.E. Rivero E.E. Castellano 《Journal of Molecular Structure》1981
Dehydration data for the tetra-, di- and monohydrate of strontium nitroprusside and the vibrational behaviour of the water molecules in normal and deuterated samples agree with crystal data previously reported (for the di- and tetrahydrate as single crystals) and in this paper (monohydrate as a powder). Four distinct types of water molecules are present in the three hydrates with one type (oxygen bonded to Sr2+) in common. Other types are a non hydrogen-bonded molecule (dihydrate), a molecule bonded by a single hydrogen atom to the nitrogen atom of a cyanide group and a set of two molecules similarly bonded to the oxygen atom of the previous type (tetrahydrate). The spatial orientation of the NO groups of the nitroprusside ions in the tetrahydrate is confirmed by the observed dichroism of the corresponding stretching band. 相似文献