AIM： To study the portal hemodynamics and their relationship with the size of esophageal varices seen at endoscopy and to evaluate whether these Doppler ultrasound parameters might predict variceal bleeding in patien...AIM： To study the portal hemodynamics and their relationship with the size of esophageal varices seen at endoscopy and to evaluate whether these Doppler ultrasound parameters might predict variceal bleeding in patients with liver cirrhosis and portal hypertension. METHODS： One hundred and twenty cirrhotic patients with esophageal varices but without any previous bleeding were enrolled in the prospective study. During a 2-year observation period, 52 patients who had at least one episode of acute esophageal variceal hemorrhage constituted the bleeding group, and the remaining 68 patients without any previous hemorrhage constituted the non-bleeding group. All patients underwent endoscopy before or after color Doppler-ultrasonic examination, and images were interpreted independently by two endoscopists. The control group consisted of 30 healthy subjects, matched to the patient group in age and gender. Measurements of diameter, flow direction and flow velocity in the left gastric vein （LGV） and the portal vein （PV） were done in all patients and controls using color Doppler unit. After baseline measurements, 30 min after oral administration of 75 g glucose in 225 mL, changes of the diameter, flow velocity and direction in the PV and LGV were examined in 60 patients with esophageal varices and 15 healthy controls. RESULTS： The PV and LGV were detected successfully in 115 （96%） and 105 （88%） of 120 cirrhotic patients, respectively, and in 27 （90%） and 21 （70%） of 30 healthy controls, respectively. Among the 120 cirrhotic patients, 37 had F1, 59 had F2, and 24 had F3 grade varices. Compared with the healthy controls, cirrhotic group had a significantly lower velocity in the PV, a significantly greater diameter of the PV and LGV, and a higher velocity in the LGV. In the cirrhotic group, no difference in portal flow velocity and diameter were observed between patients with or without esophageal variceal bleeding （EVB）. However, the diameter and blood flow velocity of the LGV were significantly higher for EVB （＋） group compared with EVB （-） group （P〈0.01）. Diameter of the LGV increased with enlarged size of varices. There were differences between F1 and F2, F1 and F3 varices, but no differences between F2 and F3 varices （P = 0.125）. However, variceal bleeding was more frequent in patients with a diameter of LGV 〉6 mm. The flow velocity in the LGV of healthy controls was 8.70＋1.91 cm/s （n = 21）. In patients with liver cirrhosis, it was 10.3＋2.1 cm/s （n = 12） when the flow was hepatopetal and 13.5＋2.3 cm/s （n = 87） when it was hepatofugal. As the size of varices enlarged, hepatofugal flow velocity increased （P〈0.01） and was significantly different between patients with F1 and F2 varices and between patients with F2 and F3 varices. Variceal bleeding was more frequent in patients with a hepatofugal flow velocity 〉15 cm/s （32 of 52 patients, 61.5%）. Within the bleeding group, the mean LGV blood flow velocity was 16.6＋2.62 cm/s. No correlation was observed between the portal blood flow velocity and EVB. In all healthy controls, the flow direction in the LGV was hepatopetal, toward the PV. In patients with F1 varices, flow direction was hepatopetal in 10 patients, to-and-fro state in 3 patients, and hepatofugal in the remaining 18. The flow was hepatofugal in 91% patients with F2 and all F3 varices. Changes in diameter of the PV and LGV were not significant before and after ingestion of glucose （PV： 1.41＋1.5 cm before and 1.46＋1.6 cm after; LGV： 0.57＋1.7 cm before and 0.60＋1.5 cm after）. Flow direction in the LGV was hepatopetal and to-and-fro in 16 patients and hepatofugal in 44 patients before ingestion of glucose. Flow direction changed to hepatofugal in 9 of 16 patients with hepatopetal and to-and-fro blood flow after ingestion of glucose. In 44 patients with hepatofugal blood flow in the LGV, a significant increase in hepatofugal flow velocity was observed in 38 of 44 patients （86%） with esophageal varices. There was a relationship between the percentage changes in flow velocity and the size of varices. Patients who responded excessively to food ingestion might have a high risk for bleeding. The changes of blood flow velocity in the LGV were greater than those in the PV （LGV： 28.3＋26.1%, PV： 7.2＋13.2%, P〈0.01）, whereas no significant changes in the LGV occurred before and after ingestion of glucose in the control subjects. CONCLUSION： Hemodynamics of the PV is unrelated to the degree of endoscopic abnormalities in patients with liver cirrhosis. The most important combinations are endoscopic findings followed by the LGV hemodynamics. Duplex-Doppler ultrasonography has no value in the identification of patients with cirrhosis at risk of variceal bleeding. Hemodynamics of the LGV appears to be superior to those of the PV in predicting bleeding.展开更多
BACKGROUND Neoadjuvant or perioperative chemotherapy combined with surgery can reduce postoperative recurrence and improve the long-term survival rate of patients with locally advanced resectable gastric carcinoma.Niv...BACKGROUND Neoadjuvant or perioperative chemotherapy combined with surgery can reduce postoperative recurrence and improve the long-term survival rate of patients with locally advanced resectable gastric carcinoma.Nivolumab combined with chemotherapy has been recommended by the National Comprehensive Cancer Network guidelines as a first-line therapy for advanced gastric carcinoma/adenocarcinoma of the gastroesophageal junction and serves as the basis for immunotherapy combined with chemotherapy to become a neoadjuvant therapy.Herein,we report a case in which pathologic complete response was achieved by neoadjuvant administration of toripalimab,Herceptin,and docetaxel,oxaliplatin,calcium folinate,and fluorouracil(FLOT)chemotherapy followed by surgery for human epidermal growth factor receptor 2(HER2)-and programmed deathligand 1(PD-L1)-positive locally advanced gastric carcinoma.We hope that this case will shed some light on neoadjuvant therapy for gastric carcinoma.CASE SUMMARY The patient was diagnosed with locally advanced adenocarcinoma of the cardia.Immunohistochemistry of the baseline tissues suggested that the tissues were HER2-(fluorescent in situ hybridization)and PD-L1-positive(combined positive score=1).The patient underwent surgery following a four-cycle neoadjuvant therapy comprising Herceptin,toripalimab,and FLOT chemotherapy.The postoperative pathological findings showed mild atypical hyperplasia of the local glands with chronic mucosal inflammation(proximal stomach),no clear residual tumor(tumor regression grade 0),no regional lymph node metastasis,and negative upper and lower cut ends.The levels of tumor markers were reduced to normal levels after re-examination.With good postoperative recovery,the four-cycle preoperative chemotherapy was continued at the same dosage as that previously administered.After the treatment,the patient was monitored every 3 mo with a follow-up of 12 mo(4 times).As of February 27,2022,he was in a good condition without disease progression.The clinical trial registration number is E2019401.CONCLUSION There are many ongoing studies on neoadjuvant immunotherapy combined with chemotherapy or radiotherapy;however,most of these studies are phase II studies with small cohorts.According to the results of some current studies,these combined regimens have shown promising results in terms of efficacy and safety.However,the clinical efficacy and safety of the neoadjuvant therapies used in these combined regimens need to be confirmed by additional prospective phase III clinical trials,and further exploration of molecular markers for effective populations is required.展开更多
