Systematic Microwave-Assisted Postsynthesis of Mn-Doped Cesium Lead Halide Perovskites with Improved Color-Tunable Luminescence and Stability.

The metal doping at the Pb2+ position provides improved luminescence performance for the cesium lead halide perovskites, and their fabrication methods assisted by microwave have attracted considerable attention due to the advantages of fast heating and low energy consumption. However, the postsynthetic doping strategy of the metal-doped perovskites driven by microwave heating still lacks systematic research. In this study, the assembly of CsPbBr3/CsPb2Br5 with a strong fluorescence peak at 523 nm is used as the CsPbBr3 precursor, and through the optimization of the postsynthetic conditions such as reaction temperatures, Mn2+/Pb2+ feeding ratios, and Mn2+ sources, the optimum Mn2+-doped product (CsPb(Cl/Br)3:Mn) is achieved. The exciton fluorescence peak of CsPb(Cl/Br)3:Mn is blueshifted to 437 nm, and an obvious fluorescence peak attributing to the doped Mn2+ ions at 597 nm is obtained. Both the CsPbBr3 precursor and CsPb(Cl/Br)3:Mn have high PLQY and stability because there are CsPb2Br5 microcubic crystals to well disperse and embed the CsPbBr3 nanocrystals (NCs) in the precursor, and after Mn2+-doping, this structure is maintained to form CsPb(Cl/Br)3:Mn NCs on the surface of their microcrystals. The exploration of preparation parameters in the microwave-assisted method provides insights into the enhanced color-tunable luminescence of the metal-doped perovskite materials.

Metal Organic Framework (MOF)/Wood Derived Multi-cylinders High-Power 3D Reactor.

3D monolithic reactor has shown great promise for varied heterogeneous catalysis reactions including water treatment, energy generation and storage, and clean fuel production. As a natural porous material, macroporous wood is regarded as an excellent support for inorganic catalyst due to its abundant polar functional groups and channels. On the other hand, a metal organic framework (MOF) has been widely used as heterogeneous catalyst due to its high specific surface area and large amount of microporosities. Combining macroporous wood and a microporous MOF is expected to produce a high-performance 3D reactor and is demonstrated here for Fischer-Tropsch synthesis. The carbonized MOF/wood reactor retains the original cellular structure with over 180 000 channels/cm2. When being decorated with hexagonal-shaped core-shell Co@C nanoparticles aggregates derived from Co-MOF, the MOF/wood reactor resembles a multi-cylinders reactor for Fischer-Tropsch synthesis. Because of the unique combination of macro- and microporous hierarchical structure, the 3D MOF/wood reactor demonstrates exceptional performance under high gas hourly space velocity (81.2% CO conversion and 48.5% C5+ selectivity at 50 L·h-1·gcat-1 GHSV). This validates that MOF/wood can serve as a multi-cylinders and high-power reactor for catalytic reactions, which is expected to be applicable for environmental and energy applications.

Construction of chromosome segment substitution lines of Dongxiang common wild rice (Oryza rufipogon Griff.) in the background of the japonica rice cultivar Nipponbare (Oryza sativa L.).

Dongxiang common wild rice (Oryza rufipogon Griff.) is believed to have the northernmost distribution of any wild rice species. Many favorable genes were lost during rice domestication, and Dongxiang common wild rice is a potential source of many genes related to biological and abiotic stress resistance and high grain yield. Despite its importance, japonica rice has not yet been used as a background material for the construction of introgression lines carrying Dongxiang common wild rice chromosome segments. In this study, we used Dongxiang common wild rice as the donor parent and Nipponbare (Oryza sativa L), a reference-sequence japonica cultivar, as the recurrent parent to develop a set of 104 chromosome segment substitution lines (CSSLs) through crossing and backcrossing with marker-assisted selection based on 203 polymorphic molecular markers evenly distributed across 12 chromosomes. The 104 CSSLs covered 87.94% of the genome of Dongxiang common wild rice. Each CSSL contained an average of four introgressed segments, and the average segment length was 3.3 Mb. Quantitative trait locus (QTL) analysis of the panicle-related traits of the CSSLs at two sites (Beijing and Nanchang, Jiangxi Province) revealed 18 QTLs for eight traits. Among these 18 QTLs were two known grain length- and width-related genes and four novel QTLs. In addition, two QTLs were verified, and two novel QTLs were identified, for panicle neck length, a domestication-related trait. The developed CSSLs potentially represent a valuable population for detecting favorable genes in common wild rice and creating germplasm resources for japonica rice breeding.

FLA, which encodes a homolog of UBP, is required for chlorophyll accumulation and development of lemma and palea in rice.

