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131.
Razavi Seyedeh Saleheh Hashemianzadeh Seyed Majid Karimi Hedayat 《Journal of molecular modeling》2011,17(5):1163-1172
Canonical Monte Carlo (CMC) simulations were carried out to investigate the behavior of CO2 and N2 mixtures upon adsorption on single walled carbon nanotubes (CNTs). In the simulation, all the particle–particle interactions
between CO2, N and C were modeled using Lennard-Jones (LJ) potential. To provide deep insight into the effect of pore width, temperature,
pressure and bulk composition on the adsorption behavior of CO2 /N2 mixtures, five different CNTs [(6,6), (7,7), (8,8) (9,9) and (10,10) CNT] with diameters ranging from 0.807 to 1.35 nm, three
temperatures (300 323 and 343 K), six pressures (0.15, 2, 4, 6, 8 and 10 MPa), and three bulk mole compositions of carbon
dioxide (0.3 0.5 and 0.7) were tested. The results from all the simulation conditions investigated in this work show that
CNTs preferentially adsorb carbon dioxide relative to nitrogen in a binary mixture. The results are consistent with the hypothesis
that stronger interaction of one component with the nanotube surface results in a higher adsorption capacity compared to the
other component. An optimized pore size of D = 8.07 nm corresponding to (6, 6) CNT, at T = 300 K and P = 0.15 MPa at a bulk
mole composition of yCO2 =0.3 was identified in which carbon nanotubes demonstrate the greatest selectivity for separation of carbon dioxide relative
to nitrogen. In addition, it is worth pointing out that, under similar simulation conditions, CNTs exhibit higher selectivity
compared to other carbon-based materials [carbon membrane polyimide (PI) and PI/multi-wall carbon nanotubes (MWCNTs)] for
CO2 adsorption. As a prototype, the selectivity of an equimolar mixture of CO2 /N2 for adsorption on (6, 6) CNTs at 300 K and 0.15 MPa reaches 9.68, which is considerably larger than that reported in carbon
membrane. Therefore, it can be concluded that carbon nanotubes can act as a capable adsorbent for adsorption/desorption of
CO2 in comparison with other carbon-based materials in the literature. 相似文献
132.
Brewer's spent grain (BSG) was used as a solid substrate for the production of α-amylase by Bacillus sp. KR-8104 in a submerged fermentation system. The production of α-amylase was maximized through statistical optimization of the BSG concentration and incubation time using the Doehlert experimental design. The highest tested amount of BSG (5%, w/v) in the optimization process resulted in a 5.1-fold enhancement of the response. Subsequently, we studied the role of the water-soluble and -insoluble fractions of BSG in the production of α-amylase. The results revealed that whole BSG had a greater effect on the production of α-amylase than each fraction had separately. Finally, when we examined the potential of BSG to replace the constituents of a medium formula, we observed that simultaneously adding BSG, omitting dextrin, and reducing the other ingredients concentration in the culture medium improved the production of α-amylase and made the production process more economical. 相似文献
133.
Tavaré R Sagoo P Varama G Tanriver Y Warely A Diebold SS Southworth R Schaeffter T Lechler RI Razavi R Lombardi G Mullen GE 《PloS one》2011,6(5):e19662
Dendritic cells (DCs) generated in vitro to present tumour antigens have been injected in cancer patients to boost in vivo anti-tumour immune responses. This approach to cancer immunotherapy has had limited success. For anti-tumour therapy, delivery and subsequent migration of DCs to lymph nodes leading to effective stimulation of effector T cells is thought to be essential. The ability to non-invasively monitor the fate of adoptively transferred DCs in vivo using magnetic resonance imaging (MRI) is an important clinical tool to correlate their in vivo behavior with response to treatment. Previous reports of superparamagnetic iron oxides (SPIOs) labelling of different cell types, including DCs, have indicated varying detrimental effects on cell viability, migration, differentiation and immune function. Here we describe an optimised labelling procedure using a short incubation time and low concentration of clinically used SPIO Endorem to successfully track murine DC migration in vivo using MRI in a mouse tumour model. First, intracellular labelling of bone marrow derived DCs was monitored in vitro using electron microscopy and MRI relaxometry. Second, the in vitro characterisation of SPIO labelled DCs demonstrated that viability, phenotype and functions were comparable to unlabelled DCs. Third, ex vivo SPIO labelled DCs, when injected subcutaneously, allowed for the longitudinal monitoring by MR imaging of their migration in vivo. Fourth, the SPIO DCs induced the proliferation of adoptively transferred CD4(+) T cells but, most importantly, they primed cytotoxic CD8(+) T cell responses to protect against a B16-Ova tumour challenge. Finally, using anatomical information from the MR images, the immigration of DCs was confirmed by the increase in lymph node size post-DC injection. These results demonstrate that the SPIO labelling protocol developed in this study is not detrimental for DC function in vitro and in vivo has potential clinical application in monitoring therapeutic DCs in patients with cancer. 相似文献
134.
