浅谈现代水墨界画表现形式的发展与创新

界画是传统中国画画种之一,指以亭台楼阁等建筑为题材,用界尺引笔在宣纸上划线的绘画。随着社会﹑经济﹑文化的发展;界画的表现形式也增加了许多新的内容。现代水墨界画新的表现形式与传统界画技巧形式相结合的独特创新是现代水墨界画的发展方向;同时,现代水墨界画如何作为一种独特的艺术语言进入当代艺术格局成为我们要关注的焦点。艺术家们必须努力使具有明显时代特点的个性、形式性、技术性话语转换成为反映当代文化与现实的公共性绘画语言。才能赢得观众,为艺术创新开辟道路。     

Syk is indispensable for CpG-induced activation and differentiation of human B cells

B cells are efficiently activated by CpG oligodeoxynucleotides (ODNs) to produce pro-inflammatory cytokines and antibody (Ab). Here, we describe a so far unidentified, spleen tyrosine kinase (Syk)-dependent pathway, which is indispensable for CpG-induced human B cell activation. We show that triggering of B cells by CpG results in Syk and src kinase phosphorylation, proliferation, as well as cytokine and Ab production independent of the BCR. Notably, all these functions are abrogated when Syk is inhibited. We demonstrate that CpG-induced Syk activation originates from the cell surface in a TLR9-dependent manner. While inhibition of Syk does not influence the uptake of CpG ODNs, activation of the kinase is a prerequisite for the delivery of CpG into TLR9-containing endolysosomes and for the CpG-induced up-regulation of TLR9 expression. Our results reveal an alternative, Syk-dependent pathway of CpG-induced B cell stimulation, which is initiated at the plasma membrane and seems to be an upstream requirement for endosomal TLR9-driven B cell proliferation and differentiation.     

面向GF-5卫星高光谱传感器的浑浊水体叶绿素a浓度反演算法研究——以鄱阳湖为例

为了分析即将发射的高分5号卫星(GF-5)的高光谱数据在内陆水体水色遥感中的应用潜力,以鄱阳湖为研究区域,利用2009年、2011年和2016年共134组现场实测光谱及其对应的叶绿素a、总悬浮物浓度数据,考虑高浑浊水体引起的叶绿素a浓度变化的光谱响应差异,在进行水体光学分区基础上通过光谱模拟与差分处理开展了叶绿素a浓度跨阶分高光谱反演研究.结果表明：1)进行光学分区有利于提高反演精度,非高浑浊水体(NDCI≥0.06)区域,反演模型判定系数R2达到0.82,均方根误差RMSE为1.12,平均相对误差MRE为0.32,而不进行光学分区的全湖区反演建模R2仅为0.37;2) 相较于鄱阳湖前期研究得到的最优多波段反演模型(R2＝0.76),利用495、591、675、679、684、688、692和696 nm等波长的原始光谱以及差分光谱(一阶差分、二阶差分)建立的跨阶分多波段组合模型可以更有效地反演非高浑浊水体叶绿素a浓度(R2＝0.82),但对于高浑浊水体(NDCI<0.06),叶绿素a浓度的高光谱反演能力还需要进一步挖掘.     

Structure of a RING E3 ligase and ubiquitin-loaded E2 primed for catalysis

Ubiquitin modification is mediated by a large family of specificity determining ubiquitin E3 ligases. To facilitate ubiquitin transfer, RING E3 ligases bind both substrate and a ubiquitin E2 conjugating enzyme linked to ubiquitin via a thioester bond, but the mechanism of transfer has remained elusive. Here we report the crystal structure of the dimeric RING domain of rat RNF4 in complex with E2 (UbcH5A) linked by an isopeptide bond to ubiquitin. While the E2 contacts a single protomer of the RING, ubiquitin is folded back onto the E2 by contacts from both RING protomers. The carboxy-terminal tail of ubiquitin is locked into an active site groove on the E2 by an intricate network of interactions, resulting in changes at the E2 active site. This arrangement is primed for catalysis as it can deprotonate the incoming substrate lysine residue and stabilize the consequent tetrahedral transition-state intermediate.     