AIM To investigate the influence of high salt on dextran sulfate sodium(DSS)-induced colitis in mice and explore the underlying mechanisms of this effect.METHODS DSS and NaC l were used to establish the proinflammator...AIM To investigate the influence of high salt on dextran sulfate sodium(DSS)-induced colitis in mice and explore the underlying mechanisms of this effect.METHODS DSS and NaC l were used to establish the proinflammatory animal model. We evaluated the colitis severity. Flow cytometry was employed for detecting the frequencies of Th1, macrophages and Tregs in spleen, mesenteric lymph node and lamina propria. The important role of macrophages in the promotion of DSS-induced colitis by NaCl was evaluated by depleting macrophages with clodronate liposomes. Activated peritoneal macrophages and lamina propria mononuclear cells(LPMCs) were stimulated with NaCl, and proteins were detected by western blotting. Cytokines and inflammation genes were analyzed by enzyme-linked immunosorbent assay and RT-PCR, respectively.RESULTS The study findings indicate that NaC l up-regulates the frequencies of CD11b^+ macrophages and CD4^+IFN-γ^+IL-17^+ T cells in lamina propria in DSS-treated mice. CD3^+CD4^+CD25^+Foxp^3+ T cells, which can secrete high levels of IL-10 and TGF-β, increase through feedback in NaCl-and DSS-treated mice. Furthermore, clodronate liposomes pretreatment significantly alleviated DSSinduced colitis, indicating that macrophages play a vital role in NaCl proinflammatory activity. NaCl aggravates peritoneal macrophage inflammation by promoting the expressions of interleukin(IL)-1, IL-6 and mouse inducible nitric oxide synthase. Specifically, high NaCl concentrations promote p38 phosphorylation in lipopolysaccharide-and IFN-γ-activated LPMCs mediated by SGK1. CONCLUSION Proinflammatory macrophages may play an essential role in the onset and development of NaCl-promoted inflammation in DSS-induced colitis. The underlining mechanism involves up-regulation of the p38/MAPK axis.展开更多
Allelopathy plays an important role in the interaction between invasive and resident plants.Atmospheric nitrogen(N)deposition has become a global problem,but it is unclear whether N enrichment affects the interaction ...Allelopathy plays an important role in the interaction between invasive and resident plants.Atmospheric nitrogen(N)deposition has become a global problem,but it is unclear whether N enrichment affects the interaction between invasive and resident plants by affecting their allelopathy.Thus,we performed a greenhouse experiment in which the resident plant community was grown under two levels of invasion by S.canadensis(invasion vs.no invasion)and fully crossed with two levels of allelopathy(with or without adding activated carbon)and two levels of N addition(with or without).The resident plant communities were constructed with eight herbaceous species that often co-occur with S.canadensis.The results showed that both allelopathy of S.canadensis and the resident plants had obvious positive effects on their own growth.Nitrogen addition had more obvious positive effects on the resident plants under invasion than those that were not invaded.Moreover,N addition also altered the allelopathy of resident plants.Specifcally,N addition improved the allelopathy of resident plants when they were invaded but decreased the allelopathy of resident plants when they grew alone.Although nitrogen addition had no obvious effect on S.canadensis,it reduced the allelopathy of S.canadensis.These results suggest that N addition could improve the resistance of resident plants to invasion by improving the allelopathy of resident plants and reducing the allelopathy of S.canadensis.These fndings provide a scientifc basis to manage and control the S.canadensis invasion.展开更多
AIM: To prepare the specific magnetic resonance(MR) probes for detection of hepatocellular carcinoma(HCC) using one-pot method.METHODS: The carboxylated dextran-coated nanoparticles were conjugated with anti-α-fetopr...AIM: To prepare the specific magnetic resonance(MR) probes for detection of hepatocellular carcinoma(HCC) using one-pot method.METHODS: The carboxylated dextran-coated nanoparticles were conjugated with anti-α-fetoprotein(anti-AFP) or anti-glypican 3(anti-GPC3) antibodies through 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide(EDC/NHS)-mediated reaction to synthesize the probes.The physical and chemical properties of the probes were determined by transmission electron microscopy(TEM) and dynamic light scattering, and the relaxivity was compared to uncombined ultrasmall superparamagnetic iron oxide nanoparticles(USPIONs) using a 1.5T clinical MR scanner.The binding efficiency of the antibodies to nanoparticles was measured with an ultravioletvisible spectrophotometer.In addition, the probes were incubated with targetable cells in vitro.RESULTS: The superparamagnetic MR probes(antiGPC3-USPION probe and anti-AFP-USPION probe) were synthesized using one-pot method.Their mean hydrodynamic diameter was 47 nm with a broader slight size distribution.The coupling efficiency of carboxylated dextran-coated ultrasmall superparamagnetic iron oxide(USPIO) with anti-GPC3 or anti-AFP antibody was 15.9% and 88.8%, respectively.Each of the USPIO nanoparticles may bind 3 GPC3 antibodies or 12 AFP antibodies.The statistical analysis showed no significance(P > 0.05) in shortening the T1 and T2 values when comparing the USPIO-AFP or USPIOGPC3 to USPIO.Analysis of TEM images revealed that anti-GPC3-USPION probes and anti-AFP-USPION probes could specifically enter into the Hep G2 cell by combining with the GPC3 receptors or AFP receptors, whereas the Hep G2 cell sample incubated with USPIONs showed no or few nanoparticles in the cytoplasm.CONCLUSION: The synthesized probes using one-pot method can be used for in vitro experimental study and have potential clinical application in MR imaging for detection of hepatocellular carcinomas.展开更多
Plants distributed in riparian regions experience frequent episodes of flooding and drought between years, and hence, riparian plants need to be flood- and drought-tolerant. Riparian plants possess various traits to s...Plants distributed in riparian regions experience frequent episodes of flooding and drought between years, and hence, riparian plants need to be flood- and drought-tolerant. Riparian plants possess various traits to survive flooding, while their sensitivity to drought has received less attention. To investigate the growth and photosynthetic responses of a riparian species （Bolboschoenus planiculmis） to flooding and drought, plants of this species were subjected to 60-d flooding or drought stress under greenhouse conditions. Growth and photosynthetic traits were measured at the end of the treatments. As well, we determined the efficiency of photosynthetic apparatus in mature leaves. Plants of B. planiculmis adequately adjusted their growth and photosynthetic traits under both flooding and drought conditions. Flooding did not affect the above-ground growth of B. planiculmis. Increased growth of roots and rhizomes and the generation of new tubers suggested a high ability of below-ground lateral growth by capturing resources under flooding conditions. Enhanced photosynthetic capacity, retained leaf pigment concentrations and chlorophyll a fluorescence capacity indicated photosynthetic adaptation to flooding. In contrast, drought significantly decreased the above-ground growth of B. planiculmis, especially the leaves, thereby minimizing water loss due to transpiration. Its increased root to shoot ratio and ＂phalanx＂ asexual propagation pattern might enhance soil water uptake ability. Although the functional leaves of B. planiculmis could retain their leaf pigment concentrations, as well as photosynthesis and chlorophyll a fluorescence, the total biomass of plants decreased, which may be a consequence of the reduced leaf area, suggesting adverse effects by drought. Therefore, both growth and photosynthetic responses of B. planiculmis are likely to contribute to the ability of this species to thrive in riparian regions, but remain susceptive to drought.展开更多
