AIM: Growth hormone (GH) directly interacts with the enterocyte stimulating ion absorption and reducing ion secretion induced by agonists of cAMR Since nitric oxide (NO) is involved in the regulation of transepit...AIM: Growth hormone (GH) directly interacts with the enterocyte stimulating ion absorption and reducing ion secretion induced by agonists of cAMR Since nitric oxide (NO) is involved in the regulation of transepithelial ion transport and acts as a second messenger for GH hemodynamic effects, we tested the hypothesis that NO may be involved in the resulting effects of GH on intestinal ion transport. METHODS: Electrical parameters reflecting transepithelial ion transport were measured in Caco-2 cell monolayers mounted in Ussing chambers and exposed to GH and cholera toxin (CT) alone or in combination, in the presence or absence of the NO synthase (NOS) inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME). Similar experiments were conducted to determine cAMP and nitrite/nitrate concentrations. NOS expression was assayed by Western blot analysis. RESULTS: L-NAME causes total abrogation of absorptive and antisecretory effects by GH on intestinal ion transport, In addition, L-NAME was able to inhibit the GH-effects on intracellular cAMP concentration under basal conditions and in response to CT, GH induced a Ca^2+ -dependent increase of nitrites/nitrates production, indicating the involvement of the constitutive rather than the inducible NOS isoform, which was directly confirmed by Western blot analysis. CONCLUSION: These results suggest that the GH effects on intestinal ion transport, either under basal conditions or in the presence of cAMP-stimulated ion secretion, are mediated at an intracellular level by the activity of cNOS.展开更多
AIM:To evaluate the effects of ginger on gastric motility and emptying,abdominal symptoms,and hormones that influence motility in dyspepsia.METHODS:Eleven patients with functional dyspepsia were studied twice in a ran...AIM:To evaluate the effects of ginger on gastric motility and emptying,abdominal symptoms,and hormones that influence motility in dyspepsia.METHODS:Eleven patients with functional dyspepsia were studied twice in a randomized double-blind manner.After an 8-h fast,the patients ingested three capsules that contained ginger(total 1.2 g) or placebo,followed after 1 h by 500 mL low-nutrient soup.Antral area,fundus area and diameter,and the frequency of antral contractions were measured using ultrasound at frequent intervals,and the gastric half-emptying time was calculated from the change in antral area.Gastrointestinal sensations and appetite were scored using visual analog questionnaires,and blood was taken for measurement of plasma glucagon-like peptide-1(GLP-1),motilin and ghrelin concentrations,at intervals throughout the study.RESULTS:Gastric emptying was more rapid after ginger than placebo [median(range) half-emptying time 12.3(8.5-17.0) min after ginger,16.1(8.3-22.6) min after placebo,P ≤ 0.05].There was a trend for more antral contractions(P = 0.06),but fundus dimensions and gastrointestinal symptoms did not differ,nor did serum concentrations of GLP-1,motilin and ghrelin.CONCLUSION:Ginger stimulated gastric emptying and antral contractions in patients with functional dyspepsia,but had no impact on gastrointestinal symptoms or gut peptides.展开更多
There is enough evidence to show that the forest biomass has decreased significantly in the Indian Himalayan state of Himachal Pradesh. The government has responded through restrictive measures to check this decline. ...There is enough evidence to show that the forest biomass has decreased significantly in the Indian Himalayan state of Himachal Pradesh. The government has responded through restrictive measures to check this decline. Using tree biomass as proxy for degradation, we assessed the current state of biomass within dominant land use types and examined its implications for sustainability. The highest above-ground mean tree biomass density of 1158 t·ha-1 was recorded for the reserved forest followed by 728, 13, 11, 8, 5 and 3 t·ha-1in the protected forest, fallow land, cultivated-unirrigated land, grassland, orchard land and cultivated-irrigated land respectively. Of the total ac- cessible biomass, only 0.31% was extracted annually by the local people for fuel, fodder and other uses. Though, the current level of ex- traction may be sustainable in the short run, insufficient regeneration is observed for long term sustainability. Forest biomass production was simulated for the next 30 years with a logistic growth model and the relative significance of input variables in influencing system be- haviour was analysed through sensitivity analysis. The model results highlighted the declining forest resources in the long run. Positive response through appropriate government policies can, however, change the scenario for the better.展开更多
Purpose: The purpose of this study was to examine, using meta-analytic measures, the evidence regarding the optimal exercise intensity at which improvements in speed of cognitive function are triggered. Specifically,...Purpose: The purpose of this study was to examine, using meta-analytic measures, the evidence regarding the optimal exercise intensity at which improvements in speed of cognitive function are triggered. Specifically, it was hypothesized that the catecholamine, lactate, and ventilatory thresholds is the point at which significant improvements in speed of cognitive function are observed. Methods: We compared mean effect sizes for threshold studies and for those studies where exercise intensity was classed as moderate (40%-- 79% VO2 or equivalent) but in which the thresholds were not measured. Results: Random effects meta-analysis showed significant, moderate, mean effect sizes for studies at the threshold (g = 0.58, Z = 2.98, p 〈 0.003) and for those during moderate intensity exercise but in which the threshold was not measured ( g = 0.54, Z = 5.0l, p 〈 0.001). There was no significant difference between mean effect sizes, which suggests that the thresholds are unlikely to represent a trigger point. Conclusion: Moderate intensity exercise, even below the thresholds, can induce improved speed of cognition, possibly due to a combination of increased peripheral catecholamine concentrations inducing vagal/nucleus tractus solitarii pathway activation and central increases due to perceptions of stress.展开更多
