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In this article, we study the evolution of immersed locally convex plane curves driven by anisotropic flow with inner normal velocity V=1αψ(x)καV=\frac{1}{\alpha }\psi \left(x){\kappa }^{\alpha } for α1\alpha \gt 1, where x∈[0,2mπ]x\in \left[0,2m\pi ] is the tangential angle at the point on evolving curves. For −1≤α1\alpha \gt 1, we show only type I singularity arises in the flow, and the rescaled flow has subsequential convergence, i.e. for any time sequence, there is a time subsequence along which the rescaled curvature of evolving curves converges to a limit function; furthermore, if the anisotropic function ψ\psi and the initial curve both have some symmetric structure, the subsequential convergence could be refined to be full-time convergence.

BACKGROUND The extractable state of soil heavy metal elements is an important index to measure their bioavailability, but its content changes with soil acid-base properties and other environmental conditions. When determining which method to use for the extractable state of soil heavy metal elements, there are more than 7 kinds of extraction reagents involved in relevant standard methods or technical specifications. These include hydrochloric acid of pH=5.8, 0.1mol/L hydrochloric acid, 0.43±0.02mol/L nitric acid, 0.11mol/L acetic acid, 1mol/L ammonium nitrate solution, 0.005mol/L DTPA leaching agent, 0.01mol/L calcium chloride solution. Different scholars have different research conclusions on different extractants. There is no systematic research report on extractants suitable for different soil types. OBJECTIVES To select and determine the general extractant suitable for the extractable state of heavy metal elements in soil with different acid-base properties. METHODS Using typical farming soil samples as the research objective, 7 kinds of extracting agent were used to extract 8 heavy metals (Cd, Ni, Cu, Zn, Cr, Pb, As and Hg). Inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine Cd, Cr, Cu, Pb, Zn, Ni, whereas atomic fluorescence spectrometry (AFS) was used to determine As and Hg. The extraction rates of 7 kinds of extractants were compared, and the effects of soil acid and alkali properties on the extraction rate of heavy metal elements were studied. RESULTS Dilute acid solution had a strong ability of leaching heavy metals from soil, and it was not related to the acidity and alkalinity of the soil. Although the extraction ability of 1mol/L ammonium nitrate solution for cadmium indicated that the activity of cadmium in acidic soil was much higher than that in alkaline soil, its extraction rate of lead in alkaline soil was higher than that of cadmium. The extraction rate of DTPA extractant for soil heavy metal elements was significantly higher than that of 0.01mol/L calcium chloride solution, especially for lead, copper and zinc. Moreover, the extraction rate of DTPA extractant for soil heavy metal elements did not change significantly with soil acid-base properties. 0.01mol/L calcium chloride solution had the highest extraction rate of cadmium in soil, which was closely related to the acid-base properties of soil. CONCLUSIONS 0.01mol/L calcium chloride solution is an ideal general extractant for the extractable state of soil heavy metal elements.

In the tumor microenvironment, tumor-infiltrating immune cells (TIICs) are a key component. Different types of TIICs play distinct roles. CD8+ T cells and natural killer (NK) cells could secrete soluble factors to hinder tumor cell growth, whereas regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) release inhibitory factors to promote tumor growth and progression. In the meantime, a growing body of evidence illustrates that the balance between pro- and anti-tumor responses of TIICs is associated with the prognosis in the tumor microenvironment. Therefore, in order to boost anti-tumor response and improve the clinical outcome of tumor patients, a variety of anti-tumor strategies for targeting TIICs based on their respective functions have been developed and obtained good treatment benefits, including mainly immune checkpoint blockade (ICB), adoptive cell therapies (ACT), chimeric antigen receptor (CAR) T cells, and various monoclonal antibodies. In recent years, the tumor-specific features of immune cells are further investigated by various methods, such as using single-cell RNA sequencing (scRNA-seq), and the results indicate that these cells have diverse phenotypes in different types of tumors and emerge inconsistent therapeutic responses. Hence, we concluded the recent advances in tumor-infiltrating immune cells, including functions, prognostic values, and various immunotherapy strategies for each immune cell in different tumors.

