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排序方式: 共有133条查询结果,搜索用时 15 毫秒
1.
A Berti M Faccini P Caputo G Zucchi G Larceri L Bonandrini 《Canadian Metallurgical Quarterly》1997,52(10):1227-1230
Authors refer about their experience on five cases of thoracic trauma. Following a review of international literature, they analyze the clinical, diagnostic and therapeutic aspects of this kind of injuries. 相似文献
2.
Summary Copolymers containing -S-CO-S-and/or -O-CO-S-groups have been synthesized mainly by interfacial polycondensation.Different chemical structures were obtained by reacting 1,3-benzene dithiol (BDT) respectively with phosgene alone, phosgene and bisphenol-A (BPA), bischloroformate of BPA, BPA polycarbonate oligomers and by reacting phosgene with the products of BPA polycarbonate degraded with BDT. The chemical structures of the copolymers were investigated by IR, 1H-NMR and 13C-NMR; molecular weights were determined by viscometry and vapor pressure osmometry. Although no attempt was made to find the optimum conditions for high molecular weight, some copolymers with fairly high mol. weight were obtained. 相似文献
3.
In this age of increasingly complex, Internet-based technologies, it's very difficult to protect original works of authorship. This article examines the problem of copyright infringement and the copyright law's desire to balance the interests of creators with the interests of the public. The author also offers some insight in how to reduce the problem of copyright infringement. 相似文献
4.
Detection of Partial Denaturation in AT-Rich DNA Fragments by Ion-Pair Reversed-Phase Chromatography
Temperature-dependent denaturation of DNA restriction fragments from the pBR322 plasmid ranging in length from 46 to 910 base pairs was detected by ion-pair reversed-phase high-performance liquid chromatography using columns packed with alkylated nonporous poly(styrene/divinylbenzene) particles. The presence of acetonitrile in the mobile phase was found to decrease the melting temperatures of DNA fragments by 1.5-2 °C/% of acetonitrile in the eluent. Small fragments (<120 bp) were completely denatured between 53.6 and 63.5 °C, depending on their total GC content. Whereas retention times of completely helical DNA fragments increased gradually with increasing temperature, partial denaturation of larger DNA fragments (>150 bp) was found to reduce retention at temperatures above 53.6 °C. Therefore, micropreparative fractionation and rechromatography, together with DNA restriction analysis, were applied to identify the correct elution order of completely helical and partially denatured fragments. Inspection of the DNA sequences of partially denatured fragments revealed domains with repeating AT base pairs. Positions of partial denaturation within the pBR322 plasmid detected by chromatographic analysis were in good agreement with partial denaturation maps obtained by electron microscopy desrcibed in the literature. 相似文献
5.
Nutrient Cycling in Agroecosystems - The benefits of soil organic input on crop yields have long been discussed, yet details of their relationship remain controversial. This study considers the... 相似文献
6.
Defined Conjugation of Glycans to the Lysines of CRM197 Guided by their Reactivity Mapping 下载免费PDF全文
Dr. Stefano Crotti Dr. Huili Zhai Dr. Jing Zhou Martin Allan Dr. Daniela Proietti Dr. Werner Pansegrau Dr. Qi‐Ying Hu Dr. Francesco Berti Dr. Roberto Adamo 《Chembiochem : a European journal of chemical biology》2014,15(6):836-843
Systematic characterisation of the reactivity of the lysine moieties in CRM197 towards N‐hydroxysuccinimide linkers bearing alkynes or azides is described. This involves two‐step conjugation of various glycans to CRM197 by click chemistry in a well‐defined manner. By semiquantitative LC‐MS/MS analysis of proteolytic digests of the conjugates formed, the reactivity of lysine residues in the protein was mapped and ranked. Computational analysis of the solvent accessibility of each lysine residue (based on the CRM197 crystal structure) established a correlation between reactivity and surface exposure. By this approach, conjugation involving lysine residues (normally a random process) can be controlled. It enables the preparation of lysine‐mediated glycoconjugates with improved batch‐to‐batch reproducibility, thereby producing neo‐glycoconjugates with more‐consistent biological activity. 相似文献
7.
Martino Colonna Corrado Berti Enrico Binassi Maurizio Fiorini Simone Sullalti Francesco Acquasanta Micaela Vannini Diana Di Gioia Irene Aloisio 《Polymer》2012,53(9):1823-1830
Imidazolium poly(butylene terephthalate) ionomers with ionic groups located randomly along the polymer chain or selectively as end-groups (telechelic) have been prepared in order to determine their antimicrobial (AM) activity. Two different approaches have been followed for the linkage of the imidazolium to the polymer backbone: a covalent bond and an ionic aggregation to sulfonated groups covalently bonded to the polymer. The ionic groups have been linked to the polymer in order to improve the long-term AM activity since the low molecular weight additives commonly used tends to migrate toward the surface during use. We have found that imidazolium ionomers present AM activity comparable with that of commercial antimicrobial agents such as Triclosan. The AM activity depends on the polymer architecture, the telechelic approach being more active compared to the random approach. We have proved that imidazolium ionomers retain their high AM activity even after 6 days in water at 60 °C while Triclosan consistently loses his activity. 相似文献
8.
C. Berti E. Binassi M. Colonna M. Fiorini T. Zuccheri S. Karanam D. J. Brunelle 《应用聚合物科学杂志》2009,114(5):3211-3217
Poly(butylene terephthalate) nanocomposites with organically modified montmorillonites have been prepared by in‐situ ring opening polymerization of PBT cyclic oligomers. High molecular weight polymers can be obtained by choosing the proper polymerization conditions and catalyst in very short polymerization time (10 min) and low temperature (205°C). A better dispersion of the clay and a consistently higher Mw have been obtained by this method respect to the standard melt intercalation approach, leading to improved thermo‐mechanical properties of the nanocomposite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
9.
Tortoli P Thompson RS Berti P Guidi F 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1999,46(6):1591-1596
The use of a multigate profiling system with steady laminar flow in plastic tubes revealed spectral artifacts not previously described. In particular, a double or split profile was often observed. In this paper, these artifacts are related to the dual mode ultrasound propagation in the plastic tube. The propagation speeds and, therefore, refraction angles and propagation paths are different for the longitudinal and the shear wave. The power transmission can be extraordinarily sensitive to small variations in the angle of incidence, and this may combine with the existence of a range of angles of incidence within any focused ultrasound beam to produce spectral distortions. The plastic tube is thus shown equivalent to a selective filter, which diminishes some frequency components in the Doppler spectrum relative to others. The spectral artifacts are explained in terms of the relative power transmitted by each mode, and the degree of beam defocusing experienced by each. Spectral distortions persist even when the beam-to-flow orientation is well away from the critical angle. The results of this study show that it is feasible to understand the acoustic transmission behavior of a flow phantom, based on a knowledge of the material properties, and to demonstrate the usefulness of doing so. 相似文献
10.