排序方式: 共有22条查询结果,搜索用时 312 毫秒
1.
Mariateresa Giustiniano Sveva Pelliccia Luca Sangaletti Fiorella Meneghetti Jussara Amato Ettore Novellino Gian Cesare Tron 《Tetrahedron letters》2017,58(45):4264-4268
A novel interrupted Ugi reaction between ortho-sulfonylaminated aryl aldehydes, secondary amines, and isocyanides affords in good to high yields N-alkyl-2,3-diaminoindoles, providing access to a so far unexplored area of the indole chemical space. With only one single chemical operation, this novel reaction affords a broad gamma of substituted 2,3-diaminoindoles with five points of diversity. The success of this novel multicomponent transformation lies in presence of the amphoteric sulfonylamino group, which sequentially acts as a Brønsted acids and as a nucleophile the lack of need for additional catalysts and the high atom economy, with the loss of only one molecule of water, renders this approach a very effective one. 相似文献
2.
D Pelliccia DM Paganin A Sorrentino I Bukreeva A Cedola S Lagomarsino 《Optics letters》2012,37(2):262-264
The problem of retrieving a complex function from the modulus of its Fourier transform has non-unique solutions in one dimension. Therefore iterative phase retrieval methods cannot in general be confidently applied to one-dimensional problems, due to the presence of ambiguities. We present a method for a posteriori reduction of the ambiguities based on the correlation analysis of the solution of a large number of runs of an iterative phase retrieval algorithm with different random starting phases. The method is applied to experimentally measured diffraction patterns from an x ray waveguide illuminated by hard x rays. We demonstrate the possibility of retrieving the complex wave field at the exit face of the waveguide and compare the result with theoretical prediction. 相似文献
3.
Raffaele Saladino Veronica NeriAnna Rita Pelliccia Enrico Mincione 《Tetrahedron》2003,59(37):7403-7408
A convenient and efficient synthesis of monoterpene epoxides by application of heterogeneous poly(4-vinylpyridine)/methyl rhenium trioxide (PVP/MTO) and polystyrene/methyl rhenium trioxide (PS/MTO) systems is described. Even highly sensitive terpenic epoxides were obtained in excellent yield. Environment friendly, easily available, and low cost H2O2 was used as oxidant. Catalysts were stable systems for at least five recycling experiments. 相似文献
4.
Mariateresa Giustiniano Sveva Pelliccia Ettore Novellino Gian Cesare Tron 《Tetrahedron letters》2018,59(13):1196-1199
N-Substituted α-amino acid amides can be easily obtained in two steps using the four-component Ugi reaction followed by chemoselective cleavage of the resulting tertiary amide. The use of the sacrificial acid, 2-hydroxymethylbenzoic acid is associated to shorter reaction times, higher yields, and safer and greener reaction conditions compared to strategies based on trifluoroacetic acid, a toxic and environmental hazardous reagent. The optimized procedure was easily scaled up to gram amounts. 相似文献
5.
Bukreeva I Popov A Pelliccia D Cedola A Dabagov SB Lagomarsino S 《Physical review letters》2006,97(18):184801
Diffraction and refraction phenomena at the entrance of a hollow x-ray waveguide with weakly absorbing dielectric cladding layers are investigated using two independent approaches: (a) analytical and (b) numerical solutions of the wave equation in the paraxial (parabolic) approximation. It is shown that the wave penetrating through the cladding material substantially modifies the wave field near the waveguide entrance. It results in a significant increase of the total energy flux inside the guiding layer and in additional spatial modulation of the electromagnetic field. 相似文献
6.
Diode laser spectroscopy of overtone bands of acetylene 总被引:1,自引:0,他引:1
A. Lucchesini M. De Rosa D. Pelliccia A. Ciucci C. Gabbanini S. Gozzini 《Applied physics. B, Lasers and optics》1996,63(3):277-282
Overtone absorption lines of acetylene in the regions around 12700 and 11800 cm–1 have been examined by the use of tunable diode lasers in free-running mode. The diode laser emission wavelength was scanned around the gas resonances by simply sweeping its injection current, permitting a direct observation of the absorption line-shapes. Weak overtone absorption lines have been detected by using the wavelength modulation (WM) spectroscopy with 2nd harmonic detection technique and the collisional broadening and shift coefficients have been obtained. The high resolving power and accuracy of the spectrometer permitted a wavenumber error of less than 0.01 cm–1. The correct interpretation of the absorption signals when detecting the second harmonic in the presence of a sloping background is discussed. 相似文献
7.
