Nitrogen-doped graphene aerogel as both a sulfur host and an effective interlayer for high-performance lithium-sulfur batteries.

Lithium-sulfur batteries have attracted great concern because of the high theoretical capacity of sulfur (1675 mA h g-1). However, the poor electrical conductivity and volumetric expansion of sulfur along with the dissolution of lithium polysulfides largely limit their practical application. In this study, nitrogen-doped graphene aerogel (NGA) with high nitrogen content and porosity is used as a host for the impregnation of sulfur. The effects of sulfur impregnation on the specific surface area, pore volume, and microstructure of NGA supported sulfur composite (S@NGA) are well investigated. Furthermore, NGA is also processed into a NGA film, which is sandwiched between a separator and S@NGA cathode. The lithium-sulfur battery with such a configuration delivers a high reversible capacity of 1514 mA h g-1 at 0.1 C, excellent rate performance (822 mA h g-1 at 2.0 C), and good cycling stability (946 mA h g-1 at 0.5 C even after 100 cycles). The enhanced electrochemical performance can be ascribed to the introduction of the NGA interlayer, the unique interconnected porous structure, and strong interaction between the three-dimensional nitrogen-doped graphene network and the homogeneously dispersed sulfur and/or lithium polysulfides.

Preparation and characterization of a composite hydrogel with graphene oxide as an acid catalyst.

In this study, a facile method for synthesizing a novel graphene oxide/pyrrole-formaldehyde (GOP-1) composite hydrogel was developed via in situ polymerization of pyrrole and formaldehyde in the presence of graphene oxide sheets without any additional catalyst. During the polymerization, graphene oxide can act as a two-dimensional template to regulate the aggregation state of polymer and as an acid catalyst to accelerate the reaction rate of pyrrole and formaldehyde. The morphology and microstructure were investigated by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, respectively. The chemical properties were analyzed via X-ray photoelectron spectroscopy, infrared spectroscopy, and Raman spectroscopy. The freeze-dried GOP-1 composite hydrogel exhibited a large specific surface area, high nitrogen content, and three-dimensional network structure. Based on the above features, the freeze-dried GOP-1 composite hydrogel used as a gas adsorbent showed a high carbon dioxide uptake capacity at 1.0 bar and 273 K (11.1 wt%), in sharp contrast to that of graphene oxide (7.4 wt%). Furthermore, the as-prepared composite hydrogel may possess attractive potential in the fields of electrode material, tissue engineering, and water treatment.

Amelioration of osteoarthritis by intra-articular hyaluronan synthase 2 gene therapy.

Osteoarthritis (OA) is a chronic, degenerative disorder of multifactorial aetiology, characterized by loss of articular cartilage and periarticular bone remodelling. Goals of managing OA include controlling pain, maintaining and improving function and health-related quality of life, and limiting functional impairment. Although several managements had been proved to ameliorate the symptoms of osteoarthritis, no methods could cure it thoroughly. High-molecular-weight hyaluronan (HMW-HA) is a major component of synovial joint fluids which physically acts as a viscous lubricant for slow joint movements and as an elastic shock absorber during rapid movements. It also has a variety of biologic effects in vivo, such as inhibiting the release of inflammatory factors and suppressing the degradation of cartilage matrix. Intra-articular injection of synthetic HMW-HA has been used as viscosupplement for knee OA and its therapeutic efficacy has been verified. However, repeated injections of HMW-HA which is needed to control symptoms increase the probability of infection and sometimes there will have acute joint pain with effusion, which requires aspiration to exclude sepsis. In order to overcome the disadvantages of repeated injections of HMW-HA, novel strategies should be developed. As HMW-HA is synthesized by hyaluronan synthase-2 (HAS2), we postulate that HAS2 gene could be delivered into intra-articular cells by methods of gene therapy to achieve long-lasting synthesis of HMW-HA. In our opinion, this strategy seems to hold interesting future prospects for the treatment of OA.

Cloning and expression of a novel human galectin cDNA, predominantly expressed in placenta(1).

