排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
Andrea Petrella Giuseppe Mascolo Sapia Murgolo Valentina Petruzzelli Ezio Ranieri Danilo Spasiano 《Chemical Engineering Communications》2016,203(10):1298-1307
An innovative pilot plant based on UVB and TiO2 (Anatase) allowed for photocatalytic degradation of organic micro-pollutants. The catalyst was immobilized onto a channel through which the solution containing a target molecule (methylene blue, MB) was re-circulated. Due to the cationic nature of the MB substrate, the adsorption reaction onto the catalyst surface provided a significant contribution to the overall degradation mechanism due to the negatively charged surface at neutral pH (TiO2 pHzpc = 6.8). The influence of the initial MB concentration was investigated in the range 0.3–2.0 mg L?1 with the Langmuir–Hinshelwood (LH) model showing good data correlations at concentrations up to 0.7 mg L?1, whereas at higher concentrations a pure zero-order (catalytic) kinetic trend was observed. Flow rate of the re-circulating solution sensibly influenced kinetics after the larger volumes of liquid exposed to UVB/TiO2 and to the better oxygen saturation in the liquid phase. UV?vis and HPLC-MS/MS experimental determinations allowed for identification of MB residual concentration and by-products. 相似文献
2.
Mecozzi A. Piazzolla S. Sapia A. Spano P. 《Quantum Electronics, IEEE Journal of》1988,24(10):1985-1988
The statistics of the instantaneous frequency fluctuations of CW narrowed-linewidth single-mode semiconductor lasers are studied under the most general conditions. In the case in which the rate equations describing the evolution of the system cannot be linearized the statistics are found to deviate appreciably from a Gaussian distribution. A Monte Carlo simulation is shown to give results in good agreement with previous experimental measurements 相似文献
3.
Lunn C.A.; Fossetta J.; Murgolo N.; Zavodny P. J.; Lundell D.; Narula S.K. 《Protein engineering, design & selection : PEDS》1992,5(3):249-252
We have identified a mutation of human gamma-interferon (IFN)causing a temperature-sensitive phenotype. We used a randomizedoligonucleotide to mutagenize a synthetic human IFN gene, thenscreened the resulting mutants produced in Escherichia colifor proteins with altered biological activity. One mutant proteinselected for detailed characterization exhibited < 0.3% ofthe specific biological activity of native IFN in an antiviralactivity assay performed at 37°C. However, the protein boundthe human IFN receptor with native efficiency at 4°C. Sequencingthe plasmid DNA encoding this protein snowed that the mutationchanged the lysine residue at amino acid 43 to glutamic acid(IFN/K43E). Site-specific mutagenesis at amino acid 43 showedthat this protein's phenotype resulted from positioning a negativecharge at position 43. Structural characterization of IFN/K43Eusing CD demonstrated that the protein had native conformationat 25°C, but assumed an altered conformation at 37°C.IFN/K43E in this altered conformation bound poorly to the IFNreceptor at 37°C, providing a rationale for the mutant'sdecreased antiviral activity. 相似文献
4.
The transient dynamics of nearly single-mode semiconductor lasers is studied analytically and numerically for lasers biased below threshold. The side-mode excitation probability is evaluated by solving a Fokker-Planck equation approximately. The validity of the approximate solution is verified through Monte Carlo simulations of the corresponding Langevin equations. The results show the relevance of the carrier-density overshoot during laser turn-on in determining the side-mode excitation probability. They also indicate the dependence of this probability on various device parameters such as the gain margin between the main and side modes. The experiments performed by using distributed feedback (DFB) semiconductor lasers show qualitative agreement with theory 相似文献
5.
The aim of this work is to investigate the cw-laser crystallization of amorphous a-Si1−xCx alloys as a function of laser power and alloy composition. As the microRaman analysis reveals, many cases occur: in a silicon
rich alloy (x ∼0.3) we can obtain two crystalline phases, i.e. polycrystalline Si or polycrystalline C, depending on the laser
energy density irradiated on the film. The presence of polycrystalline SiC is observed only in quasi-stoichiometric alloy
(x ∼ 0.48) in the cubic β-SiC phase. The experiment has been performed with a laser pattern-writing system that permits simultaneous
control of annealing energy and focused spot size. PC control allows several patterns to be traced on the same film. 相似文献
6.
