Effect of valve opening on starting performance of pump as turbine.

The study on transient characteristics of pump as turbines during atypical startup has not been deeply explored yet. In order to reveal the transient characteristics of a small centrifugal pump reversing as turbine during startup process in this paper, the transient hydraulic performance experiments are conducted for three steady rotational speed cases. Under the condition of each case, three, five and, three valve opening scenarios are completed to measure the performance. The dimensionless analysis are also employed so as to better reveal transient behavior of the pump as turbine during atypical startup. The results show that the rise rate of each performance parameter is different, wherein the shaft power and rotational speed have the fastest rising rate, followed by the flow rate, and the head rise is the slowest. It is clearly seen that the shock phenomenon in static pressure easily occurs at the outlet of pump as turbine. With the increase of valve opening, the dimensionless flow rate, head and, power coefficient all show the evolution trend of gradually increasing.

The acceleration effect of pump as turbine system during starting period.

In order to reveal the influence of starting acceleration on starting process of a pump as turbine system, this paper carries out a numerical calculation of the three-dimensional viscous unsteady flow of pump as turbine circulating piping system under three starting acceleration conditions, and obtains the external and internal flow characteristics of each overflow component during the starting process, and also analyzes the energy loss of each component in the piping system in depth with the help of entropy production method and Q criterion method. The results show that during system start-up, the flow rate and outlet static pressure curves of the pump as turbine are hysteresis relative to the rotational speed, the head curve is similar to a linear rise during slow and medium speed start-up, while it shows a parabolic rise during rapid start-up, the entropy production and vorticity in the impeller domain of the pump as turbine are mainly distributed between the blades, and the distribution decreases during start-up. In addition, the pump similarity law does not apply to the performance prediction during the transient start of the pump as turbine.

Simultaneous detection of 9 respiratory pathogens using a newly developed multiplex real-time PCR panel based on an automatic molecular detection and analysis system.

Timely identification of respiratory pathogens guides specific treatment, reduces hospital costs and minimizes the excessive use of antibiotics. A new multiplex real-time PCR panel was developed based on an automatic molecular detection and analysis system (AutoMolec system), consisting of three separate internally controlled assays. Mycoplasma pneumoniae, Chlamydia pneumoniae, adenovirus, human metapneumovirus, influenza B virus, respiratory syncytial virus and human parainfluenza virus 1-3 may be directly detected in original samples. The system's clinical performance was evaluated by comparison with an approved commercial kit, using 517 clinical samples. The limit of detection of the AutoMolec mRT-PCR panel ranged from 4 × 10-4 ∼3.3 TCID50/mL and no cross-reaction with common respiratory pathogens was observed. The AutoMolec mRT-PCR panel had 99.09% sensitivity and 100.0% specificity and overall detection consistency was 99.61%, making it comparable to that of the commercial kit. Therefore, the AutoMolec mRT-PCR panel has great potential for routine screening of respiratory infection in China.

[Effects of Omphalia lapidescens and Praziquantel on the Infectivity and Ultrastructure of Spirometra erinacei Plerocercoids].