The authors studied variations of temperature and salinity in seawater under sea ice using hydrologic data collected from polynyas south of the St.Lawrence Island during March of 2008 and 2009.The results indicate tha...The authors studied variations of temperature and salinity in seawater under sea ice using hydrologic data collected from polynyas south of the St.Lawrence Island during March of 2008 and 2009.The results indicate that the high-salinity water found during the cruises of 2008 and 2009 was due to the formation of polynyas.The salinity observed in 2008 was higher than that in 2009 as a result of higher salt production in 2008.The spatial distributions of high-salinity cores differed between the two cruises.In March 2008, a southeastward flow was formed under the persistent northerly wind in the observation region, which transported the high-salinity water produced by the polynyas to the southeast.The similar flow, however, did not exist in March 2009 because the northerly wind over the study area was interrupted by a southerly wind.Accordingly, the polynyas and the high-salinity water pro-duced by them existed for a short time.As a result, the high-salinity water in 2009 did not spread very far, and stayed within the polynyas.In addition, during the 2009 cruise, two stages of observations in the polynyas showed the core of high-salinity water was shifted to the southwest of the St.Lawrence Island.This result suggested that a southwestward flow might have existed in the area at the onset of the northerly wind, which was consistent with the alongshore and/or offshore flows caused by the northerly wind.展开更多
Densities of aqueous solutions of eight amino acids, glycine, L-alanine, L-valine, L-isoleucine, L-serine, L-threonine, L-arginine and L-phenylalanine, are measured as a function of amino acid concentration from 293.1...Densities of aqueous solutions of eight amino acids, glycine, L-alanine, L-valine, L-isoleucine, L-serine, L-threonine, L-arginine and L-phenylalanine, are measured as a function of amino acid concentration from 293.15K to 333.15K. These data are used to calculate the apparent molar volume Vφ and infinite dilution apparent molar volume Vφo (partial molar volume). Data of five amino acids are used to correlate partial molar volume Vφo usinggroup contribution method to estimate the contributions of the zwitterionic end groups (NH3+,COO-) and CH2 group, OH group, CNHNHNH2 group and C6H5(phenyl) group of amino acids. The results show that Vφo values for all kinds of groups of amino acids studied increase with increase of temperature except those for CH2 group, which are almost constant within the studied temperature range. Data of other amino acids, L-valine, L-isoleucine and L-threonine, are chosen for comparison with the predicted partial molar volume Vφo using the group additivity parameters obtained. The results confirm that this group additivity method has excellent predictive utility.展开更多
Estuarine plankton communities can serve as indicators of ecosystem modification in response to anthropogenic influences. The main objectives of this study were to describe the spatial distribution and diurnal variabi...Estuarine plankton communities can serve as indicators of ecosystem modification in response to anthropogenic influences. The main objectives of this study were to describe the spatial distribution and diurnal variability in zooplankton abundance and biomass over almost entire salinity gradient of the Changjiang (Yangtze) River estuary and to provide a background reference for future studies. To accomplish this, data were collected from 29 stations in the estuary from May 19 to 26, 2003, including two anchor stations. The spatial and diurnal variations in zooplankton characteristics, i.e. abundance, biomass, and gross taxonomic composition, were examined. Generally, both the abundance and biomass gradually increased seaward and presented distinct spatial variations. In addition, the spatial data revealed a significant correlation between abundance and biomass; however, there was no significant correlation between abundance and biomass for the diurnal data. Although the zooplankton composition indicated distinct spatial differences in terms of dominant groups, copepods accounted for >50% of the total zooplankton abundance in most regions and times. Three zooplankton assemblages were recognized through hierarchical cluster analysis. These assemblages existed along the salinity gradient from fresh water to seawater, and their positions coincided with those of the three principal water masses in the estuary. The assemblages were classified as: (1) true estuarine, (2) estuarine and marine, and (3) euryhaline marine, which were characterized by the copepods Sinocalanus dorrii, Labidocera euchaeta, and Calanus sinicus, respectively. Both spatial and diurnal data indicated that there was no significant correlation between zooplankton abundance/biomass and depth-integrated phytoplankton abundance.展开更多