Smukler SR Arntfield ME Razavi R Bikopoulos G Karpowicz P Seaberg R Dai F Lee S Ahrens R Fraser PE Wheeler MB van der Kooy D 《Cell Stem Cell》2011,8(3):281-293
The search for putative precursor cells within the pancreas has been the focus of extensive research. Previously, we identified rare pancreas-derived multipotent precursor (PMP) cells in the mouse with the intriguing capacity to generate progeny in the pancreatic and neural lineages. Here, we establish the embryonic pancreas as the developmental source of PMPs through lineage-labeling experiments. We also show that PMPs express insulin and can contribute to multiple pancreatic and neural cell types in vivo. In addition, we have isolated PMPs from adult human islet tissue that are also capable of extensive proliferation, self-renewal, and generation of multiple differentiated pancreatic and neural cell types. Finally, both mouse and human PMP-derived cells ameliorated diabetes in transplanted mice. These findings demonstrate that the adult mammalian pancreas contains a population of insulin(+) multipotent stem cells and suggest that these cells may provide a promising line of investigation toward potential therapeutic benefit. 相似文献
135.
Anderson NL Razavi M Pearson TW Kruppa G Paape R Suckau D 《Journal of proteome research》2012,11(3):1868-1878
We have investigated the precision of peptide quantitation by MALDI-TOF mass spectrometry (MS) using six pairs of proteotypic peptides (light) and same-sequence stable isotope labeled synthetic internal standards (heavy). These were combined in two types of dilution curves spanning 100-fold and 2000-fold ratios. Coefficients of variation (CV; standard deviation divided by mean value) were examined across replicate MALDI spots using a reflector acquisition method requiring 100?000 counts for the most intense peak in each summed spectrum. The CV of light/heavy peptide centroid peak area ratios determined on four replicate spots per sample, averaged across 11 points of a 100-fold dilution curve and over all six peptides, was 2.2% (ranging from 1.5 to 3.7% among peptides) at 55 fmol total (light + heavy) of each peptide applied per spot, and 2.5% at 11 fmol applied. The average CV of measurements at near-equivalence (light = heavy, the center of the dilution curve) for the six peptides was 1.0%, about 17-fold lower CV than that observed when five peptides were ratioed to a sixth peptide (i.e., a different-sequence internal standard). Response curves across the 100-fold range were not completely linear but could be closely modeled by a power law fit giving R(2) values >0.998 for all peptides. The MALDI-TOF MS method was used to determine the endogenous level of a proteotypic peptide (EDQYHYLLDR) of human protein C inhibitor (PCI) in a plasma digest after enrichment by capture on a high affinity antipeptide antibody, a technique called stable isotope standards and capture by anti-peptide antibodies (SISCAPA). The level of PCI was determined to be 770 ng/mL with a replicate measurement CV of 1.5% and a >14?000-fold target enrichment via SISCAPA-MALDI-TOF. These results indicate that MALDI-TOF technology can provide precise quantitation of high-to-medium abundance peptide biomarkers over a 100-fold dynamic range when ratioed to same-sequence labeled internal standards and enriched to near purity by specific antibody capture. The robustness and throughput of MALDI-TOF in comparison to conventional nano-LC-MS technology could enable currently impractical large-scale verification studies of protein biomarkers. 相似文献
136.
137.
Salehi H Karbalaie K Salamian A Kiani A Razavi S Nasr-Esfahani MH Baharvand H 《Stem cell research》2012,8(1):120-133
Limitations to the in vivo study of human nervous system development make it necessary to design an in vitro model to evaluate the in vivo effects of surrounding tissues on neurogenesis and regional identity of the human neural plate. Rostral neural progenitors (NPs) were initially generated from adherent human embryonic stem cells (hESCs) in a defined condition and characterized. Then, to find the role of somites (S) and notochords (N) in rostro-caudal (RC) and dorso-ventral (DV) patterning of neuronal cells, NPs were co-cultured with microencapsulated chicken S or N in alginate beads. In this study, N induced more neurogenesis as evaluated by expression of TUJ1 and MAP2-positive cells. Additionally, N induced spinal cord ventral brachiothoracic identity as well as NPs proliferation. We observed a synergic effect on motoneuron induction when S and N were used together. Moreover, S induced hindbrain identity in differentiated neuronal cells from NPs. These results indicate that highly enriched NPs can be generated in an adherent and defined system from hESCs. Moreover, S and N tissues highly influenced neuronal differentiation in point of proliferation, neurogenesis, and RC and DV regional identity. These results indicate a very simple and efficient protocol to mimic in vivo events of human neural development in vitro which is important in the context of developmental neuroscience and cellular replacement therapies. 相似文献
138.
