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排序方式: 共有152条查询结果,搜索用时 15 毫秒
41.
Rakesh Kalyanaraman Gino Rinaldi Muthukumaran Packirisamy Rama Bhat 《Microsystem Technologies》2013,19(1):61-70
Nonlinear dynamic investigation of electrostatically actuated micro-electro-mechanical-system (MEMS) microcantilever structures is presented. The nonlinear analysis aims to better quantify, than the linear model, the instability threshold associated with electrostatically actuated MEMS structures, where the pull-in voltage of the microcantilever is determined using a phase portrait analysis of the microsystem. The microcantilever is modeled as a lumped mass-spring system. The nonlinear electrostatic force is incorporated into the lumped microsystem through an equivalent area of the microcantilever for a given electrostatic potential. Electro-mechanical force balance plots are obtained for various electrostatic potentials from which the static equilibrium positions of the microcantilever are obtained and the respective conservative energy values are determined. Subsequently, phase portrait plots are obtained for the corresponding energy values from which the pull-in voltage is estimated for the microsystem. This pull-in voltage value is in good agreement with the previously published results for the same geometric and material parameters. The results obtained for linear electrostatic models are also presented for comparison. 相似文献
42.
43.
Tiziana Schioppa Hoang Oanh Nguyen Valentina Salvi Norma Maugeri Fabrizio Facchinetti Gino Villetti Maurizio Civelli Carolina Gaudenzi Mauro Passari Francesca Sozio Ilaria Barbazza Nicola Tamassia Marco A. Cassatella Annalisa Del Prete Daniela Bosisio Laura Tiberio 《International journal of molecular sciences》2022,23(9)
Neutrophils, the most abundant subset of leukocytes in the blood, play a pivotal role in host response against invading pathogens. However, in respiratory diseases, excessive infiltration and activation of neutrophils can lead to tissue damage. Tanimilast-international non-proprietary name of CHF6001—is a novel inhaled phosphodiesterase 4 (PDE4) inhibitor in advanced clinical development for the treatment of chronic obstructive pulmonary disease (COPD), a chronic inflammatory lung disease where neutrophilic inflammation plays a key pathological role. Human neutrophils from healthy donors were exposed to pro-inflammatory stimuli in the presence or absence of tanimilast and budesonide—a typical inhaled corticosteroid drug-to investigate the modulation of effector functions including adherence to endothelial cells, granule protein exocytosis, release of extracellular DNA traps, cytokine secretion, and cell survival. Tanimilast significantly decreased neutrophil-endothelium adhesion, degranulation, extracellular DNA traps casting, and cytokine secretion. In contrast, it promoted neutrophil survival by decreasing both spontaneous apoptosis and cell death in the presence of pro-survival factors. The present work suggests that tanimilast can alleviate the severe tissue damage caused by massive recruitment and activation of neutrophils in inflammatory diseases such as COPD. 相似文献
44.
Anaerobic culture is employed routinely in the primary isolation of periodontal pathogenic bacteria. However, little or no data exist on the relative abilities of the Coy anaerobic chamber (Coy Laboratory Products, Grass Lake, Mich.), the GasPak (Becton Dickinson Microbiology Systems, Cockeysville, Md.), and the AnaeroPack (Mitsubishi Gas Chemical America, Inc., New York, N.Y.) systems to grow important periodontal species, including Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Bacteroides forsythus, Eubacterium species, Campylobacter species, Fusobacterium species, and Peptostreptococcus micros. A total of 78 specimens from advanced periodontitis lesions were collected anaerobically, plated on enriched blood agar medium, and incubated at 35 degrees C for 5 to 7 days in each anaerobic culture system. The three culture systems were equally efficient in isolating Porphyromonas gingivalis and Prevotella intermedia/nigrescens. The Coy anaerobic chamber yielded the highest proportional recoveries of Campylobacter (P = 0.0001; nonparametric analysis of variance) and Eubacterium (P = 0.009). The Coy anaerobic chamber and the GasPak system demonstrated higher proportional recoveries of Bacteroides forsythus (P = 0.0006) and Peptostreptococcus micros (P = 0.0001) than the AnaeroPack system. The AnaeroPack system was most efficient in growing Fusobacterium species (P = 0.0001). Overall, the Coy anaerobic chamber and the GasPak system showed the highest proportional recoveries of putative periodontal pathogens, but the recoveries by the various anaerobic test systems varied considerably from sample to sample. 相似文献
45.
