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bHLH transcription factors are involved in multiple aspects of plant biology, such as the response to abiotic stress. Erigeron breviscapus is a composite plant, and its rich flavonoids have strong preventive and therapeutic effects on cardio cerebral vascular disease. EbbHLH80, a gene from E. breviscapus that positively regulates flavonoid synthesis, was previously characterized. However, it is unclear whether EbbHLH80 increases flavonoid accumulation, which affects salt tolerance. The function of EbbHLH80 in transgenic tobacco seeds was identified by phylogenetic analysis and metabolome-transcriptome analysis. We investigated the role of EbbHLH80 in salt stress response. Our results showed that the expression of EbbHLH80 increased following salt treatment. Integrating the metabolome and transcriptome analysis of EbbHLH80-OE and Yunyan 87 (WT) seeds, we identified several genes and metabolites related to flavonoid biosynthesis and salt stress. Moreover, EbbHLH80-OE plants displayed higher salt tolerance than wild-type plants during seed germination and seedling growth. After salt treatment, transgenic tobacco had significantly lower levels of reactive oxygen species (ROS) than WT, with enhanced levels of antioxidant enzyme expression. Altogether, our results demonstrated that EbbHLH80 might be a positive regulator, promoting salt tolerance by modulating ROS scavenging and increasing stress-responsive genes.

Highly efficient dehydrogenation of formic acid (FA) at room temperature is a safe and suitable way to obtain hydrogen and promote the development of hydrogen storage application. Herein, the phosphorous-alloyed Pd nanoclusters loading on nitrogen-doped carbon (PdP/NC) were prepared and recognized as the highly active nanocatalysts for the dehydrogenation of FA. The PdP/NCs with controlled sizes and compositions were prepared by an easy self-limiting synthesis in an aqueous solution. The best PdP/NC exhibited a remarkable catalytic activity with a high turnover frequency of ∼3253.0 h-1 than the compared nanocatalysts for the dehydrogenation of FA at room temperature. The catalytic kinetics and durability studies showed that both the alloyed P in Pd crystals and doped N in the carbon support could effectively tailor the electronic states of the Pd surface and further optimize the adsorption energy of FA. Based on the Sabatier principle, the proper adsorption energy accelerated the dehydrogenation reaction and correspondingly enhanced the activity and durability. The work proposed a high-efficiency nanocatalyst for safe hydrogen generation and may be extended to create other similar nanocatalysts with different compositions and nanostructures.

Eliminating vehicle emission is of importance due to the severe limit value. The work reports a convenient strategy of improving dispersion of platinum-based catalyst with the assistance of polyvinyl alcohol in a varied addition amount. Following the "two-step" annealing techniques, the catalytic performance of the polymer-assisted catalysts in diesel was obviously enhanced because of the improved dispersion of the platinum. Based on experimental results, the long chains of polymer resulting in the steric effect are presumed to isolate platinum ion, inhibiting the aggregation of platinum particles and then improving its dispersion. And the hydroxyl bonding between the polymers could convey electron to platinum species, leading to the lower platinum valence state. Both effects are positive resulting in an excellent NO maximum conversion of around 65% at the optimal introduction of 5 mass% of polymer, as the diesel oxidation catalyst (DOC), which could be inclined to a good purification in the diesel aftertreatment. Hopefully, the convenient research method could initiate the exploration and application of polymer-assisted catalysts for well-dispersed noble metal nanoparticles in eliminating exhaust emission.

The hydrothermal stability of NO oxidation is the key to the practical application of diesel oxidation catalysts in diesel engines, which in the laboratory requires that NO activity does not decrease after aging for 10 h with 10% H

Polyvinyl alcohol (PVA) has been shown to interact with platinum ions by manipulating the reaction time. It was interestingly found that the improved low-temperature oxidation performance of Pt-based catalysts in promoting the conversion of CO/C3H6/NO was mainly contributed to by a higher content of metallic platinum species, accompanied by relatively smaller platinum nanoparticle size. Besides, DTA and in situ DRIFTs of the un-roasted catalysts showed that an appropriate reaction time (10 h) between the platinum ions and polyvinyl alcohol resulted in a strong electronic intensity of the platinum. Both these factors led to a greater formation of formate species and the lowest light-off temperature of CO (176 °C), C3H6 (187 °C), and NO (214 °C). This simple method involving tuning the interaction of polymer and metal ions would be positive for optimizing the electronic state and size efffect of metals in catalysis.