Two-photon laser spectroscopy of antiprotonic helium and the antiproton-to-electron mass ratio

Physical laws are believed to be invariant under the combined transformations of charge, parity and time reversal (CPT symmetry). This implies that an antimatter particle has exactly the same mass and absolute value of charge as its particle counterpart. Metastable antiprotonic helium (pHe(+)) is a three-body atom consisting of a normal helium nucleus, an electron in its ground state and an antiproton (p) occupying a Rydberg state with high principal and angular momentum quantum numbers, respectively n and l, such that n?≈?l?+?1?≈?38. These atoms are amenable to precision laser spectroscopy, the results of which can in principle be used to determine the antiproton-to-electron mass ratio and to constrain the equality between the antiproton and proton charges and masses. Here we report two-photon spectroscopy of antiprotonic helium, in which p(3)He(+) and p(4)He(+) isotopes are irradiated by two counter-propagating laser beams. This excites nonlinear, two-photon transitions of the antiproton of the type (n, l)?→?(n?-?2, l?-?2) at deep-ultraviolet wavelengths (λ = 139.8, 193.0 and 197.0?nm), which partly cancel the Doppler broadening of the laser resonance caused by the thermal motion of the atoms. The resulting narrow spectral lines allowed us to measure three transition frequencies with fractional precisions of 2.3-5 parts in 10(9). By comparing the results with three-body quantum electrodynamics calculations, we derived an antiproton-to-electron mass ratio of 1,836.1526736(23), where the parenthetical error represents one standard deviation. This agrees with the proton-to-electron value known to a similar precision.     

Reversing EphB2 depletion rescues cognitive functions in Alzheimer model

Amyloid-β oligomers may cause cognitive deficits in Alzheimer's disease by impairing neuronal NMDA-type glutamate receptors, whose function is regulated by the receptor tyrosine kinase EphB2. Here we show that amyloid-β oligomers bind to the fibronectin repeats domain of EphB2 and trigger EphB2 degradation in the proteasome. To determine the pathogenic importance of EphB2 depletions in Alzheimer's disease and related models, we used lentiviral constructs to reduce or increase neuronal expression of EphB2 in memory centres of the mouse brain. In nontransgenic mice, knockdown of EphB2 mediated by short hairpin RNA reduced NMDA receptor currents and impaired long-term potentiation in the dentate gyrus, which are important for memory formation. Increasing EphB2 expression in the dentate gyrus of human amyloid precursor protein transgenic mice reversed deficits in NMDA receptor-dependent long-term potentiation and memory impairments. Thus, depletion of EphB2 is critical in amyloid-β-induced neuronal dysfunction. Increasing EphB2 levels or function could be beneficial in Alzheimer's disease.     

A novel forecasting model for the Baltic dry index utilizing optimal squeezing

Marine transport has grown rapidly as the result of globalization and sustainable world growth rates. Shipping market risks and uncertainty have also grown and need to be mitigated with the development of a more reliable procedure to predict changes in freight rates. In this paper, we propose a new forecasting model and apply it to the Baltic Dry Index (BDI). Such a model compresses, in an optimal way, information from the past in order to predict freight rates. To develop the forecasting model, we deploy a basic set of predictors, add lags of the BDI and introduce additional variables, in applying Bayesian compressed regression (BCR), with two important innovations. First, we include transition functions in the predictive set to capture both smooth and abrupt changes in the time path of BDI; second, we do not estimate the parameters of the transition functions, but rather embed them in the random search procedure inherent in BCR. This allows all coefficients to evolve in a time-varying manner, while searching for the best predictors within the historical set of data. The new procedures predict the BDI with considerable success.     

基于穷举法的鄱阳湖叶绿素a浓度高光谱反演模型与应用研究——以GF-5卫星AHSI数据为例

光学特性复杂的浑浊水体叶绿素a浓度反演一直是水环境遥感研究的难点，高光谱以其波宽窄、谱段多、获取地物信息近似连续等优势，有望成为解决该难题的有效手段.该文以鄱阳湖为研究水域，利用2009年10月、2011年7月及2016年10月获取的实测高光谱及叶绿素a浓度数据，基于穷举法建立了针对高分五号(Gaofen-5， GF-5)卫星可见短波红外高光谱相机(Advanced HyperSpectral Imager， AHSI)的叶绿素a浓度三波段反演模型(决定系数R2＝0.82；均方根误差RMSE＝1.468 μg·L－1).通过与2018年10月7日Sentinel-2A卫星多光谱成像仪(MultiSpectral Instrument， MSI)的叶绿素a浓度反演结果对比分析，两者的空间分布具有较高的一致性，超过80%的研究水域相对偏差小于8%，在一定程度上证明了GF-5卫星高光谱数据在浑浊水体叶绿素a浓度反演中的潜力.