Objective： The expression of tumor biomarkers may change after chemotherapy. However, whether secreted protein acidic and rich in cysteine （SPARC） expression changes after chemotherapy in gastric cancer （GC） is u...Objective： The expression of tumor biomarkers may change after chemotherapy. However, whether secreted protein acidic and rich in cysteine （SPARC） expression changes after chemotherapy in gastric cancer （GC） is unclear, qqais study investigated the influence of chemotherapy on SPARC expression in GC. Methods： Immunohistochemistry was used to analyze SPARC expression in 132 GC cases （including 54 cases with preoperative chemotherapy and 78 cases without preoperative chemotherapy）. SPARC expression of postoperative specimens with and without preoperative chemotherapy was assessed to analyze the influence of chemotherapy on SPARC expression. Results： SPARC was highly expressed in GC compared with the desmoplastic stroma surrounding tumor cells and noncancerous tissues. High SPAKC expression was correlated with invasion depth, lymph node, and TNM stage. After chemotherapy, a lower proportion of high SPARC expression was observed in patients with preoperative chemotherapy than in the controls. For 54 patients with preoperative chemotherapy; gross type, histology, depth of invasion, lymph node, TNM stage, and SPARC expression were related to overall survival. Further multivariate analysis showed that lymph node, histology, and SPARC expression after chemotherapy were independent prognostic factors. Conclusiou： SPARC expression may change after chemotherapy in GC. SPARC expression should be reassessed for patients with GC after chemotherapy.展开更多
In this paper,a class of brucellosis transmission model with seasonal alternation,density-dependent growth,stage-structure,maturation delay,time-varying incubation is established.The basic reproduction number Ro is de...In this paper,a class of brucellosis transmission model with seasonal alternation,density-dependent growth,stage-structure,maturation delay,time-varying incubation is established.The basic reproduction number Ro is derived,by which we find that the brucellosis is uniformly persistent if R_(0)>1,while the disease-free periodic solution is globally attractive if R_(0)<1.The theoretical results are illustrated by numerical simulation,from which we find that the brucellosis transmission would be overestimated(or underestimated)if we ignore the influence of time-varying incubation or maturation delay.If density-dependent growth of animals is ignored,the risk of brucellosis may be far underestimated,the extinction of brucellosis can be obtained by numerical simulation under the same conditions.Seasonality significantly affects the long-term dynamic behavior of brucellosis,and the inconsistency of parameter periods results in complex dynamic behavior.展开更多
Objective: To observe the influence of nicorandil combined with creatine phosphate sodium on serum BNP, CK-MB, cTnl, SOD, MMP-9 and cardiac function in patients with STEMI. Methods: A total of 60 patients with STEMI w...Objective: To observe the influence of nicorandil combined with creatine phosphate sodium on serum BNP, CK-MB, cTnl, SOD, MMP-9 and cardiac function in patients with STEMI. Methods: A total of 60 patients with STEMI were randomly divided into observation group (30 cases) and control group (30 cases). Observation group: nicorandil combined with creatine phosphate sodium;control group: patients were treated only by nicorandil. Recording and comparing the levels of BNP, CK-MB, cTnl, SOD, MMP-9 and cardiac function before and after treatment. Results: (1) Before treatment, there was no statistically significant difference in the serum BNP, CK-MB, cTnl, SOD, MMP-9 levels between the two groups. After treatment, compared with the same group before treatment, the serum BNP, CK-MB, cTnl, MMP-9 levels of the two groups were significantly lower, the serum SOD level of the two groups were significantly higher, and those levels of observation group were significantly better than the control group, there was significant difference between the two groups. (2) Before treatment, there was no statistically significant difference in LVEF, WMSI, CI between the two groups. After treatment, compared with the same group before treatment, the WMSI of the two groups were significantly lower, the LVEF and CI of the two groups were significantly higher, and those levels of observation group were significantly better than the control group, there was significant difference between the two groups. Conclusion: Nicorandil combined with creatine phosphate sodium for patients with STEMI can perfect the levels of serum BNP, CK-MB, cTnl, SOD, MMP-9 and be beneficial to protect their cardiac function.展开更多
Phenotypic plasticity enables plants to buffer against environmental stresses and match their phenotypes to local conditions.However,consistent conclusive evidence for adaptive plasticity has only been obtained for a ...Phenotypic plasticity enables plants to buffer against environmental stresses and match their phenotypes to local conditions.However,consistent conclusive evidence for adaptive plasticity has only been obtained for a few traits.More studies on a wider variety of plant functional traits and environmental factors are still needed to further understand the adaptive significance of plasticity.We grew 21 genotypes of the stoloniferous clonal plant Duchesnea indica under different light and nutrient conditions,and used selection gradient analyses to test the adaptive value(benefits)of morphological and physiological plasticity responding to variation in light and nutrient availability.Plants grown in shade exhibited lower values for fitness measures(fruit number,ramet number and biomass),shortened thinner internode length and decreased adult leaf chlorophyll content,but higher petiole length,specific leaf area and old leaf chlorophyll content,than plants grown without shade.Plants grown in the low nutrient condition had shorter petiole length,thicker and smaller leaf area,lower chlorophyll content,but higher fruit number and root:shoot ratio than plants grown under the high nutrient condition.Selection gradient analyses revealed that plasticity of petiole length and old leaf chlorophyll content in response to light variation was adaptive,and plasticity of old and adult leaf chlorophyll content in response to nutrient variation was adaptive.Therefore,the adaptive value of plasticity in different traits depends on the specific ecological context.Our findings contribute to understanding the adaptive significance of phenotypic plasticity of clonal plants in response to environmental variation.展开更多
