ABSTRACT
Queuing is common in urban public places. Automatically monitoring and predicting queuing time can not only help individuals to reduce their wait time and alleviate anxiety but also help managers to allocate resources more efficiently and enhance their ability to address emergencies. This paper proposes a novel method to estimate and predict queuing time in indoor environments based on WiFi positioning data. First, we use a series of parameters to identify the trajectories that can be used as representatives of queuing time. Next, we divide the day into equal time slices and estimate individuals' average queuing time during specific time slices. Finally, we build a nonstandard autoregressive (NAR) model trained using the previous day's WiFi estimation results and actual queuing time to predict the queuing time in the upcoming time slice. A case study comparing two other time series analysis models shows that the NAR model has better precision. Random topological errors caused by the drift phenomenon of WiFi positioning technology (locations determined by a WiFi positioning system may drift accidently) and systematic topological errors caused by the positioning system are the main factors that affect the estimation precision. Therefore, we optimize the deployment strategy during the positioning system deployment phase and propose a drift ratio parameter pertaining to the trajectory screening phase to alleviate the impact of topological errors and improve estimates. The WiFi positioning data from an eight-day case study conducted at the T3-C entrance of Beijing Capital International Airport show that the mean absolute estimation error is 147 s, which is approximately 26.92% of the actual queuing time. For predictions using the NAR model, the proportion is approximately 27.49%. The theoretical predictions and the empirical case study indicate that the NAR model is an effective method to estimate and predict queuing time in indoor public areas.
ABSTRACT
OBJECTIVE: To extract and purify of solamargine from Solanum nigrum, and to research its antineoplastic effects. METHOD: S. nigrum was extracted refluently with 80% alcohol, solamargine was purified with silica gel column chromatography and recrystallization, and then conducted its structure identification and purity checks. Screened the effect on human tumor cell groth inhibition in vitro by MTT assay, and researched on the features in mice with H22 liver cancer or Ehrlich ascites tumor of solamargine. RESULT: The concent of solamargine reached 97.9%. Solamargine had significantly inhibition on 6 tumor cells in vitro, and it had significantly inhibition on mice with H22 liver cancer or ehrlich ascites tumor in the 2.4 mg x kg(-1) dose of i.v. CONCLUSION: Solamargine have the antineoplastic effect.
Subject(s)
Antineoplastic Agents, Phytogenic/isolation & purification , Solanaceous Alkaloids/isolation & purification , Solanaceous Alkaloids/pharmacology , Animals , Cell Line, Tumor , Female , Humans , Mice , Mice, Inbred ICRABSTRACT
A sensitive and simple liquid chromatography-mass spectrometry (LC-MS) method has been developed and validated for the quantification of solamargine, a steroidal glycoalkaloid, in rat plasma. Vincristine was selected as the internal standard. Sample preparation involved simple liquid-liquid extraction by ethyl acetate with high efficiency. The chromatographical separation was performed on a Shimadzu C(18) column (150mm×2.0mm, 5µm) with a gradient elution of acetonitrile and 0.02% (v/v) formic acid. The elutes were detected under positive electrospray ionization (ESI) and the target analytes quantified by selected ion monitoring (SIM) mode. The method was sensitive with the lowest limit of quantitation (LLOQ) at 0.5ng/mL in 50µL of rat plasma. Good linearity (r(2)=0.9996) was obtained covering the concentration of 0.5-2000.0ng/mL. The intra- and inter-day assay precision ranged from 2.87 to 3.60% and 0.52 to 6.81%, respectively. In addition, the stability, extraction recovery and matrix effect involved in the method were also validated. The practical utility of the aforementioned method was successfully confirmed in the pharmacokinetic evaluation of solamargine in Sprague-Dawley rats after intravenous administration.
Subject(s)
Chromatography, Liquid/methods , Mass Spectrometry/methods , Solanaceous Alkaloids/pharmacokinetics , Animals , Calibration , Chemistry Techniques, Analytical , Chemistry, Pharmaceutical/methods , Formates/chemistry , Models, Chemical , Rats , Rats, Sprague-Dawley , Reproducibility of Results , Spectrometry, Mass, Electrospray Ionization/methods , Vincristine/chemistryABSTRACT
OBJECTIVE: To optimize the extraction conditions of the total amino acid from Bubali Cornu. METHOD: An orthogonal test of L9 (3(4)) was designed to select optimum exaction conditions of the total amino acid. The influence of solvent concentration, the dosage of solvent and time of extraction were investigated with the content of total amino acid and thrombin-induced fibrin clotting time as index. RESULT: The optimum extraction condition procedure was described as follows: the concentration of the solvent was 4 mol x L(-1), volume of solvent was 6 times amount of the materials. CONCLUSION: The optimum exaction conditions procedure is reasonable and stable.
