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During the arms race between plants and pathogens, pathogenesis-related proteins (PR) in host plants play a crucial role in disease resistance, especially PR1. PR1 constitute a secretory peptide family, and their role in plant defense has been widely demonstrated in both hosts and in vitro. However, the mechanisms by which they control host-pathogen interactions and the nature of their targets within the pathogen remain poorly understood.The present study was aimed to investigate the anti-oomycete activity of secretory PR1 proteins and elaborate their underlying mechanisms.This study was conducted in the potato-Phytophthora infestans pathosystem. After being induced by the pathogen infection, the cross-kingdom translocation of secretory PR1 was demonstrated by histochemical assays and western blot, and their targets in P. infestans were identified by yeast-two-hybrid assays, bimolecular fluorescence complementation assays, and co-immunoprecipitation assay.The results showed that the expression of secretory PR1-encoding genes was induced during pathogen infection, and the host could deliver PR1 into P. infestans to inhibit its vegetative growth and pathogenicity. The translocated secretory PR1 targeted the subunits of the AMPK kinase complex in P. infestans, thus affecting the AMPK-driven phosphorylation of downstream target proteins, preventing ROS homeostasis, and down-regulating the expression of RxLR effectors.The results provide novel insights into the molecular function of PR1 in protecting plants against pathogen infection, and uncover a potential target for preventing pre- and post-harvest late blight.

The realization of good aqueous dispersibility of commercial graphene products composed of exfoliated graphene sheets is of significance for downstream applications. However, the tap density of commercial graphene powder is quite low (0.03–0.1 kg/m3), meaning that 1 kg graphene powder occupies about 10–30 m3 in volume during transportation. And, the available content of commercial graphene dispersion/slurry in aqueous medium cannot exceed 5 wt%, although the density is high (≈ 1050 kg/m3). In this work, a graphene monolith was prepared by oven-drying of graphene sheets prefunctionalized with poloxamer surfactants. Our graphene monoliths not only have a high density (1500 kg/m3) and high graphene content (≈ 10 wt%), but also a full capability to be completely redispersed (≈ 100%) in water by bath sonication to obtain solubilized graphene sheets, whose lateral size and thickness are unchanged compared to as-exfoliated ones. Moreover, a simple empirical method was proposed to predict the redispersion capability of graphene monoliths using different poloxamers by contact angle measurements. Our results provide a universal approach to make exfoliated graphene-based products with better downstream availability and lower transportation cost.

China and the United States respectively adopted desulfurization electricity price and emission trading to achieved the effective sulfur dioxide emissions reduction in thermal power industry. By the methodology of cost-benefit analysis and comparative analysis with the United States, this paper analyzed the coal-fired power plants’ desulfurization cost, benefit, and social emission reduction cost of China’s desulfurization electricity price policy. The main findings are, the results of cost-benefit analysis show that China’s policy against the polluter pays principle, polluters can get benefit from this policy. Second, in terms of the cost of emission reduction, China’s cost is very high with 5.52 billion U.S. dollars in 2000 while the USA only cost 0.5-2.0 billion US dollars. Also, compared with the decreasing social cost of the United States, the China desulfurization electricity price policy leads the social SO2 reduction cost expanded and economic inefficiencies. The conclusion is, as the policy’s objective has been achieved, the desulfurization electricity price policy in China should be cancelled. The way of reducing pollutants emission in the form of price subsidies cannot be extended to other pollutants or other industries emission control.

We conducted two studies in different cultures to examine how two types of feedback, appreciation and attention, affect users’ decisions to make voluntary knowledge contributions to electronic networks of practice (ENP). Appreciation is reflected in positive ratings, votes, and helpfulness evaluations. Attention is reflected in the number of views of contributed content. The first study used clickstream data from a college application ENP in China, where information seekers can read asynchronously posted information and request synchronous consultations with volunteers. The second study was a controlled online experiment in the United States where we assessed users’ willingness to asynchronously answer questions in a college application ENP. In both studies, greater appreciation increased continued knowledge contribution, but greater attention without sufficient appreciation negatively affected contributions. We conclude that appreciation and attention show distinctive yet intertwined impacts on knowledge contributions in ENP in two different cultures across both synchronous and asynchronous participation.

