Tuning Lignite Structure via Hydromodification To Promote the Formation of Coal-Based CNTs: Exploration for the Carbon Source of CNTs.

Although the preparation of coal-based carbon nanotubes (CNTs) has been realized in many studies, the relationship between carbon source structure of coal and CNT growth has not been studied in depth. In this study, we used lignite and KOH as raw material and catalyst and tuned lignite structure via hydrothermal modification to promote the formation of CNTs during catalytic pyrolysis. The main carbon source of CNTs was explored from the change of coal structure and pyrolysis characteristics. The results indicate that the CNT yield of lignite pyrolysis products is only 2.39%, but the CNT yield increases significantly after lignite was hydrothermally modified in a subcritical water-CO system. The graphitization degree, the order degree, and CNT content increase continuously with the increase in modification temperature, and C-M340 has the highest CNT content of 9.41%. Hydromodification promotes the rearrangement of aromatic carbon structures to generate more condensed aromatic rings linked by short aliphatic chains and aromatic ether bonds. The variation of these structures correlates well with the formation of CNTs and leads to the change in the carbon source components released during coal pyrolysis. Compared to lignite, modified coal releases more aromatic compounds, especially polycyclic aromatic hydrocarbons with ≥3 rings and phenols during catalytic pyrolysis, which is conducive to the transformation into carbon clusters and provides carbon sources for CNT growth. In addition, modified coal releases a slightly more carbon-containing gas (CH4 and CO) than lignite, which has a limited effect on the growth of CNTs. This study provides a novel and efficient method for enhancing the growth of CNTs by a molecular tailoring strategy of coal.

Surface plasmon resonance biosensor for label-free and highly sensitive detection of point mutation using polymerization extension reaction.

A novel biosensing technique was developed for label-free and highly sensitive detection of point mutation using surface plasmon resonance (SPR) biosensor coupled with polymerization extension reaction. In this work, 3'-thiolated DNA probes with complementary sequences to target DNA were immobilized onto the sensor surface via molecular self-assembly. In the presence of wild target sequences, the primers can be selectively extended by DNA polymerase to form double-stranded DNA. In contrast, mutant target sequences, containing one mutation site mismatched with the 3'-end base of the primer, cannot be elongated. Thus, the extension reaction products can hybridize with the capture probes modified on the sensor surface to induce an SPR signal. The experimental results showed that the presented approach could detect the mutant sequences in BRCA1 gene related to inherited breast cancer, and the wild-type and mutant-type sequences were successfully discriminated. Using synthetic DNA sequences as targets, 100pM detection limits were achieved under the optimal reaction conditions. Hence, this highly sensitive and specific assay might have the potential to become an efficient alternative technique for point mutation detection in biomedical research and clinical diagnosis.

Angiogenesis of the frozen-thawed human fetal ovarian tissue at the early stage after xenotransplantation and the positive effect of Salviae miltiorrhizae.

Cryopreserving ovarian tissue followed by transplantation has been suggested to preserve fertility for young cancer survivors. However, ischemia in the early stage after transplantation causes massive follicle loss. The aim was to investigate the histological and ultrastructural characteristics of the frozen-thawed human fetal ovarian tissue after xenotransplantation and the effects of Salviae miltiorrhizae (SM) on the angiogenesis. The human fetal ovarian tissues were frozen-thawed, xenografted into the immunodeficient nu/nu mice, and then collected 2, 7, and 28 days after transplantation. SM was administered. Compared with that of the frozen-thawed ovarian tissue, the total follicle number of the grafts was greatly reduced. Nearly half of the primordial follicles were damaged at different levels on day 2. Moreover, edema was prevalent in the stroma during the first week after the graft, especially on day 2. The microvessel density of the grafts was increased on day 2, reached a peak on day 7, and then declined on day 28. Both healthy primordial follicle proportion and the total healthy primordial follicles pool in the SM group were significantly higher than those of the control group (P = 0.003 and P = 0.001). We found a statistically significant difference of microvessel density between the two groups on day 2 (P < 0.001). In the frozen-thawed fetal ovarian grafts, angiogenesis has been begun on day 2, and the first week is the critical time for the grafts to regain their function, in which SM can facilitate graft vascularization and improve the preservation of primordial follicles.

[Effect of acute exhaustive exercise on gastrointestinal transit rate and nitrergic nerves in myenteric plexus in rats ileum].

AIM: To investigate the effect of acute exhaustive exercise on gastrointestinal motility and its enteric nervous mechanisms. METHODS: 24 rats were randomly divided into control group (C) and acute exhaustive exercise group (AEE). The rate of gastrointestinal transit was measured and histologic changes of nitriergic nerves in ileum myenteric plexus were observed with enzymatic histochemical and image analytic technique. RESULTS: In the rats of AEE group, the rate of gastrointestinal transit was delayed comparing with C group (P < 0.05), the numbers of nitrergic neurons and expression levels of nitric oxide synthase (NOS) in the ileum myenteric plexus significantly increased comparing with C group (P < 0.01). CONCLUSION: It is possible that increase of nitrergic neurons and expression levels of NOS in the myenteric plexus of small intestine are one of the mechanisms of delay of gastrointestinal transit rate in acute exhaustive exercise rats.