This study examined the effect of salinity on the expression of Na+/K+-ATPase(NKA) α-subunit and vacuolar-type H+-ATPase(V-ATPase) β-subunit gene in the gill of Litopenaeus vannamei. Semi-quantitative reverse transc...This study examined the effect of salinity on the expression of Na+/K+-ATPase(NKA) α-subunit and vacuolar-type H+-ATPase(V-ATPase) β-subunit gene in the gill of Litopenaeus vannamei. Semi-quantitative reverse transcription-polymerase chain reaction(RT-PCR) assay showed that the expression of NKA α-subunit and V-ATPase β-subunit gene was significantly influenced by salinity. It was found that the NKA activity significantly varied with salinity in time and dose dependent manner; whereas the V-ATPase activity did not. The abundance of NKA α-subunit gene transcript increased rapidly when the salinity decreased from 26 b to 21, and slowly when the salinity decreased from 26 to 31 within the first 24 h. When the salinity decreased from 26 to 21, the transcription of NKA α-subunit gene in gill epithelium was higher at 12 h than that at 0 h, which was consistent with the result of immunoblotting assay of NKA α-subunit. In addition, salinity had a significant time- and dose-dependent effect on the concentration of biogenic amines in both hemolymph and gill. As compared to other parameters, the concentration of dopamine(DA) and 5-hydroxytryptamine(5-HT) varied in different patterns when the salinity decreased from 26 to 21 or increased from 26 to 31, suggesting that DA and 5-HT played different regulatory roles in osmotic adaption and modulation of shrimp when salinity varies.展开更多
Everything in the universe occurs spontaneously. The first push of the universe signifies the capabilities of the universe in automatic movement, automatic reaction and change, automatic generation and development, au...Everything in the universe occurs spontaneously. The first push of the universe signifies the capabilities of the universe in automatic movement, automatic reaction and change, automatic generation and development, automatic cognition and thinking, automatic organization, autonomous behavior and automatic control. Diverse substances, objects, thinking and life entities in the universe are all at automatic movement and change. There are 4 automatic reactions within the physical system: chemical reaction, nuclear fusion reactions, quark confinement reaction and weak interaction. Correspondingly, there are 4 similar reactions in organisms. The life entities include the life universe, organisms, human being, societies and artifacts. The automatic dynamic system exists within the life entities which has automatic cognition and thinking abilities. 4-season movement of life happens automatically. The automatic control of life movement includes 4-season control and thinking control whilst the later is an active type. The life universe forms under the automatic organization of the universe thinking. The social life entities are an active control system of thinking. The society has 5 automatic dynamic systems. The society is a life entity that automatically generates under the control and organization of thinking. The artifacts and the future artificial life are formed under the automatic organization and fabrication of human beings under the control of thinking. The earth is a life entity capable of making various biological molecules and 4-season mechanisms of organisms. The organism is created gradually during 4-season movement of earth and solar system.展开更多
Optimizing operational parameters for syngas production of Texaco coal-water slurry gasifier studied in this paper is a complicated nonlinear constrained problem concerning 3 BP(Error Back Propagation) neural networks...Optimizing operational parameters for syngas production of Texaco coal-water slurry gasifier studied in this paper is a complicated nonlinear constrained problem concerning 3 BP(Error Back Propagation) neural networks. To solve this model, a new 3-layer cultural evolving algorithm framework which has a population space, a medium space and a belief space is firstly conceived. Standard differential evolution algorithm(DE), genetic algorithm(GA), and particle swarm optimization algorithm(PSO) are embedded in this framework to build 3-layer mixed cultural DE/GA/PSO(3LM-CDE, 3LM-CGA, and 3LM-CPSO) algorithms. The accuracy and efficiency of the proposed hybrid algorithms are firstly tested in 20 benchmark nonlinear constrained functions. Then, the operational optimization model for syngas production in a Texaco coal-water slurry gasifier of a real-world chemical plant is solved effectively. The simulation results are encouraging that the 3-layer cultural algorithm evolving framework suggests ways in which the performance of DE, GA, PSO and other population-based evolutionary algorithms(EAs) can be improved,and the optimal operational parameters based on 3LM-CDE algorithm of the syngas production in the Texaco coalwater slurry gasifier shows outstanding computing results than actual industry use and other algorithms.展开更多
The weekly averages of near-surface ^7Be, ^210pb, 03, and CO2 concentrations at the Global Atmospheric Watch Observatory, Mt. Waliguan (101.98°E, 36.287°N, 3810 m a.s.l.), from October 2002 to January 2004...The weekly averages of near-surface ^7Be, ^210pb, 03, and CO2 concentrations at the Global Atmospheric Watch Observatory, Mt. Waliguan (101.98°E, 36.287°N, 3810 m a.s.l.), from October 2002 to January 2004 are presented. With the establishment of the new datasets of DCCW (Differential Concentrations in Contiguous Weeks) of ^7Be,^210pb, and O3, CO2 (△^7Be, △^210pb, △O3, △CO2, respectively, the impacts of upper-level downward transports and land-surface emissions on O3 and CO2 concentrations are implied by ^7Be and ^210pb being as independent tracers. The relations among △^7Be, △^210pb, and △O3, △CO2 are examined statistically and compared. The results indicate that with the DCCWs, the interferences with the tracing significance of ^7Be and ^210Pb from the seasonal wet scavenging of atmospheric aerosol are greatly reduced, and the weighting sources of O3 or CO2 variations are more pronounced. Basically, the variability of surface O3 is controlled predominately by air mass transported from the upper atmosphere levels while the emission from the Continent Boundary Layer (CBL) has an obvious input for CO2. The relation between △^210pb and △O3 reflects