Catalytic NO oxidation is crucial in oxidizing soot and promoting NH3 reduction during the emission eliminations of diesel vehicles by the modern after-treatment systems. To create more active oxygen species in favor of NO oxidation, ceria-modified monolithic Pt-based diesel oxidation catalyst was prepared by the step-impregnation method to improve its NO catalytic performance. Its NO maximum conversion was up to around 60% in the gas hourly space velocity of 60 kh−1. Experimental results suggested that the ceria addition could have a better dispersion due to the inhibition effect of platinum aggregation. Especially, it is found that more active oxygen and oxygen vacancies over the catalyst played a significant role in strengthening the interaction of NO molecule with catalyst surface, resulting in the formation and transformation of more bridging/chelating nitrates confirmed by in situ FTIR studies. After thermal ageing, the catalyst with ceria addition still enabled a excellent NO catalytic performance, up to 50% NO maximum conversion. It would be proposed that active oxygen from the interaction bewteen ceria and Pt improved its NO catalytic activity and thermal-stability.

To stabilize Pt, Magnesium-modified SiO2-Al2O3 materials was used to impregnate with Pt, which could strengthen the bonding effect between Pt and Mg. Before and after aging, both showed a higher dispersion. High valence state of Pt in fresh modified catalyst was unfavorable of NO oxidation, indicating that the valence state of Pt was the leader factor in fresh catalytic performance. While for the aged Mg-modified sample, its reaction temperature of 30% NO conversion lowered by around 30 °C. The Pt stabilization via interacting with Mg derives a relation that the variation of Pt valence state and its exposed sites played a significant role in fresh and aged catalytic NO activity, respectively.

Blast fungus (Magnaporthe orzyae) is the most serious pathogen of rice. As such, the objective of the current study was to investigate the infection process using a selected panel of anti-plant extracellular matrix antibodies, in infected leaves from three rice cultivars that display varying degrees of resistance to the pathogen; at selected time points post inoculation. An arabinogalactan-protein (AGP) epitope, recognized by the antibody JIM13, was shown to be temporally and spatially regulated during the infection, in all three cultivars. Prior to inoculation, expression of the epitope was confined to the epidermis, sclerenchyma, phloem, xylem and bundle sheath. As the infection progressed, the intensity of labeling increased in all the aforementioned cell types and spread to the mesophyll. Immunogold transmission electron microscopy, revealed this epitope to be most abundant at the plasma membrane. These data suggest that this epitope is borne on a plasma-membrane-associated AGP, which may act as a pattern recognition receptor (PRR), involved in the basal immune response to infection with blast fungus, in both resistant and susceptible rice cultivars. As such, this study represents the first report of a membrane – associated arabinogalactan-protein in rice, which once cloned, could be of utility in future breeding programs/genetic modification to improve the basal immune response to blast fungus and other pathogens, in this globally important food crop.

It is a recognized view that particle size could play a significant role in catalytic performance. To obtain the nanoparticles with the different size, a series of bimetallic PtPd/SiO2–Al2O3 catalysts subjected to hydrothermal treatment in different time were prepared and applied for NO oxidation under diesel exhaust. The experimental results confirmed that the average noble particle size was gradually increased at a different variation rate, along with aging time. An increasing of average particle size resulted in the reduction of the corresponding NO turnover frequencies (TOFs) by different degrees. Thus, a new sight on the relationship between particle size and NO catalytic activity is obtained. In the aging process, the overall trend of noble metal particles got larger along with receding NO catalytic performance, yet in a period, a few small particles presented more bridged/chelating nitrate and ionic nitrate species, further retarding its rate of loss activity.

