Mutual Promotion Research Articles

A Faithful Deep Sensitivity Estimation for Accelerated Magnetic Resonance Imaging.

Magnetic resonance imaging (MRI) is an essential diagnostic tool that suffers from prolonged scan time. To alleviate this limitation, advanced fast MRI technology attracts extensive research interests. Recent deep learning has shown its great potential in improving image quality and reconstruction speed. Faithful coil sensitivity estimation is vital for MRI reconstruction. However, most deep learning methods still rely on pre-estimated sensitivity maps and ignore their inaccuracy, resulting in the significant quality degradation of reconstructed images. In this work, we propose a Joint Deep Sensitivity estimation and Image reconstruction network, called JDSI. During the image artifacts removal, it gradually provides more faithful sensitivity maps with high-frequency information, leading to improved image reconstructions. To understand the behavior of the network, the mutual promotion of sensitivity estimation and image reconstruction is revealed through the visualization of network intermediate results. Results on in vivo datasets and radiologist reader study demonstrate that, for both calibration-based and calibrationless reconstruction, the proposed JDSI achieves the state-of-the-art performance visually and quantitatively, especially when the acceleration factor is high. Additionally, JDSI owns nice robustness to patients and autocalibration signals.

Investigation of gas explosion hazards and characteristics during overcharged behavior of nickel-cobalt-manganese (523) lithium-ion battery

Compared with hard-shell lithium batteries, the obvious thermal runaway (TR) characteristic of nickel‑cobalt‑manganese pouch cell (NPC) is that it cannot release a large amount of gas in time. Therefore, the fire risk during the TR process of NPC is centralized by gas explosion hazard. The overcharged TR process of nickel‑cobalt‑manganese (523) NPC (NCM523) was explored in this work. The jetting flame phenomenon still occurs during the TR process of NCM523 in the absence of air, indicating that it is primarily attributed to self-reaction and exhibits spontaneous properties. Moreover, the air environment can increase the intensity of jetting and gas explosion hazards. The gases produced during the TR process of NCM523 in the air and nitrogen are mainly CO, H2, N2, CO2, CH4, C2H6, C2H4, and C3H6. The volume percentages of combustible gases in the air and nitrogen are 64.87 % and 46.24 %, respectively. The lower explosion limit (volume ratio) of gases in the air environment is between 10 % and 11.25 %, while the upper is between 39.37 % and 40 %. The maximum flammable intensity of gases generated from the TR process of NCM523 is 25 %. As revealed by CHEMKIN simulations, H∙, O∙, and OH∙ are the most important key radicals that catalyze the entire chain reaction and gas explosion during the TR process of NCM523. The interaction and mutual promotion of reactions R1, R2, and R3 are crucial for the generation of free radicals. Therefore, the combustion and explosion risk during the TR process of NCM523 can be reduced by increasing inert gases and suppressing the free radical reaction chemically during gas phase combustion.

A LC-MS-based serum pharmacochemistry approach to reveal the compatibility features of mutual promotion/assistance herb pairs in Xijiao Dihuang decoction

Xijiao Dihuang decoction (XDT), a famous formula, was usually used to improve the prognosis of patients with blood-heat and blood-stasis syndrome-related diseases. There were some mutual promotion and mutual assistance herb pairs in XDT. However, the exact functions of these herb pairs in the compatibility of XDT were not elucidated due to the lack of appropriate methodologies. Based on the theory of serum pharmacochemistry, a systematic method was established for the qualitative and quantitative analysis of characteristic components in the extracts and drug-containing plasma samples of XDT and its relational mutual promotion/assistance herb pairs. For qualitative analysis, 85 characteristic components were identified using the liquid chromatography with triple time-of-flight mass/mass spectrometry (LC-Triple QTOF-MS/MS) based on the mass defect filtering, product ion filtering, neutral loss filtering and isotope pattern filtering techniques. For quantitative detection, a relative quantitation assay using an extract ion chromatogram (EIC) of the full scan MS experiment was validated and employed to assess the quantity of the 85 identified compounds in the test samples of single herb, herb pairs and XDT. The results of multivariate statistical analyses indicated that both the assistant and guide herbs could improve the solubilization of active compounds from the sovereign and minister herbs in XDT in vitro, might change the trans-membrane transportation, and regulate metabolism in vivo. The methods used in present study might be also valuable for the investigation of multiple components from other classic TCM formulas for the purpose of compatibility feature study.

