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Biomedical subjects

Sheng Liu

Publications and source records attributed to Sheng Liu.

26 records · Page 2Linked to original sources
PubMed2004

Species diversity and distribution for phytoplankton of the Pearl River estuary during rainy and dry seasons.

Based on data collected at 31 stations and 1 continuous station in the Pearl River estuary during cruises of July 1999 (rainy season) and January 2001 (dry season), this study examined taxonomic composition, abundance, and spatial distribution of phytoplankton. Results indicated 130 species of phytoplankton in the samples from the rainy season, and 132 species in the dry season. Among them, in the rainy season, 82 species of diatom, 39 fresh-water and half-fresh-water species and 41 species of red tide organisms were found. Within these, there were 54 tropical and sub-tropical species, 47 cosmopolitan species and 17 temperate species. The abundance of phytoplankton in the rainy season was higher than that of the dry season, with an average of 6.3 x 10(5) cells x L(-1) and 1.4 x 10(5) cells x L(-1), respectively. Diversity index (H') and evenness (J) were 2.47 and 0.57 in the rainy season, and 2.01 and 0.54 in the dry season. The dominant phytoplankton species in the rainy season was Skeletonema costatum with an average of 2.8 x 10(5) cells x L(-1) and 45.0% of the total phytoplankton abundance. In the dry season, Eucampia zoodiacus became the key dominant species (5.9 x 10(4) cells x L(-1)) when it was 43.47% of the total phytoplankton abundance. Distribution of the dominant species varied with salinity of sea-water, and their amounts correlated negatively with nutrients and zooplankton.

Animals↗
PubMed2004

Variation of phytoplankton biomass and primary production in Daya Bay during spring and summer.

Environmental factors, phytoplankton biomass (Chl a) and primary production of two water areas in Daya Bay (Dapeng'ao Bay and Aotou Bay) were investigated during the transition period from spring to summer. Chl a ranged from 3.20 to 13.62 and 13.43 to 26.49 mg m(-3) in Dapeng'ao Bay and Aotou Bay respectively, if data obtained during red tides are excluded. Primary production varied between 239.7 and 1001.4 mg Cm(-2) d(-1) in Dapeng'ao Bay. The regional distribution of Chl a and primary production were mostly consistent from spring to summer in both bays. Seasonal transition characters have been found in Daya Bay from spring to summer, including high values of DO, nitrate and silicate. Size structures of phytoplankton and its primary production do not change very much from spring to summer, with micro-phytoplankton dominating and contributing about 50% of the whole. In Daya Bay, phytoplankton is limited by nitrogen in spring, and by phosphate in summer. Artificial impacts are evident from high temperature effluent from nuclear power stations, aquaculture and sewage. During the investigation, a red tide occurred in Aotou Bay, with a maximum Chl a of 103.23 mgm(-3) at surface and primary production of 2721.9 mg Cm(-2) d(-1) in the red tide center. Raised water temperature and nutrient supply from land-sources help to stimulate annual red tides.

Biomass↗
PubMed2004

Clear speech perception in acoustic and electric hearing.

When instructed to speak clearly for people with hearing loss, a talker can effectively enhance the intelligibility of his/her speech by producing "clear" speech. We analyzed global acoustic properties of clear and conversational speech from two talkers and measured their speech intelligibility over a wide range of signal-to-noise ratios in acoustic and electric hearing. Consistent with previous studies, we found that clear speech had a slower overall rate, higher temporal amplitude modulations, and also produced higher intelligibility than conversational speech. To delineate the role of temporal amplitude modulations in clear speech, we extracted the temporal envelope from a number of frequency bands and replaced speech fine-structure with noise fine-structure to simulate cochlear implants. Although both simulated and actual cochlear-implant listeners required higher signal-to-noise ratios to achieve normal performance, a 3-4 dB difference in speech reception threshold was preserved between clear and conversational speech for all experimental conditions. These results suggest that while temporal fine structure is important for speech recognition in noise in general, the temporal envelope carries acoustic cues that contribute to the clear speech intelligibility advantage.