Objective To predict preoperative staging using a radiomics approach based on computed tomography (CT) images of patients with esophageal squamous cell carcinoma (ESCC). Methods This retrospective study included 154 patients (primary cohort: n=114; validation cohort: n=40) with pathologically confirmed ESCC. All patients underwent a preoperative CT scan from the neck to abdomen. High throughput and quantitative radiomics features were extracted from the CT images for each patient. A radiomics signature was constructed using the least absolute shrinkage and selection operator (Lasso). Associations between radiomics signature, tumor volume and ESCC staging were explored. Diagnostic performance of radiomics approach and tumor volume for discriminating between stages I-II and III-IV was evaluated and compared using the receiver operating characteristics (ROC) curves and net reclassification improvement (NRI). Results A total of 9,790 radiomics features were extracted. Ten features were selected to build a radiomics signature after feature dimension reduction. The radiomics signature was significantly associated with ESCC staging (P

Pt/SiO2-Al2O3 (Pt/SA) is commonly used as diesel oxidation catalysts (DOC) in industry, but it could be seriously deactivated caused by H2O at long-term high temperature. In this paper, the inhibition mechanism of water on Pt/SA for NO oxidation was studied. The fresh Pt/SA (Pt/SA-F) was treated in an air flow with/without 10% H2O at 700 °C for 10 h to obtain the hydrothermally/thermally aged catalysts named as Pt/SA-HA and -A, respectively. NO oxidation tests showed that Pt/SA-HA had lower activity than Pt/SA-A. A series of characterizations proved H2O didn’t affected Pt states and support structure as they were similar over two aged catalyst. 1H NMR and In-situ DRIFTS testified that water deactivation was a result of the acidity loss of catalysts, which inhibited the decomposition and desorption of reaction intermediate, finally resulting in bad NO oxidation activity.

A series of the modified Pt/SiO 2 –Al 2 O 3 diesel oxidation catalysts with different WO 3 loading were prepared through co-impregnation method. With an optimum additive loading of 2 wt% WO 3 , the catalyst significantly improved the performance and its stability. Compared to the free-tungsten sample, the catalyst increased the maximum conversion of NO by 5–10% and decreased the reaction temperature for 30% NO conversion by 7–28 °C. It was found that there exist the electron and structure interaction between platinum and tungsten species. The interactions can generate and maintain more Pt sites in metallic state for the catalytic oxidation with enhanced activity and stability.

Highlights • Patients with anti-NMDAR encephalitis showed decreased ALFF values in the bilateral posterior cingulate gyrus, left precuneus and bilateral cerebellum. • The functional connectivities between the bilateral posterior cingulate gyrus and the bilateral lingual gyrus, fusiform gyrus, calcarine, cuneus, and right posterior central gyrus were significantly increased in patients with anti-NMDAR encephalitis. • Functional connectivity strength between the bilateral posterior cingulate gyrus and bilateral cuneus were positively correlated with MoCA memory scores. • Patients with anti-NMDAR encephalitis exhibited decreased spontaneous neural activities and abnormal functional connectivity, which may participate in the process of cognition and emotion deficits., Background Anti–N-methyl-D-aspartate receptor (NMDAR) encephalitis showing severe neuropsychiatric symptoms is the most common type of autoimmune encephalitis. However, the corresponding standard clinical magnetic resonance imaging (MRI) presents normal or atypical in the majority of patients with anti-NMDAR encephalitis. Here, this study aimed to investigate the alterations in brain functional activity in patients with anti-NMDAR encephalitis and whether these alterations contributed to cognition and mood disorders. Methods Seventeen patients with anti-NMDAR encephalitis and eighteen gender, age and education-matched healthy controls were recruited. All participants underwent neuropsychological tests (including Montreal Cognitive Assessment (MoCA), Hamilton Anxiety Scale (HAMA), and Hamilton Depression Scale (HAMD24)) and resting-state functional MRI. MRI data was firstly analyzed by amplitude of low-frequency fluctuation (ALFF), and brain regions with altered ALFF between groups were selected as regions of interest for the further functional connectivity (FC) analysis. Correlation analyses were performed to investigate the associations between brain dysfunction and neuropsychological performance. Results Relative to the healthy controls, patients with anti-NMDAR encephalitis performed inferiorly in the MoCA score, and showed anxiety and depression disorders with higher HAMA and HAMD24 scores (all p