KEY MESSAGE: FLA, the homolog of ubiquitin-specific protease does not have deubiquitination activity, but it is essential for flower and chloroplast development in rice. Ubiquitin-specific proteases (UBPs) are widely distributed and highly conserved proteins and are also members of the most important family of deubiquitination enzymes. Although the functions and phylogenies of UBPs from yeast, mammals and Arabidopsis have been widely reported, the functions and evolutionary relationships of UBPs in rice remain unclear. In this study, we characterized the rice flower and leaf color aberrant mutant (fla), which exhibited a variety of developmental defects, including abnormal floral organs and pollen development, and leaf bleaching. We isolated FLA by positional cloning and found that it encodes a homolog of ubiquitin-specific protease. FLA is a ubiquitously expressed gene with the highest expression in floral organs. Subcellular localization analysis indicated that FLA is a cell membrane protein. Through searches of the rice genome database ( http://rice.plantbiology.msu.edu ), we identified 35 UBP family members in the rice genome. These proteins were grouped into 16 subfamilies based on phylogenetic analysis, and FLA was found to belong to the G8 subfamily. In vitro activity assays revealed that FLA does not have deubiquitination activity. Our data suggest that FLA plays an important role in the development of floral organs and chloroplast in rice, but that this role probably does not involve deubiquitination activity, because FLA does not have an active site and deubiquitination activity.

Carbon quantum dots as a fluorophore for "inner filter effect" detection of metronidazole in pharmaceutical preparations.

With houttuynia cordata as carbon source, photoluminescent carbon quantum dots (CDs) were obtained via a one-step hydrothermal procedure. The absorption band of metronidazole (MNZ, maximum absorption wavelength at 319 nm) can well overlap with the excitation bands of CDs (maximum excitation wavelength at 320 nm). A fluorescent approach has been developed for detection of MNZ based on the inner filter effect (IFE), in which as-prepared CDs act as an IFE fluorophore and the MNZ as an IFE absorber. We have investigated the mechanism of quenching the fluorescence of CDs and found that the IFE leads to an exponential decay in fluorescence intensity of CDs with increasing concentration of MNZ, but showed a good linear relationship (R 2 = 0.9930) between ln(F 0/F) with the concentration of MNZ in the range of 3.3 × 10-6 to 2.4 × 10-4 mol L-1. Due to the absence of surface modification of the CDs or establishing any covalent linking between the absorber (MNZ) and the fluorophore (CDs), the developed method is simple, rapid, low-cost and less time-consuming. Meanwhile, it possesses a higher sensitivity, wider linear range, and satisfactory selectivity and has potential application for detection of MNZ in pharmaceutical preparations.

Locating QTLs controlling overwintering seedling rate in perennial glutinous rice 89-1 (Oryza sativa L.).

A new cold tolerant germplasm resource named glutinous rice 89-1 (Gr89-1, Oryza sativa L.) can overwinter using axillary buds, with these buds being ratooned the following year. The overwintering seedling rate (OSR) is an important factor for evaluating cold tolerance. Many quantitative trait loci (QTLs) controlling cold tolerance at different growth stages in rice have been identified, with some of these QTLs being successfully cloned. However, no QTLs conferring to the OSR trait have been located in the perennial O. sativa L. To identify QTLs associated with OSR and to evaluate cold tolerance. 286 F12 recombinant inbred lines (RILs) derived from a cross between the cold tolerant variety Gr89-1 and cold sensitive variety Shuhui527 (SH527) were used. A total of 198 polymorphic simple sequence repeat (SSR) markers that were distributed uniformly on 12 chromosomes were used to construct the linkage map. The gene ontology (GO) annotation of the major QTL was performed through the rice genome annotation project system. Three main-effect QTLs (qOSR2, qOSR3, and qOSR8) were detected and mapped on chromosomes 2, 3, and 8, respectively. These QTLs were located in the interval of RM14208 (35,160,202 base pairs (bp))-RM208 (35,520,147 bp), RM218 (8,375,236 bp)-RM232 (9,755,778 bp), and RM5891 (24,626,930 bp)-RM23608 (25,355,519 bp), and explained 19.6%, 9.3%, and 11.8% of the phenotypic variations, respectively. The qOSR2 QTL displayed the largest effect, with a logarithm of odds score (LOD) of 5.5. A total of 47 candidate genes on the qOSR2 locus were associated with 219 GO terms. Among these candidate genes, 11 were related to cell membrane, 7 were associated with cold stress, and 3 were involved in response to stress and biotic stimulus. OsPIP1;3 was the only one candidate gene related to stress, biotic stimulus, cold stress, and encoding a cell membrane protein. After QTL mapping, a total of three main-effect QTLs-qOSR2, qOSR3, and qOSR8-were detected on chromosomes 2, 3, and 8, respectively. Among these, qOSR2 explained the highest phenotypic variance. All the QTLs elite traits come from the cold resistance parent Gr89-1. OsPIP1;3 might be a candidate gene of qOSR2.

Influence of Molecular Weight on Structure and Catalytic Characteristics of Ordered Mesoporous Carbon Derived from Lignin.

