Hydrogen Sensing Characteristics of ZnSnO_3 Micro-Particles Doped with Noble Metal Pd

Perovskite-type oxide ZnSnO_3 doped with 0.5 wt% Pd was prepared directly by a hydrothermal process,its crystal structure and ceramic microstructure were characterized by XRD and TEM,and the gas sensing properties were tested in static state.It is found that the sensors based on ZnSnO_3 micro-particles have good sensitivity and selectivity to H_2.Its sensitivity can be changed with working temperature;the sensitivity of the sensors to H_2 could arrive 21 times when the working temperature is 332℃.

Preparation and NO_2 Sensing Characteristics of LaFeO_3 Nanoparticles

LaFeO_3 nanoparticles were prepared by decomposing a precursor La[Fe(CN)_6]·4H_2O at 800℃,the precursor was synthesized by a coordination precipitation process at room temperature.The decomposing mechanism of the precursor was investigated by analyzing TG-DSC curves.Its crystal structure,particle size and ceramic microstructure were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM).Furthermore,the gas sensing properties were tested at static state.It can be shown that LaFeO_3 nanoparticles are highly crystallized after sintering at 800℃,the particle size is about 50 nm.The sensor based on LaFeO_3 nanoparticles shows remarkable sensitivity to NO_2.

MXene derivative Ta_(4)C_(3)-Ta_(2)O_(5) heterostructure as bi-functional barrier for Li-S batteries

The shuttle effect of polysulfides during the charging and discharging of lithium-sulfur(Li-S)batteries and the growth of Li dendrites are crucial obstacles to hinder the commercialization of Li-S batteries.Heterostructure engineering is an effective strategy to accelerate catalytic conversion and suppress the dissolution of polysulfides.Herein,we report a Ta_(4)C_(3)-Ta_(2)O_(5) heterostructure composite as a bi-functional modified separator that not only achieves effective protection for lithium metal but also accelerates the polysulfides redox kinetics process.This heterostructure possesses efficient chemical anchoring and abundant active sites to immobilize polysulfides by synergistic effect,which endows a stable long cycling performance for Li-S batteries.This corresponds to an initial high capacity of 801.9 mAh g^(–1) at 1 C with a decay rate of 0.086%for 500 cycles.Due to its high Young’s modulus(up to 384 GPa),Ta_(4)C_(3) contributes to forming a protective layer on the Li metal surface to inhibit the growth of Li dendrites.Accordingly,the symmetrical cell has a stable overpotential for 700 cycles at 20 mA cm^(–2)/20 mAh cm^(–2).So,this“one stone two birds”design affords a novel perspective for high-energy Li-S battery storage system design and Li metal protection.

Highly redispersible CNT dough for better processiblity

Carbon nanotubes(CNTs)have received considerable attention for their excellent thermal and electrical conductivity as well as scalable production.However,CNT dispersions are prone to settling and have a short shelf time,especially under high concentration,which significantly hinders their further processing and increases transportation costs.Here,we report a highly concentrated CNT dough enabled by ionic liquid crystal(ILC)as auxiliaries.Benefiting from the temperature-controlled physical transformation of the ILC,the CNTs of the powder state are successfully transferred to highly processable dough with excellent electrical conductivity,flame retardancy,and outstanding redispersibility even after 180 days of storage.In particular,the CNT dough exhibits excellent self-healing properties and good reshapable capability.Various bulk form CNT derived from the ILC armored CNT dough are realized by facile processing technique.Hybrid nanocomposite papers with ANF nanofiber exhibited excellent photothermal conversion and Joule heating properties.The redispersible CNT doughs presented here promise to revolutionize traditional CNT powder and dispersions as the primary raw material for building CNT-based architectures and facilitate the large-scale application of CNTs.

SDF-1/CXCR4 axis modulates bone marrow mesenchymal stem cell apoptosis, migration and cytokine secretion

Bone marrow mesenchymal stem cells(MSCs)are considered as a promising cell source to treat the acute myocardial infarction.However,over 90%of the stem cells usually die in the first three days of transplantation.Survival potential,migration ability and paracrine capacity have been considered as the most important three factors for cell transplantation in the ischemic cardiac treatment.We hypothesized that stromal-derived factor-1(SDF-1)/CXCR4 axis plays a critical role in the regulation of these processes.In this study,apoptosis was induced by exposure of MSCs to H2O2 for 2 h.After re-oxygenation,the SDF-1 pretreated MSCs demonstrated a significant increase in survival and proliferation.SDF-1 pretreatment also enhanced the migration and increased the secretion of pro-survival and angiogenic cytokines including basic fibroblast growth factor and vascular endothelial growth factor.Western blot and RT-PCR demonstrated that SDF-1 pretreatment significantly activated the pro-survival Akt and Erk signaling pathways and up-regulated Bcl-2/Bax ratio.These protective effects were partially inhibited by AMD3100,an antagonist of CXCR4.We conclude that the SDF-1/CXCR4 axis is critical for MSC survival,migration and cytokine secretion.