To promote charitable giving, donation-based crowdfunding platforms adopted match offers, whereby leadership donors commit to matching the contribution of other donors at a given rate. While match offers have great potential to improve fundraising performance, a lot remains unknown about how and when match offers work. Leveraging the data from a donation-based crowdfunding platform, our study seeks to understand (1) how the suppliers of funds (donors) evaluate charitable projects with and without match offers differently, (2) how these donors’ preferences toward match offers vary with their donation experience, and (3) how the demanders of funds (fundraisers) react to the introduction of match offers. At an individual level, we find that, on average, donors derive a higher utility when contributing to charitable projects with match offers than without them. Specifically, warm-list donors (recently active donors) are three times more likely to contribute to matched projects than unmatched projects, while cold-list donors (dormant donors) are twice more likely to do so. However, new donors, who have no historical donation records on the platform, are more interested in unmatched projects. At a market level, we focus on the ratio of matched projects over all the projects and find that a 1% increase in the matched project ratio leads to a 1.34% increase in funds asked by demanders and a 0.854% increase in the funds supplied by donors. Finally, we demonstrate the robustness of our findings in a transactional analysis with fine-grained controls at the project level. Our work is one of the first studies that connect micro-level data patterns with macro-level market evidence to disentangle the impact of match offers systematically.

Volunteer engagement is improving the well-being of individuals in society, and volunteers' retention and migration behaviors are critical to the management of non-profit organizations. Despite the existing effort to understand organization performance with network science, no prior study has tapped into the behavior of the unpaid labor force of non-profit organizations. This work looks into volunteers' engagement, retention, and migration by constructing dynamic egocentric collaboration networks using data from 827,260 unique volunteers' participation in 183,445 projects initiated by 74,556 non-profit organizations over nine years. We apply a multiplex network framework to characterize the heterogeneous relationships within the collaboration networks. We find that volunteers embedded in more cohesive networks and surrounded by fewer structural holes (gaps between individuals who have complementary sources of information) are more likely to remain in their existing non-profit organizations. These volunteers are less likely to explore unfamiliar organizations through migration, and collectively, the reduced migration rates negatively affect the development of small and newly-established organizations. Further, such volunteers have a higher volunteering engagement level overall, guaranteeing the supply of the volunteer labor force. Our work not only adds to the theories of network cohesion and structural holes but also deepens the understanding of how collaboration networks pose opportunities and constraints for volunteer behaviors. This work provides rich implications for volunteer management and public policy.

This research examines the economic impact of membership-based free-shipping (MFS) programs when introduced as an augmentation to widely accepted contingent free-shipping (CFS) policies. Under CFS, consumers waive the shipping surcharge if the order exceeds a certain threshold, whereas under MFS, consumers pay an upfront fee and enjoy the free-shipping perk throughout the membership period. We develop a stylized model that considers consumer heterogeneity in two dimensions: (1) disutility from acquiring an auxiliary product—a product that consumers would not otherwise purchase—to qualify for CFS; and (2) shopping frequency over a given period. Our analysis suggests that the introduction of MFS allows the e-tailer to segment the market further, which could lead to a higher product price. When the disutility from acquiring an auxiliary product is moderate, the e-tailer should charge a high membership fee to target only frequent shoppers who forgo CFS. However, the e-tailer should lower the fee to lure also (1) frequent shoppers who would otherwise take CFS, when the disutility is high; or (2) infrequent shoppers who would otherwise forgo CFS, when the disutility is low. In all cases, although the collected fee revenue can never compensate for the cost arising from offering the free-shipping perk, the loss can be recouped as a desirable outcome of a more segmented market. Our research generates insights into the optimal design of e-tailers’ shipping policies, shedding light on the practical challenges that confront e-tailers.

Graphene-based papers have recently triggered considerable interests in developing the application as thermal interface materials (TIMs) for addressing the interfacial heat transfer issue, but their low through-plane thermal conductivity (κ⊥), resulting from the layer-by-layer stacked architecture, limits the direct use as TIMs. Although various hybrid graphene papers prepared by combining the graphene sheets and the thermally conductive insertions have been proposed to solve this problem, achieving a satisfactory κ⊥ higher than that of commercial TIMs (>5 W m−1 K−1) remains challenging. Here, a strategy aimed at the construction of heat pathways along the through-plane direction inside the graphene paper for achieving a high κ⊥ was demonstrated through the simultaneous filtration of graphene sheets with two different lateral sizes. The as-prepared graphene paper presented a hierarchical structure composed of loosely stacked horizontal layers formed by large graphene sheets, intercalated by a random arrangement of small graphene sheets. Due to the heat pathways formed by small graphene sheets along the through-plane direction, the hierarchically structured graphene paper exhibited an improved κ⊥ as high as 12.6 W m−1 K−1 after a common graphitization post-treatment. In the practical test, our proposed paper as an all-graphene TIM achieved an enhancement in cooling efficiency of ≈ 2.2 times compared to that of the state-of-the-art TIM, demonstrating its superior performance to meet the ever-increasing heat dissipation requirement.

