青冈种群的能量积累

１引言青冈（Ｃｙｃｌｏｂａｌａｎｏｐｓｉｓｇｌａｕｃａ）种群的能量积累,是能量代谢的主要部分。能量积累过程是通过植物的三大生理代谢活动之一光合作用而实现的。在研究了青冈林能量环境的基础上,对植物的光合作用进行了测试和分析,从而阐明了能量积累的规律。青...     

Intra-Urban Human Mobility and Activity Transition: Evidence from Social Media Check-In Data

Most existing human mobility literature focuses on exterior characteristics of movements but neglects activities, the driving force that underlies human movements. In this research, we combine activity-based analysis with a movement-based approach to model the intra-urban human mobility observed from about 15 million check-in records during a yearlong period in Shanghai, China. The proposed model is activity-based and includes two parts: the transition of travel demands during a specific time period and the movement between locations. For the first part, we find the transition probability between activities varies over time, and then we construct a temporal transition probability matrix to represent the transition probability of travel demands during a time interval. For the second part, we suggest that the travel demands can be divided into two classes, locationally mandatory activity (LMA) and locationally stochastic activity (LSA), according to whether the demand is associated with fixed location or not. By judging the combination of predecessor activity type and successor activity type we determine three trip patterns, each associated with a different decay parameter. To validate the model, we adopt the mechanism of an agent-based model and compare the simulated results with the observed pattern from the displacement distance distribution, the spatio-temporal distribution of activities, and the temporal distribution of travel demand transitions. The results show that the simulated patterns fit the observed data well, indicating that these findings open new directions for combining activity-based analysis with a movement-based approach using social media check-in data.     

Two Novel Mutations in Myosin Binding Protein C Slow Causing Distal Arthrogryposis Type 2 in Two Large Han Chinese Families May Suggest Important Functional Role of Immunoglobulin Domain C2

Distal arthrogryposes (DAs) are a group of disorders that mainly involve the distal parts of the limbs and at least ten different DAs have been described to date. DAs are mostly described as autosomal dominant disorders with variable expressivity and incomplete penetrance, but recently autosomal recessive pattern was reported in distal arthrogryposis type 5D. Mutations in the contractile genes are found in about 50% of all DA patients. Of these genes, mutations in the gene encoding myosin binding protein C slow MYBPC1 were recently identified in two families with distal arthrogryposis type 1B. Here, we described two large Chinese families with autosomal dominant distal arthrogryposis type 2(DA2) with incomplete penetrance and variable expressivity. Some unique overextension contractures of the lower limbs and some distinctive facial features were present in our DA2 pedigrees. We performed follow-up DNA sequencing after linkage mapping and first identified two novel MYBPC1 mutations (c.1075G>A [p.E359K] and c.956C>T [p.P319L]) responsible for these Chinese DA2 families of which one introduced by germline mosacism. Each mutation was found to cosegregate with the DA2 phenotype in each family but not in population controls. Both substitutions occur within C2 immunoglobulin domain, which together with C1 and the M motif constitute the binding site for the S2 subfragment of myosin. Our results expand the phenotypic spectrum of MYBPC1-related arthrogryposis multiplex congenita (AMC). We also proposed the possible molecular mechanisms that may underlie the pathogenesis of DA2 myopathy associated with these two substitutions in MYBPC1.     

Generation of Peanut Drought Tolerant Plants by Pingyangmycin-Mediated In Vitro Mutagenesis and Hydroxyproline-Resistance Screening