Cook William J.; Walter Leigh J.; Murgolo Nicholas J.; Chou Chuan-Chu; Petro Mary; Zavodny Paul J.; Narula Satwant K.; Ramanathan Lata; Trotta Paul P.; Nagabhushan Tattanahalli L. 《Protein engineering, design & selection : PEDS》1996,9(7):623-628
The X-ray crystal structure of a rat monoclonal Fab JES1-39D10,raised against recombinant human interleukin-5, has been determinedwith the use of molecular replacement techniques and refinedat 2.7 Å resolution by simulated annealing. The overallstructure is similar to a murine Fab HyHEL-10 that is specificfor hen egg white lysozyme. An interesting feature of the structureis the presence of leucine residues to support the H1 complementarity-determiningregion (CDR) loop. To our knowledge this is the first Fab crystalstructure containing this unusual HI loop support pattern. Theactivity of three humanized versions of 39D10 is explained byanalysis of Fv interface residues and H1 support patterns of39D10 and the human template HLL. 相似文献
7.
R Syto NJ Murgolo EH Braswell P Mui E Huang WT Windsor 《Canadian Metallurgical Quarterly》1998,37(48):16943-16951
Human interleukin 10 (huIL-10) is a cytokine that regulates the synthesis of type 1 helper T cell derived cytokines such as gamma-interferon, interleukin 2, and tumor necrosis factor alpha. The potential immunosuppressive activities of huIL-10 suggest that this protein may be clinically useful for treating autoimmune diseases. Due to the potential clinical value of this cytokine, physicochemical studies have been performed regarding its association state and biological/structural stability. These studies include performing size-exclusion chromatography, chemical cross-linking, equilibrium ultracentrifugation, and circular dichroism spectroscopy. The results indicate huIL-10 is predominantly a noncovalent homodimer at neutral pH and 4 degreesC for concentrations greater than 0.003 mg/mL (0.08 microM dimer). An apparent pKa value of approximately 4.8 was calculated for both the pH-dependent subunit dissociation and pH-induced loss in MC/9 biological activity. A temperature analysis revealed a linear relationship between the percent dimer and relative MC/9 activity, thus, these results and the pH-dependent activity results suggest that the huIL-10 dimer is the active species. The GndHCl-induced unfolding of rhuIL-10, monitored by far-UV circular dichroism, revealed a unique biphasic unfolding process which contained both a subunit dissociation process (<1.6 M GndHCl) as well as the unfolding of a highly alpha-helical monomer intermediate ([GndHCl]1/2 = 3.5 M). The monomer intermediates generated with 1.6 M GndHCl or pH 2.5 retained approximately 80% and 89% of the alpha-helical content of the native protein, respectively. Although a soluble and highly helical monomer state can be generated, the observed correlation between unfolding studies and biological activity suggests the dimer is the active species. These results are consistent with both the recent observation that the three-dimensional structure of rhuIL-10 is a 2-fold symmetric homodimer and that a complex between the extracellular domain of the recombinant human IL-10 receptor and IL-10 is consistent with two IL-10 homodimers and four receptors. 相似文献
8.
