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关键词： 三次参数Hermite插值保形   光顺   导数振荡   应变能   极小化  

摘要： 由于分段三次参数Hermite插值的切矢往往被作为变量,故可对其进行优化以使得构造的插值曲线满足特定的要求.为了构造兼具保形性与光顺性的平面分段三次参数Hermite插值曲线,给出了一种通过同时极小化导数振荡和应变能来确定切矢的方法,首先以导数振荡函数和应变能函数为双目标建立了切矢满足的方程系统;然后证明了方程系统存在唯一解,并给出了解的具体表达式;最后给出了误差分析,并通过数值算例表明方法的有效性.结果表明,相对于导数振荡极小化方法和应变能极小化方法,所提出的导数振荡和应变能极小化方法同时兼顾了平面分段三次参数Hermite插值曲线的保形性和光顺性.

关键词： 函数与不等式   导数   函数的单调性   高三数学   展望  

摘要： 高三数学复习备考,涉及"函数与不等式"的复习内容很多,为了高效复习备考,文章从回顾2021年高考数学试卷(仅限于使用广泛的6套全国卷)中"函数与不等式"内容的试题入手,结合课程标准分析其规律,进而展望2022年高考数学试卷(全国卷)中"函数与不等式"内容试题的特点.

关键词： 洛必达法则   微分   未定式  

摘要： 洛必达法则是微分学的重要内容,是解析求极限类问题的重要方法之一。学生在学习和应用洛必达法则时,对洛必达法则未定式的类型和应用过程中的注意事项较为模糊,且部分教师在讲授和证明洛必达法则时存在一定的误区,导致学生在解析微分相关问题时,难以灵活运用洛必达法则。简单介绍了洛必达法则的主要内容,分析了洛必达法则在教学和运用中的误区,详细阐述了洛必达法则在解析求极限类问题中的具体应用,并提出了相关注意事项。

关键词： photothermal therapy   thermal dose   immunogenicity   immunogenic cell death   Prussian blue nanoparticles   neuroblastoma   nanoimmunotherapy   MYCN amplification  

摘要： Simple Summary Photothermal therapy (PTT) is an effective thermal therapy for treating tumors. PTT has been combined with immunotherapy in various preclinical cancer models showing promising treatment outcomes. However, in these studies, PTT has primarily been utilized for maximizing tumor cell death. Previously, we observed that based on the "thermal dose" applied, PTT can generate dramatically different responses from the immune system when tested in cellular and animal models. Here, we sought to provide a framework to systematically assess the effect of PTT-based thermal doses on the immunogenic correlates of treated tumors as a measure of the effectiveness of PTT in eliciting an antitumor immune response. In human neuroblastoma tumor cells in vitro, we determined specific phenotypic markers, which demonstrated that SH-SY5Y cells were more responsive to PTT-based thermal dose compared with LAN-1 cells, which possess a high-risk phenotype. Our findings suggest the importance of conducting tumor thermal dose-responsiveness studies in vitro as an early measure of PTT effectiveness against a specific tumor. Photothermal therapy (PTT) is an effective method for tumor eradication and has been successfully combined with immunotherapy. However, besides its cytotoxic effects, little is known about the effect of the PTT thermal dose on the immunogenicity of treated tumor cells. Therefore, we administered a range of thermal doses using Prussian blue nanoparticle-based photothermal therapy (PBNP-PTT) and assessed their effects on tumor cell death and concomitant immunogenicity correlates in two human neuroblastoma cell lines: SH-SY5Y (MYCN-non-amplified) and LAN-1 (MYCN-amplified). PBNP-PTT generated thermal dose-dependent tumor cell killing and immunogenic cell death (ICD) in both tumor lines in vitro. However, the effect of the thermal dose on ICD and the expression of costimulatory molecules, immune checkpoint molecules, major histocompatibility complexes, an NK cell-acti

关键词： Capacitors   Voltage control   Substations   HVDC transmission   Trajectory   Multilevel converters   Reactive power   Flatness   high-voltage direct current (HVdc)   modular multilevel converter (MMC)   multilevel inverter   nonlinear control   power converter   state-input linearization   trajectory planning  

摘要： Modular multilevel converter (MMC) is an attractive topology in industrial applications such as high-voltage direct current (HVdc) transmission system where fast power control is required. The most conventional control method for MMC uses cascaded structures, where the power transmission and internal energy dynamic (outer loops) is limited by the ``frequency separation'' constraints since the dynamic choice of the currents (inner loops) must consider the tradeoff between rapidity and robustness. In this article, we present a new control method based on a differential flatness theory. The main interest of the proposed control is the possibility to obtain a very high dynamic performance of the MMC power flow, even under noisy measurements and parametric disturbances. Using the well-known average model of the MMC, a flat output is proposed, proving the differential flatness property of the MMC. Trajectory tracking controllers of ac grid active and reactive power are proposed using input-state full-order linearization. Simulation results, including losses corresponding to a realistic case of on-shore, point-to-point HVdc interconnection, are presented to show the performance of the proposed control scheme even with strong measurement noise.

