Direct Oxidation of Methane to Methanol over Transition-Metal-Free Ferrierite Zeolite Catalysts.

Direct oxidation of methane to methanol was reported to be highly dependent on the transition- or noble-metal-loading catalysts in the past decades. Here, we show that the transition-metal-free aluminosilicate ferrierite (FER) zeolite effectively catalyzed methane and N2O to methanol for the first time. The distorted tetracoordinated Al in the framework and pentacoordinated Al on the extra framework formed during calcination, activation, and reaction processes were confirmed as the potential active centers. The possible reaction pathway similar to the Fe-containing zeolites was advocated based on the reaction results using different oxidants, N2O adsorption FTIR spectra, and 27Al MAS NMR spectra. The stable and efficient methanol production capacity of FER zeolite was ascribed to the two-dimensional straight channels and its distinctive Al distribution of FER zeolite (CP914C) from Zeolyst. The transition-metal-free FER zeolite performed better than the record in the literature and our recent results using transition-metal-containing catalysts in terms of selectivity and formation rate of methanol and stability. This work has great significance and prospects for utilizing CH4 and N2O as resources and will open new avenues for methane oxidation.

Identifying age-specific gene signatures of the human cerebral cortex with joint analysis of transcriptomes and functional connectomes.

The human cerebral cortex undergoes profound structural and functional dynamic variations across the lifespan, whereas the underlying molecular mechanisms remain unclear. Here, with a novel method transcriptome-connectome correlation analysis (TCA), which integrates the brain functional magnetic resonance images and region-specific transcriptomes, we identify age-specific cortex (ASC) gene signatures for adolescence, early adulthood and late adulthood. The ASC gene signatures are significantly correlated with the cortical thickness (P-value <2.00e-3) and myelination (P-value <1.00e-3), two key brain structural features that vary in accordance with brain development. In addition to the molecular underpinning of age-related brain functions, the ASC gene signatures allow delineation of the molecular mechanisms of neuropsychiatric disorders, such as the regulation between ARNT2 and its target gene ETF1 involved in Schizophrenia. We further validate the ASC gene signatures with published gene sets associated with the adult cortex, and confirm the robustness of TCA on other brain image datasets. Availability: All scripts are written in R. Scripts for the TCA method and related statistics result can be freely accessed at https://github.com/Soulnature/TCA. Additional data related to this paper may be requested from the authors.

Stable Tunable Luminescence of Hetero-valent Eu Ion Activated Ba2InTaO6 Phosphors Synthesized by Defect-Induced Self-Reduction in the Molten-Salt Method.

Functional materials with stable and adjustable luminescence have recently become a research hotspot for their broad application prospects. Tunable luminescence can be realized by the doping of hetero-valent europium ions. High-temperature hydrogen atmosphere reduction is required in the traditional preparation of Eu2+-doped phosphors. Herein, an anoxic molten-salt medium environment was established to form oxygen vacancy defects in the reaction system and induce the self-reduction of Eu3+ ions to obtain Eu2+ ions. X-ray photoelectron spectroscopy (XPS) results confirm the existence of Eu2+ and Eu3+ ions in the samples, and the fluorescence spectrum shows that hetero-valent Eu ions can synergistically emit light effectively. Under 266 nm ultraviolet light excitation, the white light emission was successfully realized for a Ba2InTaO6:Eu phosphor by different emission combinations of Eu3+ and Eu2+ ions. In addition, the Ba2InTaO6:Eu phosphor exhibits adjustable luminescence from greenish-yellow to red exciting at 390-490 nm, which has superior stability in a high-temperature and high-humidity environment. Therefore, it is very promising that Ba2InTaO6:Eu will be used as multi-color functional materials in many fields such as communication encryption and colorful decoration.

Fabrication of 2D/2D BiOBr/g-C3N4 with efficient photocatalytic activity and clarification of its mechanism.

