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排序方式: 共有532条查询结果,搜索用时 15 毫秒
1.
Cataldo Simari Carmelo Lo Vecchio Apostolos Enotiadis Mariano Davoli Vincenzo Baglio Isabella Nicotera 《应用聚合物科学杂志》2019,136(34):47884
Polyethersulphone (PES) is an aromatic thermoplastic, at low environmental impact, evaluated in this work as a promising candidate for new polymer electrolytes in the PEMFCs technology. A sulfonation procedure has been tuned in order to graft sulfonic acid groups on the polymer chains (sPES) and to make it hydrophilic. Homogeneous membranes with different polymer's sulfonation degrees (SD%) have demonstrated excellent mechanical properties and very low permeability toward methanol (important in the DMFCs), even if low proton conductivity. Nanocomposite sPES membranes were prepared by dispersion of highly hydrophilic lamellar particles such as layered double hydroxide (LDH) in the polymer. Deep investigations performed by a combination of PFG-NMR, EIS, XRD, DMA, and scanning electron microscopy have evidenced the exfoliation of the lamellae in polymer matrix. However, a certain anisotropy was evidenced both in the morphology and molecular diffusion, favored in the longitudinal direction (parallel to surface), while completely inhibited in the cross-section. This finding is most likely induced by the polymer structure, therefore particular attention must be paid to the choice of the filler and preparation of the composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47884. 相似文献
2.
Franco Cataldo 《Fullerenes, Nanotubes and Carbon Nanostructures》2004,12(4):765-779
The polyynes produced by the electric arc between graphite electrodes submerged in hexane are readily reduced to a mixture of polyenes and ene-ynes by a treatment with Zn dust and hydrochloric acid. Experimental evidences of this reduction reaction are presented by electronic absorption spectroscopy, FT-IR spectroscopy, and HPLC analysis with diode-array detector. Some consequences of this simple passage from polyynes to ene-ynes are briefly discussed in a biochemical context. 相似文献
3.
GM Gazzaniga G Angelini G Pastorino E Santoro M Lucchini ML Dal Prà 《Canadian Metallurgical Quarterly》1993,78(3):271-275
Four hundred forty-six patients with Tourette Syndrome (TS) and/or their parents completed a 52-item self-report survey about vocal and motor tics, and the frequency of associated co-morbid conditions of aggression, obsessions and compulsions, attentional problems, sleep disturbance, mood disturbance, anxiety, and self-mutilative behaviours which have been frequently reported in the literature on TS. Respondents also responded to an open-ended question regarding the most disabling aspects of TS. Results were analyzed within two age groups; under 18 years of age (N = 245) and 18 years of age or older (N = 177). Tics and associated conditions were the most frequently reported disabling aspect by both age groups. Subjects under age 18, however, reported significantly more frequent problems with hyperactivity, temper control, aggressive behaviours and sleepwalking than adults with TS. 相似文献
4.
Giuseppe Gradenigo (1859-1926) was an important figure in the development of Otology. Within this paper the authors consider his background and his particular contributions to the development of various aspects of audiology. 相似文献
5.
F Chiarella E Santoro S Domenicucci A Maggioni C Vecchio 《Canadian Metallurgical Quarterly》1998,81(7):822-827
Left ventricular (LV) thrombosis can be found in patients with acute myocardial infarction (AMI). No wide multicenter trial on AMI has provided information about LV thrombosis until now. The protocol of the GISSI-3 study included the search for the presence of LV thrombosis in patients from 200 coronary care units that did not specifically focus on LV thrombosis. We examined the GISSI-3 database results related to 8,326 patients at low to medium risk for LV thrombi in which a predischarge echocardiogram (9 +/- 5 days) was available. LV thrombosis was found in 427 patients (5.1%): 292 of 2,544 patients (11.5%) with anterior AMI and in 135 of 5,782 patients (2.3%) with AMI in other sites (p <0.0001). The incidence of LV thrombosis was higher in patients with ejection fraction < or = 40% (151 of 1,432 [10.5%] vs 276 of 6,894 [4%]; p <0.0001) both in the total population and in the subgroup with anterior AMI (106 of 597 [17.8%] vs 186 of 1,947 [9.6%]; p <0.0001). Multivariate analysis showed that only the Killip class > I and early intravenous beta-blocker administration were independently associated with higher LV thrombosis risk in the subgroup of patients with anterior AMI (odds ratio 1.75, 95% confidence interval 1.28 to 2.39; odds ratio 1.32, 95% confidence interval 1.02 to 1.72, respectively). In patients with anterior AMI, oral beta-blocker therapy given or not given after early intravenous beta-blocker administration does not influence the occurrence of LV thrombosis. The rate of LV thrombosis was similar in patients treated or not treated with nitrates and lisinopril both in the total population and in patients with anterior and nonanterior AMI. In conclusion, in the GISSI-3 population at low to medium risk for LV thrombi, the highest rate of occurrence of LV thrombosis was found among patients with anterior AMI and an ejection fraction < 40%. Killip class > I and the early intravenous beta-blocker administration were the only variables independently associated with a higher predischarge incidence of LV thrombosis after anterior AMI. 相似文献
6.
