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A novel sulfur/polyacrylonitrile/graphene nanocomposite has been synthesized via a simple combination of ballmilling with low temperature heat-treatment. The nanocomposite was examined as a cathode for high performance lithium/sulfur batteries. The SEM and TEM observations revealed that sulfur/polyacrylonitrile particles are incorporated into graphene networks homogenously. Charge/discharge tests and ac impedance spectroscopy have shown improved conductivity and electrochemical properties of the composite with the addition of graphene. The lithium cell with this ternary composite cathode delivered a discharge capacity of 612 mAh g-1 in the second cycle at 0.1 C, and retained about 77% of this value over 100 cycles. Even up to 4 C rate, the lithium cell demonstrated an excellent rate capability, delivering a highly reversible discharge capacity of 360 mAh g-1. [ABSTRACT FROM AUTHOR]

One of the major drawbacks of lithium/sulfur (Li/S) batteries is the dissolution of polysulfides into liquid electrolytes. In order to overcome this difficulty, polymer/silicate nanocomposite electrolytes composed of polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) and different types of nano-layered silicates were fabricated and analyzed. All the electrolyte membranes showed ionic conductivity of 5-7 mS/cm at room temperature and electrochemical stability window up to 4.8 V. Tested by two different sulfur composite cathodes, PVdF-HFP/organically-modified-silicate (OMMT) nanocomposite electrolyte delivered a higher discharge capacity and showed an improved cyclability compared to the other cells. Such electrochemical performance is attributed to the small and uniformly distributed pores within the structure of the polymer nanocomposite membrane, which promotes immobilizing the electrolyte solution and prevents dissolution of polysulfides. [ABSTRACT FROM AUTHOR]

Background: Electrical stimulation (ES) has been shown to promote nerve regeneration when it was applied to the proximal nerve stump. However, the possible beneficial effect of establishing a local electrical environment between a large nerve defect on nerve regeneration has not been reported in previous studies. The present study attempted to establish a local electrical environment between a large nerve defect, and examined its effect on nerve regeneration and functional recovery. Methodology/Findings: In the present study, a conductive scaffold was constructed and used to bridge a 15 mm sciatic nerve defect in rats, and intermittent ES (3 V, 20 Hz) was applied to the conductive scaffold to establish an electrical environment at the site of nerve defect. Nerve regeneration and functional recovery were examined after nerve injury repair and ES. We found that axonal regeneration and remyelination of the regenerated axons were significantly enhanced by ES which was applied to conductive scaffold. In addition, both motor and sensory functional recovery was significantly improved and muscle atrophy was partially reversed by ES localized at the conductive scaffold. Further investigations showed that the expression of S-100, BDNF (brain-derived neurotrophic factor), P0 and Par-3 was significantly up-regulated by ES at the conductive scaffold. Conclusions/Significance: Establishing an electrical environment with ES localized at the conductive scaffold is capable of accelerating nerve regeneration and promoting functional recovery in a 15 mm nerve defect in rats. The findings provide new directions for exploring regenerative approaches to achieve better functional recovery in the treatment of large nerve defect. [ABSTRACT FROM AUTHOR]

We present the design and implementation of BeepBeep, a high-accuracy acoustic-based system for ranging and localization. It is a pure software-based solution and uses the most basic set of commodity hardware - a speaker, amicrophone, and some form of interdevice communication. The ranging scheme works without any infrastructure and is applicable to sensor platforms and commercial-off-the-shelf mobile devices. It achieves high accuracy through three techniques: two-way sensing, self-recording, and sample counting. We further devise a scalable and fast localization scheme. Our experiments show that up to one-centimeter ranging accuracy and three-centimeter localization accuracy can be achieved. [ABSTRACT FROM AUTHOR]