Precise regulation of photoexcited charge carriers for separation and transportation is a core requirement for practical application in the photocatalysis field. Herein, a 2D/2D BiOBr/g-C3N4 heterojunction is prepared by a self-assembly method and exhibits enhanced and stable activity for photocatalytic degradation of bisphenol A (BPA) and norfloxacin (NFA) under visible light. Compared to pure g-C3N4, the kinetic constants of BPA and NFA degradation over BiOBr/g-C3N4 are enhanced by about 14.74 and 4.01 times, respectively. The separation and transportation mechanism for the photoexcited charge carriers is clarified by electron paramagnetic resonance (EPR), in situ X-ray photoelectron spectroscopy (in situ XPS), and theoretical calculations. The results show that BiOBr/g-C3N4 exhibits the feature of a relative p-n junction, in which the charges photoexcited on BiOBr/g-C3N4 with high redox potentials can be kept and spatially separated. Moreover, the built-in electric field with the direction of g-C3N4 → BiOBr and the opportune band curvature provide the driving force for charge separation and transportation. Additionally, BPA and NFA degradation intermediates are also detected by liquid chromatography-mass spectrometry. It is of great significance to fabricate efficient photocatalysts for environmental purification and other targeted reactions.

HIV-1 genotype diversity and distribution characteristics among heterosexually transmitted population in Jiangsu province, China.

BACKGROUND: Heterosexual transmission has contributed greatly to the current HIV-1 epidemic in China. However, the HIV-1 genetic characteristics in the heterosexually transmitted population in Jiangsu province remained unclear. METHODS: A molecular epidemiological investigation on heterosexual transmission of HIV-1 was conducted across Jiangsu province. 301 HIV-1 patients infected through heterosexual transmission were involved in this study. The epidemiological information was investigated by trained staff via face-to-face interviews. Blood samples were taken from each patient, HIV-1 RNA was extracted from the plasma, and used for amplifying the gag and env genes followed by further products sequencing. The genotypes of HIV-1 were determined using phylogenetic tree analyses in the neighbor-joining method. RESULTS: A total of 262 samples were successfully taken for genotyping. The main subtypes which accounted for 90.5% of all HIV-1 strains are CRF01_AE (45.4%), CRF07_BC (21.4%), subtype B (12.6%), CRF08_BC (11.1%). Minor subtypes were also detected, such as CRF68_01B, subtype C, CRF55_01B, CRF02_AG and subtype A. Time trend analysis suggested the prevalence of subtype B and CRF08_BC decreased gradually, but the prevalence of CRF01_AE increased over time. A relatively higher prevalence of CRF07_BC in Central Jiangsu and subtype B were detected in South Jiangsu, while a relatively lower prevalence of subtype B and CRF08_BC were detected in Central Jiangsu. CONCLUSION: Complex and unbalanced HIV distribution characteristics suggest that heterosexual transmission of HIV needs to be taken seriously. It is necessary to implement more effective and comprehensive intervention strategies for further control of HIV-1 dissemination.

PPIM: A Protein-Protein Interaction Database for Maize.

Maize (Zea mays) is one of the most important crops worldwide. To understand the biological processes underlying various traits of the crop (e.g. yield and response to stress), a detailed protein-protein interaction (PPI) network is highly demanded. Unfortunately, there are very few such PPIs available in the literature. Therefore, in this work, we present the Protein-Protein Interaction Database for Maize (PPIM), which covers 2,762,560 interactions among 14,000 proteins. The PPIM contains not only accurately predicted PPIs but also those molecular interactions collected from the literature. The database is freely available at http://comp-sysbio.org/ppim with a user-friendly powerful interface. We believe that the PPIM resource can help biologists better understand the maize crop.

Modulation of Al Distribution in High-Silica ZSM-5 Zeolites for Enhancing Catalytic Performance.

The spatial distribution of framework Al (AlF) has been one of the important factors that affect the catalytic properties of zeolites in diverse chemical reactions; however, the synthesis of high-silica zeolites with special AlF distribution remains a challenge. In this study, we successfully synthesized high-silica ZSM-5 zeolites with a unique AlF distribution by employing pentaerythritol (PET) as an additive in the presence of a few tetrapropylammonium hydroxide (TPAOH). The results demonstrated that the introduction of PET led to a higher proportion of Al atoms located at the sinusoidal and/or straight channels. It was observed that the addition of PET prevented the interaction between TPA+ and tetrahedral [AlO4]- during the crystallization process, resulting in enhanced availability of TPA species in the form of ion-paired TPA+. This effect leads to AlF atoms dominantly distributed away from the intersection and located in narrow channels, where acidic sites more effectively inhibit hydrogen transfer and coke formation. In the reaction of dimethyl ether (DME) to olefins, the catalyst with a unique Al distribution exhibited a significant prolonged catalytic lifetime, surpassing traditional TPA-ZSM-5 by more than 2-fold and maintaining DME conversion above 90% for a maximum of 148 h. The results of multiple pulse experiments also showed that these PET-assisted ZSM-5 zeolites significantly enhanced the selectivity of propene and butene. This approach provides an effective strategy to regulate AlF distribution in high-silica ZSM-5 catalysts with the assistance of neutral alcohol. It holds great potential for application in the synthesis of other high-silica zeolites, thereby enriching the diversity of zeolite catalysis.