Marco Bortoluzzi Gino Paolucci Giuliano Annibale Bruno Pitteri 《Inorganic chemistry communications》2010,13(8):945-948
By reacting a stoichiometric amount of BPM or Me2BPM (BPM = bis(pyrazol-1-yl)methane, Me2BPM = bis(3,5-dimethylpyrazol-1-yl)methane) with Pd(OAc)2 (OAc = acetate) in CH2Cl2, the new neutral complexes [Pd(OAc)2(BPM)] (1) and [Pd(OAc)2(Me2BPM)] (1Me) were isolated and characterized by NMR and IR spectroscopy. Acidolysis of one Pd-OAc bond of compound 1 by using aqueous perchloric acid in methanol led to the formation of the stable cationic aqua-complex [Pd(OAc)(H2O)(BPM)](ClO4) (2-ClO4). The [Pd(OAc)(H2O)(BPM)]+ cation was obtained also by reacting 1 with trifluoromethanesulfonic acid. NMR studies on inter- and intra-molecular hydrogen bonding of the aqua-ligand have been carried out and the data obtained have been interpreted on the basis of the results of DFT calculations. 相似文献
46.
Manfred Nacken Lina Ma Steffen Heidenreich Gino V. Baron 《Applied catalysis. B, Environmental》2009,88(3-4):292-298
Silicon carbide-based filter elements were catalytically activated to provide filter elements for catalytic tar removal from biomass-derived syngas. The filter element support was coated with CeO2, CaO–Al2O3 and MgO with a specific surface of 7.4, 15.9 and 21.9 m2/g synthesized by exo-templating with activated carbon. Doping of a MgO coated filter element with 60 wt% NiO has led to an increase of the specific surface from 0.15 to 0.21 m2/g, whereas in case of a MgO–Al2O3 coated filter element a decrease from 1.18 to 0.91 m2/g was found. An increase of the NiO loading from 6 to 60 wt% on a MgO coated filter element resulted in an increase of the naphthalene conversion from 91 to 100% at 800 °C and a face velocity of 2.5 cm/s at a naphthalene concentration of 5 g/Nm3 in model biomass gasification gas. In case of a MgO–Al2O3 coated filter element with 60 wt% NiO in addition to complete naphthalene conversion in the absence of H2S, a higher conversion of 66% was found in the presence of 100 ppmv H2S compared to 49% of the MgO–NiO coated filter element. After scaling up of the catalytic activation procedure to a 1520 mm long filter candle, which shows an acceptable differential pressure of 54.9 mbar, 58 and 97% naphthalene conversion was achieved in the presence and absence of H2S, respectively. The calculated WHSV value of 209.6 Nm3 h−1 kg−1 indicates the technical feasibility of a further increase of the catalytic performance by an increase of the NiO loading. 相似文献
47.
Minutolo F Bertini S Betti L Danesi R Gervasi G Giannaccini G Martinelli A Papini AM Peroni E Placanica G Rapposelli S Tuccinardi T Macchia M 《ChemMedChem》2006,1(2):218-224
Herein, we report the synthesis of novel stable analogues of geranylgeranyl diphosphate (GGPP), in which the "natural" all-trans geranylgeranyl portion has been replaced by a (Z,E,E)-geranylgeranyl chain. The change in configuration and consequent change in the relative position of the polar portion with the lipophilic side chain did not improve the properties of the E,E,E analogues in their inhibition of geranylgeranyl protein transferase I (GGTase I). However, a significant level of GGTase I inhibition and selectivity for GGTase I over farnesyl transferase (FTase) was maintained the unsubstituted phosphonoacetamidoxy derivative 4 a. This has shed light on the relative importance of the configuration at the C2=C3 double bond among GGPP derivatives. Moreover, the biological activities of all the compounds reported herein, in particular the preferential FTase inhibitory activity shown by compound 6, were in good agreement with the results of docking analysis. 相似文献
48.
