Biomedical subjects

Hao Zhou

Publications and source records attributed to Hao Zhou.

41 records · Page 3Linked to original sources

PubMed2002

Biomimetic stereoselective formation of methyllanthionine.

Fmoc-(2R,3S)-3-methyl-Se-phenylselenocysteine was used for the synthesis of dehydrobutyrine (Dhb)-containing peptides. Biomimetic cyclization via Michael addition of Cys to a Dhb yielded the B-ring of the lantibiotic subtilin as a single diastereomer. The methyllanthionine product was shown to have the natural configuration by preparation of the authentic stereoisomer. The formation of a single isomer suggests that the prepeptide has a strong intrinsic preference for the stereochemistry observed in lantibiotics. [reaction: see text]

Alanine↗

PubMed2002

[Predicting low NOx combustion property of a coal-fired boiler].

More attention was paid to the low NOx combustion property of the high capacity tangential firing boiler, but the NOx emission and unburned carbon content in fly ash of coal burned boiler were complicated, they were affected by many factors, such as coal character, boiler's load, air distribution, boiler style, burner style, furnace temperature, excess air ratio, pulverized coal fineness and the uniformity of the air and coal distribution, etc. In this paper, the NOx emission property and unburned carbon content in fly ash of a 600 MW utility tangentially firing coal burned boiler was experimentally investigated, and taking advantage of the nonlinear dynamics characteristics and self-learning characteristics of artificial neural network, an artificial neural network model on low NOx combustion property of the high capacity boiler was developed and verified. The results illustrated that such a model can predicate the NOx emission concentration and unburned carbon content under various operating conditions, if combined with the optimization algorithm, the operator can find the best operation condition of the low NOx combustion.

Carbon↗

PubMed2002

[Regulation of the expression of pulmonary arterial collagen by protein kinase C and breviscapine in chronic hypoxic rats].

OBJECTIVE: To investigate the effects of protein kinase C and breviscapine on the expression of pulmonary arterial collagen in chronic hypoxic rats. METHODS: Thirty-six rats were randomly divided into three groups: control group (A), hypoxic group(B),hypoxic + breviscapine(bre.)group (C). The ultrastructure of pulmonary arterioles was observed by electron microscope; the PKC activities of lung tissues were measured by radioactivity; the expression of PKC and collagen I and III in arterioles was observed by immunohistochemistry; the expression of procollagen I and III mRNA in arterioles was observed by in situ hybridization. The averages of integral light density( A )of PKC, collagen I and III and procollagen I and III mRNA in pulmonary arterioles were detected by image analysor and their relative contents were calculated. RESULTS: (1) The mean pulmonary arterial pressure (mPAP) and the weight ratio of RV to LV + S in group B were higher than those in group A(P < 0.01); the mPAP and the weight ratio of RV to LV + S in group C were lower than those in group B (P < 0.01). (2)Electron microscopy showed breviscapine could inhibit the deposition of collagenous fibers in pulmonary arterioles induced by hypoxia.(3) The total,cytosolic and particulate fractions of PKC activity and the ratio of particulate fraction to total PKC activity in group B were higher than those in group A(P < 0.01); the total,cytosolic and particulate fractions of PKC activity and the ratio of particulate fraction to total PKC activity in group C were lower than those in group B (P < 0.05). (4) The A values of PKC, collagen I and procollagen I mRNA in pulmonary arterioles were higher in group B than in group A(P < 0.01),and the A values of PKC, collagen I and procollagen I mRNA in pulmonary arterioles were lower in group C than in group B(P < 0.01); the differences in the A values of collagen III and procollagen III mRNA in pulmonary arterioles were not significant among the three groups (P > 0.05).(5)There were good correlations between the PKC activity of the lung tissues and the A values of collagen I and procollagen I mRNA in pulmonary arterioles(P < 0.05),and between the A values of PKC in pulmonary arterioles and those of collagen I and procollagen I mRNA in pulmonary arterioles(P < 0.01). CONCLUSIONS: The PKC signal pathway regulates the expression of pulmonary arterial collagen in chronic hypoxic rats which may play an important role in the pathogenesis of pulmonary hypertension and structural remodeling of pulmonary arterials breviscapine can lower hypoxic pulmonary hypertension by inhibiting the effect of PKC and decreasing the expression of pulmonary arterial collagen.

