11,002 research outputs found
Antiviral treatment alters the frequency of activating and inhibitory receptor-expressing natural killer cells in chronic Hepatitis B virus infected patients
Natural killer (NK) cells play a critical role in innate antiviral immunity, but little is known about the impact of antiviral therapy on the frequency of NK cell subsets. To this aim, we performed this longitudinal study to examine the dynamic changes of the frequency of different subsets of NK cells in CHB patients after initiation of tenofovir or adefovir therapy. We found that NK cell numbers and subset distribution differ between CHB patients and normal subjects; furthermore, the association was found between ALT level and CD158b+ NK cell in HBV patients. In tenofovir group, the frequency of NK cells increased during the treatment accompanied by downregulated expression of NKG2A and KIR2DL3. In adefovir group, NK cell numbers did not differ during the treatment, but also accompanied by downregulated expression of NKG2A and KIR2DL3. Our results demonstrate that treatment with tenofovir leads to viral load reduction, and correlated with NK cell frequencies in peripheral blood of chronic hepatitis B virus infection. In addition, treatments with both tenofovir and adefovir in chronic HBV infected patients induce a decrease of the frequency of inhibitory receptor+ NK cells, which may account for the partial restoration of the function of NK cells in peripheral blood following treatment
Estimating carbon emissions from forest fires during 1980 to 1999 in Daxingâan Mountain, China
A large number of carbons are released into the atmosphere from forest fires per year, which has a significant influence on carbon cycle and storage. In this study, we examined the spatio-temporal patterns of forest fires from 1980 to 1999 in Daxingâan Mountain of Heilongjiang Province, China and estimated the carbon emissions from forest fires based on both field research and laboratory experiments. The results show that (1) burned areas of larch (Larix gmelinii Rupr.), Mongolian pine (Pinus sylvestris L. var. mongolica Litv.), white birch (Betula platyphylla Suk.), mixed broadleaved-conifer (L. gmelinii & B. platyphylla) and Mongolian oak (Quercus mongolica Fish.) forests were 437 947, 20 939, 142 527, 168 532 and 1 375 hm2 during 1980 to 1999 period, respectively. The fuel consumed based on these forests were 29.0 to 46.5, 16.7 to 26.5, 18.1 to 26.5, 31.9 to 51.4 and 24.5 to 40.3 Mg hm-2, respectively; (2) the total carbon emissions from forest fires of the forest types in Daxingâan Mountain was 3.8 to 5.9 Tg during this period. Two thirds of the total amounts were caused by larch forests, while 1/4 came from white birch forests and the rest from other forest types; (3) the amounts of CO2 released from forest fires for these 20 years were 13.9 to 21.6 Tg. The estimates were incomplete or could be low because the emissions from the burning of dead organic matter (litter, dead wood, etc.) were not included in this calculation and therefore, the net carbon balance was calculated.Key words: biomass, carbonaceous gases, CO2 emissions, forest fires
High-Speed, Heavy-Load, and Direction-Controllable Photothermal Pneumatic Floating Robot.
Light-fueled actuators are promising in many fields due to their contactless, easily controllable, and eco-efficiency features. However, their application in liquid environments is complicated by the existing challenges of rapid deformation in liquids, light absorption of the liquid media, and environmental contamination. Here, we design a photothermal pneumatic floating robot (PPFR) using a boat-paddle structure. Light energy is converted into thermal energy of air by an isolated photothermal composite, which is then converted into mechanical energy of liquid to drive the movement of PPFRs. By understanding and controlling the photothermal actuation, the PPFR can achieve an average velocity of 13.1 mm s-1 in water and can be modified for remote on-demand differential steering and self-sustained oscillation. The PPFR may be modified to provide a lifting mechanism, capable of moving 4 times the PPFR mass. Various shapes and materials are suitable for the PPFR, providing a platform for liquid surface transporting, water sampling, pollutant collecting, underwater photography, and photocontrol robots in shallow water
Diversity of eukaryotic plankton of aquaculture ponds with Carassius auratus gibelio, using denaturing gradient gel electrophoresis
