24,945 research outputs found
Effect of nanoliposomes on the stabilization of incorporated retinol
Nanoliposomes containing retinol were prepared, and the stability of the incorporated retinol was evaluated. Average particle size of nanoliposomes was 98 nm. Retinol was readily incorporated into nanoliposomes with incorporation efficiencies higher than 99%. The bare retinol in the buffer was almost degraded within 2 days of storage, while at least, over 20% of the initial retinol in nanoliposomes was kept until 8 days in all experimental conditions tested. The incorporated retinol in nanoliposomes was more rapidly degraded as temperature increases under both dark and UV light condition during the whole period of storage, and UV light slightly decreased the stability of retinol in nanoliposomes.Key words: Retinol, nanoliposome, stability
Characterization of volatile organic compounds at a roadside environment in Hong Kong: An investigation of influences after air pollution control strategies
Vehicular emission is one of the important anthropogenic pollution sources for volatile organic compounds (VOCs). Four characterization campaigns were conducted at a representative urban roadside environment in Hong Kong between May 2011 and February 2012. Carbon monoxide (CO) and VOCs including methane (CH4), non-methane hydrocarbons (NMHCs), halocarbons, and alkyl nitrates were quantified. Both mixing ratios and compositions of the target VOCs show ignorable seasonal variations. Except CO, liquefied petroleum gas (LPG) tracers of propane, i-butane and n-butane are the three most abundant VOCs, which increased significantly as compared with the data measured at the same location in 2003. Meanwhile, the mixing ratios of diesel- and gasoline tracers such as ethyne, alkenes, aromatics, halogenated, and nitrated hydrocarbons decreased by at least of 37%. The application of advanced multivariate receptor modeling technique of positive matrix factorization (PMF) evidenced that the LPG fuel consumption is the largest pollution source, accounting for 60 ± 5% of the total quantified VOCs at the roadside location. The sum of ozone formation potential (OFP) for the target VOCs was 300.9 μg-O3 m-3, which was 47% lower than the value of 567.3 μg-O3 m-3 measured in 2003. The utilization of LPG as fuel in public transport (i.e., taxis and mini-buses) contributed 51% of the sum of OFP, significantly higher than the contributions from gasoline- (16%) and diesel-fueled (12%) engine emissions. Our results demonstrated the effectiveness of the switch from diesel to LPG-fueled engine for taxis and mini-buses implemented by the Hong Kong Special Administrative Region (HKSAR) Government between the recent ten years, in additional to the execution of substitution to LPG-fueled engine and restrictions of the vehicular emissions in compliance with the updated European emission standards
Phosphorylation of Ser78 of Hsp27 correlated with HER-2/neu status and lymph node positivity in breast cancer
<p>Abstract</p> <p>Background</p> <p>Abnormal amplification/expression of HER-2/<it>neu </it>oncogene has been causally linked with tumorigenesis and metastasis in breast cancer and associated with shortened overall survival of patients. Recently, heat shock protein 27 (Hsp27) was reported to be highly expressed in HER-2/<it>neu </it>positive tumors and cell lines. However, putative functional links between phosphorylation of Hsp27 with HER-2/<it>neu </it>status and other clinicopathological features remain to be elucidated.</p> <p>Results</p> <p>Comparative phosphoproteomic studies of HER-2/<it>neu </it>positive and -negative breast tumors revealed that Hsp27, one of the identified phosphoproteins, was highly phosphorylated in HER-2/<it>neu </it>positive tumors. The extent of Hsp27 phosphorylation at its Ser<sup>15</sup>, Ser<sup>78 </sup>and Ser<sup>82 </sup>residues were further evaluated with site-specific antibodies in tumor samples by tissue lysate array- and tissue microarray-based analyses, and in the BT474 breast cancer cell line treated with heregulin α1 (HRG α1) or the p38 MAPK inhibitor, SB203580. The tissue lysate array study indicated that only the level of pSer<sup>78 </sup>in HER-2/<it>neu </it>positive tumors was more than 2-fold that in HER-2/<it>neu </it>negative tumors. Treatment of BT474 cells with HRG α1 and SB203580 indicated that Ser<sup>78 </sup>phosphorylation was mainly regulated by the HER-2/<it>neu</it>-p38 MAPK pathway. Immunohistochemical staining of sections from a tissue microarray with 97 breast tumors showed that positive staining of pSer<sup>78 </sup>significantly correlated with HER-2/<it>neu </it>(<it>p </it>= 0.004) and lymph node positivity (<it>p </it>= 0.026).</p> <p>Conclusion</p> <p>This investigation demonstrated the significant correlation of enhanced phosphorylation of the Ser<sup>78 </sup>residue of Hsp27 with HER-2/<it>neu </it>and lymph node positivity in breast cancer.</p
General Steady-State Analysis and Control Principle of Electric Springs With Active and Reactive Power Compensations
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Real-time estimation of lane-based queue lengths at isolated signalized junctions
In this study, we develop a real-time estimation approach for lane-based queue lengths. Our aim is to determine the numbers of queued vehicles in each lane, based on detector information at isolated signalized junctions. The challenges involved in this task are to identify whether there is a residual queue at the start time of each cycle and to determine the proportions of lane-to-lane traffic volumes in each lane. Discriminant models are developed based on time occupancy rates and impulse memories, as calculated by the detector and signal information from a set of upstream and downstream detectors. To determine the proportions of total traffic volume in each lane, the downstream arrivals for each cycle are estimated by using the Kalman filter, which is based on upstream arrivals and downstream discharges collected during the previous cycle. Both the computer simulations and the case study of real-world traffic show that the proposed method is robust and accurate for the estimation of lane-based queue lengths in real time under a wide range of traffic conditions. Calibrated discriminant models play a significant role in determining whether there are residual queued vehicles in each lane at the start time of each cycle. In addition, downstream arrivals estimated by the Kalman filter enhance the accuracy of the estimates by minimizing any error terms caused by lane-changing behavior.postprin
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