Biogeography,ecology and history of Mediterranean Quercus ilex ecosystems

Quercus ilex sensu lato plays an important role in Western Mediterranean ecosystems, but is poorly developed in the Eastern Mediterranean where it is often replaced by Quercus calliprinos.The occurrence of Quercus ilex in the different bioclimates and their thermic subdivisions is presented on a small scale. Under certain geographical and ecological conditions, Quercus ilex participates in the organization of vegetation ecosystems from the meso-Mediterranean to the oro-Mediterranean altitudinal zones. Quercus ilex imposes microclimatic constraints on its associated species; it thus organizes and original understory vegetation structure (ethological groups) which will be defined in this study.One of the reasons for the success of Quercus ilex stems from its remarkable resistance to ecological constraints. A broad synthetic presentation of foliar area index variations in relation to different types of stress serve as a basis for an explanation of the sclerophyllous model in the Mediterranean region.Finally, historical factors are outlined as being critical characteristics in the determination of the present organization and spatial structure of Quercus ilex ecosystems. These considerations will be analyzed from a paleobioclimatical point of view, including data related to human pressure.     

在水稻体细胞愈伤组织中进行核型的分析

国内外不少学者对水稻(O. sativa)2n=24染色体的形态进平行了研究,大多数是采用种子萌发后的根尖作为适宜材料。由于水稻染色体较小,核型分析需要一定量的种子,而珍贵的远缘杂种(如栽培稻与野生稻杂交后代)结实率极低,所结种子极少。为了克     

SNMDA: A novel method for predicting microRNA‐disease associations based on sparse neighbourhood

miRNAs are a class of small noncoding RNAs that are associated with a variety of complex biological processes. Increasing studies have shown that miRNAs have close relationships with many human diseases. The prediction of the associations between miRNAs and diseases has thus become a hot topic. Although traditional experimental methods are reliable, they could only identify a limited number of associations as they are time‐consuming and expensive. Consequently, great efforts have been made to effectively predict reliable disease‐related miRNAs based on computational methods. In this study, we present a novel approach to predict the potential microRNA‐disease associations based on sparse neighbourhood. Specifically, our method takes advantage of the sparsity of the miRNA‐disease association network and integrates the sparse information into the current similarity matrices for both miRNAs and diseases. To demonstrate the utility of our method, we applied global LOOCV, local LOOCV and five‐fold cross‐validation to evaluate our method, respectively. The corresponding AUCs are 0.936, 0.882 and 0.934. Three types of case studies on five common diseases further confirm the performance of our method in predicting unknown miRNA‐disease associations. Overall, results show that SNMDA can predict the potential associations between miRNAs and diseases effectively.     

Dynamic behavior and selective adsorption of a methanol/water mixture inside a cyclic peptide nanotube

Present molecular dynamics simulations indicate that the methanol component in a methanol/water mixture is more likely to be trapped in a cyclic peptide nanotube (CPNT), while water molecules tend to be present at the channel mouths as transient guests. Channel water resides mainly between methanol and the CPNT wall, resulting in a distinct decrease in the H-bond number per channel methanol. Six designed CPNTs with different channel diameters and outer surface characteristics all possess distinct selectivity to methanol over water. Of these, the amphipathic 8?×?(AQ)₄-CPNT exhibits the best performance. Results in this study provide basic information for the application of a CPNT to enrich methanol from a methanol/water mixture.

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Graphical Abstract Typical overview of water and methanol molecular distribution in cyclic peptide nanotubes

     

Protective effect of the total flavonoids from <Emphasis Type="Italic">Apocynum venetum</Emphasis> L. on carbon tetrachloride-induced hepatotoxicity in vitro and in vivo