that influences of CBL emission are generally positive/negative for surface O3 budget in summer/winter, and the relation of △^7Be and △CO2 also reveals that upper level downward transport has positive/negative inputs for CO2 in summer/winter. With the highly correlated relations between ^7Be and O3, a quantitative estimation is made of the stratospheric contributions to the budget of surface O3 at WLG: the monthly averages of stratospheric O3 range from 6 ×10^-9 to 8 ×10^-9 (volume mixing ratio) in April and from June to August, and 2 ×10^-9 to 4 ×10^-9 in the remaining months. For the ultimate sources of the baseline concentration of surface 03, which consist of only stratospheric transport and tropospheric photochemistry production, the contribution from stratospheric transport is estimated to be about 20 ×10^-9 from May to July, and (12-15) ×10^-9 in the remaining months, and the total relative contribution rate is about 35% to 40%.展开更多
In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_x(@NO + NO_2) and VOCs(volatile organic compounds) with light. Due to the highly nonli...In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_x(@NO + NO_2) and VOCs(volatile organic compounds) with light. Due to the highly nonlinear relationships between ozone and its precursors, proper ozone mitigation relies on the knowledge of chemical mechanisms. In this study, an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain. The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign. First, the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp. The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h(1-h diurnal averaged). The contribution of individual peroxy radicals to ozone production was analyzed. In addition, the functional dependence of calculated P(O_3) reveals that ozone production was in a NO_x-limited regime during the campaign. Furthermore, the missing peroxy radical source will further extend NO_x-limited conditions to earlier in the day, making NO_xlimitation dominate more of a day than the current chemical model predicts. Finally, a multiple scenarios mode,also known as EKMA(empirical kinetic modeling approach), was used to simulate the response of P(O_3) to the imaginary change in precursor concentrations. We found that ozone production was in the NO_x-limited region. However, the use of NO_2 measured by the molybdenum converter and/or the absence of a peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production.展开更多
To provide a highly efficient adenov iral vector Ad CMV hTGFβ1 for the study of gene therapy for reversion of the intervertebral disc degeneration.Methods: A newly developed recombinant adenoviral vector constr uctio...To provide a highly efficient adenov iral vector Ad CMV hTGFβ1 for the study of gene therapy for reversion of the intervertebral disc degeneration.Methods: A newly developed recombinant adenoviral vector constr uction system was used in the study. The cDNA of hTGFβ1 was first subcloned into a shuttle plasmid pShuttle CMV. The resultant plasmid was linearized by d ig esting with restriction endonuclease PmeI, and subsequently transformed into E .coli. BJ5183 cells with an adenoviral backbone plasmid pAdEasy 1. Recombinants were selected by kanamycin resistance and confirmed by restriction endonuclease analysis. Finally, the recombinant plasmid linearized by PmeI was transfected in to 293 cells. Recombinant adenoviruses were generated within 2 weeks. Results: The recombinant adenoviral plasmids were cut by BamHI and PacI respectively, and the diagnostic fragments appeared in 0.8 % agarose electrophoresis. The infected 293 cells showed evident cytopathic effect (CPE). The productions of PCR confirmed the presence of recombinant adenovirus. The exp ression of hTGFβ1 was verified by immunohistochemical staining. Conclusions: The successful generation of the adenoviral vector Ad CMV hTGFβ1 and the confirmation of the interest gene expression make it p ossible for the experimental study of the reversion of the intervertebral disc d egeneration by gene therapy.展开更多
Biological processes and behaviors of endothelial cells on the inner surfaces of blood vessels are regulated by the stimulation from biochemical signals contained in the blood.In this paper,the transportation of dynam...Biological processes and behaviors of endothelial cells on the inner surfaces of blood vessels are regulated by the stimulation from biochemical signals contained in the blood.In this paper,the transportation of dynamic biochemical signals in non-reversing oscillatory flows in blood vessels is analyzed by numerically solving a nonlinear governing equation for the time-dependent Taylor-Aris dispersion.Results show that the nonlinear frequency-amplitude modulation of the transportation of biochemical signals is more(less) significant when the frequency of an oscillatory flow is close to(higher than) that of an oscillatory signal.Under steady flow,the transfer function for the signal transmission system is obtained,showing that the system is a low-pass filter.Lower inner radius or higher center-line velocity of a blood vessel increases the cutoff frequency of the transportation system.These results suggest the possibility and condition for the 'remote' transmission of low-frequency dynamic biochemical signals in pulsatile blood flows.展开更多
