Biomedical subjects

P Q Yang

Publications and source records attributed to P Q Yang.

4 recordsLinked to original sources

PubMed2001

Cytotoxic flavonoids with isoprenoid groups from Morus mongolica.

A new pyranoflavanone, sanggenol L (1), a Diels-Alder type adduct regarded as a cycloaddition product of a dehydrogeranylflavanone and a prenylchalcone, sanggenol M (2), along with four new 2-arylbenzofurans with isoprenoid units, mulberrofurans W-Z (3-6), were isolated together with 10 known flavonoids from Chinese Morus mongolica. The structures of these novel compounds were elucidated by spectroscopic methods. All flavanones investigated here showed higher cytotoxicity against human oral tumor cell lines (HSC-2 and HSG) than against normal human gingival fibroblasts (HGF). Among them, the cytotoxicity of compound 2 and the Diels-Alder type flavanone sanggenon C (7) isolated from Morus cathayana were the most potent. On the other hand, seven 2-arylbenzofurans exhibited lower cytotoxicity and tumor specificity as compared with flavanones.

Antineoplastic Agents↗

PubMed1998

Global interaction, global inequality, and migration of the highly trained to the United States.

The authors "argue that national variation in the size of highly trained migration can be explained by interaction and inequality between nations, both reflecting the process of global integration. Guided by this analytical framework, we tested the structural determinants of highly skilled migration to the United States. The evidence confirms our hypotheses that economic and educational interactions between sending countries and the United States increase the flow of the highly trained to the United States. Results also provide mixed proof for our hypotheses that levels of professional migration are positively associated with disparities between sending countries and the United States in living conditions, research conditions, children's educational opportunities, political conditions, and professional employment opportunities."

Americas↗

PubMed1994

Explaining immigrant naturalization.

"Prior research on immigrant naturalization has focused mainly on the effects of immigrants' adaptation experiences and demographic characteristics on their propensity to naturalize. This article proposes a broader analytical framework which incorporates immigrants' individual characteristics and larger social contexts in the country of origin and the country of destination to explain the likelihood of citizenship acquisition. The framework is tested for a cohort of recent immigrants, using the PUMS data from the 1980 U.S. census. The results show that economic, political, social, cultural and geographical conditions in the country of origin, and immigrants ethnic communities and urban concentration in the country of destination, to a large extent influence immigrants' propensity for naturalization and that, net of the contextual factors, many of the immigrants' adaptation and demographic characteristics are also significant predictors of citizenship acquisition."

Acculturation↗

PubMed1991

Cucurbitacin contents in Hemsleya dolichocarpa.

Hemsleya dolichocarpa was studied for its cucurbitacin contents during growing period. A colorimetric method was used to determine the total cucurbitacin levels, and a TLC densitometric assay was employed for estimating dihydrocucurbitacin F and its acetate, two active principles in Hemsleya plants. Cucurbitacin contents rise progressively from May to November; the month of November is thus the most desirable time for harvesting plant materials for medicinal uses. It was noticed that the spoiled plant samples gave an intense color reaction while dihydrocucurbitacin F and its acetate levels were not significantly altered. The accuracy of the assays is discussed.

Antineoplastic Agents, Phytogenic↗