Introduction:Propagule pressure(i.e.,the number of propagules)has long been recognized to play an essential role in plant invasion.But it is not clear whether propagule pressure influences the invasion of exotic plant...Introduction:Propagule pressure(i.e.,the number of propagules)has long been recognized to play an essential role in plant invasion.But it is not clear whether propagule pressure influences the invasion of exotic plants into native plant communities when different frequencies of nitrogen are added.Method:We established an experiment with three plant communities that included native plant communities alone(four grasses,two legumes and two forbs)or native plant communities with one or five invasive plants,Solidago canadensis,under three frequencies of nitrogen addition(no addition or low or high addition with the same amount).Results:High propagule pressure significantly enhanced the biomass and relative dominance index of S.canadensis.Moreover,high propagule pressure only decreased the total and aboveground biomass of the legumes.However,the competitive effect between S.canadensis and the native community and biomass of the whole native community varied according to different frequencies.Conclusion:Overall,high propagule pressure encouraged invasion by S.canadensis,while alow nitrogen frequency was advantageous for the native community to resist invasion in this experiment.The results provide a scientific basis to manage and control the invasion of S.canadensis.展开更多
Aims Clonal integration,i.e.resource sharing between interconnected ramets,can help clonal plants tolerate abiotic stress.However,few studies have directly examined the ecological significance of clonal integration in...Aims Clonal integration,i.e.resource sharing between interconnected ramets,can help clonal plants tolerate abiotic stress.However,few studies have directly examined the ecological significance of clonal integration in the ability of clonal plants to tolerate biotic stress such as herbivory.Methods We grew clonal fragments of an invasive clonal plant Alternanthera philoxeroides,each consisting of an apical part(relatively young)and a basal part(relatively old),at two levels(low and high)of soil nitrogen(N).For each fragment,the apical part was subjected to either no herbivory or herbivory for 2 weeks by a specialist insect,Agasicles hygrophila,and was either connected with or discon-nected from the basal part not subjected to herbivory.Important Findings Herbivory in the apical part severely reduced leaf growth(leaf mass,leaf number or leaf area)and ramet production of both apical and basal parts,and increased root to shoot ratio of the apical part.Irrespective of herbivory and soil N,stem connection between the apical and the basal part decreased root to shoot ratio of the ap-ical part,but did not change its growth measures.Meanwhile,con-nection increased stem N concentration of the apical part growing under high-N supply and decreased stem carbon(C)concentration of the apical part under low-N supply.By contrast,connection in-creased root to shoot ratio of the basal part,but reduced its leaf and ramet production.Connection also increased leaf and stem C concentrations of the basal part under low-N supply.Thus,clonal integration can be beneficial for the early development of young A.philoxeroides ramets,but not for their local adaptation to herbivory damage by A.hygrophila.展开更多
Aims The diversity-productivity relationship is one of the most critical questions in ecology and can be altered by environmental factors.Hydrological fluctuation affects growth of wetland plants,and such effects vary...Aims The diversity-productivity relationship is one of the most critical questions in ecology and can be altered by environmental factors.Hydrological fluctuation affects growth of wetland plants,and such effects vary with plant species.Therefore,we hypothesized that hydrological fluctuation changes effects of species richness on productivity of wetland plant communities.Methods We constructed wetland plant communities consisting of three or six wetland plant species and subjected them to hydrological fluctuation(i.e.gradually changing water level)of two frequencies and two ranges,with unchanged water level as the control.We measured height,root and shoot dry mass of each plant at harvest.Important Findings Hydrological fluctuation significantly decreased biomass of wetland plant communities,which was due to impacts of fluctuation range,but not those of fluctuation frequency.Community biomass was significantly higher when species richness was higher,and such an effect did not depend on hydrological fluctuation.Therefore,hydrological fluctuation can decrease the productivity of wetland plant communities but may not alter the diversity-productivity relationship.展开更多
Native plant communities are commonly invaded by invasive plants to different degrees.However,the relative contribution of the invasive plant abundance vs.phylogenetic evenness to the responses of wetland communities ...Native plant communities are commonly invaded by invasive plants to different degrees.However,the relative contribution of the invasive plant abundance vs.phylogenetic evenness to the responses of wetland communities to different degrees of invasion is still unclear.In addition,whether such contribution varies with environmental conditions such as flooding is also unclear.To address these questions,we chose Alternanthera philoxeroides as the invasive plant,and set up four invasive degrees by changing the community species composition under both flooding and non-flooding conditions.The relative abundance of A.philoxeroides and phylogenetic evenness changed simultaneously with the change in the community invasion degree.The invasion degree significantly affected the individual biomass of A.philoxeroides and some native species.Variation partitioning showed that the relative abundance of A.philoxeroides contributed more to variation in community indicators than phylogenetic evenness,regardless of flooding.Spearman rank correlation test showed that the relative abundance of A.philoxeroides was negatively correlated with the individual biomass of A.philoxeroides and some native species,while the phylogenetic evenness was positively correlated with only a few native species.And their correlation strength and significance were all affected by specific species and flooded environment.In conclusion,our results suggest that the relative abundance of A.philoxeroides can more effectively explain the wetland community response to different invasion degrees than phylogenetic evenness,regardless of flooding.展开更多
In most models of population dynamics, diffusion between two patches is assumed to be either continuous or discrete. However, in the real world, it is often the case that diffusion occurs at certain moment every year,...In most models of population dynamics, diffusion between two patches is assumed to be either continuous or discrete. However, in the real world, it is often the case that diffusion occurs at certain moment every year, impulsive diffusion can provide a more suitable manner to model the actual dispersal （or migration） behaviors for many eco- logical species. In addition, it is generally recognized that some kinds of time delays are inevitable in population interactions. In view of these facts, a delayed predator-prey system with impulsive diffusion between two patches is proposed. By using compari- son theorem of impulsive differential equation and some analysis techniques, criteria on the global attractivity of predator-extinction periodic solution are established, sufficient conditions for the permanence of system are obtained. Finally, numerical simulations are presented to illustrate our theoretical results.展开更多