Most seabird species display colonial behavior during the breeding period which implies that food resources around breeding sites can easily go depleted. Seabirds need to both reach profitable areas, which can be loca...Most seabird species display colonial behavior during the breeding period which implies that food resources around breeding sites can easily go depleted. Seabirds need to both reach profitable areas, which can be located far from the colony, and return to the colony regularly. In this context, flexibility in movement behavior may be crucial for breeding success. During chick-rearing, Procellariformes species can alternate short trips lasting 1-4 days for chick provisioning with longer trips for self-provisioning in what has been called a dual-foraging strategy. We analyzed foraging trips from 136 Scopoli's shearwaters from three Mediterranean colonies tracked with GPS during 6 chick-rearing seasons to assess whether the adoption of a dual fo- raging strategy depends on the quality of habitat surrounding the colony. We found a marked dual-foraging strategy only in birds from the Linosa colony which was the largest colony in terms of breeding pairs and was characterized by having a lower marine habitat quality. Birds from this colony performed foraging trips that extended up to 369 km from the nest and lasted more than 10 days. In general, the decision to perform long lasting trips was triggered by lower values of primary production and higher offspring weight. Contrary to expectation, the decision to feed far from the colony was not related to the parents' weight. At the same time, despite the higher productivity offered by distant areas, the higher proportion of long trips performed by birds breeding in poor areas was not sufficient to maintain the same body mass as the ones breeding in richer areas [Current Zoology 60 (5): 622-630, 2014].展开更多
基金a grant from the Ministero della Sanita' AIDS research project 2001 program 50.D.28 and by grant from CNR,NO. 94.02505 CT04
文摘AIM: Growth hormone (GH) directly interacts with the enterocyte stimulating ion absorption and reducing ion secretion induced by agonists of cAMR Since nitric oxide (NO) is involved in the regulation of transepithelial ion transport and acts as a second messenger for GH hemodynamic effects, we tested the hypothesis that NO may be involved in the resulting effects of GH on intestinal ion transport. METHODS: Electrical parameters reflecting transepithelial ion transport were measured in Caco-2 cell monolayers mounted in Ussing chambers and exposed to GH and cholera toxin (CT) alone or in combination, in the presence or absence of the NO synthase (NOS) inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME). Similar experiments were conducted to determine cAMP and nitrite/nitrate concentrations. NOS expression was assayed by Western blot analysis. RESULTS: L-NAME causes total abrogation of absorptive and antisecretory effects by GH on intestinal ion transport, In addition, L-NAME was able to inhibit the GH-effects on intracellular cAMP concentration under basal conditions and in response to CT, GH induced a Ca^2+ -dependent increase of nitrites/nitrates production, indicating the involvement of the constitutive rather than the inducible NOS isoform, which was directly confirmed by Western blot analysis. CONCLUSION: These results suggest that the GH effects on intestinal ion transport, either under basal conditions or in the presence of cAMP-stimulated ion secretion, are mediated at an intracellular level by the activity of cNOS.
基金Supported by Grant from National Research Program from National Science Council (NMRP870071)
文摘AIM:To evaluate the effects of ginger on gastric motility and emptying,abdominal symptoms,and hormones that influence motility in dyspepsia.METHODS:Eleven patients with functional dyspepsia were studied twice in a randomized double-blind manner.After an 8-h fast,the patients ingested three capsules that contained ginger(total 1.2 g) or placebo,followed after 1 h by 500 mL low-nutrient soup.Antral area,fundus area and diameter,and the frequency of antral contractions were measured using ultrasound at frequent intervals,and the gastric half-emptying time was calculated from the change in antral area.Gastrointestinal sensations and appetite were scored using visual analog questionnaires,and blood was taken for measurement of plasma glucagon-like peptide-1(GLP-1),motilin and ghrelin concentrations,at intervals throughout the study.RESULTS:Gastric emptying was more rapid after ginger than placebo [median(range) half-emptying time 12.3(8.5-17.0) min after ginger,16.1(8.3-22.6) min after placebo,P ≤ 0.05].There was a trend for more antral contractions(P = 0.06),but fundus dimensions and gastrointestinal symptoms did not differ,nor did serum concentrations of GLP-1,motilin and ghrelin.CONCLUSION:Ginger stimulated gastric emptying and antral contractions in patients with functional dyspepsia,but had no impact on gastrointestinal symptoms or gut peptides.
基金Norwegian University of life sciences,Aas,Norway (Sub Project Number 1526010,Main Project No 11526010)the Integrated Institute of Himalayan Studies (UGC Centre of Excellence),Shimla,India (Project Number 9-3/2005)
文摘There is enough evidence to show that the forest biomass has decreased significantly in the Indian Himalayan state of Himachal Pradesh. The government has responded through restrictive measures to check this decline. Using tree biomass as proxy for degradation, we assessed the current state of biomass within dominant land use types and examined its implications for sustainability. The highest above-ground mean tree biomass density of 1158 t·ha-1 was recorded for the reserved forest followed by 728, 13, 11, 8, 5 and 3 t·ha-1in the protected forest, fallow land, cultivated-unirrigated land, grassland, orchard land and cultivated-irrigated land respectively. Of the total ac- cessible biomass, only 0.31% was extracted annually by the local people for fuel, fodder and other uses. Though, the current level of ex- traction may be sustainable in the short run, insufficient regeneration is observed for long term sustainability. Forest biomass production was simulated for the next 30 years with a logistic growth model and the relative significance of input variables in influencing system be- haviour was analysed through sensitivity analysis. The model results highlighted the declining forest resources in the long run. Positive response through appropriate government policies can, however, change the scenario for the better.