Understanding the effect of spatially separated Cu and acid sites in zeolite catalysts on oxidation of methane.

Unraveling the effect of spatially separated bifunctional sites on catalytic reactions is significant yet challenging. In this report, we investigate the role of spatial separation on the oxidation of methane in a series of Cu-exchanged aluminosilicate zeolites. Regulation of the bifunctional sites is done either through studying a physical mixture of Cu-exchanged zeolites and acidic zeolites or by systematically varying the Cu and acid density within a family of zeolite materials. We show that separated Cu and acid sites are beneficial for the formation of hydrocarbons while high-density Cu sites, which are closer together, facilitate the production of CO2. By contrast, a balance of the spatial separation of Cu and acid sites shows more favorable formation of methanol. This work will further guide approaches to methane oxidation to methanol and open an avenue for promoting hydrocarbon synthesis using methanol as an intermediate.

Room-temperature synthesis of BiOBr sub-microflowers and their photocatalytic properties.

Flower-like BiOBr sub-microstructures about 500 nm in diameter have been synthesized in the presence of tetraethylammonium bromide (TEAB) via a solution route at room temperature. SEM observation shows that these sub-microflowers are composed of nanoflakes with the thickness of 20 nm. The photocatalytic activities of flower-like BiOBr were evaluated by the degradation of methyl orange (MO) and phenol under visible-light and UV-light irradiation, which presented the efficiencies up to 97% within 1.5 h and 45% within 4 h, respectively.

Molecular identification of Theileria equi, Babesia caballi, and Rickettsia in adult ticks from North of Xinjiang, China.

BACKGROUND: Ticks in Xinjiang distribute widely and account for one third of China. Ticks can carry and transmit bacteria, virus, and parasite. However, the research of tick-borne pathogens in Xinjiang is rather little. OBJECTIVE: To understand the situation of hard tick carry Theileria equi, Babesia caballi and Rickettsia spp. of Zhaosu and Altay in Xinjiang. METHODS: In this study, 119 tick samples were obtained from horses in Xinjiang, China, Ticks were identified morphologically to determine species and PCR was used to investigate the situation of pathogens by hard ticks. RESULTS: One hundred and seven belong to Dermacentor marginatus, five belong to D. niveus, and seven belong to D. silvarum. Theileria equi and Babesia caballi were detected in one tick and 18 ticks, respectively. However, the carrying rate of Rickettsia spp. was 51.26% (61/119). Among these, the mixed carriage rate of T. equi and Rickettsia spp. was 0.8% (1/119). The mixed carriage rate of B. caballi and Rickettsia spp. was 10.1% (12/119). CONCLUSION: Our results revealed that hard tick can carry not only haeimoparasite but also many important zoonotic pathogens in Xinjiang, and this situation was worth heeding.

OsNF-YC10, a seed preferentially expressed gene regulates grain width by affecting cell proliferation in rice.

Grain size and shape are important factors in determining the grain yield. In this study, OsNF-YC10, a member of the NF-Y transcription factor family encoding a putative histone transcription factor, was cloned and characterized. qRT-PCR and mRNA in situ hybridization analysis revealed that OsNF-YC10 was highly expressed in endosperm and spikelet hull at late developmental stages. The results showed that OsNF-YC10 was a nuclear protein showing transcription activation activity. The osnf-yc10 lines, produced using CRISPR/Cas9 technology, showed narrow, thin and light grains. Cytological experiments revealed significantly reduced cell number of spikelet hull in osnf-yc10 lines compared with that in WT. Narrow, thin, and light grains were found consistently in OsNF-YC10 RNAi transgenic lines. Moreover, the number of cells decreased in the grain-width direction than WT. These results indicated that OsNF-YC10 plays an important role in determining grain size and shape. OsNF-YC10 was further revealed to influence the expression of GW8 (a positive regulator of grain width), GW7 (a negative regulator of grain width) and cell cycle-regulated genes CYCD4, CYCA2.1, CYCB2.1, CYCB2.2, E2F2. Taken together, it is suggested that OsNF-YC10 regulates the grains size and shape by influencing the cell proliferation of spikelet hulls.

Selective oxidation of methane to methanol with H2O2 over an Fe-MFI zeolite catalyst using sulfolane solvent.

