Alleviated photoinhibition on nitrification in the Indian Sector of the Southern Ocean

Nitrification,a central process in the marine nitrogen cycle,produces regenerated nitrate in the euphotic zone and emits N_(2)O,a potent greenhouse gas as a by-product.The regulatory mechanisms of nitrification in the Southern Ocean,which is a critical region for CO_(2)sequestration and radiative benefits,remain poorly understood.Here,we investigated the in situ and dark nitrification rates in the upper 500 m and conducted substrate kinetics experiments across the Indian Sector in the Cosmonaut and Cooperation seas in the late austral summer.Our findings indicate that light inhibition of nitrification decreases exponentially with depth,exhibiting a light threshold of 0.53%photosynthetically active radiation.A positive relationship between dark nitrification and apparent oxygen utilization suggests a dependence on substrate availability from primary production.Importantly,an increased NH_(4)^(+) supply can act as a buffer against photo-inhibitory damage.Globally,substrate affinity(α)increases with depth and transitions from light to dark,decreases with increasing ambient NH_(4)^(+)and exhibits a latitudinal distribution,reflecting substrate utilization strategies.We also reveal that upwelling in Circumpolar Deep Water(CDW)stimulates nitrification through the introduction of potentially higher iron and deep diverse nitrifying microorganisms with higherα.We conclude that although light is the primary limiting factor for nitrification in summer,coupling between substrate availability and CDW upwelling can overcome this limitation,thereby alleviating photoinhibition by up to 45%±5.3%.

多体非完全经典态的基于Affinity的关联测度

在量子信息理论中,量子关联是一种极其重要的物理资源。文章首先定义了多体非完全经典态基于Affinity的一种量子关联测度,它可以量化多体非完全经典态的关联程度;接下来证明了该关联测度满足量子关联度的一些必要物理性质,包括非负性、局部酉操作下的不变性、局部量子操作下的单调性、凸性以及连续性。

New insights into the deposition of natural gas hydrate on pipeline surfaces:A molecular dynamics simulation study

Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH blockages.Previous studies suggested the water film can greatly increase hydrate adhesion in gas-dominant system.Herein,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion surfaces.Specifically,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film exists.As water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate deposition.While absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Fe<Fe_(2)O_(3)<FeO<Fe_(3)O_(4)).This is because the detachment of deposited hydrate prefers to occur at soft region of liquid layer,the process of which becomes harder as liquid layer vanishes.As a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant system.Overall,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces.

Diamond-based electron emission:Structure,properties and mechanisms

Diamond has an ultrawide bandgap with excellent physical properties,such as high critical electric field,excellent thermal conductivity,high carrier mobility,etc.Diamond with a hydrogen-terminated(H-terminated)surface has a negative electron affinity(NEA)and can easily produce surface electrons from valence or trapped electrons via optical absorption,thermal heating energy or carrier transport in a PN junction.The NEA of the H-terminated surface enables surface electrons to emit with high efficiency into the vacuum without encountering additional barriers and promotes further development and application of diamond-based emitting devices.This article reviews the electron emission properties of H-terminated diamond surfaces exhibiting NEA characteristics.The electron emission is induced by different physical mechanisms.Recent advancements in electron-emitting devices based on diamond are also summarized.Finally,the current challenges and future development opportunities are discussed to further develop the relevant applications of diamond-based electronemitting devices.