This study aimed to investigate brain white matter (WM) changes and their relationship to cognition in patients with anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis. Multivariate pattern analysis (MVPA) was used to explore brain regions that play an important role in classification. Fifteen patients and fifteen controls underwent Montreal Cognitive Assessment (MoCA) and diffusion tensor imaging. Based on fractional anisotropy (FA) and mean diffusivity (MD) for MVPA classification, the weights of each brain region were calculated. Compared with the controls, the patients showed an FA reduction in right middle temporal gyrus, left middle cerebellar peduncle, right praecuneus, and an MD increase in left medial temporal gyrus and left frontal lobe. The MoCA score for patients was lower than controls, especially in executive function, fluency, delayed recall and visual perception items. The FA value of right praecuneus was positively correlated with total MoCA score and fluency score. The MD of left frontal lobe was negatively correlated with total MoCA score, and MD of the left medial temporal gyrus was positively correlated with delayed recall. The accuracy, sensitivity and specificity of classification based on FA were 70%, 60% and 80%, respectively. Based on MD, they were each 80%. The brain regions with large weights from FA and MD overlap in temporal lobe, cerebellum and hippocampus. These results suggest that WM changes are associated with cognitive deficits. MVPA based on FA and MD has good classification ability. Our study may provide new insights into the pathophysiological mechanisms of residual cognitive deficits.

Four kinds of poly(N-isopropylacrylamide)-grafted silicas with different grafting ratios and the same grafting density were prepared by atom transfer radical polymerization. The chemical groups in the stationary phase was verified by FTIR spectroscopy, and the content of elements was measured by elemental analysis. The grafting ratio of thermoresponsive chromatographic materials was measured by thermogravimetric analysis and was 2.36-21.10% mg/m2 . The retention behaviors of the stationary phase with different grafting ratios were evaluated by separating five kinds of steroids and ten kinds of different hydrophobic properties compounds. With the increase in grafting ratio, the retention time of analytes was prolonged in high-performance liquid chromatography. The results showed that grafting ratio had a significant influence on the separation effect under the same grafting density. And the optimal grafting ratio of poly(N-isopropylacrylamide) was 5.81-13.15%.

Diesel emissions (CO/C3H6/ NO) were eliminated on FeOx-doped and CeO2-doped Pt-based catalysts respectively to compare reaction mechanism and performance features. FeOx-doped catalyst has a higher platinum dispersion, a higher platinum valance state retarding CO adsorption and a higher oxygen mobility. Both of the higher dispersion and the oxygen mobility have a positive role in low-temperature catalytic oxidation performance, lower by 26 °C for CO light-off temperature and 12 °C for C3H6 light-off temperature respectively than CeO2-doped catalyst. On FeOx-doped catalyst, the lesser surficial active oxygen species form the byproduct Fe(NO), resulting in an reduction of 10% NO maximum conversion. Besides, hydrothermal aged FeOx-doped catalyst with reduction treatment show a relatively lower light-off temperature and a higher NO max conversion. The difference in reaction characterization enlighten that the composition of oxidation catalyst would focus on the specific performance for the practical configuration in aftertreatment system for the better diesel emissions prevention.

To decrease the diesel vehicle emission, polymer-assisted platinum-based catalysts having an improvement in the dispersion of platinum were developed. This work investigated the structure and redox properties of platinum nanoparticles assisted by polyethylene glycol (PEG) with different hydroxyl value and supported on SiO2-Al2O3 following carbonization and air roasting treatments. Ultraviolet-visible (UV–vis) spectra, in situ FTIR and structural characterization measurements reveal that PEG400-assisted catalyst presents a great interaction with platinum species, affecting the electronic intensity and dispersion of platinum. Reactivity tests show that PEG400-assisted Pt-based catalysts have a better low-temperature catalytic performance in CO, C3H6 and NO oxidation, decreased by around 10−30 °C. It is concluded that the differences in reactivity could be related to the formation and stabilization of platinum species during the preparation.

