Biogenic silica in intertidal marsh plants and associated sediments of the Yangtze Estuary

Biogenic silica (BSi) contents in the marsh plants (Phragmites australis, Scirpus mariqueter and Spartina alterniflora) and associated sediments in Chongming Island eastern intertidal flat of the Yangtze Estuary were determined. The BSi contents in P. australis, S. mariqueter and S. alterniflora varied from 25.78-42.74 mg/g, 5.71-19.53 mg/g and 6.71-8.92 mg/g, respectively. Over the entire growth season, P. australis and S. mariqueter were characterized by linear accumulation patterns of BSi. The aboveground biomass (leaves and culms) of the marsh plants generally contained more BSi than underground biomass (roots). BSi contents were relatively higher in dead plant tissues than in live tissues which was probably due to the decomposition and the leaching of labile components of plant tissues such as organic carbon and nitrogen. Comparing with the habitats of S. mariqueter and S. alterniflora, the highest BSi content was recorded in sediments inhabited by P. australis, with an annual average of 15.69 mg/g. Overall, the intertidal marshes in the Yangtze Estuary may act as a net sink of BSi via plant uptake and sedimentary burial.

Neurovascular compression and decompression of the intracranial vagus for blood pressure

BACKGROUND: Previous researches demonstrated that neurovascular decompression could cure hypertension; however, whether it could effectively control refractory hypertension after hypertensive cerebral hemorrhage should be further studied. OBJECTIVE: To observe the effect of neruovascular compression on intracranial vagus for blood pressure of dogs and investigate the effect of neurovascular decompression on blood pressure of patients with hypertensive cerebral hemorrhage. DESIGN: Randomized controlled animal study, clinical effects and retrospective analysis. SETTING: Department of Neurosurgery, Changzheng Hospital Affiliated to the Second Military Medical University of Chinese PLA. MATERIALS: The experiment was carried out in the Department of Neurosurgery, Changzheng Hospital Affiliated to the Second Military Medical University of Chinese PLA from May to October 2006. A total of 15 healthy adult dogs of both genders were randomly divided into experimental group (n =10) and control group (n =5). Clinical observation: A total of 41 patients with hypertensive cerebral hemorrhage were selected from the Department of Neurosurgery, General Hospital of Nanjing Military Area Command of Chinese PLA and the Department of Neurosurgery, Changzheng Hospital Affiliated to the Second Military Medical University of Chinese PLA from October 1999 to October 2006. Among them, one patient had brain stem hemorrhage. There were 27 males and 14 females aged from 41 to 66 years. Inclusion criteria: All patients were diagnosed with CT examination once or several times. Volume of hematoma ranged from 50 to 120 mL and had obviously operative indication. All patients provided consents. In addition, another 281 patients with hypertensive cerebral hemorrhage who received traditionally internal and surgical therapies in our departments of neurosurgery, neurology and emergency room were selected in the control group. METHODS: ① Animal experiments: 20 cm autochthonous great saphenous vein was taken from dogs in the experimental group and coincided with tip of facial artery to form arterial loop so as to oppress left vagus and lateral bulb abdomen. In addition, 20 cm autochthonous great saphenous vein was taken from dogs in the control group and coincided with tip of facial artery to establish arterial loop so as to oppress left cerebellum to observe changes of blood pressure before and at 1, 2, 3 and 4 weeks after operation. ② Clinical observation: Among 41 patients with hypertensive cerebral hemorrhage including one with brain stem hemorrhage, they received microvascular decompression of vagus immediately after getting rid of intracerebral hematoma and stopping bleeding to observe its effect of depressurization. All patients and their relatives provided consents. ③ A total of 281 patients with hypertensive cerebral hemorrhage who discharged after the treatment of traditionally internal and surgical therapies were studied retrospectively to observe changes of blood pressure after routine treatment and compare the results with neurovascular decompression. MAIN OUTCOME MEASURES: ① Changes of blood pressure of experimental dogs; ② effect of vascular decompression of vagus for blood pressure of patients with hypertensive cerebral hemorrhage after clearing intracerebral hematoma; ③ different effects of neurovascular decompression and routinely internal and surgical therapies on hypertension. RESULTS: ① Results of animal experiments: Nine dogs in the experimental group survived. At 1, 2, 3 and 4 weeks after operation, blood pressure of dogs in the experimental group was (139.77±4.06), (149.11± 4.90), (148.10±4.16), (147.76±4.15) mm Hg (1 mm Hg=0.133 kPa), which was higher than that of dogs in the control group [(117.20±2.74), (116.65±3.74), (116.26±1.8), (115.81±3.76) mm Hg, P < 0.01]. ② Results of clinical observation: Among 41 patients, 8 (20%) cases died during the operation. In addition,among other 33 (80%) survival patients, 11 (33%) cases had normal blood pressure; blood pressure of 14 (43%) cases was improved or closed to normal value; blood pressure of 8 (24%) cases was not changed obviously as compared with that before operation. ③ The results demonstrated that, by using traditionally internal and surgical therapies, among 281 patients with hypertensive cerebral hemorrhage, blood pressure of about 15% cases was recovered or closed to normal value. Those mentioned above did not have history of hypertension before hemorrhage. However, patients who had history of hypertension before hemorrhage received the traditionally internal or surgical therapies, and the blood pressure was not improved to the normal value after the treatment. CONCLUSION: ① Neurovascular compression in left intracranial vagus can cause obvious increase of blood pressure of dogs, and the increasing volume was 30 mm Hg. ② Vascular decompression of vagus has a great effect on refractory hypertension, and the improvement of blood pressure is superior to traditionally internal and surgical therapies in clinic.