Decoupling the mutual promotion of inflammation and oxidative stress mitigates cognitive decline and depression-like behavior in rmTBI mice by promoting myelin renewal and neuronal survival

BackgroundRepetitive mild traumatic brain injury (rmTBI) can lead to somatic, emotional, and cognitive symptoms that persist for years after the initial injury. Although the ability of various treatments to promote recovery after rmTBI has been explored, the optimal time window for early intervention after rmTBI is unclear. Previous research has shown that hydrogen-rich water (HRW) can diffuse through the blood-brain - barrier, attenuate local oxidative stress, and reduce neuronal apoptosis in patients with severe traumatic brain injury. However, research on the effect of HRW on rmTBI is scarce. AimsThe objectives of this study were to explore the following changes after rmTBI and HRW treatment: (i) temporal changes in inflammasome activation and oxidative stress-related protein expression through immunoblotting, (ii) temporal changes in neuron/myelin-related metabolite concentrations in vivo through magnetic resonance spectroscopy, (iii) myelin structural changes in late-stage rmTBI via immunofluorescence, and (iv) postinjury anxiety/depression-like behaviors and spatial learning and memory impairment. ResultsNLRP-3 expression in the rmTBI group was elevated at 7 and 14 DPI, and inflammasome marker levels returned to normal at 30 DPI. Oxidative stress persisted throughout the first month postinjury. HRW replacement significantly decreased Nrf2 expression in the prefrontal cortex and hippocampal CA2 region at 14 and 30 DPI, respectively. Edema and local gliosis in the hippocampus and restricted diffusion in the thalamus were observed on MR-ADC images. The tCho/tCr ratio in the rmTBI group was elevated, and the tNAA/tCr ratio was decreased at 30 DPI. Compared with the mice in the other groups, the mice in the rmTBI group spent more time exploring the open arms in the elevated plus maze (P < 0.05) and were more active in the maze (longer total distance traveled). In the sucrose preference test, the rmTBI group exhibited anhedonia. In the Morris water maze test, the latency to find the hidden platform in the rmTBI group was longer than that in the sham and HRW groups (P < 0.05). ConclusionEarly intervention with HRW can attenuate inflammasome assembly and reduce oxidative stress after rmTBI. These changes may restore local oligodendrocyte function, promote myelin repair, prevent axonal damage and neuronal apoptosis, and alleviate depression-like behavior and cognitive impairment.

Scavenging Glyoxal and Methylglyoxal by Synephrine Alone or in Combination with Neohesperidin at High Temperatures.

α-Dicarbonyl compounds, such as glyoxal (GO) and methylglyoxal (MGO), are a series of chemical hazards that exist in vivo and in vitro, posing a threat to human health. We aimed to explore the scavenging effects on GO/MGO by synephrine (SYN) alone or in combination with neohesperidin (NEO). First, through LC-MS/MS, we confirmed that both SYN and NEO could effectively remove GO and form GO adducts, while NEO could also clear MGO by forming MGO adducts, and its ability to clear MGO was stronger than that of GO. Second, a synergistic inhibitory effect on GO was found when SYN and NEO were used in combination by using the Chou-Talalay method; on the other hand, SYN could promote NEO to clear more MGO, although SYN could not capture MGO. Third, after synthesizing four GO/MGO-adducts (SYN-GO-1, SYN-GO-3, NEO-GO-7, and NEO-MGO-2) and identifying their structure through NMR, strict correlations between the GO/MGO-adducts and the GO/MGO-clearance rate were found when using SYN and NEO alone or in combination. Furthermore, it was inferred that the synergistic effect between SYN and NEO stems from their mutual promotion in capturing more GO by the quantitative analysis of the adducts in the combined model. Finally, a study was conducted on flowers of Citrus aurantium L. var. amara Engl. (FCAVA, an edible tea) rich in SYN and NEO, which could serve as an effective GO and MGO scavenger in the presence of both GO and MGO. Therefore, our study provided well-defined evidence that SYN and NEO, alone or in combination, could efficiently scavenge GO/MGO at high temperatures, whether in the pure form or located in FCAVA.

