Phase transition in the one-dimensional pair-hopping model with unusual one-electron hopping

By modifying the conventional one-electron hopping behavior, we study effects of an occupation-dependent hopping on the ground state of the half-filled one-dimensional pair-hopping model. At weak coupling, the use of bosonization and renormalization-group analysis techniques helps to derive the phase diagram. Such unusual hopping is shown to drive a spin-gap transition and to introduce a new region where the triplet superconducting instability dominates for positively small pair-hopping interaction.     

基于时序多光谱影像的干旱草原区开采扰动信息提取方法

露天开采会彻底改变原有土地利用景观格局,直接破坏当地生态环境,甚至会影响附近居民的生产和生活,因此越来越多的学者开始关注开采扰动。先前有关利用时序多光谱影像提取开采扰动的研究区集中于扰动形式单一的森林区。而我国露天煤矿大多集中于草原区,且我国东北部的草原矿区因其脆弱的生态环境以及其他多种扰动形式的存在,使得开采扰动识别更加困难。为明确我国东北部生态脆弱区草原露采场的开采扰动,以胜利矿区为例,利用1986年-2017年27期Landsat多光谱遥感影像,基于归一化植被指数NDVI（normalized difference vegetation index）的长时间序列轨迹变化特征（为了去除物候、云和阴影等对时序多光谱影像的影响,利用BISE-WT滤波器对原始NDVI时间序列进行滤波处理, 有效地去除时序NDVI数据中的噪声并同时保留有效信息）,经过样本点训练,获得CV阈值（变异系数coefficient of variation）和Max阈值（植被阈值）,构建CV-Max扰动识别模型,提取研究区的扰动分布。并利用植被阈值,分析NDVI时序轨迹,获得扰动年际信息,重构扰动历史地图;进而通过分析研究区典型地物的光谱特征,构建裸煤提取规则,以此来提取研究区的裸煤分布;最后通过构建裸煤及扰动区两者间的拓扑关系,进行空间拓扑叠置分析,从而获得开采扰动信息。经过精度验证,开采扰动的提取精度达到93.17%（Kappa系数=0.85）,扰动年际信息提取精度达到83.35%（Kappa系数=0.81）。结果表明：在研究期间,空间上,开采扰动面积占研究区总面积的8.90%;时间上,开采扰动的发生集中于2000年-2009年,期间开采扰动像元占开采扰动总像元的76.70%;1988年-1998年矿区属于土地损毁初始期,2000年-2005年矿区属于土地损毁加速期,2006年-2009年矿区属于土地损毁高峰期,2010年-2017年开采扰动像元占比趋势比较平缓且持续处于较低水平,矿区土地损毁范围基本稳定。所提出的针对我国东北部生态脆弱性草原矿区,基于时序多光谱影像,利用植被指数NDVI和裸煤光谱特征提取开采扰动信息的方法是可行的,该研究结果可为干旱、半干旱草原露天矿区的可持续发展提供数据和理论方法支撑。     

Global Pathway Analysis: a hierarchical framework to understand complex chemical kinetics

An automated hierarchical framework, Global Pathway Analysis (GPA), is presented to understand complex chemical kinetics. The behaviour of the reacting system at macro level is bridged to the elementary reaction level by Global Pathways, which are the chemical pathways from an initial reactant species to a final product species. For each Global Pathway, its dominancy and effect on the system, such as those on the production or consumption of radicals, are quantified to understand its contribution to the system. Four examples are presented as demonstration: First, the classical second explosion limit of hydrogen is found to be resulted from the change of dominancy of a pressure-dependent Global Pathway, which consumes radical via H?+?O₂?+?M?=?HO₂?+?M reaction. Next, it is found that the negative temperature coefficient (NTC) regime of n-heptane is resulted from the competition between a low-temperature Global Pathway and a high-temperature Global Pathway. Third, a non-monotonic relation between autoignition delays and toluene ratio in toluene/n-decane mixture is analysed. This automated framework has been placed in public domain. Reduced kinetic models can be generated based on Global Pathways too. Finally, this methodology is demonstrated using DNS simulation results of the extinction and re-ignition of a turbulent non-premixed flame. The differences between simulation results are investigated using two different kinetics models via the analysis of global pathways.     