Mucosal vaccination has been demonstrated to be an effective means of eliciting protective immunity against aerosol infections of foot and mouth disease virus (FMDV) and various approaches have been used to improve mucosal response to this pathogen. In this study, cationic PLGA (poly(lactide-co-glycolide)) nano/microparticles were used as an intranasal delivery vehicle as a means administering FMDV DNA vaccine encoding the FMDV capsid protein and the bovine IL-6 gene as a means of enhancing mucosal and systemic immune responses in animals. Three eukaryotic expression plasmids with or without bovine IL-6 gene (pc-P12A3C, pc-IL2AP12A3C and pc-P12AIL3C) were generated. The two latter plasmids were designed with the IL-6 gene located either before or between the P12A and 3C genes, respectively, as a means of determining if the location of the IL-6 gene affected capsid assembly and the subsequent immune response. Guinea pigs and rats were intranasally vaccinated with the respective chitosan-coated PLGA nano/microparticles-loaded FMDV DNA vaccine formulations. Animals immunized with pc-P12AIL3C (followed by animals vaccinated with pc-P12A3C and pc- IL2AP12A3C) developed the highest levels of antigen-specific serum IgG and IgA antibody responses and the highest levels of sIgA (secretory IgA) present in mucosal tissues. However, the highest levels of neutralizing antibodies were generated in pc-IL2AP12A3C-immunized animals (followed by pc-P12AIL3C- and then in pc-P12A3C-immunized animals). pc- IL2AP12A3C-immunized animals also developed stronger cell mediated immune responses (followed by pc-P12AIL3Cand pc-P12A3C-immunized animals) as evidenced by antigen-specific T-cell proliferation and expression levels of IFN-c by both CD4+ and CD8+ splenic T cells. The percentage of animals protected against FMDV challenge following immunizations with pc-IL2AP12A3C, pc-P12AIL3C or pc-P12A3C were 3/5, 1/5 and 0/5, respectively. These data suggested that intranasal delivery of cationic PLGA nano/microparticles loaded with various FMDV DNA vaccine formulations encoding IL-6 as a molecular adjuvant enhanced protective immunity against FMDV, particularly pc-IL2AP12A3C with IL-6 gene located before P12A3C gene. [ABSTRACT FROM AUTHOR]

To explore the feasibility of developing a new type of plant-derived foot-and-mouth disease virus (FMDV) oral vaccine, the plant seed-specific expression vector p7SBin438/VP1 carrying the VP1 gene of the FMDV strain O/ China/99 was constructed and transformed into Agrobacterium tumefaciens strain GV3101. This strain was used for transformation of Arabidopsis thaliana via the floral-dip method. The kanamycin-resistant transgenic plants were selected, and the VP1 gene and protein expressions were confirmed by PCR and sandwich-ELISA, respectively. The ELISA positive plants were further confirmed by Western blot assay, and the VP1 gene in the transgenic progeny was confirmed by PCR. The results showed that the Agrobacterium-mediated floral-dip transformation method could produce transgenic Arabidopsis containing the VP1 gene. Therefore, this protocol provides a successful strategy to deliver viral genes to leguminous plants for genetic studies and for production of low-cost oral vaccines. [ABSTRACT FROM AUTHOR]

The goal of data-center networking is to interconnect a large number of server machines with low equipment cost while providing high network capacity and high bisection width. It is well understood that the current practice where servers are connected by a tree hierarchy of network switches cannot meet these requirements. In this paper, we explore a new server-interconnection structure. We observe that the commodity server machines used in today's data centers usually come with two built-in Ethernet ports, one for network connection and the other left for backup purposes. We believe that if both ports are actively used in network connections, we can build a scalable, cost-effective interconnection structure without either the expensive higher-level large switches or any additional hardware on servers. We design such a networking structure called FiConn. Although the server node degree is only 2 in this structure, we have proven that FiConn is highly scalable to encompass hundreds of thousands of servers with low diameter and high bisection width. We have developed a low-overhead traffic-aware routing mechanism to improve effective link utilization based on dynamic traffic state. We have also proposed how to incrementally deploy FiConn. [ABSTRACT FROM PUBLISHER]

To disseminate data to a heterogeneous body of receivers efficiently, congestion control protocols for IP multicast compose a session from several multicast groups and prescribe guidelines that enable each receiver to subscribe to an appropriate subset of the groups. However, a misbehaving receiver can ignore the group subscription rules and inflate its subscription to acquire unfairly high throughput. In this paper, we present the first solution for the problem of inflated subscription. Our design guards access to multicast groups with dynamic keys and consists of two independent components: DELTA (Distribution of ELigibility To Access)—a novel method for in-band distribution of group keys to receivers that are eligible to access the groups according to the congestion control protocol, and SIGMA (Secure Internet Group Management Architecture)—a generic architecture for key-based group access at edge routers. We apply DELTA and SIGMA to derive robust versions of prominent RLM and FLID-DL protocols. [ABSTRACT FROM AUTHOR]