Seyed Mehdi Razavi Saber Zahri Gholamreza Zarrini Hossein Nazemiyeh Sariyeh Mohammadi 《Russian Journal of Bioorganic Chemistry》2009,35(3):376-378
Cytotoxic, phytotoxic, antimicrobial and antioxidant effects of quercetin 3-O-glucoside (Q3G) isolated by HPLC from aerial parts of Prangos ferulaceae was studied by MTT assay, lettuce germination assay, disk diffusion and DPPH method. Our results showed that Q3G exhibits
high antioxidant effect with RC50 of 22 μg/mL, it has low cytotoxicity and no antibacterial effects. Q3G exhibits high phytotoxic effect with IC50 value of 282.7 μg/ml, as well. It is assumed that Q3G does not play a defense role in plants and it may act as an allelopatic
agent.
The article is published in the original. 相似文献
139.
Yehia G Schlotter F Razavi R Alessandrini A Molina CA 《The Journal of biological chemistry》2001,276(38):35272-35279
Inducible cAMP early repressor (ICER) is an important mediator of cAMP antiproliferative activity that acts as a putative tumor suppressor gene product. In this study, we examined the regulation of ICER protein by phosphorylation and ubiquitination in human choriocarcinoma JEG-3 and mouse pituitary AtT20 cells. We found that cAMP stabilized ICER protein by inhibiting the mitogen-activated protein kinase (MAPK) cascade. Activation of the MAPK pathway increased ICER phosphorylation. ICER phosphorylation was abrogated by inhibition of the MAPK pathway either by cAMP or directly by the MAPK inhibitor PD098059. The MAPKs extracellular signal-regulated kinases 1 and 2 physically interact with ICER and mediated the phosphorylation of ICER on a critical serine residue (Ser-41). A mutant form of ICER in which Ser-41 was substituted by alanine had a half-life 4-5 h longer than its wild-type counterpart. This alteration in stability was due to the inability of the Ser-41-mutant ICER to be efficiently ubiquitinated and degraded via the ubiquitin-proteasome pathway. These results present a novel cell signaling cross-talk mechanism at the cell nucleus between the MAPK and cAMP pathways, whereby MAPK targets a repressor of the cAMP-dependent gene expression for ubiquitination and proteasomal degradation. 相似文献
140.
Saadatzadeh MR Bijangi-Vishehsaraei K Hong P Bergmann H Haneline LS 《The Journal of biological chemistry》2004,279(16):16805-16812
Fanconi anemia is a genetic disorder characterized by bone marrow failure. Significant evidence supports enhanced apoptosis of hematopoietic stem/progenitor cells as a critical factor in the pathogenesis of bone marrow failure in Fanconi anemia. However, the molecular mechanism(s) responsible for the apoptotic phenotype are incompletely understood. Here, we tested whether alterations in the activation of a redox-dependent pathway may participate in the pro-apoptotic phenotype of primary Fancc -/- cells in response to oxidative stress. Our data indicate that Fancc -/- cells are highly sensitive to oxidant stimuli and undergo enhanced oxidant-mediated apoptosis compared with wild type controls. In addition, antioxidants preferentially enhanced the survival of Fancc -/- cells. Because oxidative stress activates the redox-dependent ASK1 pathway, we assessed whether Fancc -/- cells exhibited increased oxidant-induced ASK1 activation. Our results revealed ASK1 hyperactivation in H2O2-treated Fancc -/- cells. Furthermore, using small interfering RNAs to decrease ASK1 expression and a dominant negative ASK1 mutant to inhibit ASK1 kinase activity, we determined that H2O2-induced apoptosis was ASK1-dependent. Collectively, these data argue that the predisposition of Fancc -/- hematopoietic stem/progenitor cells to apoptosis is mediated in part through altered redox regulation and ASK1 hyperactivation. 相似文献