文摘Purpose: The purpose of this study was to examine, using meta-analytic measures, the evidence regarding the optimal exercise intensity at which improvements in speed of cognitive function are triggered. Specifically, it was hypothesized that the catecholamine, lactate, and ventilatory thresholds is the point at which significant improvements in speed of cognitive function are observed. Methods: We compared mean effect sizes for threshold studies and for those studies where exercise intensity was classed as moderate (40%-- 79% VO2 or equivalent) but in which the thresholds were not measured. Results: Random effects meta-analysis showed significant, moderate, mean effect sizes for studies at the threshold (g = 0.58, Z = 2.98, p 〈 0.003) and for those during moderate intensity exercise but in which the threshold was not measured ( g = 0.54, Z = 5.0l, p 〈 0.001). There was no significant difference between mean effect sizes, which suggests that the thresholds are unlikely to represent a trigger point. Conclusion: Moderate intensity exercise, even below the thresholds, can induce improved speed of cognition, possibly due to a combination of increased peripheral catecholamine concentrations inducing vagal/nucleus tractus solitarii pathway activation and central increases due to perceptions of stress.
基金supported by the National Natural Science Foundation of China under contract Nos.40631006 and D0601-40876003the National Polar Science Strategic Research Foundation of China under contract No.20070207
文摘The authors studied variations of temperature and salinity in seawater under sea ice using hydrologic data collected from polynyas south of the St.Lawrence Island during March of 2008 and 2009.The results indicate that the high-salinity water found during the cruises of 2008 and 2009 was due to the formation of polynyas.The salinity observed in 2008 was higher than that in 2009 as a result of higher salt production in 2008.The spatial distributions of high-salinity cores differed between the two cruises.In March 2008, a southeastward flow was formed under the persistent northerly wind in the observation region, which transported the high-salinity water produced by the polynyas to the southeast.The similar flow, however, did not exist in March 2009 because the northerly wind over the study area was interrupted by a southerly wind.Accordingly, the polynyas and the high-salinity water pro-duced by them existed for a short time.As a result, the high-salinity water in 2009 did not spread very far, and stayed within the polynyas.In addition, during the 2009 cruise, two stages of observations in the polynyas showed the core of high-salinity water was shifted to the southwest of the St.Lawrence Island.This result suggested that a southwestward flow might have existed in the area at the onset of the northerly wind, which was consistent with the alongshore and/or offshore flows caused by the northerly wind.
基金the Educational Department Doctor Foundation of China (No. 2000005608).
文摘Densities of aqueous solutions of eight amino acids, glycine, L-alanine, L-valine, L-isoleucine, L-serine, L-threonine, L-arginine and L-phenylalanine, are measured as a function of amino acid concentration from 293.15K to 333.15K. These data are used to calculate the apparent molar volume Vφ and infinite dilution apparent molar volume Vφo (partial molar volume). Data of five amino acids are used to correlate partial molar volume Vφo usinggroup contribution method to estimate the contributions of the zwitterionic end groups (NH3+,COO-) and CH2 group, OH group, CNHNHNH2 group and C6H5(phenyl) group of amino acids. The results show that Vφo values for all kinds of groups of amino acids studied increase with increase of temperature except those for CH2 group, which are almost constant within the studied temperature range. Data of other amino acids, L-valine, L-isoleucine and L-threonine, are chosen for comparison with the predicted partial molar volume Vφo using the group additivity parameters obtained. The results confirm that this group additivity method has excellent predictive utility.
基金Supported by the National Natural Science Foundation of China for Creative Research Groups (No. 40821004)the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX1-YW-06-02)the National Basic Research Program of China (973 Program) (No. 2007CB407305)
文摘Estuarine plankton communities can serve as indicators of ecosystem modification in response to anthropogenic influences. The main objectives of this study were to describe the spatial distribution and diurnal variability in zooplankton abundance and biomass over almost entire salinity gradient of the Changjiang (Yangtze) River estuary and to provide a background reference for future studies. To accomplish this, data were collected from 29 stations in the estuary from May 19 to 26, 2003, including two anchor stations. The spatial and diurnal variations in zooplankton characteristics, i.e. abundance, biomass, and gross taxonomic composition, were examined. Generally, both the abundance and biomass gradually increased seaward and presented distinct spatial variations. In addition, the spatial data revealed a significant correlation between abundance and biomass; however, there was no significant correlation between abundance and biomass for the diurnal data. Although the zooplankton composition indicated distinct spatial differences in terms of dominant groups, copepods accounted for >50% of the total zooplankton abundance in most regions and times. Three zooplankton assemblages were recognized through hierarchical cluster analysis. These assemblages existed along the salinity gradient from fresh water to seawater, and their positions coincided with those of the three principal water masses in the estuary. The assemblages were classified as: (1) true estuarine, (2) estuarine and marine, and (3) euryhaline marine, which were characterized by the copepods Sinocalanus dorrii, Labidocera euchaeta, and Calanus sinicus, respectively. Both spatial and diurnal data indicated that there was no significant correlation between zooplankton abundance/biomass and depth-integrated phytoplankton abundance.