FA方案用于急性髓系白血病不同治疗阶段疗效分析(英文)

Objective: To evaluate the therapeutic effect of the fludarabine and cytarabine (FA) regimen on acute myeloid leukemia (AML) at different phases during treatment. Methods: A total of 185 patients with AML were divided into 4 groups based on the outcome of previous treatments. Patients in Group 1 had no remission after the first course of induction chemotherapy (n = 55). Patients in Group 2 had no remission after no less than two courses of induction chemotherapy (n = 41). Patients in Group 3 had early relapse (n = 40). Patients in Group 4 had late relapse (n = 49). Patients in groups 2, 3 and 4 had refractory AML or AML with relapse. We assessed the efficacy and toxicity of FA combination chemotherapy in each of these 4 groups. Results: The complete remission (CR) rates of Groups 1, 2, 3 and 4 were 74.5% (41/55), 45.9% (19/41), 17.5% (7/40) and 38.8% (19/49), respectively. The CR rate was higher in Group 1 than in the other 3 groups (34.6%, 45/130) (P = 0.000). A significant correlation was found between CR rate and the number of chemotherapeutic courses (P = 0.023). The main adverse reactions included bone marrow suppression and secondary infection. Conclusion: FA regimen is a good choice for patients with AML, especially those who have failed to achieve CR after the first course of induction chemotherapy.

Invasive Spartina alterniflora accelerates the increase in microbial nitrogen fixation over nitrogen removal in coastal wetlands of China

Salt marsh plants play a vital role in mediating nitrogen(N)biogeochemical cycle in estuarine and coastal ecosystems.However,the effects of invasive Spartina alterniflora on N fixation and removal,as well as how these two processes balance to determine the N budget,remain unclear.Here,simultaneous quantifications of N fixation and removal via^(15)N tracing experiment with native Phragmites australis,invasive S.alterniflora,and bare flats as well as corresponding functional gene abundance by qPCR were carried out to explore the response of N dynamics to S.alterniflora invasion.Our results showed that N fixation and removal rates ranged from 0.77±0.08 to 16.12±1.13 nmol/(g·h)and from 1.42±0.14 to 16.35±1.10 nmol/(g·h),respectively,and invasive S.alterniflora generally facilitated the two processes rates.Based on the difference between N removal and fixation rates,net N_(2)fluxes were estimated in the range of-0.39±0.14 to 8.24±2.23 nmol/(g·h).Estimated net N_(2)fluxes in S.alterniflora stands were lower than those in bare flats and P.australis stands,indicating that the increase in N removal caused by S.alterniflora invasion may be more than offset by N fixation process.Random forest analysis revealed that functional microorganisms were the most important factor associated with the corresponding N transformation process.Overall,our results highlight the importance of N fixation in evaluating N budget of estuarine and coastal wetlands,providing valuable insights into the ecological effect of S.alterniflora invasion.

In situ nitrogen removal processes in intertidal wetlands of the Yangtze Estuary

Estuarine and intertidal wetlands are important sites for nitrogen transformation and elimination.However,the factors controlling nitrogen removal processes remain largely uncertain in the highly dynamic environments.In this study,continuous-flow experiment combined with 15 N isotope pairing technique was used to investigate in situ rates of denitrification and anaerobic ammonium oxidation(anammox)and their coupling with nitrification in intertidal wetlands of the Yangtze Estuary.The measured rates varied from below the detection limit to 152.39μmol N/(m^2·hr)for denitrification and from below the detection limit to 43.06μmol N/(m^2·hr)for anammox.The coupling links of nitrogen removal processes with nitrification were mainly dependent on nitrate,organic carbon,sulfide,dissolved oxygen and ferric iron in the estuarine and intertidal wetlands.Additionally,it was estimated that the actual nitrogen removal processes annually removed approximately 5%of the terrigenous inorganic nitrogen discharged into the Yangtze Estuary.This study gives new insights into nitrogen transformation and fate in the estuarine and intertidal wetlands.

Marine aquaculture regulates dissimilatory nitrate reduction processes in a typical semi-enclosed bay of southeastern China

Marine aquaculture in semi-enclosed bays can significantly influence nutrient cycling in coastal ecosystems.However,the impact of marine aquaculture on the dynamics of dissimilatory nitrate reduction processes(DNRPs)and the fate of reactive nitrogen remain poorly understood.In this study,the rates of DNRPs and the abundances of related functional genes were investigated in aquaculture and non-aquaculture areas.The results showed that marine aquaculture significantly increased the denitrification(DNF)and dissimilatory nitrate reduction to ammonium(DNRA)rates and decreased the rate of anaerobic ammonium oxidation(ANA),as compared with non-aquaculture sites.DNF was the dominant pathway contributing to the total nitrate reduction,and its contribution to the total nitrate reduction significantly increased from 66.72%at non-aquaculture sites to 78.50%at aquaculture sites.Marine aquaculture can significantly affect the physicochemical characteristics of sediment and the abundances of related functional genes,leading to variations in the nitrate reduction rates.Although nitrate removal rates increased in the marine aquaculture area,ammonification rates and the nitrogen retention index in the aquaculture areas were 2.19 and 1.24 times,respectively,higher than those at non-aquaculture sites.Net reactive nitrogen retention exceeded nitrogen removal in the aquaculture area,and the retained reactive nitrogen could diffuse with the tidal current to the entire bay,thereby aggravating N pollution in the entire study area.These results show that marine aquaculture is the dominant source of nitrogen pollution in semi-enclosed bays.This study can provide insights into nitrogen pollution control in semi-enclosed bays with well-developed marine aquaculture.