Study on the Influence of Digital Economy on High-quality Trade Development Under the "Double Cycle" Pattern

With the deepening of globalization and the rapid development of digital technology, digital economy has become a new important force to promote economic growth. The new development pattern of "double cycle" proposed by China focuses on realizing the mutual promotion of internal circulation and external circulation on the basis of expanding domestic demand. This paper aims to explore in the "binary" development pattern, based on the benchmark regression study how digital economy has a positive impact on trade quality development, the results show that the digital economy to improve the level of trade facilitation, promote the trade structure optimization, accelerate the trade pattern innovation, and by promoting the proportion of trade in services effectively promote the high quality development of China's trade. At the end of the paper, the countermeasures and suggestions are put forward.

Theoretical Analysis of the Integration of Entrepreneurship and Professional Education in Higher Vocational Education

This paper provides a theoretical analysis of integrating entrepreneurship education and professional education in higher vocational institutions. It examines the essence of entrepreneurship as a teachable set of knowledge and skills rather than purely innate traits. The core qualities of entrepreneurship are outlined, stemming from psychological attributes, skills, and opportunity-seizing abilities. The social ideo-logical shifts enabling the rise of entrepreneurship education are explored, centered on pragmatism and colleges expanding social service role. The relationship between vocational and entrepreneurship education is discussed, arguing they have a profound intrinsic connection based on shared knowledge foundations and service values that allow mutual promotion. Integrating the two through curricular design can cultivate professional entrepreneurs with knowledge of entrepreneurship capacities. The teachability of entrepreneurship and the mutually reinforcing nature of vocational and entrepreneurship education provide the basis for their integration to enhance talent development.

The Relationship between the Popularization of Music Education and the Level of Economic Development

Education plays a crucial role in the growth of both society and the economy, serving as the foundation upon which progress is built. However, it is not enough to simply have an education system in place; it must be continually improved and developed to meet the changing needs of society. With the progress of economic development, the width of education continues to expand, people pay attention to quality education increasingly, among which the popularity of music education is also changing. In order to further enhance the popularity of music education in the future, while looking for new ways to promote economic growth, it needs to explore the connection between the two. This paper discusses the relationship between the popularity of music education and the level of economic development. By studying the changing trend of the economic development stage and the popularity of music education since New China and the popularity of music education in the context of the significant economic development gap between countries in the world, the basic idea of promoting the popularity of music education and economic development can be found : economic development and the popularity of music education promote each other. In the future, by coordinating the development of the two, mutual promotion can be achieved and get twice the result with half the effort.

Electromagnetic forming of AA1060 sheet based on mixed forces generated by a three-coil dual-power system

The electromagnetic force used in electromagnetic forming is mainly divided into attraction and repulsion. Dual-coil attractive electromagnetic forming can be used in the field of sheet pit repair. However, the magnetic field and eddy current generated by the two coils compete with each other, and the energy utilization rate is low. Therefore, a compensation coil is introduced, and an electromagnetic forming scheme of a three-coil dual-power sheet based on mixed force is proposed and verified by simulation. It is found that the three-coil mixed force can effectively improve the competition between the magnetic field and eddy current. The loading of the mixing force is not a simple superposition of attraction and repulsion, but the mutual promotion of the two. The forming displacement of the three-coil mixed force forming scheme is 582% higher than that of the dual-coil attraction forming scheme, and 89% higher than that of the attract first and then repel forming scheme. The forming effect of the three-coil mixing force is related to the number of turns of the compensation coil. The research results can improve the energy utilization rate of electromagnetic forming and provide a new idea for the loading scheme of electromagnetic forming force field.

Assessment of low-carbon tourism development from multi-aspect analysis: a case study of the Yellow River Basin, China

Climate change has become an unavoidable problem in achieving sustainable development. As one of the major industries worldwide, tourism can make a significant contribution to mitigating climate change. The main objective of the paper is to assess the development level of low-carbon tourism from multi-aspect, using the Yellow River Basin as an example. Firstly, this study quantified tourism carbon dioxide emissions and tourism economy, and analyzed their evolution characteristics. The interaction and coordination degree between tourism carbon dioxide emissions and tourism economy were then analyzed using the improved coupling coordination degree model. Finally, this study analyzed the change in total factor productivity of low-carbon tourism by calculating the Malmquist–Luenberger productivity index. The results showed that: (1) the tourism industry in the Yellow River Basin has the characteristics of the initial environmental Kuznets curve. (2) There was a strong interaction between tourism carbon dioxide emissions and tourism economy, which was manifested as mutual promotion. (3) The total factor productivity of low-carbon tourism was increasing. Based on the above results, it could be concluded that the development level of low-carbon tourism in the Yellow River Basin has been continuously improved from 2000 to 2019, but it is still in the early development stage with the continuous growth of carbon dioxide emissions.

