Size Effect for Inhibiting Polysulfides Shuttle in Lithium-Sulfur Batteries.

It is undeniable that the dissolution of polysulfides is beneficial in speeding up the conversion rate of sulfur in electrochemical reactions. But it also brings the bothersome "shuttle effect". Therefore, if polysulfides can be retained on the cathode side, the efficient utilization of the polysulfides can be guaranteed to achieve the excellent performance of lithium-sulfur batteries. Based on this idea, considerable methods have been developed to inhibit the shuttling of polysulfides. It is necessary to emphasize that no matter which method is used, the solvation mechanism, and existence forms of polysulfides are essential to analyze. Especially, it is important to clarify the sizes of different forms of polysulfides when using the size effect to inhibit the shuttling of polysulfides. In this review, a comprehensive summary and in-depth discussion of the solvation mechanism, the existing forms of polysulfides, and the influencing factors affecting polysulfides species are presented. Meanwhile, the size of diverse polysulfide species is sorted out for the first time. Depending on the size of polysulfides, tactics of using size effect in cathode, separator, and interlayer parts are elaborated. Finally, a design idea of materials pore size is proposed to satisfy the use of size effect to inhibit polysulfides shuttle.

Immunogenicity of a scalable inactivated rotavirus vaccine in mice.

Inactivated rotavirus vaccine is a safe and effective potential vaccine for the prevention of rotavirus infection among children, but no approved licensed vaccine is available now. In this study, a scalable inactivated rotavirus vaccine, prepared in Vero cells cultured by microcarrier fermentation, inactivated by formalin and absorbed by Al(OH)(3) adjuvant, was vaccinated into the six weeks-old female Balb/c mice by intramuscular injection. After twice immunization at interval of three weeks, both humoral and cell-mediated immune responses were assessed by ELISA, microneutralization assay and EISPOT assay. The results indicated that the scalable inactivated rotavirus vaccines induced not only high serum IgG antibody and neutralizing antibody responses, but Th1 and Th2 cytokine-secreting cell responses in mice immunized by the inactivated rotavirus vaccines. These results suggest that the scalable inactivated rotavirus vaccine has good immunogenicity, which provided the base for the scaled development of inactivated rotavirus vaccine in the future.

The first dinosaurs from the Early Cretaceous Hami Pterosaur Fauna, China.

The Early Cretaceous Hami Pterosaur Fauna in Northwest China preserves a large number of specimens of the sexually dimorphic pteranodontoid pterosaur Hamipterus tianshanensis, including 3D eggs and embryos. During the last decade, several more fossils have been collected in this area, including three somphospondylan sauropod specimens. The first is Silutitan sinensis gen. et sp. nov., which consists of an articulated middle to posterior cervical vertebrae series. The second, Hamititan xinjiangensis gen. et sp. nov., consists of an incomplete articulated caudal sequence that could be assigned to lithostrotian titanosaurs based on the strongly procoelous caudal vertebrae with lateral concave surface, as well as marked ventrolateral ridges. The third specimen consists of four sacral vertebral elements, apparently unfused, with exposed camellate internal bone and regarded as somphospondylan. Cladistic analyses based on different datasets recovered Silutitan sinensis as an euhelopodid closely related to Euhelopus and Hamititan xinjiangensis as a titanosaur. Besides the pterosaur Hamipterus and one theropod tooth, these dinosaurs are the first vertebrates reported in this region, increasing the diversity of the fauna as well as the information on Chinese sauropods, further supporting a widespread diversification of somphospondylans during the Early Cretaceous of Asia.

Fabrication of 3D Porous Polyvinyl Alcohol/Sodium Alginate/Graphene Oxide Spherical Composites for the Adsorption of Methylene Blue.

In this study, three-dimensional (3D) networked porous polyvinyl alcohol/sodium alginate/graphene oxide (PVA/SA/GO) spherical composites were fabricated by the sol-gel method and employed as adsorbents for the adsorption of methylene blue (MB) in aqueous solution. The obtained samples were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermal property analysis, and nitrogen adsorption/desorption isotherms. Moreover, the adsorption properties for MB were investigated by batch experiments. The pseudo-first-order and pseudo-second-order equations were used to fit the adsorption kinetics data, and the Langmuir and Freundlich isothermal models were used to analyze the adsorption isothermals. The results showed that the spherical composites had 3D porous structures, and GO, PVA and SA were fused and linked together by self-assembly, physical intertwining, hydrogen bonding, and Ca2+ and boric acid crosslinking. The maximum adsorption capacity of the 3D porous PVA/SA/GO spherical composites for MB was 759.3 mg/g. The adsorption kinetics had a better agreement with the pseudo-secondorder equation than the pseudo-first-order equation, and the equilibrium data followed the Freundlich model.

Copper leaching from waste printed circuit boards using typical acidic ionic liquids recovery of e-wastes' surplus value.

