Search

The effect of temperature (T) on stability of squeezed soybean oil (SSO) were studied by four characterization parameters (CPs, conductivity, peroxide value, isovolumetric combustion heat and acid value)similarities and differences of CPs characterization results were further compared.Under the fixed conditions of relative humidity was 40%, partial pressure of oxygen was 21 kPa, illumination was 800 lx and initial headspace rate was 50%, regulated and controled T to 30 ℃, 40 ℃, 50 ℃, 60 ℃ and 70 ℃ respectively,SSO test samples were oxidized continuously in airtight container for a long time, four CPs at different oxidation time (t) were multiple measured in the same time, curve of CP～t was plotted, kinetic equation was regressed, rate constant (k) and apparent activation energy were calculated, the prediction model of metamorphic time was established and coincidence rate was verified.The results show that CP changed significantly with the increase of T and the extension of t, the oxidative rancidity of SSO has characteristic of simple series reaction,the prediction model of metamorphic time has a good coincidence, CP was different, and there was a big difference in k.The stability of squeezed soybean oil of SSO should be described by multiple CPs.

One popular method for dealing with large-scale data sets is sampling. For example, by using the empirical statistical leverage scores as an importance sampling distribution, the method of algorithmic leveraging samples and rescales rows/columns of data matrices to reduce the data size before performing computations on the subproblem. This method has been successful in improving computational efficiency of algorithms for matrix problems such as least-squares approximation, least absolute deviations approximation, and low-rank matrix approximation. Existing work has focused on algorithmic issues such as worst-case running times and numerical issues associated with providing high-quality implementations, but none of it addresses statistical aspects of this method. In this paper, we provide a simple yet effective framework to evaluate the statistical properties of algorithmic leveraging in the context of estimating parameters in a linear regression model with a fixed number of predictors. In particular, for several versions of leverage-based sampling, we derive results for the bias and variance, both conditional and unconditional on the observed data. We show that from the statistical perspective of bias and variance, neither leverage-based sampling nor uniform sampling dominates the other. This result is particularly striking, given the well-known result that, from the algorithmic perspective of worst-case analysis, leverage-based sampling provides uniformly superior worst-case algorithmic results, when compared with uniform sampling. Based on these theoretical results, we propose and analyze two new leveraging algorithms: one constructs a smaller least-squares problem with "shrinkage" leverage scores (SLEV), and the other solves a smaller and unweighted (or biased) least-squares problem (LEVUNW). A detailed empirical evaluation of existing leverage-based methods as well as these two new methods is carried out on both synthetic and real data sets. The empirical results indicate that our theory is a good predictor of practical performance of existing and new leverage-based algorithms and that the new algorithms achieve improved performance. For example, with the same computation reduction as in the original algorithmic leveraging approach, our proposed SLEV typically leads to improved biases and variances both unconditionally and conditionally (on the observed data), and our proposed LEVUNW typically yields improved unconditional biases and variances.

Objective To describe the characteristics of commercial sexual behavior of HIV-infected men who have sex with men (MSM) and analyze its influencing factors. Methods An anonymous questionnaire survey was conducted through the recruitment of HIV-infected MSM by two social organizations in Chongqing. The x² test was used to compare the commercial sexual behavior of HIV infected with MSM with different social demographic characteristics, mental health status, and sexual behavioral characteristics. Multivariate Logistic regression model was used to analyze the influencing factors of commercial behavior. Results A total of 1 501 cases of HIV infection with MSM were investigated in this study. In total 12.50% of the respondents reported same-sex commercial sex in the past six months, of which 28.34% reported unprotected commercial sex behavior. The results of multivariate Logistic regression showed HIV-infected MSM with marital status as marriage/cohabitation (OR =2.345, 95%CI: 1.442-3.814), working status as part-time and others (OR=6.522, 95%CI: 3.575-11.900), monthly income exceeding 5 000 yuan (OR=7.890, 95%CI: 4.254-14.634), age of first sexual intercourse less than 18 years old (OR= 1.818, 95%CI: 1.014-3.260), using same-sex dating software (using one: OR=2.984, 95%CI: 1.477-6.030; using two: OR = 3.683, 95%C$: 1.650-8.221; using 3 and above: OR=21.777, 95%CI: 8.349-56.804), drinking (0R=2.528, 95%C$: 1.5684.074), and using Rush (OR=3.114, 95%CI: 1.988-4.877) were more likely to have commercial sexual behavior (P < 0.05). Conclusion The commercial sexual behavior of HIV infection with MSM is common in Chongqing, and the proportion of commercial sexual behavior without condom is high_ Comprehensive measures should be taken to intervene the drinking, Rush use, and commercial sexual behavior of this population in order to reduce the further spread of HIV/STIs. [ABSTRACT FROM AUTHOR]

Pulmonary arterial hypertension (PAH) is a life‐threatening disease characterised by elevated pulmonary pressure, right ventricular failure (RVF) and ultimately death. Aggressive treatment of RVF is considered an important therapeutic strategy to treat PAH. Previous studies have indicated that betaine may be may a promising therapeutic approach for PAH‐induced RVF. Therefore, in this study, betaine solution for injection was prepared and characterised using various techniques. The therapeutic efficacy of three different methods of administration (intragastric, nebulised inhalation and intravenous injection) were comprehensively evaluated in terms of pharmacokinetics, tissue distribution and pharmacodynamics. The pharmacokinetic results demonstrated that betaine injection administered via nebulised inhalation significantly prolonged betaine's half‐life and increased its internal circulation time compared to the intragastric and intravenous routes. Biodistribution experiments verified that the betaine formulation accumulated in the lung tissue when administered via inhalation. The results of the pharmacodynamic analysis further confirmed that right ventricular systolic pressure, mean pulmonary artery pressure and right ventricular hypertrophy index increased in the model group and that inhaled betaine suppressed these pathological changes to a level comparable to those observed in the control group. Taken together, these results indicate that betaine administered by inhalation is a promising strategy for the treatment of PAH‐induced RVF. [ABSTRACT FROM AUTHOR]