Accelerating Factor Xa inhibitor discovery with a de novo drug design pipeline

Small-molecule drugs are essential for maintaining human health. The objective of this study is to identify a molecule that can inhibit the Factor Xa protein and be easily procured. An optimization-based de novo drug design framework, Drug CAMD, that integrates a deep learning model with a mixed-integer nonlinear programming model is used for designing drug candidates. Within this framework, a virtual chemical library is specifically tailored to inhibit Factor Xa. To further filter and narrow down the lead compounds from the designed compounds, comprehensive approaches involving molecular docking,binding pose metadynamics(BPMD), binding free energy calculations, and enzyme activity inhibition analysis are utilized. To maximize efficiency in terms of time and resources, molecules for in vitro activity testing are initially selected from commercially available portions of customized virtual chemical libraries. In vitro studies assessing inhibitor activities have confirmed that the compound EN300-331859shows potential Factor Xa inhibition, with an IC_(50)value of 34.57 μmol·L^(-1). Through in silico molecular docking and BPMD, the most plausible binding pose for the EN300-331859-Factor Xa complex are identified. The estimated binding free energy values correlate well with the results obtained from biological assays. Consequently, EN300-331859 is identified as a novel and effective sub-micromolar inhibitor of Factor Xa.

Fixed-Time Antidisturbance Consensus Tracking for Nonlinear Multiagent Systems With Matching and Mismatching Disturbances

In this paper,fixed-time consensus tracking for mul-tiagent systems(MASs)with dynamics in the form of strict feed-back affine nonlinearity is addressed.A fixed-time antidistur-bance consensus tracking protocol is proposed,which consists of a distributed fixed-time observer,a fixed-time disturbance observer,a nonsmooth antidisturbance backstepping controller,and the fixed-time stability analysis is conducted by using the Lyapunov theory correspondingly.This paper includes three main improvements.First,a distributed fixed-time observer is developed for each follower to obtain an estimate of the leader’s output by utilizing the topology of the communication network.Second,a fixed-time disturbance observer is given to estimate the lumped disturbances for feedforward compensation.Finally,a nonsmooth antidisturbance backstepping tracking controller with feedforward compensation for lumped disturbances is designed.In order to mitigate the“explosion of complexity”in the tradi-tional backstepping approach,we have implemented a modified nonsmooth command filter to enhance the performance of the closed-loop system.The simulation results show that the pro-posed method is effective.

Complexation process and binding parameters of curcumin and short amylose with V7-type helix structure

Pre-formed V7-type short amylose(SA)could interact with curcumin to form inclusion complex(IC)thereby to improve the stability of curcumin.However,the complexation mechanism of V7-type SA and curcumin is not clear,which limit the improvement of inclusion efficiency.To obtain a starch nanocarrier with high loading capacity,the encapsulation process and interaction parameters of V7-type SA-curcumin IC was studied.The analysis results demonstrated that stoichiometric ratio value of the SA-curcumin complex was around 1.V7-type SA performed excellently in the delivery of curcumin attributing to their high loading capacity(over 20%).It was found that curcumin could enter into the pre-formed helical cavity of SA to form an IC.The conformation change of SA caused the reduction in the interaction ratio in the last 20 ns of simulation.However,SA and curcumin always remained complexation status during the simulation.Hydrogen bonds(H-bonds)and hydrophobic interaction were the most critical acting forces involved in the formation and stability of V7-type SA-curcumin complex.Molecular docking presented that H-bonds interaction between curcumin ligand and V7-type SA chain(O3 at the 25th glucose unit,and O6 at the 17th and 20th glucose units)were found.Furthermore,the hydrophobic interactions were discovered between curcumin ligand and SA chain(18th,19th,21st,22nd and 23rd glucose units).

An Algorithm for Short-Circuit Current Interval in Distribution Networks with Inverter Type Distributed Generation Based on Affine Arithmetic

