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401.
402.
Vilar S González-Díaz H Santana L Uriarte E 《Journal of computational chemistry》2008,29(16):2613-2622
Network theory allows relationships to be established between numerical parameters that describe the molecular structure of genes and proteins and their biological properties. These models can be considered as quantitative structure-activity relationships (QSAR) for biopolymers. The work described here concerns the first QSAR model for 122 proteins that are associated with human breast cancer (HBC), as identified experimentally by Sj?blom et al. (Science 2006, 314, 268) from over 10,000 human proteins. In this study, the 122 proteins related to HBC (HBCp) and a control group of 200 proteins that are not related to HBC (non-HBCp) were forced to fold in an HP lattice network. From these networks a series of electrostatic potential parameters (xi(k)) was calculated to describe each protein numerically. The use of xi(k) as an entry point to linear discriminant analysis led to a QSAR model to discriminate between HBCp and non-HBCp, and this model could help to predict the involvement of a certain gene and/or protein in HBC. In addition, validation procedures were carried out on the model and these included an external prediction series and evaluation of an additional series of 1000 non-HBCp. In all cases good levels of classification were obtained with values above 80%. This study represents the first example of a QSAR model for the computational chemistry inspired search of potential HBC protein biomarkers. 相似文献
403.
404.
An efficient and general synthesis of aziridines by the reaction of imines derived from p-toluenesulfonamides with in situ generated iodomethyllithium, with a simple and rapid experimental protocol, is reported for the first time. The reaction with the chiral aldimine derived from phenylalaninal allowed access to (2R,1'S)-2-(1'-aminoalkyl)aziridine with very high diastereoselectivity, in enantiopure form. A mechanism to explain this novel reaction is proposed. 相似文献
405.
406.
Humberto Rodríguez-Solla Carmen Concellón Noemí Alvaredo Raquel G. Soengas 《Tetrahedron》2012,68(6):1736-1744
A novel reaction of bromonitromethane with a variety of imines in very mild conditions promoted by SmI2 and NaI to afford nitroamines or bromonitroamines is described. When these reactions were performed on sugar-based imines, the corresponding nitroamines or bromonitroamines were obtained in high yields and from moderate to good stereoselectivities. Synthetic possibilities of nitroamines were also shown by their reduction with SmI2/H2O in the presence of pyrrolidine at room temperature. A mechanism is proposed for this novel aza-Henry reaction. 相似文献
407.
Agakishiev G Aggarwal MM Ahammed Z Alakhverdyants AV Alekseev I Alford J Anderson BD Anson CD Arkhipkin D Averichev GS Balewski J Barnby LS Beavis DR Behera NK Bellwied R Betancourt MJ Betts RR Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Bordyuzhin IG Borowski W Bouchet J Braidot E Brandin AV Bridgeman A Brovko SG Bruna E Bueltmann S Bunzarov I Burton TP Cai XZ Caines H Sánchez MC Cebra D Cendejas R Cervantes MC Chaloupka P Chattopadhyay S Chen HF Chen JH Chen JY Chen L Cheng J 《Physical review letters》2012,108(7):072301
We report new STAR measurements of midrapidity yields for the Λ, Λ[over ˉ], K(S)(0), Ξ(-), Ξ[over ˉ](+), Ω(-), Ω[over ˉ](+) particles in Cu+Cu collisions at √S(NN)==200 GeV, and midrapidity yields for the Λ, Λ[over ˉ], K(S)(0) particles in Au+Au at √S(NN)==200 GeV. We show that, at a given number of participating nucleons, the production of strange hadrons is higher in Cu+Cu collisions than in Au+Au collisions at the same center-of-mass energy. We find that aspects of the enhancement factors for all particles can be described by a parametrization based on the fraction of participants that undergo multiple collisions. 相似文献
408.
Alvaro Javier Gmez Rodríguez Dagoberto Oyola Lozano Humberto Bustos Rodríguez Yebrail Rojas Martínez German Antonio Prez Alczar Ligia Edith Zamora Alfonso Juan Sebastian Trujillo Hernandez 《Molecules (Basel, Switzerland)》2022,27(21)
The objective of this work is to evaluate the applicability of exchange coupling between nanoparticles of Nd2Fe14B (hard magnetic material) and Fe90Al10 (soft magnetic material), as permanent magnets produced by surfactant-assisted mechanical alloying. The obtained powders were then mixed with 85% of the Nd2Fe14B system and 15% of the Fe90Al10 system and subsequently sintered at 300 °C, 400 °C and 500 °C for one hour. The results obtained by Mössbauer spectrometry (MS) show a ferromagnetic behavior with six magnetic sites represented by sextets (16k1, 16k2, 8j1, 8j2, 4c and 4e), characteristic of the Nd2Fe14B system. X-ray diffraction (XRD) results show a tetragonal and BCC structure for the Nd2Fe14B and FeAl systems, respectively. The results obtained by vibrating sample magnetometry (VSM), for mixtures of the Nd2Fe14B and Fe90Al10 sy stems sintered at 300 °C, 400 °C and 500 °C, allow for the conclusion that the coercive field (Hc) decreases drastically with temperature and the percentage of soft phase at values of Hc = 132 Oe compared to the coercive field values reported for Nd2Fe14B Hc = 6883 Oe, respectively. Images obtained by transmission electron microscopy (TEM), for the Fe90Al10 system, show a tendency for the nanoparticles to agglomerate. 相似文献
409.
Gustavo M. do Nascimento Wdeson P. Barros Yoong Ahm Kim Hiroyuki Muramatsu Takuya Hayashi Morinobu Endo Noriberto A. Pradie Cristiano Fantini Marcos A. Pimenta Mildred S. Dresselhaus Humberto O. Stumpf 《Journal of Raman spectroscopy : JRS》2012,43(12):1951-1956
The electronic interactions between the [Cu(opba)]2− anions (where opba is orthophenylenebis (oxamato)) and single‐wall carbon nanotubes (SWCNTs) were investigated by resonance Raman spectroscopy. The opba can form molecular magnets, and the interactions of opba with SWCNTs can produce materials with very different magnetic/electronic properties. It is observed that the electronic interaction shows a dependence on the SWCNT diameter independent of whether they are metallic or semiconducting, although the interaction is stronger for metallic tubes. The interaction also is dependent on the amount of complex that is probably adsorbed on the carbon surface of the SWCNTs. Some charge transfer can be also occurring between the metallic complex and the SWCNTs. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
410.
Dr. Martín Soto Paula Pérez-Ramos Prof. Dr. Raquel G. Soengas Prof. Dr. Humberto Rodríguez-Solla 《European journal of organic chemistry》2023,26(16):e202300139
A new substrate-controlled hydrogenation of flavanones to selectively obtain different hydrogenation products is herein reported. Thus, hydrogenation of flavanones bearing different electron-donating and electron withdrawing substituents (Cl, Br, Me, OMe, OH) provided the corresponding 1,3-diarylpropanes in excellent yields. This procedure offers a straightforward, simple, and cost-effective method for the preparation of glycosylated 2′-hydroxy-1,3-diarylpropanes derived from natural flavanones such as Naringin and Hesperedin. On the contrary, when the hydrogenation was performed over fluorinated flavanones, the corresponding flavans were selectively obtained in excellent yields. 相似文献