Adult↗
PubMed2004

[The analysis of HLA-B15 and B40 antigen polymorphism in Xi'an].

AIM: To study the distribution character of HLA-B15 and B40 in Xi'an population. METHODS: PCR-SSP and reverse PCR-SSOP reaction pattern were used to type the HLA-B15 and B40 alleles of 3 601 blood samples in Xi an. RESULTS: HLA-B15 and B40 gene frequencies were 0.1483 and 0.1414, respectively, among 3 601 blood samples from Xi'an population which take up 57.91% in HLA-B alleles. CONCLUSION: The distribution character of HLA-B15 and B40 alleles in Xi'an population were different compared with other populations.

Black or African American↗
PubMed2004

Gels and more gels: probing toxicity.

Two-dimensional electrophoresis (2-DE) remains an important technology in the study of protein expression. In many applications, 2-DE has been supplanted by liquid chromatographic and mass spectrometric approaches that overcome some of its limitations and labor intensiveness. Nevertheless, 2-DE has exceptional relevance in toxicology and, despite the challenges, its implementation continues to support toxicologists in understanding the biological effects of chemical exposures in living systems. This review will address the use of 2-DE-based proteomics in toxicology and recent developments in this strategy, considering the unique nature of toxicity testing and the issues of dynamic range and reproducibility that have previously limited the overall utility of 2-DE in this field.

Animals↗
PubMed2003

[Radionuclide pulmonary perfusion imaging in evaluating pulmonary hypertension in patients with rheumatic heart disease].

OBJECTIVE: To evaluate the degree of pulmonary hypertension in patients with rheumatic heart disease using radionuclide pulmonary perfusion imaging. METHODS: The pulmonary perfusion in 25 patients with rheumatic heart disease was examined using scintigram with macroaggregates of (99m)Tc-labeled human serum albumin (PPS) before and 7 days after operation. PPS was analyzed for (1) pulmonary perfusion steady time (PT), right upper and lower lung count ratio (RULR). The results were compared with those of catheterization examination during the operation. RESULTS: The pulmonary arterial systolic pressure (PAs) and total pulmonary resistance (TPR) were (60 +/- 21) mm Hg and (421 +/- 106) dyn if PT > or = 20 seconds and RULR > or = 2; The PAs and TPR were (28 +/- 5) mm Hg and (188 +/- 28) dyn if PT < 20 seconds and RULR < 2. The PPS changed in most of the patients during early operation. CONCLUSION: The degree of injury in pulmonary vascular in patients with rheumatic heart disease could be quantitatively analysed by PPS.

Adult↗
PubMed2002

[Transarterial intrahepatic xenotransplantation of microencapsulated newborn porcine islets--an experimental study of type 1 diabetes mellitus].

OBJECTIVE: To evaluate the physiologic features and probable side effects of transarterial intrahepatic xenotransplantation of microencapsulated newborn porcine islets. METHODS: Six artificial diabetic canines were transplanted intrahepatically with 6-9 x 10(5) encapsulated newborn porcine islets without immunosuppression. Before and after the transplantation, the serum C peptide, glucose tolerance test, and dosage of insulin were measured. Samples of the livers and pancreases were examined pathologically 6 months after the operation. RESULTS: After the transplantation of microencapsulated porcine islets, the serum C peptides were elevated significantly. The plasma glucose returned to normal gradually. The dosage of insulin decreased. Six months after the operation, the usage of insulin in 2 dogs was stopped and the normal plasma glucose was kept for 180 days. The pathologic examination showed the xenografts located in the interlobular artery of the livers and the livers of canines were not damaged. CONCLUSION: The transplantation may correct the high plasma glucose level of diabetic canines without immunosuppression and has no side reactions.

Animals↗