In this study, using several types of acidic ionic liquids as the leaching reagents, the leaching behaviors of the copper present in waste printed circuit boards (WPCBs) were investigated. The effects of various parameters on the copper leaching rate were studied, such as the particle size of the shredded WPCB, type of ionic liquid used, hydrogen peroxide dosage, solid-to-liquid ratio, leaching temperature, and leaching time. The experimental results showed that the copper leaching rate increases continuously when the powder particle size is increased from 0.071 to 0.500 mm. Moreover, the copper leaching rate also increases with an increase in the leaching temperature. In contrast, the leaching rate first increases and then decreases with increases in the leaching time, hydrogen peroxide dosage, and solid-to-liquid ratio. The optimal conditions that provided a 98.31% copper leaching rate were: particle size >0.500 mm, 8.5 mL 90% (v/v) ionic liquid, 1.5 mL 30% hydrogen peroxide, solid-to-liquid ratio of 1/20, leaching temperature of 80 °C, and leaching time of 2 h.

Preparation of polyamidoamine dendrimers functionalized magnetic graphene oxide for the adsorption of Hg(II) in aqueous solution.

In this study, using graphene oxide supported Fe3O4 nanoparticles as carriers, ethylenediamine and methyl acrylate as functional monomer, different generations of polyamidoamine dendrimers functionalized magnetic graphene oxide (MGO-PAMAM), up to generation 4.0, were successfully synthesized via step by step growth chemical grafting approach and magnetic separation technology. In the process of synthesizing dendrimers, the generation of dendrimers was increased with the increasing of reaction cycles. In other words, the dendrimers generation is determined from the number of branch iterations. The obtained MGO-PAMAM were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), elemental analysis, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), nitrogen adsorption/desorption isotherm and Zeta potential analysis. The adsorption properties of the synthesized products for Hg(II) in aqueous solution were investigated by batch experiments. The results showed that the MGO-PAMAM with generation 3.0 of dendrimers (MGO-PAMAM-G3.0) has the maximum adsorption capacity of 113.71mg·g-1. The adsorption process of MGO-PAMAM-G3.0 for Hg(II) was well described by the pseudo-second-order kinetics model and the Langmuir isotherm model. The Hg(II) adsorbed on the surface of MGO-PAMAM-G3.0 was reduced to Hg(I) in the adsorption process. In addition, the MGO-PAMAM possesse good magnetic separation performance.

Design of Block Copolymer Micellar Aggregates for Co-Delivery of Enzyme and Anticancer Prodrug.

Traditional enzyme-prodrug therapy (EPT) is a two-step strategy, which has many serious deficiencies, so having a one-step EPT treatment becomes a problem of immediate interest. This study aims to achieve an effective co-delivery of horseradish peroxidase (HRP) as a kind of enzyme for prodrug activation and ethyl 3-indoleacetate (EIA) as anticancer prodrug. A ternary block copolymer PEG-PAsp(AED)-CA consisting of poly(ethylene glycol) (PEG), reduction-sensitive poly (N-(2,2'-dithiobis(ethylamine)) aspartamide) PAsp(AED), and cholic acid (CA) was synthesized and assembled into spherical micelles which encapsulated EIA in its hydrophobic core and HRP in a reduction-sensitive interlayer. TEM photographs show that the polymer micelle is around 40 nm, and the cell survival rate test shows that the EIA/HRP polymer micelle is highly lethal to human lung adenocarcinoma cells. Thus, co-delivery of EIA and HRP demonstrates great potential in cancer therapy, offering a structurally simple and highly tunable platform for the synchronous delivery of enzymes and prodrugs in EPT.

Synthesis of magnetic graphene oxide grafted polymaleicamide dendrimer nanohybrids for adsorption of Pb(II) in aqueous solution.

In this paper, using maleic anhydride and ethylenediamine as functional monomers, graphene oxide (GO) loaded magnetic Fe3O4 nanoparticles modified by (3-Aminopropyl) triethoxysilane as support, magnetic graphene oxide grafted polymaleicamide dendrimer (GO/Fe3O4-g-PMAAM) nanohybrids were fabricated by divergent method and magnetic separation technology. The obtained samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, elementary analyzer and vibrating sample magnetometer. The effects of PMAAM generations, solution pH, Pb(II) initial concentration, temperature and contact time on the adsorption property of the samples for Pb(II) in aqueous solution were studied. The results demonstrated that nitrogen content and adsorption capacity of the as-synthesized samples with amino terminal groups were all higher than their adjacent generations PMAAM with carboxyl terminal groups. Moreover, with increasing generations of PMAAM grafted on to the GO/Fe3O4, the nitrogen content and the adsorption capacity of the samples with the same terminal groups gradually increased. The maximum adsorption capacity of GO/Fe3O4-g-G3.0 for Pb(II) was 181.4mgg-1 at 298K. The rising of temperature was beneficial for the adsorption. The adsorption kinetics had a better agreement with pseudo-second-order equation, and equilibrium data followed the Langmuir model.