Abstract Background Nattokinase is a fibrinolytic enzyme that has huge market value as a nutritional supplement for health promotion. In order to increase nattokinase yields, fermentation conditions, strains, cultivation media, and feeding strategies have been optimized. Nattokinase has been expressed using several heterologous expression systems. Pichia pastoris heterologous expression system was the alternative. Results This report aimed to express high levels of nattokinase from B. subtilis natto (NK-Bs) using a Pichia pastoris heterologous expression system and assess its fibrinolytic activity in vivo. Multicopy expression strains bearing 1–7 copies of the aprN gene were constructed. The expression level of the target protein reached a maximum at five copies of the target gene. However, multicopy expression strains were not stable in shake-flask or high-density fermentation, causing significant differences in the yield of the target protein among batches. Therefore, P. pastoris bearing a single copy of aprN was used in shake-flask and high-density fermentation. Target protein yield was 320 mg/L in shake-flask fermentation and approximately 9.5 g/L in high-density fermentation. The recombinant nattokinase showed high thermo- and pH-stability. The present study also demonstrated that recombinant NK-Bs had obvious thrombolytic activity. Conclusions This study suggests that the P. pastoris expression system is an ideal platform for the large-scale, low-cost preparation of nattokinase.

Based on the theory of the existing research of the project portfolio management, the paper analyzes the key factors of the project portfolio selection, and evaluates them using the fuzzy comprehensive evaluation method. Finally, the paper builds a project portfolio choice integer programming model based on 0/1 integer programming, which is based on the organizations strategies.

Rare earth elements (REEs) in ore have many different forms, mainly ion adsorption and mineral lattice types. The occurrence state of rare earth elements has a great impact on accurate analysis. In this study, the effects of different pretreatment methods in REEs analysis are discussed from the perspective of REEs occurrence states in ore. Four pretreatment methods including HCl-HNO3-HF-HClO4 under normal pressure (the open acid digestion), HCl-HNO3-HF-HClO4-H2SO4 under normal pressure (the open acid digestion, adding sulfuric acid), HF-HNO3 in confining pressure (the pressurized acid digestion) as well as NaOH-Na2O2 alkali fusion were conducted for REEs ores. 15 rare earth elements were determined by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The results of the open HCl-HNO3-HF-HClO4 acid digestion for the two National Standard Substances (GBW 07161, GBW 07188) which are ion adsorption-type rare earth ores, are significantly lower, mostly 10%-20% lower than certified values. Meanwhile, the results from the pressurized acid digestion, the open HCl-HNO3-HF-HClO4-H2SO4 acid digestion and alkaline fusion are in agreement with certified values. For the two Baiyun Ebo REEs ore samples (SS-1 and BY-1) which are mineral lattice-type, results from all three acid digestions are lower than those from alkaline fusion. The results of the open HCl-HNO3-HF-HClO4 acid digestion are the lowest, approximately 20% lower than those from alkaline fusion, and results of the open HCl-HNO3-HF-HClO4-H2SO4 acid digestion and the pressurized acid digestion essentially are as low as approximately 5%-15%. In summary, for ion adsorption-type rare earth ores, the the open HCl-HNO3-HF-HClO4-H2SO4 acid digestion and pressurized acid digestion could replace the traditional alkaline fusion, while for mineral lattice-type rare earth ores, the most suitable pretreatment method is still alkaline fusion.

Based on the analysis of traditional state maintenance strategy and big data-based state maintenance strategy, this paper builds a transformer state duration simulation model based on Monte Carlo method and builds an annual cost model based on the running state of the transformer. Finally, a typical case is selected to simulate a time series of 8760 hours of transformer operation under two operational inspection strategies, and the annual cost is calculated separately. The example shows that the annual cost of the transformer is lower under the big data-based inspection strategy.

The Large High Altitude Air Shower Observatory (LHAASO) is a new hybrid array for very high energy gamma ray astronomy and cosmic ray physics. The KM2A array, one of the main parts of LHAASO, covers an area of 1.3 km2 to observe gamma rays above 10 TeV up to 1 PeV for many sources. A prototype with 1% the size of the whole KM2A has been in stable operation for more than two years. A Monte Carlo simulation program named G4KM2A was developed; based on this work, the trigger rate, hit multiplicity, angular and core reconstruction are compared with KM2A prototype data. Finally, the moon shadow with -6.5 significance was obtained. The G4KM2A simulation results are consistent with KM2A prototype data and can be used for the whole KM2A array in future.

A two-species model with variable population interactions and harvesting on one of the species is studied. Existence and stability of equilibria and existence of periodic solutions are established, existence of some bifurcation phenomena are analytically and numerically studied, explicit threshold values are computed to determine the kind of interaction ( mutualism, competition, host-parasite) between the two species. A brief discussion on the influence of the harvesting function on the dynamics of the model is also included.