A thermally responsive boronate affinity chromatographic material, which showed thermal sensitivity, had been successfully applied for the enrichment and separation of cis-diol-containing compounds, and the capture and release process could be facilitated by adjusting the temperature. However, in this system, the pH of the mobile phase must be higher than 9.8, and alkaline media can lead to the degradation of labile compounds; the use of silica beads also limits its use. In this study, thermally responsive boronate affinity chromatographic material, namely poly(N-isopropylacrylamide-co-N-acryloyl-3-aminophenylboronic acid) grafted silica, was successfully prepared by atom transfer radical polymerization. Its structure was confirmed by IR spectroscopy and the graft ratio was 20.8%, determined by thermogravimetric analysis. Furthermore, the capture/release of adenosine, a cis-diol, was performed from pH 5.0-9.0 and 10-50°C. The elution of adenosine was remarkably retarded at decreased temperatures and adenosine could be captured completely at 10°C at pH values of 5.0-9.0. The enrichment of adenosine could be achieved by simply changing the temperature from 10 to 50°C. Therefore, this material not only improved the stability of the silica, but was also suitable for the capture of oxidation-sensitive biological analytes. Moreover, it could be used for the enrichment of cis-diol-containing compounds in LC with MS.

The gene ABK52392 from the thermophilic bacterium Acidothermus cellulolyticus 11B was predicted to be endoglucanase and classified into glycoside hydrolase family 12. ABK52392 encodes a protein containing a catalytic domain and a carbohydrate binding module. ABK52392 was cloned and functionally expressed in Escherichia coli. After purification by Ni-NTA agarose affinity chromatography and Q-Sepharose® Fast Flow chromatography, the properties of the recombinant protein (AcCel12B) were characterized. AcCel12B exhibited optimal activity at pH 4.5 and 75 °C. The half-lives of AcCel12B at 60 and 70 °C were about 90 and 2 h, respectively, under acidic conditions. The specific hydrolytic activities of AcCel12B at 70 °C and pH 4.5 for sodium carboxymethylcellulose (CMC) and regenerated amorphous cellulose (RAC) were 118.3 and 104.0 U·mg(-1), respectively. The Km and Vmax of AcCel12B for CMC were 25.47 mg·mL(-1) and 131.75 U·mg(-1), respectively. The time course of hydrolysis for RAC was investigated by measuring reducing ends in the soluble and insoluble phases. The total hydrolysis rate rapidly decreased after the early stage of incubation and the generation of insoluble reducing ends decreased earlier than that of soluble reducing ends. High thermostability of the cellulase indicates its potential commercial significance and it could be exploited for industrial application in the future.

Poly (N-isopropylacrylamide) (PNIPAAm)-grafted silica beads with variable graft densities were prepared by atom transfer radical polymerization (ATRP). The ATRP initiator on the surface of silica was prepared through the aminopropyl silica and 2-bromoisobutyryl bromide. Acetyl chloride was used to control the graft density. The content of carbon, hydrogen, and nitrogen were measured by elemental analyzer. The graft ratio was characterized by thermogravimetric analysis and the molecular weight of the polymer was determined by GPC analysis. The retention behavior of five steroids under different temperature was studied. Furthermore, the influence of temperature and graft densities to the separation of steroid compounds was investigated. The results indicated that graft density had a significant influence on the separation efficiency. Thinner PNIPAAm chains on hydrophilic silica surface can achieve the stationary phase with enhanced temperature sensitivity and better separation property.

Biological synthesis of nanoparticles is best way to avoid exposure of hazardous materials as compared to chemical manufacturing process which is a severe threat not only to biodiversity but also to environment. In present study, we reported a novel method of finding antiradiation compounds by bioreducing mechanism of silver nanoparticles formation using 50% ethanol extract of Dragons blood, a famous Chinese herbal plant. Color change during silver nanoparticles synthesis was observed and it was confirmed by ultra violet (UV) visible spectroscopy at wave length at 430 nm after 30 min of reaction at 60 °C. Well dispersed round shaped silver nanoparticles with approximate size (4 nm to 50 nm) were measured by TEM and particle size analyser. Capping of biomolecules on Ag nanoparticles was characterized by FTIR spectra. HPLC analysis was carried out to find active compounds in the extract. Furthermore, antiradiation activity of this extract was tested by MTT assay in vitro after incubating the SH-SY5Y cells for 24 h at 37 °C. The results indicate that presence of active compounds in plant extract not only involves in bioreduction process but also shows response against radiation. The dual role of plant extract as green synthesis of nanoparticles and exhibit activity against radiation which gives a new way of fishing out active compounds from complex herbal plants.