A novel human galectin cDNA (PPL13) was isolated by screening a human 18-week fetal brain library. The mRNA was predominantly expressed in placenta, while the expression of it was not or barely detectable in heart, brain, lung, liver, skeletal muscle, kidney, and pancreas by Northern blot. COS-7 cells transfected with cDNA encoding human PPL13 sequestered the protein in nuclei although it lacked any known nuclear localization signal. STS of Unigene Hs. 24236 placed the cDNA to human chromosome 19q13.2.

Cloning and expression of a novel retinoblastoma binding protein cDNA, RBBP10.

A 2860-bp cDNA was isolated from a human fetal brain cDNA library by high throughput cDNA sequencing, which encodes a putative protein with 186 amino acids. The putative protein shares 90.7% identity with rat pBOG (3403163) and shares 93.4% identity with human RBBP9 (NP_006597.1). A conserved RB binding domain, L x C x E, located between residue 63 and 68 was recognized. Therefore, it was named RBBP10. Mapviewer analysis locates it on human chromosome 20q11.22. RBBP10 spans about 9.6 kb of the genome and consists of six exons and five introns. RT-PCR revealed that the gene was expressed widely in various human tissues, and the expression level is somewhat higher in tumor tissues than in normal tissues. But subsequent sequencing analysis did notfound any mutation of this in tumor tissues. The COS 7 cell transfected with the ORF of RBBP10 showed that the protein was distributed both in the cytoplasm and in the nucleus. Our results suggest that RBBP10 is the orthologue of the rat BOG gene (AF025819) and a paralogue of human RBBP9 (AF039564).

Cloning and expression pattern of a spermatogenesis-related gene, BEX1, mapped to chromosome Xq22.

Through screening a human fetal brain cDNA library, a cDNA similar to the mouse Bex1 was isolated. This new gene was named brain expressed X-linked protein 1 (BEX1). Northern blot analysis revealed a 1.0 kb transcript highly expressed in brain, pancreas, testis, and ovary, with lower levels present in heart, placenta, liver, kidney, spleen, thymus, prostate, small intestine, colon (no mucus), thyroid, spinal cord, and adrenal gland. No hybridization signal was seen in lung, skeletal muscle, peripheral blood leukocyte, stomach, lymph node, trachea, and bone marrow. The BEX1 gene was localized to chromosome band Xq22 between markers between DXS990 and DXS1059 by screening Stanford radiation hybrid G3 panels. In situ hybridization of mouse testis using BEX1 as a probe detected the signal in the pachytene spermatocytes and spermatids but not in spermatogonia. Furthermore, it was not detected at 6, 9, and 12 days postpartum, was present in low amount on Days 15 and 18 and its expression increased sharply after the initiation of puberty (about 21 days) in mouse testis.

Cloning, expression, and genomic structure of a novel human Rap2 interacting gene (RPIP9).

During a large-scale screen of a human fetal brain cDNA library, a full-length cDNA encoding a novel Rap2 interacting protein was isolated and sequenced. The cDNA is 3397bp long and has a predicted open reading frame encoding a protein of 329 aa. The predicted protein shows high homology to mouse and human RPIP8, and has a RUN domain near its C-terminus. The gene was mapped to human chromosome 7q21-7q22 and has 9 exons and 8 introns. The expression pattern was also detected by cycle-limited reverse polymerase chain reaction (RT-PCR).

Cloning and identification of a cDNA that encodes a novel human protein with thrombospondin type I repeat domain, hPWTSR.

A cDNA was isolated from the fetal brain cDNA library by high throughput cDNA sequencing. The 2390 bp cDNA with an open reading fragment (ORF) of 816 bp encodes a 272 amino acids putative protein with a thrombospondin type I repeat (TSR) domain and a cysteine-rich region at the N-terminus, so it is named hPWTSR. We used Northern blot detected two bands with length of about 3 kb and 4 kb respectively, which expressed in human adult tissues with different intensities. The expression pattern was verified by RT-PCR, revealing that the transcripts were expressed ubiquitously in fetal tissues and human tumor tissues too. However, the transcript was detected neither in ovarian carcinoma GI-102 nor in lung carcinoma LX-1. Blast analysis against NCBI database revealed that the new gene contained at least 5 exons and located in human chromosome 6q22.33. Our results demonstrate that the gene is a novel member of TSR supergene family.