On-water surface synthesis of charged two-dimensional polymer single crystals via the irreversible Katritzky reaction

Two-dimensional polymers (2DPs) and their layer-stacked 2D covalent organic frameworks (2D COFs) are classes of structurally defined crystalline polymeric materials with exotic physical and chemical properties. Yet, synthesizing 2DP and 2D COF single crystals via irreversible reactions remains challenging. Here we report the synthesis of charged 2DP (C2DP) single crystals through an irreversible Katritzky reaction, under pH control, on a water surface. The periodically ordered 2DPs comprise aromatic pyridinium cations and counter BF4− anions. The C2DP crystals, which are composed of linked porphyrin and pyrylium monomers (C2DP-Por), have a tunable thickness of 2–30 nm and a lateral domain size up to 120 μm2. Single crystals with a square lattice (a = b = 30.5 Å) are resolved by imaging and diffraction methods with near-atomic precision. Furthermore, the integration of C2DP-Por crystals in an osmotic power generator device shows an excellent chloride ion selectivity with a coefficient value reaching ~0.9 and an output power density of 4 W m−2, superior to those of graphene and boron nitride

Alternative-Splicing in the Exon-10 Region of GABAA Receptor β2 Subunit Gene: Relationships between Novel Isoforms and Psychotic Disorders

BACKGROUND: Non-coding single nucleotide polymorphisms (SNPs) in GABRB2, the gene for beta(2)-subunit of gamma-aminobutyric acid type A (GABA(A)) receptor, have been associated with schizophrenia (SCZ) and quantitatively correlated to mRNA expression and alternative splicing. METHODS AND FINDINGS: Expression of the Exon 10 region of GABRB2 from minigene constructs revealed this region to be an "alternative splicing hotspot" that readily gave rise to differently spliced isoforms depending on intron sequences. This led to a search in human brain cDNA libraries, and the discovery of two novel isoforms, beta(2S1) and beta(2S2), bearing variations in the neighborhood of Exon-10. Quantitative real-time PCR analysis of postmortem brain samples showed increased beta(2S1) expression and decreased beta(2S2) expression in both SCZ and bipolar disorder (BPD) compared to controls. Disease-control differences were significantly correlated with SNP rs187269 in BPD males for both beta(2S1) and beta(2S2) expressions, and significantly correlated with SNPs rs2546620 and rs187269 in SCZ males for beta(2S2) expression. Moreover, site-directed mutagenesis indicated that Thr(365), a potential phosphorylation site in Exon-10, played a key role in determining the time profile of the ATP-dependent electrophysiological current run-down. CONCLUSION: This study therefore provided experimental evidence for the importance of non-coding sequences in the Exon-10 region in GABRB2 with respect to beta(2)-subunit splicing diversity and the etiologies of SCZ and BPD

The Critical Analysis of Catalytic Steam Explosion Pretreatment of Corn Stalk, Lignin Degradation, Recovery, and Characteristic Variations

The lignin degradation and its structural change as a result of catalytic steam explosion pretreatment can be considered of great importance for both the subsequent fermentation and the further utilization of the lignin fraction. This work investigated the degradation mechanism and change in the characteristics of lignin during dilute sulphuric-acid catalytic steam explosion (SE) pretreatment and ammonia catalytic steam explosion (AE) pretreatment of corn stalk. For this purpose, two types of lignin samples obtained from the two pretreatments of aqueous products and solid residues were fractionated, and they were then characterized by a series of comprehensive analyses that consisted of gas chromatography-mass spectroscopy (GC-MS), ion chromatography (IC), Fourier transform infrared (FT-IR), Carbon-13 nuclear magnetic resonance (13C NMR), Carbon-Hydrogen two-dimensional heteronuclear single quantum coherence (13C-1H 2D HSQC), pyrolysis-GC-MS (Py-GC-MS), and field emission scanning electron microscopy (FE-SEM). Overall, the characteristic diversity of the lignin provides useful reference for high-value applications of lignin

Urban ecological network construction in Loess Plateau regions in China-case study of Huanxian city

Cities in ecologically vulnerable areas have high ecological sensitivity, and the balance between urban expansion and the ecological environment is easily broken, leading to various environmental problems. These problems seriously interrupt the sustainable health development of urban ecosystems. Studying urban ecological network construction from the perspective of multifactor ecological processes is of important significance to the ecological safety and resource management of cities. In this study, an analysis of ecological elements was conducted separately to account for the “vertical” and “horizontal” ecological processes present in the ecological network. By using the superposition mode of vertical ecological processes, the composition of vital ecological patches was analyzed, and important ecological patches within the ecosystem were identified through ecological sensitivity evaluation index system. On the other hand, the composition of ecological corridors was analyzed through the use of horizontal ecological processes. The biological corridor was determined by source identification of biological processes and resistance surface analysis while the catchment corridor was determined through runoff simulation. Based on these findings, it was possible to propose an urban ecological network construction system specifically designed for Loess Plateau regions using a superposition of ecological sensitivity, biological processes, and catchment processes. Finally, a case study of the urban ecological network system of Loess Plateau regions was conducted in Huanxian City. Comparing the proposed urban ecological network of the Loess Plateau regions and the generated scheme with the overall planning scheme of 2016, the patch density and the largest patch index decreased by 1.522 and 13.794, respectively, while the fractal dimension, interspersion and juxtaposition index, the contagion index, and the connectivity index increased by 0.003, 2.188, 14.076, and 1.366, respectively. This trend proves that the research scheme improved in terms of ecological performance. Research conclusions can provide useful references for the construction of urban ecological networks in underdeveloped and ecologically vulnerable areas in China while offering guidelines for making decisions on the green development and management of urban spaces