During faults in a distribution network,the output power of a distributed generation(DG)may be uncertain.Moreover,the output currents of distributed power sources are also affected by the output power,resulting in uncertainties in the calculation of the short-circuit current at the time of a fault.Additionally,the impacts of such uncertainties around short-circuit currents will increase with the increase of distributed power sources.Thus,it is very important to develop a method for calculating the short-circuit current while considering the uncertainties in a distribution network.In this study,an affine arithmetic algorithm for calculating short-circuit current intervals in distribution networks with distributed power sources while considering power fluctuations is presented.The proposed algorithm includes two stages.In the first stage,normal operations are considered to establish a conservative interval affine optimization model of injection currents in distributed power sources.Constrained by the fluctuation range of distributed generation power at the moment of fault occurrence,the model can then be used to solve for the fluctuation range of injected current amplitudes in distributed power sources.The second stage is implemented after a malfunction occurs.In this stage,an affine optimization model is first established.This model is developed to characterizes the short-circuit current interval of a transmission line,and is constrained by the fluctuation range of the injected current amplitude of DG during normal operations.Finally,the range of the short-circuit current amplitudes of distribution network lines after a short-circuit fault occurs is predicted.The algorithm proposed in this article obtains an interval range containing accurate results through interval operation.Compared with traditional point value calculation methods,interval calculation methods can provide more reliable analysis and calculation results.The range of short-circuit current amplitude obtained by this algorithm is slightly larger than those obtained using the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Therefore,the proposed algorithm has good suitability and does not require iterative calculations,resulting in a significant improvement in computational speed compared to the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Furthermore,the proposed algorithm can provide more reliable analysis and calculation results,improving the safety and stability of power systems.

在复二维仿射锥上的完备余齐性一Kahler度量

In this paper,we revisit the Kahler structures on the affine quadrics M1={z_(1)^(2)+z_(2)^(2)+z_(3)^(2)=1}in the paper by Bo Yang and Fang-Yang Zheng.We found that the Kahler structures on the complex surface are more complicated than what they have thought.We shall also give some detail calculations and found that our results fit quite well with earlier papers of the first author,one of them with X.X.Chen.

A Remark on the Affine Coordinates for KdV Tau-Functions

We give a proof of an explicit formula for affine coodinates of points in the Sato’s infinite Grassmannian corresponding to tau-functions for the KdV hierarchy.

Effect of Freeze-Thaw and Urea in Solubility of GPC3-Csub Protein Expressed in Escherichia coli

Glypican-3 is a protein encoded by the Glypican-3 gene located on human X chromosome (Xq26), composed of two subunits, a 40 kDa N-terminal subunit, and a 30 kDa C-terminal subunit. Glypican-3 is a currently potential target molecule for liver cancer treatments because of its over-expression and growth effects on hepatocellular carcinoma (HCC). This study examined the expression and purification of a C-terminal subunit of Glypican-3 protein (GPC3-Csub) due to its application in both diagnosis and therapy for hepatocellular carcinoma. The gene encoding for GPC3-Csub was successfully cloned into plasmid pET28a fused with an affinity tag composed of six consecutive histidine residues (His-tag). Recombinant protein GPC3-Csub was expressed in Escherichia coli BL21 (DE3) in the condition of adding 3% ethanol with IPTG induction. GPC3-Csub was extracted using repeated freeze-thaw cycles with lysozyme, and inclusion bodies were solubilized by 8M Urea, SDS 10% in pH 12. His-tag fused GPC3-Csub proteins allowed it to be purified by affinity chromatography method using the Nickel-nitrilotriacetic acid (Ni-NTA) column. High expression of GPC3-Csub was confirmed by Coomassie staining and western-blot. GPC3-Csub could be isolated with a Ni-NTA column and have a purity of about 90%.

Strategies for Enhancing the Affinity of College Ideological and Political Course Teachers

This article aims to explore effective ways to enhance the affinity of ideological and political course teachers in universities.By analyzing the connotation of affinity,the factors that affect the affinity of ideological and political course teachers are analyzed,and corresponding improvement strategies are proposed.Research suggests that strengthening the construction of teacher ethics and conduct,improving teaching skills,enhancing emotional engagement,and enhancing practical training are key paths to enhance the affinity of ideological and political course teachers.The implementation of these paths will help improve the teaching quality and effectiveness of ideological and political courses,and promote the comprehensive development of students.

Heteroclinic Cycles in a Class of 3-Dimensional Piecewise Affine Systems

This paper explores the existence of heteroclinic cycles and corresponding chaotic dynamics in a class of 3-dimensional two-zone piecewise affine systems. Moreover, the heteroclinic cycles connect two saddle foci and intersect the switching manifold at two points and the switching manifold is composed of two perpendicular planes.