OBJECTIVE: To study the effects of Omphalia lapidescens and praziquantel on the infectivity and ultrastructure of Spironetra erinacei plerocercoids. METHODS: The plerocercoids were taken from frogs (Rana nigromaculata). A total of 168 mice were divided into 21 groups (8 mice per group), each of them was orally infected with 5 plerocercoids. The mice in group 1-9 were inoculated with plerocercoids cultured in media respectively containing different concentrations of O. lapidescens suspension (20, 40 or 80 mg/ml) for 4, 12 or 24 h, respectively. The mice in group 10-18 were inoculated with plerocercoids cultured in media respectively containing different concentrations of praziquantel (20, 80 or 320 µg/ml) for 4, 12 or 24 h, respectively. The mice in group 19-21 were inoculated with plerocercoids cultured in normal culture fluid for 4, 12 or 24 h, respectively, and served as controls. One week after infection, the mice were sacrificed to collect the plerocercoids. Worm reduction rate was calculated. The ultrastructure changes of plerocercoids were observed under transmission electron microscope (TEM) and scanning electron microscope (SEM), respectively. RESULTS: The average number of plerocercoids detected from mice infected by pleroceroids treated with 40, 80 mg/ml O. lapidescens suspension for 4, 12 or 24 h were 1.6, 1.0, and 0.3; 0.3, 0, and 0, respectively, and significantly lower than that of the infected controls (4.1, 3.5 and 3.3) (P < 0.05); the worm reduction rates were 60.0%, 71.4%, and 90.1%; 92.7%, 100%, and 100%, respectively. The average number of pleroceroids detected from mice infected with pleroceroids treated with 320 µg/ml praziquantel for 4, 12, or 24 h were 1.9, 1.3, and 0.4, and significantly lower than that of the infected controls (P < 0.05); the worm reduction rates were 53.7%, 62.9%, and 87.9%, and lower than that of 20 µg/ml praziquantel group (14.6%, 2.9%, and 6.1%) and 80 µg/ml praziquantel group (24.4%, 17.1%, and 24.2%) (P < 0.05). The ultrastructure of plerocercoids cultured in 20 mg/ml O. lapidescens suspension, 20 or 80 µg/ml praziquantel for 4, 12 or 24 h had no significant difference compared with control groups. The plerocercoids cultured in 40 mg/ml O. lapidescens for 4 h or 320 µg/ml praziquantel for 4 or 12 h, showed mild contracture. The pleroceroids cultured in 40 mg/ml O. lapidescens for 12-24 h showed: agglutinate, fusion, fracture or abscission of microtriches, breakdown of plasma membrane, excretion of calcareous corpuscles, and tegument tissue damages. After cultured in 80 mg/ml of O. lapidescens for 24 h, the tissues of plerocercoid were damaged seriously. After cultured in 320 µg/ml praziquantel for 24 h, the plerocercoids showed: obvious contracture in the anterior end of plerocercoid, edema and bulge of plasma membrane, morphological changes of calcareous corpuscles, increase of secretory granules, glycogen depletion, and chromatin compaction in flame cells. CONCLUSION: The infectivity of Spironetra erinacei plerocercoids decreases along with the time of culture and the increase of drug concentration. Omphalia lapidescens and praziquantel can cause extensive tissue damage to the plerocercoids in vitro, and the effect of 0. lapidescens on the infectivity and ultrastructure of plerocercoid is more considerable than that of praziquantel.

A potential association between Toxoplasma gondii infection and schizophrenia in mouse models.

Schizophrenia is a serious neuropsychiatric disease of uncertain etiology, which causes human mental disorder and affects about 1% of the population. In recently years, some studies showed that some cases of schizophrenia may be associated with Toxoplasma gondii infection. In order to investigate a potential association between Toxoplasma infection and schizophrenia, we investigated the relative clinical symptom of schizophrenia such as learning and memory capability, depression and stereotypy to find some useful information by behavioral test in mouse models. Our results demonstrated that mice from Toxoplasma infection and MK-801 administration (as the model of schizophrenia) were impaired in learning and memory capability, and they had more serious depression and stereotypy compared with the control mice, especially the mice from congenital Toxoplasma infection. In addition, our results clearly showed that the number of cysts in brain tissue of congenital Toxoplasma infection mice was significantly low than in acquired Toxoplasma infected mice. Collectively, these results suggested a potential association between Toxoplasma infection and schizophrenia.

[Immunogenicity of the recombinant plasmid of Leishmania donovani amastigote gene].

OBJECTIVE: To investigate the immunogenicity of recombinant plasmid pcDNA3.1-amastigote with Leishmania donovani amastigote gene. METHODS: Eighteen female BALB/c mice were randomly divided into experimental group and control group. Mice in experimental group and control group were intramuscularly injected with 50 microg recombinant plasmid pcDNA3.1-amastigote and blank plasmid vector pcDNA3.1(+), respectively, and then received equivalent dose of plamid after 2 weeks. On days 7, 14, and 21 after the second immunization, serum samples were collected from 3 mice each group. The mice were then sacrificed, spleens were removed and splenocytes were collected. Serum antibody level was determined by indirect ELISA. Splenocyte proliferation responses and cytotoxicity of spleen-derived lymphocytes were analyzed by MTT colorimetry after stimulation with ConA. Level of IFN-gamma, IL-2 and IL-4 in the splenocyte culture supernatants was determined by double antibody sandwich ELISA. RESULTS: On days 7, 14, and 21 after the second immunization, specific IgG antibody (more than 1:640) was found in experimental group, but not in the control (P < 0.01); stimulation index (SI) of spleen cells in experimental group (428 +/- 0.51, 5.01-0.60, and 4.39 +/- 0.50) was higher than that of control group (P < 0.01); the level of IFN-gamma [(42.06 +/- 4.26), (66.02 +/- 6.02), and (58.29 +/- 3.75) pg/ml] and IL-2 [(38.21 +/- 5.11), (64.79 +/- 8.67), and (52.69 +/- 7.15) pg/ml] in splenocyte culture supernatants of experimental group was higher than that of control group (P < 0.01); IL-4 was not found in the two groups; cytotoxicity of spleen-derived lymphocytes in experimental group [(42.20 +/- 5.96)%, (63.66 +/- 5.44)%, and (52.24 +/- 4.56)%] was stronger than that of control (P < 0.01). CONCLUSION: The recombinant plasmid pcDNA3.1-amastigote can induce specific humoral and Th1 type cellular immune responses in mice.