Animals↗

PubMed2002

The effect of losartan intervention on the regulation of pulmonary arterial collagen expression by protein kinase C in chronic hypoxic rat models.

OBJECTIVE: To investigate the regulating role of protein kinase C(PKC) and the effects of losartan intervention on the expression of pulmonary arterial collagen in chronic hypoxic rat models. METHODS: Thirty six rats were randomly divided into three groups: healthy control group(A), hypoxic model group(B),and hypoxic + losartan intervention group (C). MT% (vessel medial thichness/ total thichness) and WA% (vessel wall area/total area) of pulmonary arterioles were measured with light microscopy,the ultrastructures of pulmonary arterioles were observed by electronic microscope, the PKC activities of lung tissues were detected with radioactive method,the protein and(or) mRNA expression of PKC and collagen I, III in arterioles were observed using immunohistochemistry and in situ hybridization. The relative contents [integral light density(LD)] of PKC, collagen I, III and procollagen I, III mRNA in pulmonary arterioles were calculated with image analysor. RESULTS: (1) The mean pulmonary arterial pressure and weight ratio of right ventricle (RV) to left ventricle(LV)+septum( S)(RV/LV+S) in group B were significantly higher than those in group A(P < 0.01), but in group C they were significantly lower than those in group B (P < 0.01). (2) MT% and WA% of pulmonary arterioles in group B were significantly increased than those in group A (P < 0.01) while in group C both the parameters were significantly decreased than those in group B (P < 0.01). Collagen fiber deposition in pulmonary arteriolar walls were inhibited in group C by electronic microscopy.(3) The total,cytoplasmic and cytomembrane PKC activities, as well as the ratio of cytomembrane PKC activity to total one in group B were significantly increased than those in group A(P < 0.01),while all these parameters in group C were significantly decreased than those of group B (P < 0.01). (4)LD of PKC,collagen I and procollagen I m RNA expressions in pulmonary arterioles were significantly increased in group B than those in group A(P < 0.01), but in group C they were significantly decreased than those in group B(P < 0.01). There were no significant differences in collagen III and procollagen IIImRNA expressions among the three groups(P > 0.05).(5)Significant positive correlations were found between the PKC activities and collagen I expressions(P < 0.05) and between the expressions of PKC and collagen I in pulmonary arterioles(P < 0.01). CONCLUSIONS: The PKC signal pathway participated the regulation of pulmonary arterial collagen expression in chronic hypoxic rat models and may play an important role in the pathogenesis of pulmonary hypertension and structural remodeling of pulmonary arterials. Losartan could reduce the hypoxic pulmonary hypertension by interference the role of PKC on pulmonary arterial collagen expression.

Animals↗

PubMed2002

[Detection of epileptic waves in EEG based on wavelet transform].

Detection of epileptic waves in EEG is particularly helpful in the interpretation of the underlying process in seizures. This study is aimed at providing a new method for automatic detection of epileptic waves through the wavelet analysis of EEGs. It mainly deals with the detection of spikes or spike-waves based on wavelet transform. Since spikes and spike-waves contain high frequency energy, they will be represented in a particular scale localized in a small time window. According to these feature waveforms of epileptic waves, a continuous processing system for epileptic waveforms detection is constructed. We apply discrete wavelet transform on EEGs. Because of the time-frequency domain localization of wavelet transforms, we can get the local maximal positions across several successive dyadic scales of wavelet transform. And these positions indicate the points of sharp transitions in EEGs. Then we calculate the distance between every two successive maximal positions in each scale. This distance stands for the period of subwave. Furthermore, the distribution of subwave periods of each scale can be worked out. Then, comparing the distribution of normal EEG's and epileptic EEG's. The difference between these two waveforms provides us the criteria for automatic detection and classification. In order to reduce the detection workload, we also compare the detection efficiency of each scale. The scale that provides highest accuracy is selected for our automatic detection system. The results presented in this study show that scale 3 provides the best detection accuracy. So, scale 3 is deemed to be the proper scale for automatic detection. This system has the following advantages: (1) Reduced the workload significantly by selecting proper scale(s) for automatic selection; (2) Enhanced the detection accuracy by selecting proper criteria and threshold; (3) Capable of continuous detection; (4) It is also fit for the detection of other biomedical signals. This system showed good performance, and the initial clinical results obtained are also encouraging.

Electroencephalography↗