Egg accumulation with 3D embryos provides insight into the life history of a pterosaur.

Fossil eggs and embryos that provide unique information about the reproduction and early growth of vertebrates are exceedingly rare, particularly for pterosaurs. Here we report on hundreds of three-dimensional (3D) eggs of the species Hamipterus tianshanensis from a Lower Cretaceous site in China, 16 of which contain embryonic remains. Computed tomography scanning, osteohistology, and micropreparation reveal that some bones lack extensive ossification in potentially late-term embryos, suggesting that hatchlings might have been flightless and less precocious than previously assumed. The geological context, including at least four levels with embryos and eggs, indicates that this deposit was formed by a rare combination of events, with storms acting on a nesting ground. This discovery supports colonial nesting behavior and potential nesting site fidelity in the Pterosauria.

Facile solvothermal synthesis of mesostructured Fe3O4/chitosan nanoparticles as delivery vehicles for pH-responsive drug delivery and magnetic resonance imaging contrast agents.

We report a facile fabrication of a host-metal-guest coordination-bonding system in a mesostructured Fe3O4/chitosan nanoparticle that can act as a pH-responsive drug-delivery system. The mesostructured Fe3O4/chitosan was synthesized by a solvothermal approach with iron(III) chloride hexahydrate as a precursor, ethylene glycol as a reducing agent, ammonium acetate as a porogen, and chitosan as a surface-modification agent. Subsequently, doxorubicin (DOX), acting as a model drug (guest), was loaded onto the mesostructured Fe3O4/chitosan nanoparticles, with chitosan acting as a host molecule to form the NH2-Zn(II)-DOX coordination architecture. The release of DOX can be achieved through the cleavage of coordination bonds that are sensitive to variations in external pH under weakly acidic conditions. The pH-responsive nature of the nanoparticles was confirmed by in vitro releases and cell assay tests. Furthermore, the relaxation efficiency of the nanoparticles as high-performance magnetic resonance imaging contrast agents was also investigated. Experimental results confirm that the synthesized mesostructured Fe3O4/chitosan is a smart nanovehicle for drug delivery owing to both its pH-responsive nature and relaxation efficiency.

Sexually dimorphic tridimensionally preserved pterosaurs and their eggs from China.

BACKGROUND: The pterosaur record is generally poor, with little information about their populations, and pterosaur eggs are even rarer, with only four isolated and flattened eggs found to date. RESULTS: We report here a population of a new sexually dimorphic pterosaur species (Hamipterus tianshanensis gen. et sp. nov.), with five exceptionally well-preserved three-dimensional eggs, from the Early Cretaceous deposit in northwestern China. About 40 male and female individuals in total were recovered, but the actual number associated might be in the hundreds. All of the discovered skulls have crests, which exhibit two different morphologies in size, shape, and robustness. The eggs show pliable depressions with cracking and crazing on the outer surface. The eggshell, observed by scanning electron microscopy and energy-dispersive spectroscopy, comprises a thin calcareous external hard shell followed by a soft membrane. CONCLUSIONS: These fossils shed new light on the reproductive strategy, ontogeny, and behavior of pterosaurs. The cranial crests show sexually dimorphic morphologies, with presumed males and females differing in crest size, shape, and robustness. Ontogenetic variation is reflected mainly in the expansion of the rostrum. The eggs have some external rigidity of the general pliable eggshell, and the microstructure of the eggshell is similar to that of some modern "soft" snake eggs. We suggest that this new pterosaur nested in colonies and thus exhibited gregarious behavior, a possible general trend for at least derived pterodactyloid pterosaurs.

Synthesis of novel inorganic-organic hybrid materials for simultaneous adsorption of metal ions and organic molecules in aqueous solution.

In this paper, atom transfer radical polymerization (ATRP) and radical grafting polymerization were combined to synthesize a novel amphiphilic hybrid material, meanwhile, the amphiphilic hybrid material was employed in the absorption of heavy metal and organic pollutants. After the formation of attapulgite (ATP) ATRP initiator, ATRP block copolymers of styrene (St) and divinylbenzene (DVB) were grafted from it as ATP-P(S-b-DVB). Then radical polymerization of acrylonitrile (AN) was carried out with pendent double bonds in the DVD units successfully, finally we got the inorganic-organic hybrid materials ATP-P(S-b-DVB-g-AN). A novel amphiphilic hybrid material ATP-P(S-b-DVB-g-AO) (ASDO) was obtained after transforming acrylonitrile (AN) units into acrylamide oxime (AO) as hydrophilic segment. The adsorption capacity of ASDO for Pb(II) could achieve 131.6 mg/g, and the maximum removal capacity of ASDO towards phenol was found to be 18.18 mg/g in the case of monolayer adsorption at 30°C. The optimum pH was 5 for both lead and phenol adsorption. The adsorption kinetic suited pseudo-second-order equation and the equilibrium fitted the Freundlich model very well under optimal conditions. At the same time FT-IR, TEM and TGA were also used to study its structure and property.