Green synthesis and chemical characterization of Thymus vulgaris leaf aqueous extract conjugated gold nanoparticles for the treatment of acute myeloid leukemia in comparison to doxorubicin in a leukemic mouse model

Recently, metallic nanoparticles have been used for the treatment of several disorders, such as cancer. Indeed, finding the chemotherapeutic drug of nanoparticles is in researching the priority of both developed and developing countries. The present study confirms the ability of aqueous extract of Thymus vulgaris grown under in vitro condition for the biosynthesis of gold nanoparticles (AuNPs). Also, in this study, we indicated the antioxidant, cytotoxicity, and anti-acute myeloid leukemia properties of AuNPs compared to doxorubicin in a leukemic mouse model. The synthesized AuNPs were characterized using different techniques including X-ray diffraction (XRD), energy Dispersive X-ray Spectrometry (EDS), fourier-transform infrared spectroscopy (FT-IR) spectroscopy, ultraviolet–visible spectroscopy (UV–Vis.), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). In vivo design, induction of acute myeloid leukemia was done by 7,12-Dimethylbenz[a]anthracene (DMBA) in 75 mice. Then, the animals were randomly divided into six subgroups, including control, untreated, doxorubicin, AuNPs, T. vulgaris, and HAuCl₄. By quantitative real-time PCR, sphingosine-1-phosphate receptor-1 and sphingosine-1-phosphate receptor-5 mRNA expression in lymphocytes were significantly (P ≤ 0.01) raised by treating the leukemic mice with the AuNPs and doxorubicin. Also, AuNPs similar to doxorubicin, significantly (P ≤ 0.01) enhanced the anti-inflammatory cytokines (IL4, IL5, IL10, IL13, and IFNα) and the platelet, lymphocyte, and red blood cell (RBC) parameters and reduced the pro-inflammatory cytokines (IL1, IL6, IL12, IL18, IFNY, and TNFα), and the total white blood cell (WBC), blast, monocyte, neutrophil, eosinophil, and basophil counts as compared to the untreated mice. In vitro design, 2,2-diphenyl-1-picrylhydrazyl (DPPH) test revealed similar antioxidant potentials for doxorubicin and AuNPs. Furthermore, AuNPs similar to doxorubicin had low cell viability dose-dependently against 32D-FLT3-ITD, Human HL-60/vcr, and Murine C1498 cell lines without any cytotoxicity on HUVEC cell line. Above results confirm the excellent antioxidant, cytotoxicity, and anti-acute myeloid leukemia effects of AuNPs compared to doxorubicin. After confirming these results in clinical trial studies, AuNPs can be used as a chemotherapeutic drug for the treatment of acute myeloid leukemia in human.     

Novel green synthesis of Boswellia serrata leaf aqueous extract conjugated gold nanoparticles with excellent anti-acute myeloid leukemia property in comparison to mitoxantrone in a leukemic mice model: Introducing a new chemotherapeutic drug