[Synergism of plant volatiles to insect pheromones and related mechanisms].

Host plant volatiles and insect pheromones are the most important semiochemicals for insects, and their synergism can modulate insect behaviors. The attraction to sex- and aggregation pheromones of insects can be greatly enhanced by specific plant volatiles through the increased electroantennogram, pheromone incepting neuron action potential, and pulse-frequency. When the specific plant volatiles are bound with octopamine receptors, the threshold of sex pheromone incepting neuron to sex pheromones is decreased, while the sensibility of sex pheromone incepting neuron is increased, which may be the main mechanism for the synergism of plant volatiles to insect pheromones.

[Cloning of avastin gene of leishmania donovani isolates from Sichuan Province and its expression in eucaryotic system].

OBJECTIVE: To clone and express the avastin gene of two Leishmania donovani isolates from Sichuan Province of China. METHODS: Avastin gene was amplified from nuclear DNA of two L.donovani isolates, cloned into pcDNA3.1(+), and sequenced by the dideoxy chain termination. NIH3T3 cell was transfected by recombinant plasmid. Transient expression of avastin gene was detected by immunofluoresence and stable expression was detected by RT-PCR and Western blot. RESULTS: Avastin gene of both isolates was 552 bp. Sequence analysis showed that the similarity was 86% between the two isolates. A high green fluorescence was found on the cell membrane and inside the cell. The NIH3T3 cell was transfected by the recombinant plasmid successfully. Avastin gene was obtained by RT-PCR from the transfected NIH3T3 cells. Western blot analysis showed that there was a protein about Mr 20 000 in lysate of the transfected NIH3T3 cells, indicating that the avastin gene was expressed in the cells. CONCLUSION: Avastin gene of the two L.donovani isolates has been cloned and the gene can be expressed stably in the NIH3T3 cell.

[Construction and expression of recombinant eucaryotic expression plasmid of amastin gene of Leishmania Donovani].

AIM: To construct recombinant eukaryotic expression plasmid of amastin gene of Leishmania Donovani and detect expression of the gene in NIH3T3 cells. METHODS: Amastin gene was amplified from nuclear DNA of Leishmania Donovani isolates and cloned into an eukaryotic expression vector pcDNA3.1(+). The recombinant plasmid was named pcDNA3.1-amastin. NIH3T3 cell was transfected by pcDNA3.1-amastin. Transient and stable expression of amastin gene were detected by immunofluoresence and RT-PCR. RESULTS: It was found that there was high green fluorescence on the cell membrane and inside the cell. It showed that NIH3T3 cell was transfected by pcDNA3.1-amastin successfully. CONCLUSION: A recombinant eukaryotic expression plasmid of amastin gene of Leishmania Donovani was successfully constructed, and can be expressed stably in the NIH3T3 cells.

[Epidemiological investigation of Taenia saginata asiatica in Duyun, Guizhou and detection of amino acids and elements of adult worms].

OBJECTIVE: To study epidemiological factors of taeniasis and to detect amino acid and element components of adult worms in Duyun of Guizhou Province. METHODS: 1. Traditional methods were used for epidemiological investigation. 2. Automatic amino acid analyzer and bioassay were applied for the detection. RESULTS: Among 70 persons with clinical symptoms, 25 patients (24 men and 1 woman) were found to have adult taenia worms in their faeces after taking Areca catechu L. and other drugs. Sixteen amino acids and 12 elements were determined in adult worms. CONCLUSION: Duyun area in Guizhou is a highly endemic area of taeniasis. The pathogenic parasite is identified as Taenia saginata asiatica. Its clinical symptoms are similar to that of Taenia saginata saginata.