一种基于仿射变换的SURF图像配准算法

传统的SURF算法对仿射变化较大的图像配准效果差。为此,提出了一种仿射-加速鲁棒性特征(Affine-SURF)的图像配准算法,通过增加经度角和纬度角不变特征引入仿射形变参数来模拟图像在不同角度的变形。实验结果表明,与SIFT、SURF、MSER等配准算法相比,该算法能够获得更多特征匹配对,提高了算法对仿射变化的鲁棒性。

基于AWCRF模型的微博情感倾向分类方法

为有效解决中文微博情感数据分布不平衡的分类问题,提出一种融合Affinity Propogation(AP)算法、Word2vec技术和条件随机场(CRF)模型的分类方法。通过AP算法对微博数据进行聚类,将多数类样本按照相似性的度量划分为若干簇类,使类间距离极大化、类内距离极小化。利用欠采样技术构建情感倾向分布平衡的训练集,采用Word2vec计算并求出语义相似度最高的文本来扩展微博句子以增加情感信息,使用CRF模型计算已经平衡并扩展后的训练集标签序列,在数据集情感倾向分布不平衡时也能准确地分类微博情感倾向。实验结果表明,与ACRF方法、CRF方法及SCRF方法相比,该方法在召回率和G均值评价标准上具有更好的效果。

基于扩展的Kanade-Lucas的背景运动参数估计

复杂背景下运动分析首先需要进行背景运动参数估计。提出一种采用KLT算子并结合Kanade-Lucas跟踪算法来计算帧间特征点的匹配,然后利用帧间特征点间的匹配关系采用RANSAC算法来进行背景运动参数估计。实验结果证明这种方法具有计算量小,能实时实现并提供可靠的背景运动模型估计。

Euclid算法及扩展在密码学中的研究和应用

信息安全是网络时代的焦点,密码技术是信息安全的核心,而算法是密码学的精髓。文中研究了基于因数分解的Euclid算法和扩展Euclid算法,包括算法的基本原理、算法流程及编程实现。分析了Euclid算法的算法复杂性,介绍了Eu-clid算法在RSA和Affine Cipher密码系统中的应用,最后指出了该算法存在的缺陷和算法需要改进的方向。

大规模航测图像高速匹配平台的实现

对不同年度所采集的航测图像进行自动匹配,对地图数据公司来说是更新数据的有效辅助手段。介绍一个面向对象大规模航测图像高速匹配平台的实现。该平台使用带缓冲机制的图像控制类解决大规模图像读取的问题,采用分层匹配的方式大大减少了匹配搜索时间,并且实现了数据与处理算法的分离,使系统具有易扩展性、低耦合性和高安全性。

基于灰度共生矩阵和聚类方法的木材缺陷识别

文章提出了一种新的基于灰度共生矩阵的木材纹理特征提取和聚类分析的木材缺陷识别方法。该方法基于灰度共生矩阵,提取5个具有代表性的纹理特征:能量(E),惯性矩(I),均值和(SOA),聚类阴影(SOC),方差和(SOV),实现数据降维,对产生的特征数据集分别利用k-means算法及AP算法进行聚类,自动找出并正确标识木材表面缺陷位置,并对比分析不同木材表面缺陷类型识别效率。实验结果表明,该方法能快速有效地进行木材表面缺陷自动识别。

飞机舱音记录器背景声的联合时频分析研究

飞机舱音记录器记录的舱音主要是由话语音、噪声和具有不同物理意义的背景声组成的复杂混合体,用传统的辨听和分析方法难以获取较多的舱音特征参数。本文以一个舱音记录器记录的主告警声为例,针对传统短时傅立叶变换在舱音辨听、分析的不足,将联合时频分析引入到飞机舱音分析中,扩展了舱音分析方法。对比分析结果表明:时频分布及其重排,在时频分辨率、时频凝聚性、交叉项干扰的抑制上各有所长,都适合分析非平稳舱音背景声,从而为飞行事故调查提供一种值得采用的方法。