In order to enlarge the potential resources of drought-tolerant peanuts, we conducted in vitro mutagenesis with Pingyangmycin (PYM) as the mutagen as well as directed screening on a medium supplemented with Hydroxyproline (HYP). After being extracted from mature seeds (cv. Huayu 20), the embryonic leaflets were cultured on somatic embryogenesis-induction medium with 4 mg/L PYM and the generated embryos were successively transferred to a germination medium with 4 and then 8 mmol/L HYP to screen HYP-tolerant plantlets. After that, these plantlets were grafted and transplanted to the experimental field. In the next generation, all seeds were sown in the field, and phenotype variation and trait segregation can be observed in most of the offspring (M₂ generation). The M₃ generation individuals were subjected to drought stress at the seedling stages. The activities of SOD and POD were substantially increased in eight offspring of 11 HYP-tolerant, regenerated plants than in their mutagenic parents. To determine the correlation between mutant phenotypes and genomic modification, we carried out a comparison of the DNA polymorphisms between the mutagenic parents and 13 M₃ generation individuals from different HYP-tolerant, regenerated plants with SSR primers. Results showed that most mutants and parent plants had signs of polymorphisms. Under drought stress, some M₃ generation individuals of 10 original HYP-tolerant, regenerated plants produced more pods than the mutagenic parent; twenty individuals among them produced >60 g pods/plant. M₄-generation seeds were tested for quality characteristics by Near Infrared Spectroscopy (NIS) and nine individuals with higher protein content (>30%) and 21 individuals with higher oil content (>58%) were screened. We concluded that the use of PYM-based in vitro mutagenesis in combination with directed screening with HYP is effective for the creation of potential drought-tolerant mutants of peanut.     

The preparation of ethylenediamine‐modified fluorescent carbon dots and their use in imaging of cells

In this work, fluorescent carbon dots (CDs) were synthesized using a hydrothermal method with glucose as the carbon source and were surface‐modified with ethylenediamine. The properties of as‐prepared CDs were analyzed by transmission electron microscopy (TEM), Fourier transform infrared (FTIR), ultraviolet–visible light (UV/vis) absorption and fluorescent spectra. Furthermore, CDs conjugated with mouse anti‐(human carcinoembryonic antigen) (CEA) monoclonal antibody were successful employed in the biolabeling and fluorescent imaging of human gastric carcinoma cells. In addition, the cytotoxicity of CDs was also tested using human gastric carcinoma cells. There was no apparent cytotoxicity on human gastric carcinoma cells. These results suggest the potential application of the as‐prepared CDs in bioimaging and related fields. Copyright © 2015 John Wiley & Sons, Ltd.     

Novel mechanism of cardiac protection by valsartan: synergetic roles of TGF‐β1 and HIF‐1α in Ang II‐mediated fibrosis after myocardial infarction

Transforming growth factor (TGF)‐β1 is a known factor in angiotensin II (Ang II)‐mediated cardiac fibrosis after myocardial infarction (MI). Hypoxia inducible factor‐1 (Hif‐1α) was recently demonstrated to involve in the tissue fibrosis and influenced by Ang II. However, whether Hif‐1α contributed to the Ang II‐mediated cardiac fibrosis after MI, and whether interaction or synergetic roles between Hif‐1α and TGF‐β pathways existed in the process was unclear. In vitro, cardiac cells were incubated under hypoxia or Ang II to mimic ischaemia. In vivo, valsartan was intravenously injected into Sprague–Dawley rats with MI daily for 1 week; saline and hydralazine (another anti‐hypertensive agent like valsartan) was used as control. The fibrosis‐related proteins were detected by Western blotting. Cardiac structure and function were assessed with multimodality methods. We demonstrated in vitro that hypoxia would induce the up‐regulation of Ang II, TGF‐β/Smad and Hif‐1α, which further induced collagen accumulation. By blocking with valsartan, a blocker of Ang II type I (AT1) receptor, we confirmed that the up‐regulation of TGF‐β/Smad and Hif‐1α was through the Ang II‐mediated pathway. By administering TGF‐β or dimethyloxalylglycine, we determined that both TGF‐β/Smad and Hif‐1α contributed to Ang II‐mediated collagen accumulation and a synergetic effect between them was observed. Consistent with in vitro results, valsartan significantly attenuated the expression of TGF‐β/Smad, Hif‐1α and fibrosis‐related protein in rats after MI. Heart function, infarcted size, wall thickness as well as myocardial vascularization of ischaemic hearts were also significantly improved by valsartan compared with saline and hydralazine. Our study may provide novel insights into the mechanisms of Ang II‐induced cardiac fibrosis as well as into the cardiac protection of valsartan.     