Transmission control protocol (TCP) performance enhancement proxy (PEP) mechanisms have been proposed, and in some cases widely deployed, to improve TCP performance in all-Internet protocol (IP) wireless networks. However, this technique is conflicted with IP-security (IPsec)--a standard IP security protocol that will make inroad into wireless networks. This paper analyzes the fundamental problem behind this conflict and develops a solution called multilayer IP-security (ML-IPsec). The basic principle is to use a multilayer protection model and a fine grain access control to make IP security protocols compatible with TCP PEP. It allows wireless network operators or service providers to grant base stations or wireless routers limited and controllable access to the TCP headers for performance enhancement purposes. Through careful design, implementation, and evaluation, we show that we can easily add ML-IPsec to existing IPsec software and the overhead is low. We conclude that ML-IPsec can help wireless networks provide both security and performance. [ABSTRACT FROM AUTHOR]

The rapid proliferation of wireless networks and mobile computing applications has changed the landscape of network security. The traditional way of protecting networks with firewalls and encryption software is no longer sufficient and effective. We need to search for new architecture and mechanisms to protect the wireless networks and mobile computing application. In this paper, we examine the vulnerabilities of wireless networks and argue that we must include intrusion detection in the security architecture for mobile computing environment. We have developed such an architecture and evaluated a key mechanism in this architecture, anomaly detection for mobile ad-hoc network, through simulation experiments. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li/S) batteries are promising portable energy storage devices if the defects of insufficient conductivity and obvious shuttle effect can be effectively suppressed. In this work, a unique caddice-like ball carbon nanotubes/CoO (CNTs/CoO) microspheres have been synthesized through a facile spray drying and following calcination method. By using cobalt acetate (Co(CHCOO)2) as a cobalt source, polymethyl methacrylate (PMMA) as a pore former and CNTs as the supporting frame, the as-prepared CNTs/CoO microspheres endowed with enriched interconnected pores and abundant scattered CoO nanoparticles on CNT walls. CNTs provided physical adsorption platforms for adsorption of polysulfides while ensuring the conductivity of the overall material. Polycrystalline CoO nanoparticles are uniformly deposited on CNT walls, providing additional confinement of polysulfides by strong chemical adsorption. In addition, the different content of CoO in the microspheres was regulated by the amount of added cobalt source during the preparation process. With both physical entrapment by CNTs and strong chemical interaction with CoO nanocrystals, this unique design can effectively promote the active material utilization and inhibit the shuttle effect. When employed as the sulfur host, an excellent electrochemical performance was achieved on the resulting sulfur-impregnated CNTs/CoO (S-CNTs/CoO) composite with the sulfur content of 73.0%. The obtained S-CNTs/CoO microspheres delivered an exceptional initial discharge capacity of 1340 mAh g−1 and a prominent cycling stability of 1116 mAh g−1 after 100 cycles at 0.2 C, as well as a superb rate capability of 600 mAh g−1 and 506 mAh g−1 at 2.0 C and 3.0 C, respectively. The results revealed that the S-CNTs/CoO composite was an enviable cathode material and showed an excellent potentiality in the application of Li/S batteries. [ABSTRACT FROM AUTHOR]

[Objective] Copper has a wide range of applications in new energy vehicles, electric power, communication, and other fields, and is a key metal that cannot be replaced in the process of energy transformation. China is the world’s largest copper consumer and demand country, and its industrial chain and supply chain security issues are increasingly prominent, therefore it is important to scientifically evaluate the resilience of its copper resources industrial chain and supply chain. [Methods] This study constructed a comprehensive evaluation indicator system for the resilience of China’s copper resources industrial chain and supply chain from four dimensions of resilience: resistance, recovery capacity, reorganization capacity, and renewal capacity, combined with the characteristics of the copper resources industry. The independence-adjusted entropy weight method was used to evaluate the resilience of the copper resources industrial chain and supply chain from 2000 to 2021, and the indicator barrier degree model and indicator contribution degree model were applied to identify the main factors that affect the improvement of resilience. [Results] The study found that: (1) From 2000 to 2021, the resilience of China’s copper resources industrial chain and supply chain showed a fluctuating upward trend, which was more rapid after 2012; (2) The lack of resistance was the main factor that led to the slow improvement of resilience, while the improvement of renewal capacity and recovery capacity was the main path to improving the overall resilience; (3) The coordination degree of resistance, recovery capacity, reorganization capacity, and renewal capacity fluctuated and increased after 2010, which contributed to the above-average resilience of the industrial chain and supply chain. [Conclusion] China should continue to improve the level of renewal capacity and recovery capacity of the copper resources industry, facilitate the integration of industry, academia, and research, and accelerate the transformation of scientific research results; reduce the negative impact of lack of resistance, identify the risks of chain breakage, strengthen the assessment and early warning of risks, and improve the secondary recovery rate of copper resources; collaborate in all aspects of the industrial chain and talent chain, and inject green kinetic energy into the industrial chain and supply chain.