基金Supported by the Natural Science Foundation of Shanghai, No. 034119921
文摘AIM： To study the portal hemodynamics and their relationship with the size of esophageal varices seen at endoscopy and to evaluate whether these Doppler ultrasound parameters might predict variceal bleeding in patients with liver cirrhosis and portal hypertension. METHODS： One hundred and twenty cirrhotic patients with esophageal varices but without any previous bleeding were enrolled in the prospective study. During a 2-year observation period, 52 patients who had at least one episode of acute esophageal variceal hemorrhage constituted the bleeding group, and the remaining 68 patients without any previous hemorrhage constituted the non-bleeding group. All patients underwent endoscopy before or after color Doppler-ultrasonic examination, and images were interpreted independently by two endoscopists. The control group consisted of 30 healthy subjects, matched to the patient group in age and gender. Measurements of diameter, flow direction and flow velocity in the left gastric vein （LGV） and the portal vein （PV） were done in all patients and controls using color Doppler unit. After baseline measurements, 30 min after oral administration of 75 g glucose in 225 mL, changes of the diameter, flow velocity and direction in the PV and LGV were examined in 60 patients with esophageal varices and 15 healthy controls. RESULTS： The PV and LGV were detected successfully in 115 （96%） and 105 （88%） of 120 cirrhotic patients, respectively, and in 27 （90%） and 21 （70%） of 30 healthy controls, respectively. Among the 120 cirrhotic patients, 37 had F1, 59 had F2, and 24 had F3 grade varices. Compared with the healthy controls, cirrhotic group had a significantly lower velocity in the PV, a significantly greater diameter of the PV and LGV, and a higher velocity in the LGV. In the cirrhotic group, no difference in portal flow velocity and diameter were observed between patients with or without esophageal variceal bleeding （EVB）. However, the diameter and blood flow velocity of the LGV were significantly higher for EVB （＋） group compared with EVB （-） group （P〈0.01）. Diameter of the LGV increased with enlarged size of varices. There were differences between F1 and F2, F1 and F3 varices, but no differences between F2 and F3 varices （P = 0.125）. However, variceal bleeding was more frequent in patients with a diameter of LGV 〉6 mm. The flow velocity in the LGV of healthy controls was 8.70＋1.91 cm/s （n = 21）. In patients with liver cirrhosis, it was 10.3＋2.1 cm/s （n = 12） when the flow was hepatopetal and 13.5＋2.3 cm/s （n = 87） when it was hepatofugal. As the size of varices enlarged, hepatofugal flow velocity increased （P〈0.01） and was significantly different between patients with F1 and F2 varices and between patients with F2 and F3 varices. Variceal bleeding was more frequent in patients with a hepatofugal flow velocity 〉15 cm/s （32 of 52 patients, 61.5%）. Within the bleeding group, the mean LGV blood flow velocity was 16.6＋2.62 cm/s. No correlation was observed between the portal blood flow velocity and EVB. In all healthy controls, the flow direction in the LGV was hepatopetal, toward the PV. In patients with F1 varices, flow direction was hepatopetal in 10 patients, to-and-fro state in 3 patients, and hepatofugal in the remaining 18. The flow was hepatofugal in 91% patients with F2 and all F3 varices. Changes in diameter of the PV and LGV were not significant before and after ingestion of glucose （PV： 1.41＋1.5 cm before and 1.46＋1.6 cm after; LGV： 0.57＋1.7 cm before and 0.60＋1.5 cm after）. Flow direction in the LGV was hepatopetal and to-and-fro in 16 patients and hepatofugal in 44 patients before ingestion of glucose. Flow direction changed to hepatofugal in 9 of 16 patients with hepatopetal and to-and-fro blood flow after ingestion of glucose. In 44 patients with hepatofugal blood flow in the LGV, a significant increase in hepatofugal flow velocity was observed in 38 of 44 patients （86%） with esophageal varices. There was a relationship between the percentage changes in flow velocity and the size of varices. Patients who responded excessively to food ingestion might have a high risk for bleeding. The changes of blood flow velocity in the LGV were greater than those in the PV （LGV： 28.3＋26.1%, PV： 7.2＋13.2%, P〈0.01）, whereas no significant changes in the LGV occurred before and after ingestion of glucose in the control subjects. CONCLUSION： Hemodynamics of the PV is unrelated to the degree of endoscopic abnormalities in patients with liver cirrhosis. The most important combinations are endoscopic findings followed by the LGV hemodynamics. Duplex-Doppler ultrasonography has no value in the identification of patients with cirrhosis at risk of variceal bleeding. Hemodynamics of the LGV appears to be superior to those of the PV in predicting bleeding.
基金Supported by Chinese Research Hospital Association,No.Y2019FH-DTCC-SC3。
文摘BACKGROUND Neoadjuvant or perioperative chemotherapy combined with surgery can reduce postoperative recurrence and improve the long-term survival rate of patients with locally advanced resectable gastric carcinoma.Nivolumab combined with chemotherapy has been recommended by the National Comprehensive Cancer Network guidelines as a first-line therapy for advanced gastric carcinoma/adenocarcinoma of the gastroesophageal junction and serves as the basis for immunotherapy combined with chemotherapy to become a neoadjuvant therapy.Herein,we report a case in which pathologic complete response was achieved by neoadjuvant administration of toripalimab,Herceptin,and docetaxel,oxaliplatin,calcium folinate,and fluorouracil(FLOT)chemotherapy followed by surgery for human epidermal growth factor receptor 2(HER2)-and programmed deathligand 1(PD-L1)-positive locally advanced gastric carcinoma.We hope that this case will shed some light on neoadjuvant therapy for gastric carcinoma.CASE SUMMARY The patient was diagnosed with locally advanced adenocarcinoma of the cardia.Immunohistochemistry of the baseline tissues suggested that the tissues were HER2-(fluorescent in situ hybridization)and PD-L1-positive(combined positive score=1).The patient underwent surgery following a four-cycle neoadjuvant therapy comprising Herceptin,toripalimab,and FLOT chemotherapy.The postoperative pathological findings showed mild atypical hyperplasia of the local glands with chronic mucosal inflammation(proximal stomach),no clear residual tumor(tumor regression grade 0),no regional lymph node metastasis,and negative upper and lower cut ends.The levels of tumor markers were reduced to normal levels after re-examination.With good postoperative recovery,the four-cycle preoperative chemotherapy was continued at the same dosage as that previously administered.After the treatment,the patient was monitored every 3 mo with a follow-up of 12 mo(4 times).As of February 27,2022,he was in a good condition without disease progression.The clinical trial registration number is E2019401.CONCLUSION There are many ongoing studies on neoadjuvant immunotherapy combined with chemotherapy or radiotherapy;however,most of these studies are phase II studies with small cohorts.According to the results of some current studies,these combined regimens have shown promising results in terms of efficacy and safety.However,the clinical efficacy and safety of the neoadjuvant therapies used in these combined regimens need to be confirmed by additional prospective phase III clinical trials,and further exploration of molecular markers for effective populations is required.
