Chemical-free Extraxtion of Cotton Stalk Bark Fibers by Steam Flash Explosion

Cotton stalk bark fibers (CSBF) were extracted by steam flash explosion, completed within 0.09 s, and the extracted fibers were compared with those obtained by conventional alkaline treatment. Results indicate that the optimum steam pressure was 2.5 MP a when steaming time was set to 2 min for extracting CSBF. Under the optimized conditions, the obtained CBSF had a cellulose content of 72%, length of 48 mm, fineness of 45 dtex, crystallinity index of 68, moisture regain of 8%, water rention of 98%, and tensile strength of 2.4 cN/dtex, which were similar to results obtained by conventional alkaline treatment. Compared with bark of cotton stalks, CSBF had lower moisture regain and water retention, and higher onset decomposition temperature. The results sow that moderate steam flash explosion is a chemical-free, quick, and effective method for exploring the industrial applications of bark of cotton stalks as natural cellulose fibers

Chemical-free Extraxtion of Cotton Stalk Bark Fibers by Steam Flash Explosion

Cotton stalk bark fibers (CSBF) were extracted by steam flash explosion, completed within 0.09 s, and the extracted fibers were compared with those obtained by conventional alkaline treatment. Results indicate that the optimum steam pressure was 2.5 MP a when steaming time was set to 2 min for extracting CSBF. Under the optimized conditions, the obtained CBSF had a cellulose content of 72%, length of 48 mm, fineness of 45 dtex, crystallinity index of 68, moisture regain of 8%, water rention of 98%, and tensile strength of 2.4 cN/dtex, which were similar to results obtained by conventional alkaline treatment. Compared with bark of cotton stalks, CSBF had lower moisture regain and water retention, and higher onset decomposition temperature. The results sow that moderate steam flash explosion is a chemical-free, quick, and effective method for exploring the industrial applications of bark of cotton stalks as natural cellulose fibers

Correction of Channel Imbalance for MIMO SAR Using Stepped-Frequency Chirps

To simultaneously achieve two-dimensional high resolution and wide swath in synthetic aperture radar (SAR), azimuth MIMO structure combined with stepped-frequency chirp signals was developed via splitting the antenna into N subapertures. During transmitting each subaperture transmits a chirp pulse at a different carrier frequency, while during receiving every subaperture receives the N scattered pulses at the same time. Separating the N scattered pulses received by each subaperture and downlinking them to the ground yield N2 different signal paths. Due to the dedicated network in the SAR system, the channel imbalance is inevitable. To correct the channel imbalance, this paper presents an external calibration method, where the channel characteristics are estimated from the peak value of a strong point target for each channel. Simulation and real raw data experiments are performed to validate the proposed method

In Silico Screening of Novel α1-GABAA Receptor PAMs towards Schizophrenia Based on Combined Modeling Studies of Imidazo [1,2-a]-Pyridines

The ionotropic GABAA receptor (GABAAR) has been proven to be an important target of atypical antipsychotics. A novel series of imidazo [1,2-a]-pyridine derivatives, as selective positive allosteric modulators (PAMs) of α1-containing GABAARs with potent antipsychotic activities, have been reported recently. To better clarify the pharmacological essentiality of these PAMs and explore novel antipsychotics hits, three-dimensional quantitative structure–activity relationships (3D-QSAR), molecular docking, pharmacophore modeling, and molecular dynamics (MD) were performed on 33 imidazo [1,2-a]-pyridines. The constructed 3D-QSAR models exhibited good predictive abilities. The dockings results and MD simulations demonstrated that hydrogen bonds, π–π stackings, and hydrophobic interactions play essential roles in the binding of these novel PAMs in the GABAAR binding pocket. Four hit compounds (DS01–04) were then screened out by the combination of the constructed models and computations, including the pharmacophore model, Topomer Search, molecular dockings, ADME/T predictions, and MD simulations. The compounds DS03 and DS04, with higher docking scores and better predicted activities, were also found to be relatively stable in the binding pocket by MD simulations. These results might provide a significant theoretical direction or information for the rational design and development of novel α1-GABAAR PAMs with antipsychotic activities

Resorption efficiency of leaf nutrients in woody plants on Mt. Dongling of Beijing, North China

Aims To explore resorption efficiency of nitrogen (NRE) and phosphorus (PRE) of woody plants in relation to soil nutrient availability, climate and evolutionary history, in North China. Methods We measured concentrations of nitrogen ([N]) and phosphorus ([P]) in both full expanded mature green and senescent leaves of the same individuals for 88 woody species from 10 sites of Mt. Dongling, Beijing, China. We built a phylogenetic tree for all these species and compared NRE and PRE among life forms (trees, shrubs and woody lianas) and between functional groups (N-fixers and non-N-fixers). We then explored patterns of NRE and PRE along gradients of mean annual temperature (MAT), soil inorganic N and available P, and phylogeny using a general linear model. Important Findings Mass-based NRE (NREm) and PRE (PREm) averaged 57.4 and 61.4%, respectively, with no significant difference among life forms or functional groups. Neither NREm nor PREm exhibited significant phylogenetic signals, indicating that NREm and PREm were not phylogenetically conserved. NREm was not related to [N] in green leaves; PREm was positively correlated with [P] in green leaves; however, this relationship disappeared for different groups. NREm decreased with [N] in senescent leaves, PREm decreased with [P] in senescent leaves, for all species combined and for trees and shrubs. NREm decreased with soil inorganic N for all species and for shrubs; PREm did not exhibit a significant trend with soil available P for all species or for different plant groups. Neither NREm nor PREm was significantly related to MAT for overall species and for species of different groups