Fibrillin-2 is dispensable for peripheral nerve development,myelination and regeneration

The extracellular matrix of peripheral nerve is formed from a diverse set of macromolecules, including glycoproteins, collagens and proteoglycans. Recent studies using knockout animal models have demonstrated that individual components of the extracellular matrix play a vital role in peripheral nerve development and regeneration. In this study we identified fibrillin-1 and fibrillin-2, large modular structural glycoproteins, as components of the extracellular matrix of peripheral nerve. Previously it was found that fibrillin-2 null mice display joint contractures, suggesting a possible defect of the peripheral nervous system in these animals. Close examination of the peripheral nerves of fibrillin-2 deficient animals described here revealed some structural abnormalities in the perineurium, while general structure of the nerve and molecular composition of nerve extracellular matrix remained unchanged. We also found that in spite of the obvious motor function impairment, fibrillin-2 null mice failed to display changes of nerve conduction properties or nerve regeneration capacity. Based on the data obtained we can conclude that peripheral neuropathy should be excluded as the cause of the impairment of locomotory function and joint contractures observed in fibrillin-2 deficient animals.     

Discovery of N-methyl-4-(4-methoxyanilino)quinazolines as potent apoptosis inducers. Structure–activity relationship of the quinazoline ring

As a continuation of our efforts to discover and develop apoptosis inducing N-methyl-4-(4-methoxyanilino)quinazolines as novel anticancer agents, we explored substitution at the 5-, 6-, 7-positions of the quinazoline and replacement of the quinazoline by other nitrogen-containing heterocycles. A small group at the 5-position was found to be well tolerated. At the 6-position a small group like an amino was preferred. Substitution at the 7-position was tolerated much less than at the 6-position. Replacing the carbon at the 8-position or both the 5- and 8-positions with nitrogen led to about 10-fold reductions in potency. Replacement of the quinazoline ring with a quinoline, a benzo[d][1,2,3]triazine, or an isoquinoline ring showed that the nitrogen at the 1-position is important for activity, while the carbon at the 2-position can be replaced by a nitrogen and the nitrogen at the 3-position can be replaced by a carbon. Through the SAR study, several 5- or 6-substituted analogs, such as 2a and 2c, were found to have potencies approaching that of lead compound N-(4-methoxyphenyl)-N,2-dimethylquinazolin-4-amine (1g, EP128495, MPC-6827, Azixa®).     

Mass transport in a microchannel bioreactor with a porous wall

A two-dimensional flow model has been developed to simulate mass transport in a microchannel bioreactor with a porous wall. A two-domain approach, based on the finite volume method, was implemented. For the fluid part, the governing equation used was the Navier-Stokes equation; for the porous medium region, the generalized Darcy-Brinkman-Forchheimer extended model was used. For the porous-fluid interface, a stress jump condition was enforced with a continuity of normal stress, and the mass interfacial conditions were continuities of mass and mass flux. Two parameters were defined to characterize the mass transports in the fluid and porous regions. The porous Damkohler number is the ratio of consumption to diffusion of the substrates in the porous medium. The fluid Damkohler number is the ratio of the substrate consumption in the porous medium to the substrate convection in the fluid region. The concentration results were found to be well correlated by the use of a reaction-convection distance parameter, which incorporated the effects of axial distance, substrate consumption, and convection. The reactor efficiency reduced with reaction-convection distance parameter because of reduced reaction (or flux), and smaller local effectiveness factor due to the lower concentration in Michaelis-Menten type reactions. The reactor was more effective, and hence, more efficient with the smaller porous Damkohler number. The generalized results could find applications for the design of bioreactors with a porous wall.