基金Supported by National Natural Science Foundation of China,No.81271813 and No.81570497
文摘AIM To investigate the influence of high salt on dextran sulfate sodium(DSS)-induced colitis in mice and explore the underlying mechanisms of this effect.METHODS DSS and NaC l were used to establish the proinflammatory animal model. We evaluated the colitis severity. Flow cytometry was employed for detecting the frequencies of Th1, macrophages and Tregs in spleen, mesenteric lymph node and lamina propria. The important role of macrophages in the promotion of DSS-induced colitis by NaCl was evaluated by depleting macrophages with clodronate liposomes. Activated peritoneal macrophages and lamina propria mononuclear cells(LPMCs) were stimulated with NaCl, and proteins were detected by western blotting. Cytokines and inflammation genes were analyzed by enzyme-linked immunosorbent assay and RT-PCR, respectively.RESULTS The study findings indicate that NaC l up-regulates the frequencies of CD11b^+ macrophages and CD4^+IFN-γ^+IL-17^+ T cells in lamina propria in DSS-treated mice. CD3^+CD4^+CD25^+Foxp^3+ T cells, which can secrete high levels of IL-10 and TGF-β, increase through feedback in NaCl-and DSS-treated mice. Furthermore, clodronate liposomes pretreatment significantly alleviated DSSinduced colitis, indicating that macrophages play a vital role in NaCl proinflammatory activity. NaCl aggravates peritoneal macrophage inflammation by promoting the expressions of interleukin(IL)-1, IL-6 and mouse inducible nitric oxide synthase. Specifically, high NaCl concentrations promote p38 phosphorylation in lipopolysaccharide-and IFN-γ-activated LPMCs mediated by SGK1. CONCLUSION Proinflammatory macrophages may play an essential role in the onset and development of NaCl-promoted inflammation in DSS-induced colitis. The underlining mechanism involves up-regulation of the p38/MAPK axis.
基金supported by the New Area Science and Technology Innovation Project(2022XACX1000)the Fundamental Research Funds for the Central Universities(QNTD202304)+4 种基金the National Key Research and Development Program of China(2021YFC2600400)the National Natural Science Foundation of China(31470475,31761123001)the Fundamental Research Funds for the Central Universities(2015ZCQ-BH-01)the China Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07602-004-003)the Beijing Municipal Education Commission through Innovative Transdisciplinary Program‘Ecological Restoration Engineering’.
文摘Allelopathy plays an important role in the interaction between invasive and resident plants.Atmospheric nitrogen(N)deposition has become a global problem,but it is unclear whether N enrichment affects the interaction between invasive and resident plants by affecting their allelopathy.Thus,we performed a greenhouse experiment in which the resident plant community was grown under two levels of invasion by S.canadensis(invasion vs.no invasion)and fully crossed with two levels of allelopathy(with or without adding activated carbon)and two levels of N addition(with or without).The resident plant communities were constructed with eight herbaceous species that often co-occur with S.canadensis.The results showed that both allelopathy of S.canadensis and the resident plants had obvious positive effects on their own growth.Nitrogen addition had more obvious positive effects on the resident plants under invasion than those that were not invaded.Moreover,N addition also altered the allelopathy of resident plants.Specifcally,N addition improved the allelopathy of resident plants when they were invaded but decreased the allelopathy of resident plants when they grew alone.Although nitrogen addition had no obvious effect on S.canadensis,it reduced the allelopathy of S.canadensis.These results suggest that N addition could improve the resistance of resident plants to invasion by improving the allelopathy of resident plants and reducing the allelopathy of S.canadensis.These fndings provide a scientifc basis to manage and control the S.canadensis invasion.
基金Supported by National Natural Science Foundation of China,No.81071996
文摘AIM: To prepare the specific magnetic resonance(MR) probes for detection of hepatocellular carcinoma(HCC) using one-pot method.METHODS: The carboxylated dextran-coated nanoparticles were conjugated with anti-α-fetoprotein(anti-AFP) or anti-glypican 3(anti-GPC3) antibodies through 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide(EDC/NHS)-mediated reaction to synthesize the probes.The physical and chemical properties of the probes were determined by transmission electron microscopy(TEM) and dynamic light scattering, and the relaxivity was compared to uncombined ultrasmall superparamagnetic iron oxide nanoparticles(USPIONs) using a 1.5T clinical MR scanner.The binding efficiency of the antibodies to nanoparticles was measured with an ultravioletvisible spectrophotometer.In addition, the probes were incubated with targetable cells in vitro.RESULTS: The superparamagnetic MR probes(antiGPC3-USPION probe and anti-AFP-USPION probe) were synthesized using one-pot method.Their mean hydrodynamic diameter was 47 nm with a broader slight size distribution.The coupling efficiency of carboxylated dextran-coated ultrasmall superparamagnetic iron oxide(USPIO) with anti-GPC3 or anti-AFP antibody was 15.9% and 88.8%, respectively.Each of the USPIO nanoparticles may bind 3 GPC3 antibodies or 12 AFP antibodies.The statistical analysis showed no significance(P > 0.05) in shortening the T1 and T2 values when comparing the USPIO-AFP or USPIOGPC3 to USPIO.Analysis of TEM images revealed that anti-GPC3-USPION probes and anti-AFP-USPION probes could specifically enter into the Hep G2 cell by combining with the GPC3 receptors or AFP receptors, whereas the Hep G2 cell sample incubated with USPIONs showed no or few nanoparticles in the cytoplasm.CONCLUSION: The synthesized probes using one-pot method can be used for in vitro experimental study and have potential clinical application in MR imaging for detection of hepatocellular carcinomas.
