Biomedical subjects

Yanjie Xu

Publications and source records attributed to Yanjie Xu.

3 recordsLinked to original sources

PubMed2004

Heterogeneous catalysis using a nanostructured solid acid resin based on lyotropic liquid crystals.

The catalytic reactivity and selectivity of the first example of a nanostructured solid acid resin (1) are described. This new type of solid acid catalyst is formed by the self-assembly and copolymerization of two acidic lyotropic liquid crystals (LLCs), affording a columnar hexagonal polymer network with monodisperse nanochannels lined with sulfonic acid groups. The performance of this material as a heterogeneous catalyst was compared against that of two commercially available, amorphous sulfonic acid resins: Amberlyst-15 and Nafion NR50. Using the acid-catalyzed esterification of benzyl alcohol with 1-hexanoic acid in dry toluene as a test reaction, it was found that resin 1 displayed only slightly lower overall reactivity as compared to Amberlyst-15 and Nafion NR50 but more than an order of magnitude higher selectivity for the desired ester product over dibenzyl ether side-product. Control experiments revealed that the higher product selectivity is not due to differences in relative acidity between the nanostructured acid resin and the two amorphous resins. Instead, it appears that a large component of the enhanced selectivity is due to the regular nanostructure present in the LLC resin, which affords a much more uniform local acid microenvironment for reactions to occur. Resin 1 can also be recycled with almost complete recovery of catalytic activity and selectivity, and with essentially no leaching of reactive groups into the solution phase.

Journal Article↗

PubMed2003

Diagnosis, treatment and prognosis of thymoma: an analysis of 116 cases.

OBJECTIVE: To study the diagnosis and treatment of thymoma and to assess its prognostic factors. METHODS: The clinical data of 116 patients with thymoma were collected. A retrospective analysis was performed, by comparing the survival rate calculated by the Kaplan-Meier method with the rate of recurrence or metastasis. RESULTS: The standard posteroanterior and lateral chest radiographs were reliable means of detection of most thymomas. Myasthenia gravis was the most commonly paraneoplastic disease (25.0%, 29/116). The extensive radical resection was beneficial for reducing the rate of recurrence of stage I or stage II thymomas (chi(2) = 4.941, P = 0.0219). The survival time could be prolonged by postoperative radiotherapy and chemotherapy. There was a strong correlation between the clinical stage and the histological classification (according to MH classification), through which the invasive behavior of thymoma could be predicted (chi(2) = 19.76, P = 0.007, RR = 1.47). The 3- 5- and 10-year survival rates were 81.2%, 67.9%, and 40.5%, respectively. Statistical analysis showed a significant negative correlation between the stage and the survival rate (chi(2) = 29.73, P = 0.0000, RR = 0.15). CONCLUSION: The prognosis of thymoma depends mainly on the histological classification, clinical stage and multimodality treatment rather than on the paraneoplastic diseases.

Adolescent↗

PubMed2002

[Diagnosis, treatment and prognosis of thymoma: analysis of 116 cases].

OBJECTIVES: To study the diagnosis and treatment of thymoma and to assess prognosis factors. METHODS: The clinical data on 116 patients with thymoma were collected. A retrospective analysis was performed by comparison of their survival rates computed by the actuarial method and rate of recurrence and metastasis. RESULTS: Chest radiograph was used chiefly for the preoperative diagnosis of thymoma; myasthenia gravis (MG) (25.0%, 29/116) was the most common paraneoplastic disease. An extensive and radical resection was carried out to reduce the recurrence rate of thymoma with stage I and stage II (chi(2) = 4.941 P = 0.0219). The survival time was prolonged by postoperative radiotherapy and chemotherapy. A strong correlation was noted between the clinical stage and histologic subtype of M-H classification, by which the invasive behavior of thymoma was predicted (r = 0.385, P = 0.007). The 3-, 5-, and 10-year survival rates were 81.2%, 67.9% and 40.5%, respectively. Statistical analysis showed a significant negative correlation between stage and survival rate (r = -0.897, P = 0.0000). CONCLUSION: The prognosis of thymoma depends mainly on the histologic subtype, clinical stage and multimodality treatment rather than paraneoplastic diseases.

Adolescent↗