PCR-denaturing gradient gel electrophoresis (DGGE) and canonical correspondence analysis (CCA) were used to explore the relationship between eukaryotic plankton community succession and environmental factors in two aquaculture pond models with gibel carp Carassius auratus gibelio. The main culture species of pond 1 were gibel carp and grass carp, and the combined density was 46224 fingerling/ha (gibel carp/grass carp/silver carp/bighead carp, 17:4:6:1). The main culture species of pond 2 was gibel carp, and the combined density was 37551 fingerling/ha (gibel carp/silver carp/bighead carp, 52:1:1). Water samples were collected monthly. The results showed that the annual average concentrations of TP and PO_4-P in pond 1 were significantly higher than pond 2 (p>0.05). The concentration of chlorophyll a (chl a) has no significantly difference between pond 1 and pond 2. DGGE profiles of 18S rRNA gene fragments from the two ponds revealed that the diversity of eukaryotic plankton assemblages was highly variable. 91 bands and 71 bands were detected in pond 1 and pond 2, respectively. The average ShannonâWiener index of pond 1 was significantly higher than pond 2. Canonical correspondence analysis (CCA) revealed that temperature played a key role in the structure of the eukaryotic plankton community in both ponds, but the nutrient concentration did not affect it. Our results suggest that DGGE method is a cost-effective way to gain insight into seasonal dynamics of eukaryotic plankton communities in culture ponds, and the increase in the number of filter-feeding silver carp and bighead carp could increase the diversity of the eukaryotic plankton community
Temperature oscillation of a dual compensation chamber loop heat pipe under acceleration conditions
Loop heat pipe has a wide application in the fields of airborne electronics cooling and thermal management. However, the pertinent temperature oscillation of the loop heat pipe could lead to adverse effects on the electronics. In the current study, an ammonia-stainless steel dual compensation chamber loop heat pipe was developed to experimentally investigate the temperature oscillation under different acceleration conditions. The impact of several control parameters such as different heat loads, loading modes, acceleration directions and magnitudes on the operational performance of the loop heat pipe was analyzed in a systematic manner. The heat load applied on the evaporator ranged from 25 W to 300 W. The acceleration magnitude varied from 1 g to 9 g and four different acceleration direction, i.e. configurations A, B, C and D, were taken into account. Two different loading modes were applied with different heat load and acceleration force. Experimental results show that (i) the loop temperature will change and oscillate as the acceleration force was applied under all test conditions. It can be easily found that the temperature oscillation occurred at both heat loads of 250 W and 300 W. (ii) for the case of the first loading mode, periodic temperature oscillation is observed on the liquid line, whereas for the second loading mode, periodic temperature oscillation can be easily appeared on the entire loop. (iii) the loop temperature under both configurations A and B with acceleration of 7 g does not oscillate at heat load of 150 W, 200 W and 250 W when the first loading mode is applied. Especially under configuration B, the acceleration could contribute to repress the temperature oscillation. Under the current heat loads for almost all cases, the temperature oscillation can be observed for configurations A, C and D with acceleration of 5 g. (iv) the amplitude of evaporator at heat load of 300 W under configuration C are 0.6 °C, 0.3 °C, 0.2 °C and 0.3 °C with acceleration of 3 g, 5 g, 7 g and 9 g. The corresponding period is 66 s, 36 s, 34 s and 36 s, respectively
The implement of plastic oval tags for mark-recapture in juvenile Japanese flounder (Paralichthys olivaceus) on the northeast coast of Shandong Province, China
As part of the stock enhancement research project of Shandong Province, China, plastic oval tags (POTs) were used to mark juvenile Japanese flounder for release, Paralichthys olivaceus (70 to 133 mm total length, TL), in 2009 and 2010. Optimal tag placement locations, retention, tagging rates, and mortality were initially evaluated. Markârecapture experiments were carried out in the coastal waters of Weihai City to study their migratory movements: 21,202 individuals in July 2009 at Beihai and 18,350 individuals in July 2010 at Lidao. The number of recaptured individuals were 434 (2.05% recapture rate) in 2009 and 620 (3.38% recapture rate) in 2010. A radiative movement from the release site was observed in the 2009 experiment; however, the tagging experiment showed a predominantly northward dispersal of tagged flounder from the release site in 2010. The mean movement speed of the released fish was calculated as 0.46 km day-1 in 2009 and 1.05 km day-1 in 2010. Furthermore, in 2009, the average TL and wet mass increments were 36.3 ± 8.4 mm month-1 and 27.13 ± 16.09 g month-1, respectively 1 to 6 months after releasing; however, the increments were 14.7 ± 8.8 mm month-1 and 5.65 ± 4.17 g month-1, respectively in 2010.Key words: Paralichthys olivaceus, plastic oval tag, markârecapture, movement, growth
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