基金supported by the National Natural Sciences Foundation of China (31072193)the Scientific Research Foundation for Outstanding Young Scientists of Shandong Province (2006BS07005)
文摘This study examined the effect of salinity on the expression of Na+/K+-ATPase(NKA) α-subunit and vacuolar-type H+-ATPase(V-ATPase) β-subunit gene in the gill of Litopenaeus vannamei. Semi-quantitative reverse transcription-polymerase chain reaction(RT-PCR) assay showed that the expression of NKA α-subunit and V-ATPase β-subunit gene was significantly influenced by salinity. It was found that the NKA activity significantly varied with salinity in time and dose dependent manner; whereas the V-ATPase activity did not. The abundance of NKA α-subunit gene transcript increased rapidly when the salinity decreased from 26 b to 21, and slowly when the salinity decreased from 26 to 31 within the first 24 h. When the salinity decreased from 26 to 21, the transcription of NKA α-subunit gene in gill epithelium was higher at 12 h than that at 0 h, which was consistent with the result of immunoblotting assay of NKA α-subunit. In addition, salinity had a significant time- and dose-dependent effect on the concentration of biogenic amines in both hemolymph and gill. As compared to other parameters, the concentration of dopamine(DA) and 5-hydroxytryptamine(5-HT) varied in different patterns when the salinity decreased from 26 to 21 or increased from 26 to 31, suggesting that DA and 5-HT played different regulatory roles in osmotic adaption and modulation of shrimp when salinity varies.
文摘Everything in the universe occurs spontaneously. The first push of the universe signifies the capabilities of the universe in automatic movement, automatic reaction and change, automatic generation and development, automatic cognition and thinking, automatic organization, autonomous behavior and automatic control. Diverse substances, objects, thinking and life entities in the universe are all at automatic movement and change. There are 4 automatic reactions within the physical system: chemical reaction, nuclear fusion reactions, quark confinement reaction and weak interaction. Correspondingly, there are 4 similar reactions in organisms. The life entities include the life universe, organisms, human being, societies and artifacts. The automatic dynamic system exists within the life entities which has automatic cognition and thinking abilities. 4-season movement of life happens automatically. The automatic control of life movement includes 4-season control and thinking control whilst the later is an active type. The life universe forms under the automatic organization of the universe thinking. The social life entities are an active control system of thinking. The society has 5 automatic dynamic systems. The society is a life entity that automatically generates under the control and organization of thinking. The artifacts and the future artificial life are formed under the automatic organization and fabrication of human beings under the control of thinking. The earth is a life entity capable of making various biological molecules and 4-season mechanisms of organisms. The organism is created gradually during 4-season movement of earth and solar system.
基金Supported by the National Natural Science Foundation of China(61174040,U1162110,21206174)Shanghai Commission of Nature Science(12ZR1408100)
文摘Optimizing operational parameters for syngas production of Texaco coal-water slurry gasifier studied in this paper is a complicated nonlinear constrained problem concerning 3 BP(Error Back Propagation) neural networks. To solve this model, a new 3-layer cultural evolving algorithm framework which has a population space, a medium space and a belief space is firstly conceived. Standard differential evolution algorithm(DE), genetic algorithm(GA), and particle swarm optimization algorithm(PSO) are embedded in this framework to build 3-layer mixed cultural DE/GA/PSO(3LM-CDE, 3LM-CGA, and 3LM-CPSO) algorithms. The accuracy and efficiency of the proposed hybrid algorithms are firstly tested in 20 benchmark nonlinear constrained functions. Then, the operational optimization model for syngas production in a Texaco coal-water slurry gasifier of a real-world chemical plant is solved effectively. The simulation results are encouraging that the 3-layer cultural algorithm evolving framework suggests ways in which the performance of DE, GA, PSO and other population-based evolutionary algorithms(EAs) can be improved,and the optimal operational parameters based on 3LM-CDE algorithm of the syngas production in the Texaco coalwater slurry gasifier shows outstanding computing results than actual industry use and other algorithms.
基金supported by National Natural Science Foundation of China (Grant Nos.40575013,40175032 and 40830102)
文摘The weekly averages of near-surface ^7Be, ^210pb, 03, and CO2 concentrations at the Global Atmospheric Watch Observatory, Mt. Waliguan (101.98°E, 36.287°N, 3810 m a.s.l.), from October 2002 to January 2004 are presented. With the establishment of the new datasets of DCCW (Differential Concentrations in Contiguous Weeks) of ^7Be,^210pb, and O3, CO2 (△^7Be, △^210pb, △O3, △CO2, respectively, the impacts of upper-level downward transports and land-surface emissions on O3 and CO2 concentrations are implied by ^7Be and ^210pb being as independent tracers. The relations among △^7Be, △^210pb, and △O3, △CO2 are examined statistically and compared. The results indicate that with the DCCWs, the interferences with the tracing significance of ^7Be and ^210Pb from the seasonal wet scavenging of atmospheric aerosol are greatly reduced, and the weighting sources of O3 or CO2 variations are more pronounced. Basically, the variability of surface O3 is controlled predominately by air mass transported from the upper atmosphere levels while the emission from the Continent Boundary Layer (CBL) has an obvious input for CO2. The relation between △^210pb and △O3 reflects that influences of CBL emission are generally positive/negative for surface O3 budget in summer/winter, and the relation of △^7Be and △CO2 also reveals that upper level downward transport has positive/negative inputs for CO2 in summer/winter. With the highly correlated relations between ^7Be and O3, a quantitative estimation is made of the stratospheric contributions to the budget of surface O3 at WLG: the monthly averages of stratospheric O3 range from 6 ×10^-9 to 8 ×10^-9 (volume mixing ratio) in April and from June to August, and 2 ×10^-9 to 4 ×10^-9 in the remaining months. For the ultimate sources of the baseline concentration of surface 03, which consist of only stratospheric transport and tropospheric photochemistry production, the contribution from stratospheric transport is estimated to be about 20 ×10^-9 from May to July, and (12-15) ×10^-9 in the remaining months, and the total relative contribution rate is about 35% to 40%.
