Long‐term terrestrial carbon dynamics in the Midwestern United States during 1850–2015: Roles of land use and cover change and agricultural management

To meet the increasing food and biofuel demand, the Midwestern United States has become one of the most intensively human‐disturbed hotspots, characterized by widespread cropland expansion and various management practices. However, the role of human activities in the carbon (C) cycling across managed landscape remains far from certain. In this study, based on state‐ and national census, field experiments, and model simulation, we comprehensively examined long‐term carbon storage change in response to land use and cover change (LUCC) and agricultural management in the Midwest from 1850 to 2015. We also quantified estimation uncertainties related to key parameter values. Model estimation showed LUCC led to a reduction of 1.35 Pg (with a range of 1.3–1.4 Pg) in vegetation C pool of the Midwest, yet agricultural management barely affected vegetation C change. In comparison, LUCC reduced SOC by 4.5 Pg (3.1 to 6.2 Pg), while agricultural management practices increased SOC stock by 0.9 Pg. Moreover, we found 45% of the study area was characterized by continuously decreasing SOC caused by LUCC, and SOC in 13% and 31% of the area was fully and partially recovered, respectively, since 1850. Agricultural management was estimated to increase the area of full recovery and partial recovery by 8.5% and 1.1%. Our results imply that LUCC plays an essential role in regional C balance, and more importantly, sustainable land management can be beneficial for strengthening C sequestration of the agroecosystems in the Midwestern US, which may serve as an important contributor to C sinks in the US.     

Fractal (NixCo1−x)9Se8 Nanodendrite Arrays with Highly Exposed () Surface for Wearable,All‐Solid‐State Supercapacitor

Hierarchical nanostructures with highly exposed active surfaces for high‐performance pseudocapacitors have attracted considerable attention. Herein, a one‐step growth of (Ni _xCo_1?x)₉Se₈ solid solution series in various conductive substrates as advanced electrodes for flexible, foldable supercapacitors is developed. The formation of (Ni_xCo_1?x)₉Se₈ solid solution is confirmed by Vegard's law. Interestingly, the as‐grown (Ni_xCo_1?x)₉Se₈ solid solution series spontaneously crystallized into nanodendrite arrays with hierarchical morphology and fractal feature. The optimized (Ni_0.1Co_0.9)₉Se₈ nanodendrites deliver a specific capacitance of 3762 F g^?1 at a current density of 5 A g^?1 and remains 94.8% of the initial capacitance after 5000 cycles, owing to the advantage from fractal feature with numerous exposed () surface as well as fast ion diffusion. The as‐assembled flexible (Ni_0.1Co_0.9)₉Se₈@carbon fiber cloth (CFC)//PVA/KOH//reduced graphene oxide@CFC device exhibits an ultrahigh energy density of 17.0 Wh kg^?1@ 3.1 kW kg^?1, outperforming recently reported pseudocapacitors based on nickel‐cobalt sulfide and selenide counterparts. This study provides rational guidance toward the design of fractal feature with superior electrochemical performances due to the significantly increased electrochemical active sites. The resulting device can be easily folded, pulled, and twisted, enabling potential applications in high‐performance wearable and gadget devices.     

JS‐K induces reactive oxygen species‐dependent anti‐cancer effects by targeting mitochondria respiratory chain complexes in gastric cancer

