6 research outputs found

    Purification and In Situ Immobilization of Papain with Aqueous Two-Phase System

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    Papain was purified from spray-dried Carica papaya latex using aqueous two-phase system (ATPS). Then it was recovered from PEG phase by in situ immobilization or preparing cross-linked enzyme aggregates (CLEAs). The Plackett-Burman design and the central composite design (CCD) together with the response surface methodology (RSM) were used to optimize the APTS processes. The highly purified papain (96–100%) was achieved under the optimized conditions: 40% (w/w) 15 mg/ml enzyme solution, 14.33–17.65% (w/w) PEG 6000, 14.27–14.42% (w/w) NaH2PO4/K2HPO4 and pH 5.77–6.30 at 20°C. An in situ enzyme immobilization approach, carried out by directly dispersing aminated supports and chitosan beads into the PEG phase, was investigated to recover papain, in which a high immobilization yield (>90%) and activity recovery (>40%) was obtained. Moreover, CLEAs were successfully used in recovering papain from PEG phase with a hydrolytic activity hundreds times higher than the carrier-bound immobilized papain

    Study on the deformation behavior of AZ31B-O magnesium alloy with the VPSC model

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    The mechanical anisotropy of the magnesium alloy AZ31B-O was investigated using the Viscoplastic-Self-Consistent (VPSC)-Twinning and Detwinning (TDT) model. The anisotropic behavior of the material under uniaxial strain was studied using five distinct sheet orientations. In order to investigate the mechanical behavior under uniaxial compression, four alternative specimen orientations were employed. The VPSC model with the TDT mechanism was used to simulate the uniaxial tension and compression experiments. For tensile strain, the magnesium alloy samples were mainly regulated by base slip and prismatic slip. In compression of magnesium alloy samples, it was dominated by basal slip and {10–12} twinning. In all compression specimens, the grain c-axes are parallel to the compression axis regardless of the initial orientation. The r-values under different uniaxial strain paths have been also predicted by using the VPSC-TDT model. The negative r-values under uniaxial compression along RD to TD were further explained. The contribution of {10–12} twinning to plastic strain and the extra hardening induced by {10–12} extension twinning were discussed in depth. This study confirms that the extra hardening induced by {10–12} extension twinning will perform an important function when the twin volume fraction reaches a degree of about 50% with the active pyramidal slip at the same time

    Effectiveness of EGFR-TKIs versus Chemotherapy as First-line Treatment for Advanced Non-small Cell Lung Cancer: A Meta-analysis

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    Background and objective Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) has been used for the first-line treatment of non-small cell lung cancer (NSCLC) and has shown good clinical effects. However, some patients fail to benefit from this treatment. The aim of this study is to analyze whether or not clinical-selected patients (Asian, adenocarcinoma histology, non-smoking) and EGFR mutation-selected patients benefit from EGFR-TKIs or chemotherapy. Our results could be used as basis to guide clinical therapy. Methods Randomized controlled trials evaluating the efficacy of EGFR-TKIs versus chemotherapy as first-line treatments of NSCLC were obtained from electronic databases, namely, PubMed, Embase, American Society of Clinical Oncology (ASCO), European Society for Medical Oncology, and China Biology Medicine disc. Assessment, data collection, and statistical analysis were performed according to Cochrane Handbook 5.1.0. Results A total of 14 randomized controlled trials with 5,000 patients were included in this study. Compared with the chemotherapy group, EGFR-TKI therapy group in EGFR mutation-selected NSCLC patients showed a higher response rate (RR=2.31; 95%CI: 1.88-2.84) and more significant improvement in progression free survival (PFS; HR=0.39; 95%CI: 0.30-0.49); by contrast, no significant difference was observed in overall survival (OS; HR=0.99; 95%CI: 0.84-1.16). The response rate of clinical-selected patients treated with EGFR-TKI significantly increased (RR=1.30; 95%CI: 1.15-1.47) compared with that of the patients treated with chemotherapy; PFS (HR=0.93; 95%CI: 0.58-1.49) and OS (HR=0.91; 95%CI: 0.81-1.02) of the two groups did not significantly differ. Likewise, the PFS and the OS of the unselected patients in the EGFR-TKI treatment group and the chemotherapy group did not significantly differ, although the OS of the former was shorter than that of the latter. Conclusion EGFR mutation-selected patients received more benefits from EGFR-TKI first-line treatment than other treatments. First-line EGFR-TKI treatment was recommended for clinically selected patients who were unsuitable for themotherapy. By comparison, first-line EGFR-TKI treatment was not a suitable choice for unselected patients

    Design and Verification of a Double-Grating Spectrometer System (DGSS) for Simultaneous Observation of Aerosols, Water Vapor and Clouds

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    Simultaneous observation of aerosols, water vapor, and clouds is conducive to the analysis of their interactions, and the consistency of observation equipment, instrument performance, and observation time is crucial. Molecular oxygen A-band (758–778 nm) and water vapor absorption band (758–880 nm) are two bands with similar wavelengths, and the hyperspectral remote sensing information of these two bands can be exploited to invert the vertical profile of aerosol and water vapor. In this paper, a double-grating spectrometer system (DGSS) was developed. DGSS uses a telescope system and fiber to introduce multi-angle, double-band sunlight, and it splits light synchronously (non-sequentially) to different positions of the detector through a slit plate and two gratings. The DGSS was calibrated in the laboratory and observed in the external field. The results indicated that the spectral resolution reached 0.06 nm (molecular oxygen A-band, 758–778 nm) and 0.24 nm (water vapor absorption band, 758–880 nm). Meanwhile, the spectra of the two bands (three angles in each band) are not aliased on the detector. Besides, the multi-angle simultaneous observation of the high-resolution spectra of the two bands is realized, which proves the effectiveness of this method. This study will provide a scientific basis for the observation of aerosol, water vapor, and cloud ground-based networks

    A Transmissive Imaging Spectrometer for Ground-Based Oxygen A-Band Radiance Observation

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    The oxygen A-band (759–770 nm) is a commonly used band for atmospheric observations. The signal in this band has wide dynamic range and can be used to invert several atmospheric parameters, such as air pressure and atmospheric optical depth, at different altitudes. High-resolution oxygen A-band radiance imaging spectrometer (HARIS) is an imaging spectrometer that operates in the oxygen A-band, which is designed for the observation of the direct solar radiance that passes through the atmosphere. HARIS is a transmissive imaging spectrometer that uses a compact transmissive optical system combined with reflective grating spectroscopy, while an area scan CMOS detector is used as the photosensitive element for the observations. HARIS response is associated with the observed target through a calibration process, which uses a monochromator with a supercontinuum laser for the spectral calibration, an integrating sphere with a spectrophotometer for the radiometric calibration and a meridian for the geometric calibration is employed to correct for distortions. The calibration results show that HARIS has an average spectral resolution of 0.33 nm and a field-of-view of 3.085 × 0.03° with an average spatial sampling interval of 0.0138°. Finally, the performance of HARIS is verified through field tests, in which the solar radiance data with an average signal-to-noise ratio of 438.93 is obtained
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