We use a stochastic dynamic programming (SDP) approach to solve the problem of determining the optimal routing policies in a stochastic dynamic network. Due to its long time for solving SDP, we propose three techniques for pruning stochastic dynamic networks to expedite the process of obtaining optimal routing policies. The techniques include: (1) use of static upper/lower bounds, (2) pre-processing the stochastic dynamic networks by using the start time and origin location of the vehicle, and (3) a mix of pre-processing and upper/lower bounds. Our experiments show that while finding optimal routing policies in stochastic dynamic networks, the last two of the three strategies have a significant computational advantage over conventional SDP. Our main observation from these experiments was that the computational advantage of the pruning strategies that depend on the start time of the vehicle varies according to the time input to the problem. We present the results of this variation in the experiments section. We recommend that while comparing the computational performances of time-dependent techniques, it is very important to test the performance of such strategies at various time inputs. 相似文献
49.
Bazzichi L Ciregia F Giusti L Baldini C Giannaccini G Giacomelli C Sernissi F Bombardieri S Lucacchini A 《Proteomics. Clinical applications》2009,3(11):1296-1304
In the last few years, many attempts have been carried out for the research of specific biological biomarkers in fibromyalgia (FM) since, so far, no laboratory tests have been appropriately validated for the diagnosis and the prognostic stratification of the disease. In our study for the first time, we carried out a proteomic analysis of the whole saliva of FM patients in order to evaluate salivary biomarkers. Twenty-two FM patients with all fulfilling the American College of Rheumathology diagnostic criteria for FM and 26 sex-and age-matched healthy subjects were enrolled in the study. Proteomic analysis was performed by combining 2-DE and MALDI-TOF-MS. The most relevant observation which emerged from the data analysis was the exclusive and significant over-expression of transaldolase and phosphoglycerate mutase I. These findings were validated by Western blot analysis and the total optical density confirmed the significant up-regulation of transaldolase and phosphoglycerate mutase I in FM samples with respect to healthy subjects. It was noteworthy that seven further salivary proteins resulted differentially expressed, namely: calgranulin A, calgranulin C, cyclophilin A, profilin 1, Rho GDP-dissociation inhibitor 2, proteasome subunit-α-type-2 and haptoglobin-related protein precursor. These preliminary results demonstrated the utility of salivary proteomic analysis in the identification of salivary biomarkers in FM patients and in clarifying some of the pathogenetic aspects of the disease. 相似文献
50.
Ilbige C. Arik Joeri F. Denayer Gino V. Baron 《Microporous and mesoporous materials》2003,60(1-3):111-124
The influence of the composition and synthesis method on the low-coverage adsorption properties of C5–C9 n-alkanes on ZSM-5 zeolites was studied using the pulse chromatographic technique at temperatures between 200 and 400 °C. Experiments were performed with materials having Si/Al ratios between 12 and 400, synthesized with and without an organic template. For all ZSM-5 samples, the Henry adsorption constants increase exponentially with the carbon number, while zero-coverage adsorption enthalpies increase in a linear way. With decreasing Al content, the Henry constants and adsorption enthalpies decrease. An increase in adsorption enthalpy of 10.1 kJ/mol per added –CH2– group is observed for an Si/Al ratio of 400, while an increase of 12.1 kJ/mol is found for an Si/Al ratio of 15. The contribution to the adsorption entropy per carbon atom depends on the ZSM-5 composition and varies between 11.2 and 14.4 J/(mol K). A significant effect of the synthesis method on the Henry constants, adsorption enthalpies and entropies is observed. All ZSM-5 samples synthesized using organic templates show the same unique relationship between adsorption enthalpy and entropy, different from that of zeolites synthesized without organic template. 相似文献