Growth of ultra-dense MoS_(2) nanosheets on carbon fibers to improve the mechanical and tribological properties of polyimide composites

To enhance the interface bonding of polyimide(PI)/carbon fiber(CF)composites,CFs were functionalized by introducing a polydopamine(PDA)transition layer,whose active groups provide absorption sites for the growth of molybdenum disulfide(MoS_(2))nanosheets and improve the bonding strength with PI.Uniform and dense MoS_(2) nanosheets with thicknesses of 30–40 nm on the surface of the PDA@CF were obtained via a subsequent hydrothermal method.As a result,the interface between the CF and the PI matrix becomes more compact with the help of the PDA transition layer and MoS_(2) nanosheets.This is beneficial in forming PI/CF–MoS_(2) composites with better thermal stability,higher tensile strength,and enhanced tribological properties.The lubricating and reinforcing effects of the hybrid CF–MoS_(2) in the PI composite are discussed in detail.The tensile strength of the PI/CF–MoS_(2) composite increases by 43%,and the friction coefficient and the wear rate reduce by 57%and 77%,respectively,compared to those of the pure PI.These values are higher than those of the PI/CF composites without MoS_(2) nanosheets.These results indicate that the CF–MoS_(2) hybrid material can be used as an additive to improve the mechanical and tribological properties of polymers.

Ferritin nanocages for early theranostics of tumors via inflammation-enhanced active targeting

Engineered nanocarriers have been widely developed for tumor theranostics.However,the delivery of imaging probes or therapeutic drugs to the tumor pre-formation site for early and accurate detection and therapy remains a major challenge.Here,by using tailor-functionalized human H-ferritin(HFn),we developed a triple-modality nanoprobe IRdye800-M-HFn and achieved the early imaging of tumor cells before the formation of solid tumor tissues.Then,we developed an HFn-doxorubicin(Dox)drug delivery system by loading Dox into the HFn protein cage and achieved early-stage tumor therapy.The intravenous injection of HFn nanoprobes enabled the imaging of tumor cells as early as two days after tumor implantation,and the triple-modality imaging techniques,namely,near-infrared fluorescence molecular imaging(NIR-FMI),magnetic resonance imaging(MRI),and photoacoustic imaging(PAI),ensured the accuracy of detection.Further exploration indicated that HFn could specifically penetrate into pre-solid tumor sites by tumor-associated inflammation-mediated blood vessel leakage,followed by effective accumulation in tumor cells by the specific targeting property of HFn to transferrin receptor 1.Thus,the HFn-Dox drug delivery system delivered Dox into the tumor pre-formation site and effectively killed tumor cells at early stage.IRDye800-M-HFn nanoprobes and HFn-Dox provide promising strategies for early-stage tumor diagnosis and constructive implications for early-stage tumor treatment.

SnO/SnO_(2) heterojunction:an alternative candidate for sensing NO_(2) with fast response at room temperature

The SnO_(2)-based family is a traditional but important gas-sensitive material.However,the requirement for high working temperature limits its practical application.Much work has been done to explore ways to improve its gas-sensing performance at room temperature(RT).For this report,SnO_(2),SnO,and SnO/SnO_(2) heterojunction was successfully synthesized by a facile hydrothermal combined with subsequent calcination.Pure SnO_(2) requires a high operating temperature(145℃),while SnO/SnO_(2) heterojunction exhibits an excellent performance for sensing NO_(2) at RT.Moreover,SnO/SnO_(2) exhibits a fast response,of 32 s,to 50 ppm NO_(2) at RT(27℃),which is much faster than that of SnO(139 s).The superior sensing properties of SnO/SnO_(2) heterojunction are attributed to the unique hierarchical structures,large number of adsorption sites,and enhanced electron transport.Our results show that SnO/SnO_(2) heterojunction can be used as a promising high-performance NO_(2) sensitive material at RT.

Space-Terrestrial Integrated Mobility Management via Named Data Networking

In Future Space-Terrestrial Integrated Networks （FSTINs）, mobility is the norm rather than the exception, the current TCP/IP architecture is not competent. As a promising future network architecture, Named Data Networking （NDN） can support content consumer mobility naturally, but the content producer mobility support remains a challenging problem. Most previous research simply considered this problem in terrestrial scenarios, which involve stable infrastructures to achieve node mobility management. In this paper, we consider the problem in an FSTIN scenario without special handover management infrastructures. Specifically, we propose a tracing-based producer mobility management scheme and an addressing-assisted forwarding method via NDN architecture. We formally describe Multi-Layered Satellite Networks via a Time Varying Graph model and define the foremost path calculating problem to calculate the route of space segment, as well as an algorithm that can function in both dense （connected） and sparse （delay/disruption tolerant） scenarios. Finally, we discuss the acceleration method that can improve the Space-Terrestrial Integrated forwarding efficiency. Performance evaluation demonstrates that the proposed scheme can support fast handover and efficient forwarding in the FSTIN scenario.

Advances in magnetic particle imaging and perspectives on liver imaging

Magnetic particle imaging(MPI)is an emerging technique to visualize the spatial distribution of super-paramagnetic iron oxide with high temporal–spatial resolution,high sensitivity,unlimited image depth,and true quantitative information.MPI is based on the nonlinear response of superparamagnetic iron oxide in an alter-nating magnetic field without tissue background noise.It is a promising imaging modality for various applica-tions,including vascular imaging,cell tracking,tumor imaging,and catheter navigation.Many applications of liver imaging could be improved or created with MPI.In this review,we cover the principle and construction of MPI,we evaluate the features and advantages of MPI with relation to its own rationale and via comparison with other imaging modalities,and we review MPI liver imaging applications with a view toward assisting hepatic researchers in drawing inspiration.