Apocynum venetum L., belonging to the family Apocynaceae, is a popular medicinal plant, which is commonly used in the treatment of hypertension, neurasthenia, and hepatitis in China. In the present study, the total flavonoids (TFs) were prepared from the leaves of A. venetum, and its protective effects on carbon tetrachloride (CCl₄)-induced hepatotoxicity in a cultured HepG2 cell line and in mice were investigated. Cell exposed to 0.4% CCl₄ (v/v) for 6 h led to a significant decrease in cell viability, increased LDH leakage, and intracellular reactive oxygen species (ROS). CCl₄ also induced cell marked apoptosis, which was accompanied by the loss of mitochondrial membrane potential (MMP). Pretreatment with TFs at concentrations of 25, 50, and 100 μg/mL effectively relieved CCl₄-induced cellular damage in a dose-dependent manner. In vivo, TFs (100, 200, and 400 mg/kg BW) were administered via gavage daily for 14 days before CCl₄ treatment. The high serum ALT and AST levels induced by CCl₄ were dose-dependently suppressed by pretreatment of TFs (200 and 400 mg/kg BW). Histological analysis also supported the results obtained from serum assays. Furthermore, TFs could prevent CCl₄-caused oxidative damage by decreasing the MDA formation and increasing antioxidant enzymes (CAT, SOD, GSH-Px) activities in liver tissues. In summary, both in vitro and in vivo data suggest that TFs, prepared from A. venetum, showed a remarkable hepatoprotective and antioxidant activity against CCl₄-induced liver damage.     

Anti-tumor and anti-metastatic roles of cordycepin,one bioactive compound of Cordyceps militaris

Public interest in complementary and alternative medicine has been increased worldwide, due to its wide applications in cancer prevention and treatment. Cordycepin is one of the most common and crucial types of complementary and alternative medicine. Cordycepin (3′-deoxyadenosine), a derivative of adenosine, was first isolated from medicine drug Cordyceps militaris. Cordycepin has been widely used as one compound for antitumor, which has been found to exert antiangiogenic, anti-metastatic, and antiproliferative effects, as well as inducing apoptosis. However, the mechanism of its anti-tumor activity is not well known. This review will clarify anti-tumor mechanisms of Cordycepin, which regulate signaling pathways related with tumor growth and metastasis. Cordycepin inhibit tumor growth via upregulating tumor apoptosis, inducing cell cycle arrest and targeting cancer stem cells (CSCs). Cordycepin regulates tumor microenvironment via suppressing tumor metastasis-related pathways. Thus, Cordycepins may be one of important supplement or substitute medicine drug for cancer treatment.     

Boosting Fast Sodium Storage of a Large‐Scalable Carbon Anode with an Ultralong Cycle Life

Sodium‐ion batteries (SIBs) are considered to be a promising alternative for large‐scale electricity storage. However, it is urgent to develop new anode materials with superior ultralong cycle life performance at high current rates. Herein, a low‐cost and large‐scalable sulfur‐doped carbon anode material that exhibits the best high‐rate cycle performance and the longest cycle life ever reported for carbon anodes is developed. The material delivers a reversible capacity of 142 mA h g^?1 at a current rate up to 10 A g^?1. After 10 000 cycles the capacity is remained at 126.5 mA h g^?1; 89.1% of the initial value. Density functional theory computations demonstrate that the sulfur‐doped carbon has a strong binding affinity for sodium which promotes sodium storage. Meanwhile, the kinetics analysis identifies the capacitive charge storage as a large contributor to sodium storage, which favors ultrafast storage of sodium ions. These results demonstrate a new way to design carbon‐based SIBs anodes for next‐generation large‐scale electricity storage.     

Hot‐Substrate Deposition of Hole‐ and Electron‐Transport Layers for Enhanced Performance in Perovskite Solar Cells

Charge transport layers play an important role in determining the power conversion efficiencies (PCEs) of perovskite solar cells (PSCs). However, it has proven challenging to produce thin and compact charge transport layers via solution processing techniques. Herein, a hot substrate deposition method capable of improving the morphology of high‐coverage hole‐transport layers (HTLs) and electron‐transport layers (ETLs) is reported. PSC devices using HTLs deposited on a hot substrate show improvement in the open‐circuit voltage (V_oc) from 1.041 to 1.070 V and the PCE from 17.00% to 18.01%. The overall device performance is then further enhanced with the hot substrate deposition of ETLs as the V_oc and PCE reach 1.105 V and 19.16%, respectively. The improved performance can be explained by the decreased current leakage and series resistance, which are present in PSCs with rough and discontinuous HTLs and ETLs.