A novel organophosphonate-based polyoxovanadate, Cs1·5Na3.5[H{V3(H2O)O3}{O3PC- (OH)(CH3)PO3}3]·15H2O (1) has been synthesized and further investigated by single-crystal X-ray diffraction analysis, IR spectrum, UV–vis spectroscopy, X-ray powder diffraction, thermogravimetric analysis and X-ray photoelectron spectroscopy. Single-crystal X-ray analysis reveals that compound 1 crystallizes in the triclinic space group P-1 with a = 9.506(3) A, b = 15.150(5) A, c = 17.915(6) A, V = 2437.9(14) A3 and Z = 2. Compound 1 exhibits a ring-shaped cluster with three branches of the 1-hydroxyethane 1, 1-diphosphonic acid [HEDP = H2O3P(OH)C(CH3)PO3H2] ligands. Furthermore, the magnetic property of compound 1 has also been studied.

The present study was conducted to investigate the expression of apoptosis-related factors in peripheral blood mononuclear cells (PBMC) of patients with chronic hepatitis B and their correlation to clinical prognosis. Sixty-two patients that were diagnosed with chronic hepatitis B were admitted to Xuzhou Hospital from March 2015 to February 2016 and were enrolled as the observation group, while 60 healthy subjects who were examined in the health examination center were selected as the control group. The PBMC of patients were collected, and mRNA expression levels of the apoptotic molecules (FAS, CASP3, CASP8 and CASP9) were measured using real-time fluorescence quantitative PCR. The protein expression levels of apoptosis-related genes in the plasma were detected using enzyme-linked immunosorbent assay (ELISA) and the serum HBV-DNA was quantitatively measured using real-time fluorescence quantitative PCR. The mRNA and protein expression levels of FAS, CASP3, CASP8 and CASP9 in the observation group were significantly higher than those in the control group (P

Based on the successful graft of P(N-isopropylacrylamide-4-vinylphenylboronic acid) [P(NIPAAm-co-VPBA)] on glass substrates by surface-initiated atom transfer radical polymerization, a microfludic chip with the performance of thermoresponsive boronate affinity was fabricated and was used for capture–release of the cis-diol biomolecule adenosine. The copolymers modified successfully on the surface of glass substrate were characterized by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results demonstrated that, by simply adjusting the temperature from 4 to 55 °C, the microchip grafted with P(NIPAAm-co-VPBA) was specific to the cis-diol-containing molecules, and can selectively and quickly realize the capture and release of the cis-diol biomolecule adenosine from the mixture of adenosine and deoxyadenosine, which was validated by high performance liquid chromatography/electronic spray ion–ion trap mass spectrometry (HPLC/ESI–ion trap MS). Moreover, less than 10 min was taken from injection to the collection of the sample at the end of the channel. With further development, the P(NIPAAm-co-VPBA)-grafted microchip with high selectivity and repeatability may be chosen as a promising tool for the enrichment of the cis-diol-containing biomolecules, such as glycoproteins, carbohydrates, glycosylated peptides, nucleosides, etc.