Construction and evolutionary pattern of the coupling relationship network of regional sustainable development in China

Climate change poses a serious threat to the survival and development of humankind. Accordingly, sustainable socioeconomic transformation has become a major global concern. This study quantitatively assesses the process and speed of regional-level sustainable development in China, as well as the degree of coupling and the degree of coupling coordination among Sustainable Development Goals (SDGs). To this end, based on regional development and data monitoring in China, we construct a regional sustainable development assessment system containing 111 indicators, which combines existing sustainable development assessment indicators with the indicators of the 2030 Agenda for Sustainable Development. On that basis, using network topology construction and modal transformation, we propose a framework for analyzing the coupling relationships and evolutionary patterns of regional sustainable development. The study found that the score for SDGs at the national level increased from 50.80 in 2010 to 60.86 in 2020, showing a good development trend and the differences between provinces and regions was gradually reduced. The development speed of regional sustainable transformation shows a change from decreasing to increasing. In recent years, there is a significant change in the acceleration of regional sustainable development in China, with the vast majority of provinces having positive acceleration and only three provinces having negative acceleration. China's regional sustainable development shows that mutual coordination and promotion among provinces was higher in the eastern area than in the central region, which was higher than in the western area. The sustainable processes of each region and the coordination of sustainable development steadily increased toward a high level of coupling, all achieving coordinated development. The degree of coupling coordination and the SDG scores in each region were positively correlated with economic development, reflecting the role of economic development in the promotion of sustainability. However, this positive correlation showed a tendency of strengthening and then weakening. The correlation of the evolution patterns in the eastern–central, eastern–western, and central–western regions over time presented a trend of first weakening, then strengthening, and then weakening. Although the process of promoting sustainable development in western and central regions over time is weak synergistic consistency with that in eastern regions, overall, China's regional sustainable development presents a development model of multi-province linkage and multi-goal coordination.

Chinese Judicial Reform and Legislative Reform: Conflicts and Mutual Promotion

In the Chinese law context, judicial reform has close consequences on legislation. On the one hand, some judicial reform outcomes have become laws. On the other hand, when some of the measures and policies of the judicial reform are not consistent with the Constitution and other laws, they could cause problems in practice. This paper argues that judicial reform should be coherent with legislative reform in order to ensure consistency with the Constitution, maintain uniformity in the application of law, and prevent the legislature from exceeding its authority. The purpose of this paper is to consider the legitimacy and limit of the judicial reform power, and search for a balance between efficiency and legitimacy in judicial reform.

Incentive policy for the comprehensive development of young medical talents: an evolutionary game study.

Currently in China, there is a lack of well-defined and viable incentive mechanisms at the governmental and hospital levels to support the development of young medical talents, thereby hindering their growth Existing studies primarily investigate the current state and trajectory of incentives, yet they inadequately address the distinctive characteristics of various stakeholders involved in medical talent incentive processes, particularly the lack of research on incentive mechanisms with Chinese attributes. This study adopts evolutionary game theory to investigate the dynamics of replication and the strategies for achieving evolutionary stability in the comprehensive development of young medical talents, considering both scenarios with and without supportive policies. In the absence of any supportive policy measures, the evolutionarily stable strategy (ESS) point is O(0,0), the unstable equilibrium point is C(1,1), and the saddle points are A(0,1), B(1,0). The initial state of the system is at the unstable equilibrium point C(1,1), which means that the young medical talents and medical institutions adopt a combination of strategies (actively seeking comprehensive development and taking incentive measures). Under the scenario with supportive policies, the ESS point is C(1,1), the unstable equilibrium point is O(0,0), and the saddle points are A(0,1), B(1,0). The initial state of the system is at the unstable equilibrium point O(0,0), which means that young medical talents and medical institutions adopt (N,N) strategy combinations (inactively seeking comprehensive development, implementing no incentive measure). (1) Government incentives play a crucial role in motivating young medical talents to seek comprehensive development. (2) The level of government incentive support for young medical talents should exceed the cost increment of individual efforts. Additionally, the policy support provided by the government to medical institutions should surpass the incentive support offered by these institutions to young medical talents. This will enhance the motivation and encouragement efforts of medical institutions in actively promoting comprehensive development among young medical talents. (3) With the backing of certain government incentive policies, medical institutions implementing incentive measures and young medical talents actively seeking comprehensive development will establish a virtuous cycle of mutual promotion.