基金supported by the Forestry Commonwealth Project (Grant No. 201004078)the National Science Foundation of China (Grant No.31200314)
文摘Plants distributed in riparian regions experience frequent episodes of flooding and drought between years, and hence, riparian plants need to be flood- and drought-tolerant. Riparian plants possess various traits to survive flooding, while their sensitivity to drought has received less attention. To investigate the growth and photosynthetic responses of a riparian species （Bolboschoenus planiculmis） to flooding and drought, plants of this species were subjected to 60-d flooding or drought stress under greenhouse conditions. Growth and photosynthetic traits were measured at the end of the treatments. As well, we determined the efficiency of photosynthetic apparatus in mature leaves. Plants of B. planiculmis adequately adjusted their growth and photosynthetic traits under both flooding and drought conditions. Flooding did not affect the above-ground growth of B. planiculmis. Increased growth of roots and rhizomes and the generation of new tubers suggested a high ability of below-ground lateral growth by capturing resources under flooding conditions. Enhanced photosynthetic capacity, retained leaf pigment concentrations and chlorophyll a fluorescence capacity indicated photosynthetic adaptation to flooding. In contrast, drought significantly decreased the above-ground growth of B. planiculmis, especially the leaves, thereby minimizing water loss due to transpiration. Its increased root to shoot ratio and ＂phalanx＂ asexual propagation pattern might enhance soil water uptake ability. Although the functional leaves of B. planiculmis could retain their leaf pigment concentrations, as well as photosynthesis and chlorophyll a fluorescence, the total biomass of plants decreased, which may be a consequence of the reduced leaf area, suggesting adverse effects by drought. Therefore, both growth and photosynthetic responses of B. planiculmis are likely to contribute to the ability of this species to thrive in riparian regions, but remain susceptive to drought.
文摘Objective： The expression of tumor biomarkers may change after chemotherapy. However, whether secreted protein acidic and rich in cysteine （SPARC） expression changes after chemotherapy in gastric cancer （GC） is unclear, qqais study investigated the influence of chemotherapy on SPARC expression in GC. Methods： Immunohistochemistry was used to analyze SPARC expression in 132 GC cases （including 54 cases with preoperative chemotherapy and 78 cases without preoperative chemotherapy）. SPARC expression of postoperative specimens with and without preoperative chemotherapy was assessed to analyze the influence of chemotherapy on SPARC expression. Results： SPARC was highly expressed in GC compared with the desmoplastic stroma surrounding tumor cells and noncancerous tissues. High SPAKC expression was correlated with invasion depth, lymph node, and TNM stage. After chemotherapy, a lower proportion of high SPARC expression was observed in patients with preoperative chemotherapy than in the controls. For 54 patients with preoperative chemotherapy; gross type, histology, depth of invasion, lymph node, TNM stage, and SPARC expression were related to overall survival. Further multivariate analysis showed that lymph node, histology, and SPARC expression after chemotherapy were independent prognostic factors. Conclusiou： SPARC expression may change after chemotherapy in GC. SPARC expression should be reassessed for patients with GC after chemotherapy.
文摘In this paper,a class of brucellosis transmission model with seasonal alternation,density-dependent growth,stage-structure,maturation delay,time-varying incubation is established.The basic reproduction number Ro is derived,by which we find that the brucellosis is uniformly persistent if R_(0)>1,while the disease-free periodic solution is globally attractive if R_(0)<1.The theoretical results are illustrated by numerical simulation,from which we find that the brucellosis transmission would be overestimated(or underestimated)if we ignore the influence of time-varying incubation or maturation delay.If density-dependent growth of animals is ignored,the risk of brucellosis may be far underestimated,the extinction of brucellosis can be obtained by numerical simulation under the same conditions.Seasonality significantly affects the long-term dynamic behavior of brucellosis,and the inconsistency of parameter periods results in complex dynamic behavior.
文摘Objective: To observe the influence of nicorandil combined with creatine phosphate sodium on serum BNP, CK-MB, cTnl, SOD, MMP-9 and cardiac function in patients with STEMI. Methods: A total of 60 patients with STEMI were randomly divided into observation group (30 cases) and control group (30 cases). Observation group: nicorandil combined with creatine phosphate sodium;control group: patients were treated only by nicorandil. Recording and comparing the levels of BNP, CK-MB, cTnl, SOD, MMP-9 and cardiac function before and after treatment. Results: (1) Before treatment, there was no statistically significant difference in the serum BNP, CK-MB, cTnl, SOD, MMP-9 levels between the two groups. After treatment, compared with the same group before treatment, the serum BNP, CK-MB, cTnl, MMP-9 levels of the two groups were significantly lower, the serum SOD level of the two groups were significantly higher, and those levels of observation group were significantly better than the control group, there was significant difference between the two groups. (2) Before treatment, there was no statistically significant difference in LVEF, WMSI, CI between the two groups. After treatment, compared with the same group before treatment, the WMSI of the two groups were significantly lower, the LVEF and CI of the two groups were significantly higher, and those levels of observation group were significantly better than the control group, there was significant difference between the two groups. Conclusion: Nicorandil combined with creatine phosphate sodium for patients with STEMI can perfect the levels of serum BNP, CK-MB, cTnl, SOD, MMP-9 and be beneficial to protect their cardiac function.
基金supported by the National Natural Science Foundation of China(31870610,32071527,31761123001)the Ten Thousand Talent Program of Zhejiang Province(2018R52016)the Joint Fund of Zhejiang Provincial Natural Science Foundation(LTZ20C030001).
文摘Phenotypic plasticity enables plants to buffer against environmental stresses and match their phenotypes to local conditions.However,consistent conclusive evidence for adaptive plasticity has only been obtained for a few traits.More studies on a wider variety of plant functional traits and environmental factors are still needed to further understand the adaptive significance of plasticity.We grew 21 genotypes of the stoloniferous clonal plant Duchesnea indica under different light and nutrient conditions,and used selection gradient analyses to test the adaptive value(benefits)of morphological and physiological plasticity responding to variation in light and nutrient availability.Plants grown in shade exhibited lower values for fitness measures(fruit number,ramet number and biomass),shortened thinner internode length and decreased adult leaf chlorophyll content,but higher petiole length,specific leaf area and old leaf chlorophyll content,than plants grown without shade.Plants grown in the low nutrient condition had shorter petiole length,thicker and smaller leaf area,lower chlorophyll content,but higher fruit number and root:shoot ratio than plants grown under the high nutrient condition.Selection gradient analyses revealed that plasticity of petiole length and old leaf chlorophyll content in response to light variation was adaptive,and plasticity of old and adult leaf chlorophyll content in response to nutrient variation was adaptive.Therefore,the adaptive value of plasticity in different traits depends on the specific ecological context.Our findings contribute to understanding the adaptive significance of phenotypic plasticity of clonal plants in response to environmental variation.