The rapid increase of the packaging integration and power density of devices in electronics leads to urgent demands for high-performance thermal interface materials (TIMs) to efficiently solve the accompanying thermal management problem. Although various highly thermally conductive materials (such as graphene, carbon nanotube, and boron nitride nanosheet) combined with diversified structure design have been proposed to address this issue, it remains challenging to achieve a satisfactory TIM with both high through-plane thermal conductivity (κ⊥) and low contact thermal resistance (Rcontact) for meeting the practical application requirements. This study solves this problem by constructing a loosely packed and vertically aligned graphene monolith (VAGM), which was prepared by simply rolling up hybrid double-layer strips composed of porous polymer foam adhered onto the graphene paper, exhibiting an ultrahigh κ⊥ of 276 W m-1 K-1. Moreover, a cap modification strategy by transferring the nanometer-thick gold (Au) foils onto both sides of VAGM was carried out to further optimize the contact state with roughness surface from heater/heat sink, finally giving a low Rcontact of 0.41 K cm2 W-1 (double sides). As a result, our proposed graphene-based TIM exhibits an enhancement in cooling efficiency of ≈1.15 times compared to that of the state-of-the-art TIM (≈30 W m-1 K-1) in the TIM performance test, manifesting its superior ability to meet the ever-increasing heat dissipation requirement.

In order to explore the feasibility of the natural smoke extraction of the undivided large space warehouse buildings, the paper analyzes the characteristics, factors and feasibility of natural smoke extraction of the undivided large space warehouse buildings which have been fire damaged, based on the idea of performance-based fire protection design. FDS software is used for fire hazard analysis of the building by simulating the fire scene temperature, smoke layer height and visibility during the natural smoke extraction. It draws the conclusion that: during natural smoke extraction, increased area of the smoke vent and heightened warehouse both, under certain conditions, can lower the fire scene temperature, slow the sinking of smoke and weaken the ground radiation so that the fire scene safety can be guaranteed even in the most unfavorable condition. However, to ensure stable smoke extraction and eliminate the influence from the external environments, some proven fire safety measures can be provided in certain positions.

The distribution of forests can be hindcast or forecast when robust data and validation proofs are available. Distribution consequences for temperate coniferous forests during the Quaternary and future climatic fluctuations are little understood in China. Temperate coniferous forests are subdivided into two types where Pinus, Keteleeria, Tsuga and Cupressus species characterize the warm forests while Abies, Picea, Larix and Juniperus species characterize the cold forests. Both forest types were investigated using 12,675 unique records in the MaxEnt model to infer distribution patterns during six time periods: the present time, mid-Holocene, Last Glacial Maximum, Last Interglacial and the near- and far-future (2050, 2070). The results showed that the mean temperature of the driest quarter, followed by the temperature annual range and the precipitation of the warmest quarter were the most important variables controlling forests distribution. Suitable areas capable of supporting the presence of warm coniferous forests were highly contracted during the Quaternary; meanwhile, the cold coniferous forests expanded westwards from the last glacial maximum through the mid-Holocene to the present. The predicted future distributions showed a significant range-shift of warm forests northeastwards in response to climate change while cold coniferous forests are expected to migrate towards the Tibetan Plateau. Under increased global warming, the bioclimatic variables of the past and future periods were used as ecological indicators for the identification of areas showing “climatic stability”, and predicted to be refugia for coniferous forests and as good tools for conservation planning in Sichuan and the Hengduan-Tibetan migration corridor.

As a part of the visual cycle, all-trans-retinol (all-trans-ROL), the major form of vitamin A in circulating blood, is transported to the retinal pigment epithelium (RPE). All-trans-ROL is essential for normal retina function. However, recent researches have shown that excessive retinol intake can cause increase of all-trans-retinal. This can lead to the accumulation of lipofuscin, which is important in the pathogenesis of retina degeneration disease, such as dry type age-related macular degeneration (AMD). Since there are few reports regarding the involvement of all-trans-ROL in exudative AMD, we investigated the effects of all-trans-ROL in vitro and in vivo. We evaluated vascular endothelial growth factor (VEGF) expression in ARPE-19 cells and THP-1 cells after all-trans-ROL treatment using ELISA and real-time RT-PCR. In-vitro tube formation assay was performed with HUVEC cells using the conditioned medium (CM) obtained from ARPE-19 cells treated with all-trans-ROL. Transcriptional activity of retinoic acid receptor (RAR) was evaluated using luciferase assay. In mice, VEGF expressions were investigated in the retina and RPE/choroid after three weeks of excessive oral retinol intake. Laser-induced choroidal neovascularization (CNV) models were evaluated after they were fed with various doses of retinol. VEGF mRNA expression and VEGF production were significantly increased in all-trans-ROL treated ARPE-19 cells, which were inhibited by an RAR antagonist LE540. In contrast, there were no significant changes in VEGF production in THP-1 cells. Transcriptional activity of RAR was upregulated by all-trans-ROL treatment in ARPE-19 cells. The CM, obtained from ARPE-19 cells treated with all-trans-ROL, induced more capillary-like tube formation than cells treated with control vehicles. In vivo, the high retinol diet group has increased VEGF expression in the RPE/choroid and larger lesion size was induced. Our results suggest that all-trans-ROL is a pro-angiogenic factor. Excessive retinoid intake may be a potential risk factor for exudative AMD.