Exploration of N-Arylsulfonyl-indole-2-carboxamide Derivatives as Novel Fructose-1,6-bisphosphatase Inhibitors by Molecular Simulation

A series of N-arylsulfonyl-indole-2-carboxamide derivatives have been identified as potent fructose-1,6-bisphosphatase (FBPase) inhibitors (FBPIs) with excellent selectivity for the potential therapy of type II diabetes mellitus. To explore the structure–activity relationships (SARs) and the mechanisms of action of these FBPIs, a systematic computational study was performed in the present study, including three-dimensional quantitative structure–activity relationship (3D-QSAR) modeling, pharmacophore modeling, molecular dynamics (MD), and virtual screening. The constructed 3D-QSAR models exhibited good predictive ability with reasonable parameters using comparative molecular field analysis (q2 = 0.709, R2 = 0.979, rpre2 = 0.932) and comparative molecular similarity indices analysis (q2 = 0.716, R2 = 0.978, rpre2 = 0.890). Twelve hit compounds were obtained by virtual screening using the best pharmacophore model in combination with molecular dockings. Three compounds with relatively higher docking scores and better ADME properties were then selected for further studies by docking and MD analyses. The docking results revealed that the amino acid residues Met18, Gly21, Gly26, Leu30, and Thr31 at the binding site were of great importance for the effective bindings of these FBPIs. The MD results indicated that the screened compounds VS01 and VS02 could bind with FBPase stably as its cognate ligand in dynamic conditions. This work identified several potential FBPIs by modeling studies and might provide important insights into developing novel FBPIs

Enhanced ethanol production inside carbon-nanotube reactors containing catalytic particles

Carbon nanotubes (CNTs) have well-defined hollow interiors and exhibit unusual mechanical and thermal stability as well as electron conductivity. This opens intriguing possibilities to introduce other matter into the cavities, which may lead to nanocomposite materials with interesting properties or behaviour different from the bulk. Here, we report a striking enhancement of the catalytic activity of Rh particles confined inside nanotubes for the conversion of CO and H(2) to ethanol. The overall formation rate of ethanol (30.0 mol mol(-1)Rh h(-1)) inside the nanotubes exceeds that on the outside of the nanotubes by more than an order of magnitude, although the latter is much more accessible. Such an effect with synergetic confinement has not been observed before in catalysis involving CNTs. We believe that our discovery may be of a quite general nature and could apply to many other processes. It is anticipated that this will motivate theoretical and experimental studies to further the fundamental understanding of the host-guest interaction within carbon and other nanotube systems

Resorption efficiency of leaf nutrients in woody plants on Mt. Dongling of Beijing, North China

Aims To explore resorption efficiency of nitrogen (NRE) and phosphorus (PRE) of woody plants in relation to soil nutrient availability, climate and evolutionary history, in North China. Methods We measured concentrations of nitrogen ([N]) and phosphorus ([P]) in both full expanded mature green and senescent leaves of the same individuals for 88 woody species from 10 sites of Mt. Dongling, Beijing, China. We built a phylogenetic tree for all these species and compared NRE and PRE among life forms (trees, shrubs and woody lianas) and between functional groups (N-fixers and non-N-fixers). We then explored patterns of NRE and PRE along gradients of mean annual temperature (MAT), soil inorganic N and available P, and phylogeny using a general linear model. Important Findings Mass-based NRE (NREm) and PRE (PREm) averaged 57.4 and 61.4%, respectively, with no significant difference among life forms or functional groups. Neither NREm nor PREm exhibited significant phylogenetic signals, indicating that NREm and PREm were not phylogenetically conserved. NREm was not related to [N] in green leaves; PREm was positively correlated with [P] in green leaves; however, this relationship disappeared for different groups. NREm decreased with [N] in senescent leaves, PREm decreased with [P] in senescent leaves, for all species combined and for trees and shrubs. NREm decreased with soil inorganic N for all species and for shrubs; PREm did not exhibit a significant trend with soil available P for all species or for different plant groups. Neither NREm nor PREm was significantly related to MAT for overall species and for species of different groups.National Basic Research Program of China on Global Change [2010CB950600, 2014CB954004]; National Natural Science Foundation of China [31321061, 31330012]; 'Strategic Priority Research Program' of the Chinese Academy of Sciences [XDA05050300]SCI(E)[email protected]