Combined Photosensitive Gene Therapy Effective Against Triple-Negative Breast Cancer in Mice Model.

Tumor hypoxia and invasion present significant challenges for the efficacy of photodynamic therapy (PDT) in triple-negative breast cancer (TNBC). This study developed a mitochondrial targeting strategy that combined PDT and gene therapy to promote each other and address the challenges. The positively charged amphiphilic material triphenylphosphine-tocopherol polyethylene glycol succinate (TPP-TPGS, TPS) and the photosensitizer chloride e6 (Ce6) formed TPS@Ce6 nanoparticles (NPs) by hydrophobic interaction. They electrostatically condensed microRNA-34a (miR-34a) to form stable TPS@Ce6/miRNA NPs. Firstly, Ce6 disrupted the lysosomal membrane, followed by successful delivery of miR-34a by TPS@Ce6/miRNA NPs. Meanwhile, miR-34a reduced ROS depletion and further enhanced the effectiveness of PDT. Consequently, the mutual promotion between PDT and gene therapy led to enhanced anti-tumor effects. Furthermore, the TPS@Ce6/miRNA NPs promoted apoptosis by down-regulating Caspase-3 and inhibited tumor cell migration and invasion by down-regulating N-Cadherin. In addition, in vitro and in vivo experiments demonstrated that the TPS@Ce6/miRNA NPs achieved excellent anti-tumor effects. These findings highlighted the enhanced anticancer effects and reduced migration of tumor cells through the synergistic effects of PDT and gene therapy. Taken together, the targeted co-delivery of Ce6 and miR-34a will facilitate the application of photodynamic and genic nanomedicine in the treatment of aggressive tumors, particularly TNBC.

Research on the integration of labor education and ideological and political education in colleges and universities in the new era

As an important part of the socialist education system with Chinese characteristics, labor education and ideological and political education are the central tasks of school education, with moral cultivation as its fundamental goal and important mission. Ideological and political education plays the role of ideological guidance in the process of labor education, and labor education can concretely realize the goal of ideological and political education and promote the mutual promotion of students' ideological and political education and the sense of labor acquisition. Facing the new requirements, new opportunities and new challenges of the new era, strengthening the integration of labor education and ideological and political education is an important way to strengthen and improve the ideological and political work in colleges and universities, improve the labor quality of college students, and train qualified talents who meet the needs of society.

Exploring the relationship between regional tourism development and land use efficiency: A case study of Guangxi Zhuang Autonomous Region, China.

The utilization efficiency of land resources is an essential embodiment of economic development, social development, and ecological development and is a critical core to measure how to maximize the efficiency of land resources under limited conditions. The land is an important content and essential carrier of the research of tourism development level. This paper selects Panel Data from 2010 to 2019 to research the Guangxi regional tourism development. The entropy weight method and stochastic frontier production function (SFA) model were used to evaluate the development level of urban-rural tourism and the utilization efficiency of land resources in Guangxi. This paper uses the Panel Vector Autoregression (PVAR) model to analyze the internal relationship between urban-rural tourism development. The results show that: (1) Guangxi has a good level of tourism development and a high land use efficiency. (2) There is a reciprocal causation relationship between the regional tourism development level and land use efficiency in Guangxi, with significant levels of 0.005 and 0.034 respectively, indicating high credibility. This indicates that there is a mutual promotion and interaction between the two, which rely on and drive each other, promoting the joint sustainability of tourism development and land use efficiency. (3) . The tourism development level is greatly influenced by itself, with impact values all above 0.99. At the same time, land use also has a significant self-impact, with impact values all above 0.87. Their internal optimization system is solid and endogenous impetus is robust, which can drive their development. Establishing an effective strategy for developing and protecting land use is beneficial to promote the long-term effectiveness of sustainable tourism development, enhancing high-quality development of the tourism economy and improving people's living standards and quality.