The soil freeze-thaw cycle in the permafrost regions has a significant impact on regional surface energy and water balance. Although increasing efforts have been made to understand the responses of spring thawing to climate change, the mechanisms controlling the global interannual variability of the start date of permafrost frozen (SOF) remain unclear. Using long-term SOF from the combinations of multiple satellite microwave sensors between 1979 and 2020, and analytical techniques, including partial correlation, ridge regression, path analysis, and machine learning, we explored the responses of SOF to multiple climate change factors, including warming (surface and air temperature), start date of permafrost thawing (SOT), soil properties (soil temperature and volume of water), and the snow depth water equivalent (SDWE). Overall, climate warming exhibited the maximum control on SOF, but SOT in spring was also an important driver of SOF variability; among the 65.9% significant SOT and SOF correlations, 79.3% were positive, indicating an overall earlier thawing would contribute to an earlier frozen in winter. The machine learning analysis also suggested that apart from warming, SOT ranked as the second most important determinant of SOF. Therefore, we identified the mechanism responsible for the SOT-SOF relationship using the SEM analysis, which revealed that soil temperature change exhibited the maximum effect on this relationship, irrespective of the permafrost type. Finally, we analyzed the temporal changes in these responses using the moving window approach and found increased effect of soil warming on SOF. In conclusion, these results provide important insights into understanding and predicting SOF variations with future climate change. [ABSTRACT FROM AUTHOR]

The article offers information on the diurnal patterns of photosynthesis and evapotranspiration in Amazonian forests and their responses to atmospheric warming and drying. Topics discussed include the depression of dry season afternoon photosynthesis and evapotranspiration; positive response of morning photosynthesis to vapor pressure deficit (VPD); and the projection of future compensatory increases in morning photosynthesis to offset the depressed afternoon photosynthesis in dry seasons.

Industrial emissions play a major role in the global methane budget. The Permian basin is thought to be responsible for almost half of the methane emissions from all U.S. oil- and gas-producing regions, but little is known about individual contributors, a prerequisite for mitigation. We use a new class of satellite measurements acquired during several days in 2019 and 2020 to perform the first regional-scale and high-resolution survey of methane sources in the Permian. We find an unexpectedly large number of extreme point sources (37 plumes with emission rates >500 kg hour-1), which account for a range between 31 and 53% of the estimated emissions in the sampled area. Our analysis reveals that new facilities are major emitters in the area, often due to inefficient flaring operations (20% of detections). These results put current practices into question and are relevant to guide emission reduction efforts. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease virus (FMDV) causes a highly contagious, debilitating disease in cloven-hoofed animals with devastating economic consequences. To survive in the host, FMDV has evolved to antagonize the host type I interferon (IFN) response. Previous studies have reported that the leader proteinase (Lpro) and 3Cpro of FMDV are involved in the inhibition of type I IFN production. However, whether the proteins of FMDV can inhibit type I IFN signaling is less well understood. In this study, we first found that 3Cpro of FMDV functioned to interfere with the JAK-STAT signaling pathway. Expression of 3Cpro significantly reduced the transcript levels of IFN-stimulated genes (ISGs) and IFN-stimulated response element (ISRE) promoter activity. The protein level, tyrosine phosphorylation of STAT1 and STAT2, and their heterodimerization were not affected. However, the nuclear translocation of STAT1/STAT2 was blocked by the 3Cpro protein. Further mechanistic studies demonstrated that 3Cpro induced proteasome- and caspase-independent protein degradation of karyopherin1 (KPNA1), the nuclear localization signal receptor for tyrosine-phosphorylated STAT1, but not karyopherin α2 α3, or α4. Finally, we showed that the protease activity of 3Cpro contributed to the degradation of KPNA1 and thus blocked STAT1/STAT2 nuclear translocation. Taken together, results of our experiments describe for the first time a novel mechanism by which FMDV evolves to inhibit IFN signaling and counter-act host innate antiviral responses. [ABSTRACT FROM AUTHOR]

We have prepared columnar self-assembled Cu2S hexagonal nanoplates induced by a Sn-X complex for the first time and demonstrated that the Sn-X complex can affect not only the morphology of the nanocrystals but also the self-assembly ability of the nanocrystals. [ABSTRACT FROM AUTHOR]