As a nitric oxide (NO) donor prodrug, JS‐K inhibits cancer cell proliferation, induces the differentiation of human leukaemia cells, and triggers apoptotic cell death in various cancer models. However, the anti‐cancer effect of JS‐K in gastric cancer has not been reported. In this study, we found that JS‐K inhibited the proliferation of gastric cancer cells in vitro and in vivo and triggered mitochondrial apoptosis. Moreover, JS‐K induced a significant accumulation of reactive oxygen species (ROS), and the clearance of ROS by antioxidant reagents reversed JS‐K‐induced toxicity in gastric cancer cells and subcutaneous xenografts. Although JS‐K triggered significant NO release, NO scavenging had no effect on JS‐K‐induced toxicity in vivo and in vitro. Therefore, ROS, but not NO, mediated the anti‐cancer effects of JS‐K in gastric cancer. We also explored the potential mechanism of JS‐K‐induced ROS accumulation and found that JS‐K significantly down‐regulated the core proteins of mitochondria respiratory chain (MRC) complex I and IV, resulting in the reduction of MRC complex I and IV activity and the subsequent ROS production. Moreover, JS‐K inhibited the expression of antioxidant enzymes, including copper‐zinc‐containing superoxide dismutase (SOD1) and catalase, which contributed to the decrease of antioxidant enzymes activity and the subsequent inhibition of ROS clearance. Therefore, JS‐K may target MRC complex I and IV and antioxidant enzymes to exert ROS‐dependent anti‐cancer function, leading to the potential usage of JS‐K in the prevention and treatment of gastric cancer.     

Nitrogen removal performance of anaerobic ammonia oxidation (ANAMMOX) in presence of organic matter

A sequencing batch reactor (SBR) was used to test the nitrogen removal performance of anaerobic ammonium oxidation (ANAMMOX) in presence of organic matter. Mesophilic operation (30 ± 0.5 °C) was performed with influent pH 7.5. The results showed, independent of organic matter species, ANAMMOX reaction was promoted when COD was lower than 80 mg/L. However, specific ANAMMOX activity decreased with increasing organic matter content. Ammonium removal efficiency decreased to 80% when COD of sodium succinate, sodium potassium tartrate, peptone and lactose were 192.5, 210, 225 and 325 mg/L, respectively. The stoichiometry ratio resulting from different OM differed largely and R₁ could be as an indicator for OM inhibition. When COD concentration was 240 mg/L, the loss of SAA resulting from lactose, peptone, sodium potassium tartrate and sodium succinate were 28, 36, 50 and 55%, respectively. Sodium succinate had the highest inhibitory effect on SAA. When ANAMMOX process was used to treat wastewater containing OM, the modified Logistic model could be employed to predict the NRE_max.     

芝田硫化叶菌麦芽寡糖基海藻糖合酶基因在大肠杆菌中的克隆和表达

用ＰＣＲ 方法从芝田硫化叶菌中扩增了编码一种新酶,即麦芽寡糖基海藻糖合酶（ ＭＴＳａｓｅ） 的基因,扩增的２－２ｋｂ ＤＮＡ 插入到原核表达载体ｐＢＶ２２０ 中,构建成重组质粒ｐＳＢＧＴ１ 。ｐＳＢＧＴ１ 中ＭＴＳａｓｅ 基因在大肠杆菌中得到表达。ＳＤＳＰＡＧＥ 分析表达产物ＭＴＳａｓｅ蛋白的分子量约为７４ｋＤａ ,同核苷酸序列测定所推导的值相符。表达产物占细胞总蛋白约４－４ ％ 。ｐＳＢＧＴ１ 产生的重组酶作用于淀粉部分水解物,使ＤＥ 值降低,得到非还原糖或低还原糖。     

部分植物抗氧化活性的初步研究

用ＤＰＰＨ法测定了２０多种植物的抗氧化活性,其中火炬树、法国梧桐等７种植物的叶或其它部位的抗氧化活性较高,与银杏叶的接近或相当,值得进一步研究。     

YAP1 regulates chondrogenic differentiation of ATDC5 promoted by temporary TNF-α stimulation through AMPK signaling pathway

Molecular and Cellular Biochemistry - Local injection of tumor necrosis factor-alpha (TNF-α) at bone fracture sites during the early stage of the inflammatory response is reported to improve...     

Structural insights into the human D1 and D2 dopamine receptor signaling complexes

1. Download : Download high-res image (263KB)
2. Download : Download full-size image