GABA(A) receptor subtype selectivity underlying selective anxiolytic effect of baicalin

Baicalin, a naturally occurring flavonoid, was previously reported to induce anxiolytic-like effect devoid of sedation and myorelaxation in mice, acting through type A gamma-aminobutyric acid (GABA(A)) receptor benzodiazepine (BZ) site. The present Study further expanded the behavioral pharmacology profile of baicalin and subtype selectivity was explored as a possible mechanism underlying its in vivo effects on mice. Baicalin was characterized using convulsion, memory, and motor function related animal tests; and its selectivity towards recombinant GABA(A) receptor subtypes expressed in HEK 293T cells was determined by radioligand binding assay and electrophysiological studies. In the picrotoxin-induced seizure, step-through passive avoidance and rotarod tests, the anticonvulsant, amnesic and motor incoordination effects commonly associated with classical BZs were not observed when baicalin was administered at effective anxiolytic doses, demonstrating a separation of the anticonvulsant, amnesic and motor incoordination effects from the anxiolytic-like effect. Although baicalin exhibited higher binding affinity for the alpha(1)-containing GABAA subtype compared with alpha(2)-, alpha(3)-, and alpha(5)-containing subtypes, this was not statistically significant. In contrast to the classical BZ diazepam, baicalin showed significant preference for alpha(2)- and alpha(3)-containing subtypes compared to alpha(1)- and alpha(5)-containing subtypes in whole-cell patch clamp studies (P< 0.01). Its subtype selectivity suggested that baicalin exerted its in vivo anxiolytic-like effect mainly through the alpha(2)- and alpha(3)-containing subtypes. Therefore, the present study revealed an underlying mechanism for the selective anxiolytic profile of baicalin, suggesting alpha(2)- and alpha(3)-containing subtypes were important drug targets for flavonoid-based anxiolytics. (C) 2008 Elsevier Ltd. All rights reserved

Phylogenetic analysis of CDK and cyclin proteins in premetazoan lineages

BACKGROUND: The molecular history of animal evolution from single-celled ancestors remains a major question in biology, and little is known regarding the evolution of cell cycle regulation during animal emergence. In this study, we conducted a comprehensive evolutionary analysis of CDK and cyclin proteins in metazoans and their unicellular relatives. RESULTS: Our analysis divided the CDK family into eight subfamilies. Seven subfamilies (CDK1/2/3, CDK5, CDK7, CDK 20, CDK8/19, CDK9, and CDK10/11) are conserved in metazoans and fungi, with the remaining subfamily, CDK4/6, found only in eumetazoans. With respect to cyclins, cyclin C, H, L, Y subfamilies, and cyclin K and T as a whole subfamily, are generally conserved in animal, fungi, and amoeba Dictyostelium discoideum. In contrast, cyclin subfamilies B, A, E, and D, which are cell cycle-related, have distinct evolutionary histories. The cyclin B subfamily is generally conserved in D. discoideum, fungi, and animals, whereas cyclin A and E subfamilies are both present in animals and their unicellular relatives such as choanoflagellate Monosiga brevicollis and filasterean Capsaspora owczarzaki, but are absent in fungi and D. discoideum. Although absent in fungi and D. discoideum, cyclin D subfamily orthologs can be found in the early-emerging, non-opisthokont apusozoan Thecamonas trahens. Within opisthokonta, the cyclin D subfamily is conserved only in eumetazoans, and is absent in fungi, choanoflagellates, and the basal metazoan Amphimedon queenslandica. CONCLUSIONS: Our data indicate that the CDK4/6 subfamily and eumetazoans emerged simultaneously, with the evolutionary conservation of the cyclin D subfamily also tightly linked with eumetazoan appearance. Establishment of the CDK4/6-cyclin D complex may have been the key step in the evolution of cell cycle control during eumetazoan emergence

Stackelberg-Game-Based Demand Response for Voltage Regulation in Distribution Network with High Penetration of Electric Vehicles

With the development of the economy, electricity demand continues to increase, and the time for electricity consumption is concentrated, which leads to increasing pressure on the voltage regulation of the distribution network. For example, a large number of electric vehicles charging during a low-price period may cause the problem of under-voltage of the distribution network. On the other hand, the penetration of distributed power generation of renewable energy may cause over-voltage problems in the distribution network. This study proposes a Stackelberg game model between the distribution system operator and the load aggregator. In the Stackelberg game model, the distribution system operator affects the users’ electricity consumption time by issuing subsidies to decrease the frequency of voltage violations. As the representative of users, the load aggregator helps the users schedule the demand during the subsidized period to maximize profits. Case studies are carried out on the IEEE 33-bus power distribution system. The results show that the time of the subsidy can be optimized based on the Stackelberg game model. Both the distribution system operator and the load aggregator can obtain the optimal economic profits and then comprehensively improve the operating reliability and economy of the power distribution system