The present research confirms the capacity of aqueous extract of Boswellia serrata grown under in vitro condition for the green synthesis of gold nanoparticles (AuNPs). Also, we showed the cytotoxicity, antioxidant, and anti-acute myeloid leukemia properties of AuNPs compared to mitoxantrone in a leukemic mouse model. The synthesized AuNPs were characterized using several techniques including XRD, TEM, FE-SEM, UV–Vis, and FT-IR. From the XRD pattern, four distinct diffraction peaks at 38.2°, 44.2°, 64.7° and 77.4° are indexed as (111), (200), (220) and (311) planes of FCC metallic gold. TEM and FE-SEM images revealed an average diameters of 15–30 nm for the nanoparticles. FT-IR findings offered antioxidant compounds in the nanoparticles were the sources of reducing power, reducing gold ions to AuNPs. UV–Vis revealed an absorption band at 536 nm that is related to the surface plasmon resonance of AuNPs. In vivo design, induction of acute myeloid leukemia was done by DMBA in 75 mice. Then, the mice were randomly divided into six subgroups, including untreated, control, HAuCl₄, B. serrata, AuNPs, and mitoxantrone. AuNPs (In the dose of 1 mg/kg body weight) similar to mitoxantrone, significantly (p ≤ 0.05) increased the platelet, lymphocyte, and RBC parameters and the anti-inflammatory cytokines (IL4, IL5, IL10, IL13, and IFNα) and reduced the weights and volumes of liver and spleen and their sub-compartment, the total WBC, blast, monocyte, neutrophil, eosinophil, and basophil counts, and the pro-inflammatory cytokines (IL1, IL6, IL12, IL18, IFNY, and TNFα) as compared to the untreated mice. By quantitative Real-Time PCR, S1PR1 and S1PR5 mRNA expression in lymphocytes were significantly (p ≤ 0.05) increased by treating the leukemic mice with the AuNPs and mitoxantrone. In vitro design, AuNPs similar to mitoxantrone had low cell viability dose-dependently against Human HL-60/vcr, 32D-FLT3-ITD, and Murine C1498 cell lines without any cytotoxicity on HUVEC cell line. Besides, the DPPH assay showed similar antioxidant potentials for AuNPs and mitoxantrone. In conclusion, the results of this research indicated the excellent capacity of synthesized gold nanoparticles using B. serrata leaf aqueous extract in the treatment of acute myeloid leukemia in leukemic mice.     

Bogdanov-Takens Bifurcation in a Host-parasitoidModel

In this paper, we study a host-parasitoid model with Holling II Functional response, where we focus on a special case: the carrying capacity K2 for parasitoids is equal to a critical valuer 1η. It is shown that the model can undergo Bogdanov-Takens bifurcation. The approximate expressions forsaddle-node, Homoclinic and Hopf bifurcation curves are calculated. Numerical simulations, including bifurcation diagrams and corresponding phase portraits, are also given to illustrate the theoretical results.     

Exact solution of the two-mode quantum Rabi model

An analytical method is developed to study the two-mode quantum Rabi model. For certain specific parameter conditions, especially for the resonant conditions, we obtain an infinite number of the exact solutions of the eigenfunctions and associated energies. It is shown that there exist new types of the exact energies which do not correspond to the level-crossings. Our analytical method may find applications in some related models.     

化学实验操作技能测试评分者效应研究*

基于Rasch模型对化学实验操作技能测试的评分者效应开展研究。通过对Infit、Outfit、t、怀特图和宽严度波动图等的分析,研究测试中评委的宽严度、内部一致性、外部一致性以及评委与考生间的偏差规律。得到系列减弱化学实验操作技能测试中评分者效应的建议。     

On log-normal convolutions: An analytical–numerical method with applications to economic capital determination

We put forward an efficient algorithm for approximating the sums of independent and log-normally distributed random variables. Namely, by combining tools from probability theory and numerical analysis, we are able to compute the cumulative distribution functions of the just-mentioned sums to a high precision and in a relatively short computing time. We illustrate the effectiveness of the new method in the contexts of the individual and collective risk models, aggregate economic capital determination, and economic capital allocation.     

Mechanical effects of acupuncture

Acupuncture, a physiotherapy, has been widely accepted all around the world. This study focuses on the influence of membrane structures and explains the acupuncture sensations from the aspect of mechanical properties. By mathematical modeling and numerical simulation, the scientific meaning of the acupuncture depth is investigated and phenomena and theory of acupuncture are discussed. The simulation results show that (a) the fascial structure is the main contributor to the force on the needle, the axial force will gradually increase before piercing the fascial, and suddenly decrease after piercing the fascial; (b) there is an inverse relationship between the needle radius and the maximum radial stress, which indicates that the needle should not be too sharp to cause local stress concentration and piece the fascia layer; and (c) the simulation results of comprehensively considering the static friction and sliding friction is identical with the experiment results. This study proposes a preliminary study of mechanical effects of acupuncture manipulation, clarifies key factors affecting the stress on the needle, and explains the objective requirement of acupuncture depth to effective treatment.