Xavier Ekolle Ndode-Ekane Maria del Mar Puigferrat Prez Rossella Di Sapia Niina Lapinlampi Asla Pitknen 《International journal of molecular sciences》2021,22(12)
Traumatic brain injury (TBI) disrupts thalamic and cortical integrity. The effect of post-injury reorganization and plasticity in thalamocortical pathways on the functional outcome remains unclear. We evaluated whether TBI causes structural changes in the thalamocortical axonal projection terminals in the primary somatosensory cortex (S1) that lead to hyperexcitability. TBI was induced in adult male Sprague Dawley rats with lateral fluid-percussion injury. A virus carrying the fluorescent-tagged opsin channel rhodopsin 2 transgene was injected into the ventroposterior thalamus. We then traced the thalamocortical pathways and analyzed the reorganization of their axonal terminals in S1. Next, we optogenetically stimulated the thalamocortical relays from the ventral posterior lateral and medial nuclei to assess the post-TBI functionality of the pathway. Immunohistochemical analysis revealed that TBI did not alter the spatial distribution or lamina-specific targeting of projection terminals in S1. TBI reduced the axon terminal density in the motor cortex by 44% and in S1 by 30%. A nematic tensor-based analysis revealed that in control rats, the axon terminals in layer V were orientated perpendicular to the pial surface (60.3°). In TBI rats their orientation was more parallel to the pial surface (5.43°, difference between the groups p < 0.05). Moreover, the level of anisotropy of the axon terminals was high in controls (0.063) compared with TBI rats (0.045, p < 0.05). Optical stimulation of the sensory thalamus increased alpha activity in electroencephalography by 312% in controls (p > 0.05) and 237% (p > 0.05) in TBI rats compared with the baseline. However, only TBI rats showed increased beta activity (33%) with harmonics at 5 Hz. Our findings indicate that TBI induces reorganization of thalamocortical axonal terminals in the perilesional cortex, which alters responses to thalamic stimulation. 相似文献
9.
Lunn C.A.; Fossetta J.; Dalgarno D.; Murgolo N.; Windsor W.; Zavodny P. J.; Narula S.K.; Lundell D. 《Protein engineering, design & selection : PEDS》1992,5(3):253-257
We identified a single amino acid mutation that abolished thebioactivity of human IFN. The mutation was identified by screeninga mutagenized IFN expression library for molecules with alteredbiological activity. The mutant protein was expressed at highlevels in Escherichia coli, and remained soluble upon purification.However, the protein was completely inactive in all IFN assaysinvestigated, exhibiting < 0.0006% of the specific activityof native IFN antiviral activity. Sequencing the plasmid DNAencoding this mutant protein showed that the histidine at position111 of native human IFN is changed to aspartic acid (IFN/H111D).Other mutations at this site showed that only hydrophobic aminoacids at position 111 maintain significant, though low, biologicalactivity. Structural characterization of the IFN/H111D proteinby NMR as well as CD spectroscopy demonstrated that the proteinhas limited conformational differences from native IFN. Modelsof the X-ray crystal structure of human IFN [Ealick, P.E., W.J.Cook,S.Vijay-Kumar, M.Carson, T.L.Nagabhushan, P.P.Trotta and C.E.Bugg(1991) Science, 252, 698702] suggest that this histidineresidue is located at a severe 55° bend in the C-terminalF helix. We conclude that H111 lies within or affects the receptorbinding domain of human IFN. 相似文献
10.
Irina S. Moreira Sapia Murgolo Giuseppe Mascolo Paula M. L. Castro 《International journal of molecular sciences》2022,23(11)
Endocrine disrupting compounds (EDCs) in the environment are considered a motif of concern, due to the widespread occurrence and potential adverse ecological and human health effects. The natural estrogen, 17β-estradiol (E2), is frequently detected in receiving water bodies after not being efficiently removed in conventional wastewater treatment plants (WWTPs), promoting a negative impact for both the aquatic ecosystem and human health. In this study, the biodegradation of E2 by Rhodococcus sp. ED55, a bacterial strain isolated from sediments of a discharge point of WWTP in Coloane, Macau, was investigated. Rhodococcus sp. ED55 was able to completely degrade 5 mg/L of E2 in 4 h in a synthetic medium. A similar degradation pattern was observed when the bacterial strain was used in wastewater collected from a WWTP, where a significant improvement in the degradation of the compound occurred. The detection and identification of 17 metabolites was achieved by means of UPLC/ESI/HRMS, which proposed a degradation pathway of E2. The acute test with luminescent marine bacterium Aliivibrio fischeri revealed the elimination of the toxicity of the treated effluent and the standardized yeast estrogenic (S-YES) assay with the recombinant strain of Saccharomyces cerevisiae revealed a decrease in the estrogenic activity of wastewater samples after biodegradation. 相似文献