摘要： Background: The association between fine particulate matter (PM2.5) and mortality widely differs between as well as within countries. Differences in PM2.5 composition can play a role in modifying the effect estimates, but there is little evidence about which components have higher impacts on mortality. Methods: We applied a 2-stage analysis on data collected from 210 locations in 16 countries. In the first stage, we estimated location-specific relative risks (RR) for mortality associated with daily total PM2.5 through time series regression analysis. We then pooled these estimates in a metaregression model that included city-specific logratio-transformed proportions of seven PM2.5 components as well as meta-predictors derived from city-specific socio-economic and environmental indicators. Results: We found associations between RR and several PM2.5 components. Increasing the ammonium (NH4+) proportion from 1% to 22%, while keeping a relative average proportion of other components, increased the RR from 1.0063 (95% confidence interval [95% CI] = 1.0030, 1.0097) to 1.0102 (95% CI = 1.0070, 1.0135). Conversely, an increase in nitrate (NO3-) from 1% to 71% resulted in a reduced RR, from 1.0100 (95% CI - 1.0067, 1.0133) to 1.0037 (95% CI = 0.9998, 1.0077). Differences in composition explained a substantial part of the heterogeneity in PM2.5 risk. Conclusions: These findings contribute to the identification of more hazardous emission sources. Further work is needed to understand the health impacts of PM2.5 components and sources given the overlapping sources and correlations among many components.

关键词： reliability-based design   differential settlement   angular distortion   total settlement   foundation design  

摘要： The serviceability limit state (SLS) design of foundations typically proceeds by limiting the total settlement of individual foundations and thereby attempting to restrict the differential settlement between pairs of foundations. Due to the uncertain nature of the supporting ground, the magnitude of settlement and differential settlement are random. As it is often the differential settlement that governs serviceability, it is desirable to provide design requirements that suitably restrict differential settlements. This paper investigates, by Monte Carlo simulation, the distribution of the maximum differential settlement between pairs of foundations as a function of the spacing between foundations and the number of foundations - groups of four, nine, or 16 foundations, arranged on a grid - are considered. The effects of the correlations between the equivalent stiffness of the ground under each foundation, as well as between the loads applied to the foundations, on the distribution of the maximum differential settlements and angular distortions are investigated. Ratios of resistance factor to resistance bias factor are presented that can be used to calibrate design requirements on the total settlement of individual foundations that also simultaneously achieve acceptable performance with respect to angular distortion.

关键词： gastroesophageal reflux disease   liquid chromatography tandem mass spectrometry (UPLC-MS   MS)   quantification method   bile acids   proton pump inhibitor  

摘要： Goals: The aim was to measure bile acids in human saliva using a sensitive ultraperformance liquid chromatography tandem mass spectrometry analysis method to distinguish quantitative differences in refractory gastroesophageal reflux disease (GERD) patients as compared with proton pump inhibitor (PPI) controlled GERD patients and healthy volunteers. Study: Human saliva samples were analyzed from 2 separate studies. The first a meal-controlled pilot, in which premeal and postmeal saliva samples were analyzed from 20 healthy subjects and 20 patients with GERD symptoms controlled by PPIs. In a subsequent exploratory study, saliva was collected from 34 patients with continuing GERD symptoms despite PPI treatment (refractory GERD), 30 healthy subjects, and 30 PPI-controlled GERD patients at >= 4 hours postmeal. Results: In the meal-controlled pilot study, both healthy subjects and patients with PPI-controlled GERD, had total saliva bile acid increase for the first hour after consumption of a meal and returned to baseline levels 4 hours later. There was no difference in bile acid levels between the 2 groups. In the exploratory study, the saliva from patients with refractory GERD had statistically significant higher levels of total bile acid concentration compared with those of healthy volunteers and patients with PPI-controlled GERD (P=0.0181). Conclusions: Bile acids can be detected and accurately quantitated in human saliva using a sensitive ultraperformance liquid chromatography tandem mass spectrometry assay. Increases above threshold could indicate an underlying disease. This method could potentially be used to evaluate biliary reflux as an underlying pathophysiology of refractory GERD.

关键词： Vestibular migraine   Vertigo   Migraine   Dizziness   Diagnosis  

摘要： Background Vestibular migraine (VM) is considered the most common cause of spontaneous episodic vertigo and the second most common cause of vertigo. However, without a biomarker or a complete understanding of the pathophysiology, VM remains underrecognized and underdiagnosed. Therefore, definite diagnostic criteria are urgently needed. Meanwhile, VM should be clearly differentiated from other similar diseases. This paper may help clinicians improve the diagnostic rate of VM and reduce the rate of misdiagnosis. A PubMed search was performed using the following terms: vestibular migraine, migraine-associated vertigo/dizziness, migraine-related vertigo, migraine-related vestibulopathy, benign recurrent vertigo, vertiginous migraine, migraine, headache, vertigo, dizziness, and diagnosis. This paper also summarizes the diagnostic criteria and differential diagnoses of VM. The diagnosis of VM is based on the symptoms, degree, frequency, and duration of the vestibular episodes, a history of migraine, and the temporal association of migraine symptoms with vestibular episodes in at least 50% of cases, while ruling out what may be due to other reasons. In addition to vestibular symptoms and migraine, transient auditory symptoms, nausea, vomiting, and susceptibility to motion sickness may also be associated with VM. Thus, VM should be differentiated from other diseases such as Meniere's disease, benign paroxysmal positional vertigo, migraine with brainstem aura, vestibular neuritis, posterior circulation ischemia, multiple lacunar infarction, vestibular paroxysmia, motion sickness, and episodic ataxia type 2. Conclusion Only if the diagnostic criteria of VM and differential diagnosis can be mastered clearly, we can make a definite diagnosis and treat patients properly.