The mechanism of maternal in vivo haploid induction is not fully understood. In this study, the young embryos were identified by morphology, cytology and simple sequence repeat (SSR) markers at different developmental stages in the cross HZ514 (sweet corn) × HZI1 (inducer). The results indicated that the low seed setting rate was determined by the inducer pollen during the process of fertilization. The mosaic endosperm kernels and the different percentages of aneuploidy, mixploidy, lagged chromosome, micronuclei, chromosomal bridge and ring chromosome were found in the cross; 7.37% of the haploid embryos carried chromosome segments from HZI1. About 1% twin seedlings resulted from the cross and were analyzed by cytology and SSR markers. Four pairs of twin seedlings had different chromosome numbers (2n = 20 and 2n = 10–20) and there were some chromosome fragments from HZI1. Aneuploidy, mixploidy and the abnormal chromosomes occurred in the in vivo haploid induction by HZI1, which is the cytological basis for haploid induction and indicates that the inducer's chromosomes are prone to be lost during mitotic and meiotic divisions. Morphological, cellular and molecular evidences reveal that complete or partial chromosome elimination from inducer HZI1 controls the maize in vivo haploid induction. DATA The link refers to the raw data from: Morphological, cellular and molecular evidences of chromosome random elimination in vivo upon haploid induction in maize. Current Plant Biology. Raw data for phenotype, maker sequence and cytology could be directly downloaded by the link: http://dx.doi.org/10.5061/dryad.bt963

A single metal atom stabilized on two dimensional materials (such as graphene and h-BN) exhibits extraordinary activity in the oxidation of CO. The oxidation of CO by molecular O2 on a single cobalt atom embedded in a hexagonal boron nitride monolayer (h-BN) is investigated using first-principles calculations with dispersion-correction. It is found that the single Co atom prefers to reside in a boron vacancy and possesses great stability. There are three mechanisms for CO oxidation: the traditional Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms and the termolecular Eley-Rideal (TER) mechanism proposed recently. Given the relatively small reaction barriers of the rate-limiting steps for the ER, LH and TER mechanisms (0.59, 0.55 and 0.41 eV, respectively), all three mechanisms are able to occur at low temperature. The current study may provide useful clues to develop low cost single atom catalysts.

Peptide separation technology is significant and is still an analytical challenge in proteomic studies. We report a simple preparation method for poly(N-isopropylacrylamide) grafted silica through the copolymerization of N-isopropylacrylamide with acetyl moieties immobilized on the silica surfaces. Differential scanning calorimetry results indicated that the prepared silica exhibited a sharp phase transition at 35.03°C. Silica grafted with poly(N-isopropylacrylamide) was evaluated as a temperature-responsive chromatography medium for the separation of peptides using 0.2 M NaCl solution as a mobile phase. Results indicated that at 10°C, the peptides were not resolved, but baseline separation with prolonged retention time at 50°C was attained. Particularly, a mixture of four peptides was efficiently separated within 8 min. The theoretical plate number of every peptide was more than 2500, and the resolutions were more than 3.40. The increased selectivity of the temperature-responsive column resulted from the temperature-modulated hydrophobic interaction with peptides. The retention times of these peptides were related to their hydrophobicities. This protocol provided a reliable set of chromatographic tool usable across all research and development applications that required isolation and analysis of peptides. It may represent a step forward in the complex analysis of hydrophobic and other proteins.

Thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) brushes were densely grafted onto silica surface via surface-initiated atom transfer radical polymerization (SI-ATRP). The grafting reaction started from the surfaces of 2-bromoisobutyratefunctionalized silica particles in 2-propanol aqueous solution at ambient temperature using CuCl/CuCl2/N,N,N′,N′,N″-pentamethyldiethylenetriamine (PMDETA) as the catalytic system. Based on thermogravimetric analysis (TGA) results, the grafting amount and grafting density of PNIPAM chains on the surface of silica were calculated to be 1.29 mg/ m2 and 0.0215 chains/nm2, respectively. The gel permeation chromatography (GPC) result showed the relatively narrow molecular weight distribution (Mw/Mn= 1.21) of the grafted PNIPAAm. The modified silica particles were applied as high-performance liquid chromatography (HPLC) packing materials to successfully separate three aromatic compounds using water as mobile phase by changing column temperature. Temperature-dependent hydrophilic/hydrophobic property alteration of PNIPAAm brushes grafted on silica particles was determined with chromatographic interaction between stationary phase and analytes. Retention time was prolonged and resolution was improved with increasing temperature. Baseline separation with high resolution at relatively low temperatures was observed, demonstrating dense PNIPAAm brushes were grafted on silica surfaces.