Analysis of the Close Relationship between Chinese Films and the Economy

Due to the continuous economic development in recent years, there is a phenomenon that people begin to pursue spiritual satisfaction while meeting the basic material needs. Film is an important way of mankind's Daily pastime. As the consumer power in film increases, the economy of film production also develops. This article chose the Huayi brothers, the Light media, Wanda film, Chinese film co., LTD., 4 listed Chinese film and TV making company to analysis the relationship between the economy. Based on their financial statements, revenue expenditure analysis of their income in recent years as well as the spending of filmmaking, this study summarizes the close ties between Chinese movies and economic and carries on the development of some prediction. According to the analysis, China's film and economic relationship is mutual promotion, and after the outbreak of the new champions league era, the development of China's film will continue to accelerate. These results can help people understand more about the development between Chinese film and economy and the development background of Chinese film economy.

BECI System of Business English Reading and Writing

Purpose: This study puts forward the BECI system under the background of Chinese new liberal arts construction and the guidance of postmodern philosophy and the blended teaching mode in order to sustainably improve students’ Business English Reading and Writing ability and cultivate Business English compound talents who meet the market demand. Theoretical framework: The research makes use of post-modern philosophy and blended teaching mode to explore the BECI system. Design/ methodology/ approach: The BECI system teaching mode integrates traditional teaching and digital teaching, and uses information technology, online and offline, multi-modal teaching and process assessment mechanism to comprehensively improve students’ participation and subjective learning status, and cultivate their good study habits. Findings: BECI system is market-demand-oriented, student-centered and teacher-scaffolded, which includes business knowledge, English knowledge, cross-cultural knowledge and ideological and political knowledge, and advocates the mutual promotion of Business English Reading (input) and Business English Writing (output). Research, Practice &amp; Social Implications: The research not solely solves some problems, such as complicated teaching content and low learning efficiency of students, Business English Reading and Writing facing with, but also endows learners with the sustainable Business English Reading and Writing ability and good study habits.

Parameter-Agnostic Deep Graph Clustering

Deep graph clustering, efficiently dividing nodes into multiple disjoint clusters in an unsupervised manner, has become a crucial tool for analyzing ubiquitous graph data. Existing methods have acquired impressive clustering effects by optimizing the clustering network under the parametric condition—predefining the true number of clusters ( K tr ). However, K tr is inaccessible in pure unsupervised scenarios, in which existing methods are incapable of inferring the number of clusters ( K ), causing limited feasibility. This article proposes the first Parameter-Agnostic Deep Graph Clustering method (PADGC), which consists of two core modules: K -guidence clustering and topological-hierarchical inference, to infer K efficiently and gain impressive clustering predictions. Specifically, K -guidence clustering is employed to optimize the cluster assignments and discriminative embeddings in a mutual promotion manner under the latest updated K , even though K may deviate from K tr . In turn, such optimized cluster assignments are utilized to explore more accurate K in the topological-hierarchical inference, which can split the dispersive clusters and merge the coupled ones. In this way, these two modules are complementarily optimized until generating the final convergent K and discriminative cluster assignments. Extensive experiments on several benchmarks, including graphs and images, can demonstrate the superiority of our method. The mean values of our inferred K , in 11 out of 12 datasets, deviates from K tr by less than 1. Our method can also achieve competitive clustering effects with existing parametric deep graph clustering.

The Mutual Influence Between Economic Globalization and Internationalization of Higher Education

The internationalization of higher education has emerged as one of the major research areas in the current era of economic globalization. However, there are still some unified explanations about the relationship between the two. This paper will explain the relationship between economic globalization and the internationalization of higher education, analyzing a part of the history of economic globalization as well as some literature on higher education internationalization. The research found that higher education internationalization and globalization of the economy are mutually reinforcing, that is, the internationalization of higher education may be able to promote further globalization, while economic globalization can facilitate higher education's internationalization to grow more quickly. However, there are still some problems and obstacles in the mutual promotion of the two, such as anti-globalization, the single way of internationalization of higher education, and few returns. This paper then gives suggestions such as taking education as an important strategy to promote the economy, expanding ways of developing internationalization of higher education, and providing more opportunities to the returned students to these problems at the end that might smoothen the mutual promotion of the two.