Sample introduction for microfluidic systems.
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Journal Article↗
Biomedical subjects
Qun Fang
Publications and source records attributed to Qun Fang.
Cardiovascular regulation and expressions of NO synthase-tyrosine hydroxylase in nucleus tractus solitarius of ovine fetus.
The purpose of this study was to examine cardiovascular responses to fourth cerebral ventricle (4V) administration of nitroglycerin (NTG) or an inhibitor of nitric oxide (NO) synthase (NOS) in the near-term ovine and to determine whether, during birth, neuronal NOS (nNOS) is induced in noradrenergic A1 neurons in the medial nucleus tractus solitarius (mNTS). In chronically instrumented fetal sheep, 4V injection of NTG (1.2 nmol), an NO donor, produced an arterial blood depressor and a moderate decrease in heart rate. Arterial blood pressure is increased by 4V administration of NG-nitro-L-arginine methyl ester (10 nmnol), an inhibitor of NOS, in fetuses. Sections of the medulla from fetuses and newborn lambs were examined by using immunolabeling with tyrosine hydroxylase (TH) antibody combined with NADPH diaphorase (NADPHd) histochemistry, a marker of nNOS activity. The NADPHd-positive cells and TH-positive cells containing NADPHd reactivity were significantly increased in the mNTS of newborns compared with the fetuses. The results suggest that during birth, there is upregulation of NADPHd/nNOS in the noradrenergic neurons of mNTS resulting in a centrally mediated reduction of fetal arterial blood pressure.
Animals↗
[A survey of the level of AIDS knowledge among people concerned in Nanjing City].
OBJECTIVES: To investigate the level of AIDS knowledge among people concerned in Nanjing city in order to provide scientific evidence and constructive suggestions for the government to formulate relevant policies for AIDS control. METHODS: Three sets of questionnaires on AIDS knowledge were designed, the scores calculated, and the results evaluated. RESULTS: Of the 2,500 questionnaires issued to 4 different groups of people, 2,436 were collected back with effective answers, 991 from medical and health-related workers with the mean score of 58, 473 from college students with the mean score of 39.9, 524 from common city residents with the mean score of 42.3, and 448 from those working in high risk environment with the mean score of 47. CONCLUSIONS: The level of AIDS knowledge among people concerned in Nanjing city was far below the requirement of the nation, especially among medical and health-related workers. Efforts must be made to raise the level of AIDS knowledge of people concerned so as to enhance the prevention and treatment of the disease.
Acquired Immunodeficiency Syndrome↗
A high-throughput continuous sample introduction interface for microfluidic chip-based capillary electrophoresis systems.
The development of efficient sample introduction and pretreatment systems for microfluidic chip-based analytical systems is important for their application to real-life samples. In this work, world-to-chip interfacing was achieved by a novel flow-through sampling reservoir featuring a guided overflow design. The flow-through reservoir was fabricated on a 30 x 60 x 3 mm planar glass chip of crossed-channel design used for capillary electrophoresis separations. The 20-microL sample reservoir was produced from a section of plastic pipet tip and fixed at one end of the sampling channel. Sample change was performed by pumping 80-microL samples sandwiched between air segments at approximately 0.48 mL/min flow rate through the flow-through reservoir, introduced from an access hole on the bottom side of the chip. A filter paper collar wrapped tightly around the reservoir guided the overflowing sample solution into a plastic trough surrounding the reservoir and then to waste. The performance of the system was demonstrated in the separation and determination of FITC-labeled arginine, glycine, phenylalanine, and glutamic acid with LIF detection, by continuously introducing a train of different samples through the system without electrical interruption. Employing a separation channel of 4 cm (2-cm effective separation length) and 1.4-kV separation voltage, maximum throughputs of 80/h were achieved with <4.1% carryover and precisions ranging from 1.5% for arginine to 2.6% RSD (n = 11) for glycine. The sampling system was tested in the continuous monitoring of the derivatizing process of amino acids by FITC over a period of 4 h, involving 166 analytical cycles. An outstanding overall precision of 4.8% RSD (n = 166) was achieved for the fluorescein internal standard.
Journal Article↗