基金supported from the research projects of the Environmental Public Welfare Industry in China (201509001,201409005)the National Science and Technology Support Program of China (2014BAC21B01)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB05010500)the Special Fund of State Key Joint Laboratory of Environment Simulation and Pollution Control (18K03ESPCP)the EU-project AMIS (Fate and Impact of Atmospheric Pollutants,PIRSES-GA-2011295132)
文摘In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_x(@NO + NO_2) and VOCs(volatile organic compounds) with light. Due to the highly nonlinear relationships between ozone and its precursors, proper ozone mitigation relies on the knowledge of chemical mechanisms. In this study, an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain. The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign. First, the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp. The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h(1-h diurnal averaged). The contribution of individual peroxy radicals to ozone production was analyzed. In addition, the functional dependence of calculated P(O_3) reveals that ozone production was in a NO_x-limited regime during the campaign. Furthermore, the missing peroxy radical source will further extend NO_x-limited conditions to earlier in the day, making NO_xlimitation dominate more of a day than the current chemical model predicts. Finally, a multiple scenarios mode,also known as EKMA(empirical kinetic modeling approach), was used to simulate the response of P(O_3) to the imaginary change in precursor concentrations. We found that ozone production was in the NO_x-limited region. However, the use of NO_2 measured by the molybdenum converter and/or the absence of a peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production.
文摘To provide a highly efficient adenov iral vector Ad CMV hTGFβ1 for the study of gene therapy for reversion of the intervertebral disc degeneration.Methods: A newly developed recombinant adenoviral vector constr uction system was used in the study. The cDNA of hTGFβ1 was first subcloned into a shuttle plasmid pShuttle CMV. The resultant plasmid was linearized by d ig esting with restriction endonuclease PmeI, and subsequently transformed into E .coli. BJ5183 cells with an adenoviral backbone plasmid pAdEasy 1. Recombinants were selected by kanamycin resistance and confirmed by restriction endonuclease analysis. Finally, the recombinant plasmid linearized by PmeI was transfected in to 293 cells. Recombinant adenoviruses were generated within 2 weeks. Results: The recombinant adenoviral plasmids were cut by BamHI and PacI respectively, and the diagnostic fragments appeared in 0.8 % agarose electrophoresis. The infected 293 cells showed evident cytopathic effect (CPE). The productions of PCR confirmed the presence of recombinant adenovirus. The exp ression of hTGFβ1 was verified by immunohistochemical staining. Conclusions: The successful generation of the adenoviral vector Ad CMV hTGFβ1 and the confirmation of the interest gene expression make it p ossible for the experimental study of the reversion of the intervertebral disc d egeneration by gene therapy.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11172060 and 10972139)the Fundamental Research Funds for the Central Universities in China (Grant No. DUT12JB11)
文摘Biological processes and behaviors of endothelial cells on the inner surfaces of blood vessels are regulated by the stimulation from biochemical signals contained in the blood.In this paper,the transportation of dynamic biochemical signals in non-reversing oscillatory flows in blood vessels is analyzed by numerically solving a nonlinear governing equation for the time-dependent Taylor-Aris dispersion.Results show that the nonlinear frequency-amplitude modulation of the transportation of biochemical signals is more(less) significant when the frequency of an oscillatory flow is close to(higher than) that of an oscillatory signal.Under steady flow,the transfer function for the signal transmission system is obtained,showing that the system is a low-pass filter.Lower inner radius or higher center-line velocity of a blood vessel increases the cutoff frequency of the transportation system.These results suggest the possibility and condition for the 'remote' transmission of low-frequency dynamic biochemical signals in pulsatile blood flows.
文摘Most seabird species display colonial behavior during the breeding period which implies that food resources around breeding sites can easily go depleted. Seabirds need to both reach profitable areas, which can be located far from the colony, and return to the colony regularly. In this context, flexibility in movement behavior may be crucial for breeding success. During chick-rearing, Procellariformes species can alternate short trips lasting 1-4 days for chick provisioning with longer trips for self-provisioning in what has been called a dual-foraging strategy. We analyzed foraging trips from 136 Scopoli's shearwaters from three Mediterranean colonies tracked with GPS during 6 chick-rearing seasons to assess whether the adoption of a dual fo- raging strategy depends on the quality of habitat surrounding the colony. We found a marked dual-foraging strategy only in birds from the Linosa colony which was the largest colony in terms of breeding pairs and was characterized by having a lower marine habitat quality. Birds from this colony performed foraging trips that extended up to 369 km from the nest and lasted more than 10 days. In general, the decision to perform long lasting trips was triggered by lower values of primary production and higher offspring weight. Contrary to expectation, the decision to feed far from the colony was not related to the parents' weight. At the same time, despite the higher productivity offered by distant areas, the higher proportion of long trips performed by birds breeding in poor areas was not sufficient to maintain the same body mass as the ones breeding in richer areas [Current Zoology 60 (5): 622-630, 2014].