In social broadcasting sites, users’ charitable content generation is affected by both their followees (to whose content they subscribe) and followers (people who subscribe to these users’ broadcasts). In this paper, we examine how reciprocity of followees affects social influence on users’ charitable content generation by leveraging an annual fundraising event on social media. We employ a latent instrumental variable approach which effectively controls for the endogeneity issue arising from followees’ charitable engagement. In addition, a field experiment is conducted to investigate the role of followers. We find that within a specific charitable topic, reciprocal relationship has a positive impact on social influence, and non-reciprocal relationship has a negative impact on social influence that drives content generation following the topic. Our findings suggest an effect of information overload caused by excessive messages generated by non-reciprocal nodes such as news media and nonprofit organizations. We also reveal that users usually generate charitable content out of their altruistic motivations. However, those users who include pictures in their previous charitable content are more likely to be driven by reputation-based motivations in generating charitable content.

Live chatting tools have emerged as a new channel for sellers and buyers to communicate with each other. Live chats facilitate human-based interactions to reduce information asymmetry and build trust between sellers and buyers, exhibiting great potential to complement the existing feedback system used in online marketplaces. This paper analyzes the context of Alibaba where live chatting tools are offered by the platform to every seller. We use clickstream data of 3000 customers’ page viewing, live chatting, and purchasing activities to investigate the role played by live chats in online marketplaces. We find that 1) live chats positively impact repeat visits for sellers with low reputation; 2) live chats improve conversion rates; 3) live chats improve conversion more effectively for sellers with low reputation; and 4) people are more likely to initiate live chats when they face sellers with low reputation or products with few reviews. These findings indicate that live chats can work as substitutes for reputation.

With the growing popularity of social media, social networking sites have become an important channel for online donor engagement and charitable fundraising. Many crowd-based donation platforms have integrated social functions to encourage donors to announce their donations in social media. Some social networking sites, like Facebook, initiate their own charitable campaigns by collaborating with nonprofit organizations. Despite the great theoretical and practical values, social media users’ motivations for charitable giving are underexplored. Using individual-level data from a microblogging platform where a donation service is embedded, we investigate how individual donation decisions are influenced by reputation incentive design, peer effects, and popularity effects. We find that despite the platform designer’s desire to improve fundraising performance, higher visibility of donors’ contributions may have negative impact on fundraising. Peer effects are found to be positive and, hence, provide a potential solution to the free-rider problem. Finally, it is observed that while most users crowd to popular projects, a group of users who exhibit leadership features crowd out from popular projects. Investing more fundraising effort on this crowding-out group may alleviate the rich-get-richer problem.

Free shipping policy is widely used by e-tailers to improve customers’ online shopping experience. In this paper, we study two shipping policies that are intensively used in the current electronic market: membership free shipping (MFS) and contingent free shipping (CFS). In MFS, consumers pay a membership fee upfront and enjoy unlimited, free expedited shipping for a certain period, whereas in CFS, consumers are eligible for free standard shipping if the total transaction amount of an order exceeds a pre-determined threshold. We develop a game-theoretical model in which two competing e-tailers choose their shipping strategies in a sequential order to maximize their profits. Our main findings are threefold. First, when both e-tailers use the same shipping policy, MFS leads to a higher profit than CFS if faster shipping is employed. Second, while e-tailers have an incentive to adopt MFS, under some conditions they find themselves in the prisoner’s dilemma — both e-tailers end up choosing the less profitable CFS. Third, such a prisoner’s dilemma no longer exists when consumers’ valuation of expedited shipping offered by MFS is sufficiently higher than that of standard shipping attached to CFS. This study contributes to the literature on shipping pricing and provides useful implications for e-tailers.The Online Technical Appendix for this paper is available at the following URL: http://ssrn.com/abstract=2820355