The effect of reaction conditions for direct oxidation of methane to methanol over Fe-MFI zeolite with H2O2 has been investigated. Sulfolane has been proved to be an efficient solvent for liquid-phase methane oxidation. A sulfolane/water mixture with an appropriate proportion led to an extremely high methanol production with a high selectivity.

Geographic Distribution and Temporal Trends of HIV-1 Subtypes through Heterosexual Transmission in China: A Systematic Review and Meta-Analysis.

Background: Heterosexual transmission (HST) has become the current predominant transmission pathways of the HIV-1 epidemic in China. The aim of this study was to explore the geographic and dynamic change of HIV-1 subtypes through HST in China from published studies. Methods: Several electronic databases were searched to identify the studies, and the overall prevalence of HIV-1 subtypes was estimated by a meta-analysis method. Subgroup analysis was conducted by study region and time period. Publication bias was evaluated using Egger's test. The χ² test was used to evaluate the proportion differences among subgroups. Sensitivity analysis was carried out to assess the stability of the overall prevalence estimates. Results: 42 studies were included in our final analysis. The overall prevalence of CRF01_AE was 46.34% (95% CI: 40.56-52.17%), CRF07_BC was 19.16% (95% CI: 15.02-23.66%), B/B' was 13.25% (95% CI: 9.68-17.25%), CRF08_BC was 10.61% (95% CI: 7.08-14.70%), and C was 4.29% (95% CI: 1.85-7.48%). In subgroup analysis, the prevalence of CRF01_AE and CRF07_BC increased, while the prevalence of B/B' decreased over time, whereby the prevalence of CRF07_BC and CRF08_BC have exceeded that of B/B' since 2010. A significant higher prevalence of CRF01_AE was found in the South provinces, CRF07_BC in East provinces, CRF08_BC and C in Southwest provinces, and B/B' in North provinces. Conclusions: The HIV-1 prevalent strains have evolved into complicated and diverse subtypes, and the proportion of HIV-1 subtypes through HST has changed constantly in different regions and periods in China. This highlights the urgent need to vigorously strengthen the prevention and control of the HIV-1 epidemic.

GEAR: A database of Genomic Elements Associated with drug Resistance.

Drug resistance is becoming a serious problem that leads to the failure of standard treatments, which is generally developed because of genetic mutations of certain molecules. Here, we present GEAR (A database of Genomic Elements Associated with drug Resistance) that aims to provide comprehensive information about genomic elements (including genes, single-nucleotide polymorphisms and microRNAs) that are responsible for drug resistance. Right now, GEAR contains 1631 associations between 201 human drugs and 758 genes, 106 associations between 29 human drugs and 66 miRNAs, and 44 associations between 17 human drugs and 22 SNPs. These relationships are firstly extracted from primary literature with text mining and then manually curated. The drug resistome deposited in GEAR provides insights into the genetic factors underlying drug resistance. In addition, new indications and potential drug combinations can be identified based on the resistome. The GEAR database can be freely accessed through http://gear.comp-sysbio.org.

Response mechanism of the phase transitions of poly(n-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) using infrared spectroscopy.

The thermal and ionic effects on the phase transitions of poly(N-isopropylacrylamide) (PNIPAAm) and its copolymer with benzo-18-crown-6-acrylamide, poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (PNIPAAm-co-BCAm), were investigated using infrared (IR) spectral variations of methyl (CH3), C=O, and amine (NH) groups. Subsequently, perturbation correlation moving-window two-dimensional correlation infrared spectroscopy (PCMW 2D-IR) was applied to clarify the differences in the phase-transition mechanisms of the polymers. The dominant influence on the phase-transition mechanism of PNIPAAm is whether the anion is evenly distributed in the bulk solution. The results show that the phase transition shifts to a lower temperature with increasing barium chloride (BaCl2) concentrations. In addition, the effect of the anion on the chemical group is homogeneous upon heating. As a result, the relevant transition temperature ranges have remain approximately constant. In contrast, the dominant influence on the phase-transition mechanism of PNIPAAm-co-BCAm is the interactions of the polymer chains with barium ions (Ba(2+)). The hydrophilic BCAm-Ba(2+) complexes distributed in the PNIPAAm-co-BCAm chain prevent the water molecules from leaving the polymer chains, which leads to an increase in the transition temperature and the complicated variation of the transition temperature range, as environmental stimuli-response behavior, with increasing BaCl2 concentrations.