Summary Diode laser spectroscopy of ammonia ro-vibrational overtone transitions has been performed in the near IR, by using direct
absorption, wavelength modulation, and two-tone frequency modulation techniques. Pressure broadening coefficients in air,
hydrogen, helium and self-broadening have been measured. The high sensitivity of the apparatus permitted the detection of
70 p.p.m. of NH3 in air per meter of path at atmospheric pressure. New lines have been observed in the 719.9 nm band.
The authors of this paper have agreed to not receive the proofs for correction. 相似文献
8.
Daniele Pelliccia Christopher M. Poole Jayde Livingstone Andrew W. Stevenson Lloyd M. L. Smyth Peter A. W. Rogers Daniel Haüsermann Jeffrey C. Crosbie 《Journal of synchrotron radiation》2016,23(2):566-573
The protocol for image‐guided microbeam radiotherapy (MRT) developed for the Australian Synchrotron's Imaging and Medical Beamline (IMBL) is described. The protocol has been designed for the small‐animal MRT station of IMBL to enable future preclinical trials on rodents. The image guidance procedure allows for low‐dose monochromatic imaging at 50 keV and subsequent semi‐automated sample alignment in 3D with sub‐100 µm accuracy. Following the alignment, a beamline operation mode change is performed and the relevant beamline components are automatically aligned for the treatment (pink) beam to be delivered on the sample. Here, the small‐animal MRT station, the parameters and procedures for the image guidance protocol, as well as the experimental imaging results using phantoms are described. Furthermore, the experimental validation of the protocol using 3D PRESAGE® dosimeters is reported. It is demonstrated that the sample alignment is maintained after the mode change and the treatment can be delivered within the same spatial accuracy of 100 µm. The results indicate that the proposed approach is viable for preclinical trials of small‐animal MRT. 相似文献
9.
To every egglike inversive plane
there is associated a family
of involutions of the point set of
such that
circles of
are the fixed point sets of the involutions in
. Korchmaros and Olanda characterized a family
of involutions on a set of size n2 + 1to be
for
an egglike inversive plane of order n by four conditions. In this
paper, we give an alternative proof where the Galois space PG(3,n) in
which
is embedded is built up directly by using concepts and
results on finite linear spaces. 相似文献
10.
Thioredoxin Reductase Activity may be More Important than GSH Level in Protecting Human Lens Epithelial Cells against UVA Light 下载免费PDF全文
Vanita A. Padgaonkar Victor R. Leverenz Aparna V. Bhat Sara E. Pelliccia Frank J. Giblin 《Photochemistry and photobiology》2015,91(2):387-396
This study compares the abilities of the glutathione (GSH) and thioredoxin (Trx) antioxidant systems in defending cultured human lens epithelial cells (LECs) against UVA light. Levels of GSH were depleted with either L‐buthionine‐(S,R)‐sulfoximine (BSO) or 1‐chloro‐2,4‐dinitrobenzene (CDNB). CDNB treatment also inhibited the activity of thioredoxin reductase (TrxR). Two levels of O2, 3% and 20%, were employed during a 1 h exposure of the cells to 25 J cm?2 of UVA radiation (338–400 nm wavelength, peak at 365 nm). Inhibition of TrxR activity by CDNB, combined with exposure to UVA light, produced a substantial loss of LECs and cell damage, with the effects being considerably more severe at 20% O2 compared to 3%. In contrast, depletion of GSH by BSO, combined with exposure to UVA light, produced only a slight cell loss, with no apparent morphological effects. Catalase was highly sensitive to UVA‐induced inactivation, but was not essential for protection. Although UVA light presented a challenge for the lens epithelium, it was well tolerated under normal conditions. The results demonstrate an important role for TrxR activity in defending the lens epithelium against UVA light, possibly related to the ability of the Trx system to assist DNA synthesis following UVA‐induced cell damage. 相似文献