基金This work was supported by the National Key R&D Program of China[2021YFC2600400]Fundamental Research Funds for the Central Universities[2015ZCQ-BH-01]+2 种基金China Major Science and Technology Program for Water Pollution Control and Treatment[2017ZX07602-004-003]National Natural Science Foundation of China[31470475]Zhejiang Provincial Ten Thousand Plan for Young Top Talents[2018R52016].
文摘Introduction:Propagule pressure(i.e.,the number of propagules)has long been recognized to play an essential role in plant invasion.But it is not clear whether propagule pressure influences the invasion of exotic plants into native plant communities when different frequencies of nitrogen are added.Method:We established an experiment with three plant communities that included native plant communities alone(four grasses,two legumes and two forbs)or native plant communities with one or five invasive plants,Solidago canadensis,under three frequencies of nitrogen addition(no addition or low or high addition with the same amount).Results:High propagule pressure significantly enhanced the biomass and relative dominance index of S.canadensis.Moreover,high propagule pressure only decreased the total and aboveground biomass of the legumes.However,the competitive effect between S.canadensis and the native community and biomass of the whole native community varied according to different frequencies.Conclusion:Overall,high propagule pressure encouraged invasion by S.canadensis,while alow nitrogen frequency was advantageous for the native community to resist invasion in this experiment.The results provide a scientific basis to manage and control the invasion of S.canadensis.
基金This work was supported by National Key Research and Development Program of China(2016YFC1201101,2016YFC1202102)the National Natural Science Foundation of China(31500331,31670428)+1 种基金the Fundamental Research Funds for the Central Universities(2015ZCQ-BH-01)Undergraduate Innovation and Entrepreneurship Training Program of Beijing Forestry University(X201710022152).
文摘Aims Clonal integration,i.e.resource sharing between interconnected ramets,can help clonal plants tolerate abiotic stress.However,few studies have directly examined the ecological significance of clonal integration in the ability of clonal plants to tolerate biotic stress such as herbivory.Methods We grew clonal fragments of an invasive clonal plant Alternanthera philoxeroides,each consisting of an apical part(relatively young)and a basal part(relatively old),at two levels(low and high)of soil nitrogen(N).For each fragment,the apical part was subjected to either no herbivory or herbivory for 2 weeks by a specialist insect,Agasicles hygrophila,and was either connected with or discon-nected from the basal part not subjected to herbivory.Important Findings Herbivory in the apical part severely reduced leaf growth(leaf mass,leaf number or leaf area)and ramet production of both apical and basal parts,and increased root to shoot ratio of the apical part.Irrespective of herbivory and soil N,stem connection between the apical and the basal part decreased root to shoot ratio of the ap-ical part,but did not change its growth measures.Meanwhile,con-nection increased stem N concentration of the apical part growing under high-N supply and decreased stem carbon(C)concentration of the apical part under low-N supply.By contrast,connection in-creased root to shoot ratio of the basal part,but reduced its leaf and ramet production.Connection also increased leaf and stem C concentrations of the basal part under low-N supply.Thus,clonal integration can be beneficial for the early development of young A.philoxeroides ramets,but not for their local adaptation to herbivory damage by A.hygrophila.
基金Fundamental Research Funds for the Central Universities(TD-JC-2013-1)Specialized Research Fund for the Doctoral Program of Higher Education(20120014120001)National Natural Science Foundation of China(31200314,31470475).
文摘Aims The diversity-productivity relationship is one of the most critical questions in ecology and can be altered by environmental factors.Hydrological fluctuation affects growth of wetland plants,and such effects vary with plant species.Therefore,we hypothesized that hydrological fluctuation changes effects of species richness on productivity of wetland plant communities.Methods We constructed wetland plant communities consisting of three or six wetland plant species and subjected them to hydrological fluctuation(i.e.gradually changing water level)of two frequencies and two ranges,with unchanged water level as the control.We measured height,root and shoot dry mass of each plant at harvest.Important Findings Hydrological fluctuation significantly decreased biomass of wetland plant communities,which was due to impacts of fluctuation range,but not those of fluctuation frequency.Community biomass was significantly higher when species richness was higher,and such an effect did not depend on hydrological fluctuation.Therefore,hydrological fluctuation can decrease the productivity of wetland plant communities but may not alter the diversity-productivity relationship.
基金supported by the Fundamental Research Funds for the Central Universities(2015ZCQ-BH-01)the National Key Research and Development Program(2016YFC1201100)the China Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07602-004-003).
文摘Native plant communities are commonly invaded by invasive plants to different degrees.However,the relative contribution of the invasive plant abundance vs.phylogenetic evenness to the responses of wetland communities to different degrees of invasion is still unclear.In addition,whether such contribution varies with environmental conditions such as flooding is also unclear.To address these questions,we chose Alternanthera philoxeroides as the invasive plant,and set up four invasive degrees by changing the community species composition under both flooding and non-flooding conditions.The relative abundance of A.philoxeroides and phylogenetic evenness changed simultaneously with the change in the community invasion degree.The invasion degree significantly affected the individual biomass of A.philoxeroides and some native species.Variation partitioning showed that the relative abundance of A.philoxeroides contributed more to variation in community indicators than phylogenetic evenness,regardless of flooding.Spearman rank correlation test showed that the relative abundance of A.philoxeroides was negatively correlated with the individual biomass of A.philoxeroides and some native species,while the phylogenetic evenness was positively correlated with only a few native species.And their correlation strength and significance were all affected by specific species and flooded environment.In conclusion,our results suggest that the relative abundance of A.philoxeroides can more effectively explain the wetland community response to different invasion degrees than phylogenetic evenness,regardless of flooding.
文摘In most models of population dynamics, diffusion between two patches is assumed to be either continuous or discrete. However, in the real world, it is often the case that diffusion occurs at certain moment every year, impulsive diffusion can provide a more suitable manner to model the actual dispersal （or migration） behaviors for many eco- logical species. In addition, it is generally recognized that some kinds of time delays are inevitable in population interactions. In view of these facts, a delayed predator-prey system with impulsive diffusion between two patches is proposed. By using compari- son theorem of impulsive differential equation and some analysis techniques, criteria on the global attractivity of predator-extinction periodic solution are established, sufficient conditions for the permanence of system are obtained. Finally, numerical simulations are presented to illustrate our theoretical results.