In this paper, polyvinylidene fluoride (PVDF)/polymethyl acrilate (PMMA)/cellulose acetate (CA) blend UF membranes were prepared by chemical reaction introduced phase-inversion method. The results of the experiment show that: (1) The membrane pore size distribution is more uniform due to the presence of carbonates or bicarbonates in the coagulation bath; (2) No more than the stoichiometric ratio amount of carbonates or bicarbonates in the coagulation bath can effectively improve the membrane pore size distribution and make the pore size of membrane more uniform; (3) The membrane prepared by carbonates solution as a working solution in coagulation bath possess superior performance than that by bicarbonates.

In this paper, a multi-regression method was used to study the influence of different operating conditions on the specific cake resistance (SCR) of yeast suspensions in order to optimize the operating conditions in the crossflow microfiltration. The experimental results showed that the crossflow velocity, transmembrane pressure, concentration and temperature had an obvious influence on the SCR. The SCR decreased with the rising temperature, and increased with the increasing crossflow velocity or pressure, and also increased with the increase of the concentration in the range of 1.0–3.0 g/l first and then decreased in the range of 3.0–5.0 g/l. The relative degrees of the influence of the crossflow velocity, concentration, transmembrane pressure and temperature on the SCR of yeast suspensions were 38.85%, 28.32%, 19.34%, and 13.49%, respectively. A reasonably quantitative regression relationship between the SCR (α) and the crossflow velocity (U), transmembrane pressure (P), feed concentration (C) and temper...

An orthogonal table and a linear multi-regression model were used to optimize the preparation procedure of polyvinylidene fluoride/polymethyl acrilate/cellulose acetate (PVDF/PMMA/CA) blend ultrafiltration membrane, which was prepared via combination of the phase-inversion process and chemical reaction. The pure water flux, the feed solution flux of BSA, the observed retention of BSA, the pore size distribution and SEM images of the membranes were used to estimate the characteristics of the membrane. The results showed that: (1) the combination of orthogonal table and linear multi-regression model is an efficient method to ascertain the optimum preparation conditions for the membrane-making process; (2) solid content, solvent species, additive species, additive content, category of coagulation medium affect characteristics of the membrane, and among them the solid content and additive species are the most remarkable influencing factors; The relationship is Y4 = 4.921 – 1.871X1 – 0.462X2 + 0.719X3 – 0.153X4 – 0.292X7, where, Y4 is a function of simultaneous consideration of the influence of the pure water flux, feed solution flux and observed retention, X1 is solid content, X2 is solvent species, X3 is additive species, X4 is additive content, X7 is the interaction between additive content and additive species; (3) when solid content of PVDF/PMMA/CA is 16%, solvent is DMF, additive is PEG2000 with 2%, content of glacial acetic acid (CH3COOH) is 10%, the coagulation medium is an aqueous solution of sodium carbonate (Na2CO3), and gelation time is 30 min, the PVDF/PMMA/CA is a blend of UF membranes with a uniform membrane pore size distribution (0.07–0.10 μm) and high pure water flux is prepared.

In present study, three kinds of temperature-responsive chromatography materials with different graft densities under the same graft chain length were synthesized via Atom transfer radical polymerization (ATRP), and they were characterized by Infrared detection and Thermo gravimetric analysis (TGA). Furthermore, the influences of temperature and graft density on the separation performance of steroidal compounds were investigated. The results showed that the graft ratio was higher with higher graft density under the same graft chain length. It is also found that when graft density was too high, it was not suitable for chromatographic materials, and when the graft density was too low, the separation performance was not obvious with the change of temperature. Therefore, choosing a suitable graft density was important for the separation performance of temperature-responsive stationary phase under the same graft chain length.

Three kinds of chromatography materials with temperature response have been prepared, and they were characterized by IR and TGA. By using the three materials, we studied the separation performance of four different steroids under 5 different temperatures. The results showed that bigger grafting density would lead to shorter chain, lower temperature response and longer retention time. Thus, it is important for the preparation of stationary phase with temperature response ability to choose adaptive grafting ratio, grafting density and grafting chain length.