R Martinez A Saponaro R Russo G Dragagna N Leopardi L Santoro E Martelli 《Canadian Metallurgical Quarterly》1993,35(1):9-11
Cytokines are central to the development of effective immunity against microbial pathogens and their beneficial effects in the control of a variety of infections of man and animals are well-documented. However, it appears that cytokines may also have detrimental effects in infections by actually enhancing microbial growth. These observations emphasise the fact that many successful pathogens possess mechanisms enabling them to evade the immune response and that caution needs to be exercised in using cytokines as therapeutic agents to control infections in various human diseases. 相似文献
7.
The stabilizing free energy of beta-trypsin was determined by hydrogen ion titration. In the pH range from 3.0 to 7.0, the change in free energy difference for the stabilization of the native protein relative to the unfolded one (delta delta G0 titration) was 9.51 +/- 0.06 kcal/mol. An isoelectric point of 10.0 was determined, allowing us to calculate the Tanford and Kirkwood electrostatic factor w. This factor presented a nonlinear behavior and indicated more than one type of titratable carboxyl groups in beta-trypsin. In fact, one class of carboxyl group with a pK = 3.91 +/- 0.01 and another one with a pK = 4.63 +/- 0.03 were also found by hydrogen ion titration of the protein in the folded state. 相似文献
8.
Franco Cataldo 《Fullerenes, Nanotubes and Carbon Nanostructures》2003,11(1):1-13
A brief survey of the chemical structural analogies and differences between graphite oxide and fullerene ozopolymers or polymeric fullerene oxides (PFO) is presented. Graphite oxide is the product of oxidation of graphite prepared with strong oxidizing agents while PFO is the products formed by prolonged ozonation of C60 or C70 in solution. Notwithstanding the different starting substrates and oxidation conditions, elemental analyses, FT-IR spectroscopy and 13C-NMR spectroscopy suggest a very similar chemical structure for graphite oxide and PFO. A further analogy is the possibility to perform reduction or oxidation reactions on both substrates considered. Graphite oxide and PFO have also in common the ability to act as ion exchangers and as metal ion binders. Even the thermal behavior is comparable. However, X-ray powder diffraction has confirmed that graphite oxide still has a layered structure derived from graphite but with the graphene sheets at much bigger distance from each other due to the intercalation of oxidized groups and solvent molecules, while PFO do not show at all any sign of layered structure either from the X-ray spectra and also by its behavior in solution which is strikingly different from that shown by graphite oxide. 相似文献
9.
JF Richmond S Lu JC Santoro J Weng SL Hu DC Montefiori HL Robinson 《Canadian Metallurgical Quarterly》1998,72(11):9092-9100
DNA vaccination is an effective means of eliciting strong antibody responses to a number of viral antigens. However, DNA immunization alone has not generated persistent, high-titer antibody and neutralizing antibody responses to human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env). We have previously reported that DNA-primed anti-Env antibody responses can be augmented by boosting with Env-expressing recombinant vaccinia viruses. We report here that recombinant Env protein provides a more effective boost of DNA-initiated antibody responses. In rabbits primed with Env-expressing plasmids, protein boosting increased titer, persistence, neutralizing activity, and avidity of anti-Env responses. While titers increased rapidly after boosting, avidity and neutralizing activity matured more slowly over a 6-month period following protein boosting. DNA priming and protein immunization with HIV-1 HXB-2 Env elicited neutralizing antibody for T cell line-adapted, but not primary isolate, viruses. The most effective neutralizing antibody responses were observed after priming with plasmids which expressed noninfectious virus-like particles. In contrast to immunizations with HIV-1 Env, DNA immunizations with the influenza virus hemagglutinin glycoprotein did not require a protein boost to achieve high-titer antibody with good avidity and persistence. 相似文献
10.
Talita da Cunha Mattos Flávia Maria Santoro Kate Revoredo Vanessa Tavares Nunes 《Computers in Industry》2014
A business process is a set of activities performed in a coordinated manner within an organizational and technical environment that is aimed toward a business goal. The flexibility of a process is related to an understanding of the unexpected events that occur when people, systems and resources interact and require adjustments. Thus, business processes must be designed to respond to information about different events and their specificity. This information defines what the literature calls “context”. To broaden the perception of context in the case of a business process, this work proposes an approach to characterize the context of a business process activity in a given domain through conceptual models structured in layers. A case study was conducted to evaluate the proposal, which provided evidence of the applicability of the model. 相似文献