Bio-renewable lignin has been used as a carbon source for the preparation of porous carbon materials. Nevertheless, up to now, there are few studies about the influence of molecular weight of lignin on the structure and morphology of the ordered mesoporous carbon. Here, we synthesized the ordered mesoporous carbon derived from different molecular weights of lignin and Pluronic F127. Fortunately, we found that molecular weight is an important factor for obtaining highly ordered channels, high specific surface area, and ordered mesoporous carbon. More importantly, the narrow well-defined mesoporous channel could exert a spatial restriction effect to some extent, which can serve as nanoreactors for efficient reactions and enhance catalytic performance. The highly ordered mesoporous carbon from lignin is a good candidate for Fischer-Tropsch synthesis catalyst supports.

Preparation of polymethacrylate monolith modified with cysteine for the determination of Cr(iii) ions.

In this study, a simple and rapid polymer monolith microextraction procedure was developed for the determination of Cr(iii) ions by inductively coupled plasma-atomic emission spectrometry. A monolithic column modified with cysteine was synthesized and characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis, specific surface area analysis and pore size distribution analysis. The influences of analytical parameters such as sample pH, adsorption time, eluent type, and coexisting ions were examined. The limit of detection (LOD) and limit of quantification (LOQ) for Cr(iii) ions were 0.005 µg mL-1 and 0.017 µg mL-1, and the relative standard deviation (RSD) was 7.4% (n = 5). The prepared cysteine functionalized monolithic column displayed good enrichment capacity and was successfully applied to the determination of Cr(iii) ions in real samples.

Optimizing mixed culture of two acidophiles to improve copper recovery from printed circuit boards (PCBs).

In the previous research, the effects of different addition time and amount of printed circuit boards (PCBs) on cells growth and metals recovery in separated and mixed culture of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans were investigated. This paper aimed to optimize mixed culture of both acidophiles for maximizing PCBs addition amounts and copper leaching percentage simultaneously. Initially, influences of inoculums ratio between two acidophiles on their cells growth were studied. Then, initial medium pH and concentrations of FeSO4 · 7H2O and elemental sulfur (S(0)) were optimized by response surface methodology (RSM) to improve copper recovery. Finally, multiple-point PCBs addition was tested to determine maximal amounts. Results showed that with initial inoculums ratio (Af:At) 1:2, pH 1.56, FeSO4 · 7H2O and S(0) at 16.88 and 5.44 g/L, and PCBs addition 28.8 g/L, copper recovery reached 92.6% after 240 h cultivation. It was indicated that copper could be efficiently leached out from increased PCBs addition amount and FeSO4 · 7H2O was remarkably reduced from 22.1 to 16.88 g/L.

Simple and sensitive spectrofluorometric method for the determination of protein using an europium-thenoyltrifluoroacetone probe.

The fluorescence intensity of the europium (Eu3+)-thenoyltrifluoroacetone (TTA) complex can be remarkably enhanced by human serum albumin (HSA) in a Britton-Robinson buffer solution. Based on this fact, a simple, rapid, and sensitive method has been developed for the determination of proteins at the nanogram level by fluorescence spectroscopy. Under the optimum conditions, the enhanced fluorescence intensity is proportional to the concentration of HSA. The linear ranges for HSA are 0-5.1 and 5.1-44.4 microg ml(-1) and the limit of detection is 20.7 ng ml(-1). Moreover, there is very little interference from common inorganic ions and other coexisting compounds. The binding site number and the binding constant of Eu(3+)-TTA used as a fluorescence probe to HSA were calculated by using the Rosenthal graphic method. This method has been applied to the determination of total protein in human serum samples. The results are good agreement with data obtained by clinical physicians.

Analysis of eupatilin-human serum albumin interactions by means of spectroscopic and computational modelling.

The interaction of eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) with human serum albumin (HSA) was studied at simulative physiological pH, with a HSA concentration of 3.0 x 10(-6)mol L(-1) and eupatilin concentrations over the range of 6.0 x 10(-6) to 1.9 x 10(-5) mol L(-1). Fluorescence spectroscopy in combination with UV absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy were used to study the binding properties (including binding mechanism, the binding constants, the number of binding sites and the binding mode) of the interaction of eupatilin with HSA and the effect of this drug on HSA conformation changes. According to the Scatchard equation there was only one class of binding site that could bind to HAS; the binding constants were 1.53 x 10(5), 1.20 x 10(5), 1.05 x 10(5), 0.87 x 10(5) L mol(-1) at temperatures of 287, 298, 310 and 318 K, respectively. The FTIR spectra revealed that the protein secondary structure changed, with reductions in alpha-helices of about 3.65% at a drug to protein molar ratio of 3. The thermodynamic analysis (enthalpy and entropy change: DeltaH(0) and DeltaS(0)) and the computational modelling study indicated that hydrophobic force played an important role in eupatilin-HSA complex stabilization, and eupatilin could bind within the subdomain IIA of HSA.

Method development for the determination of coumarin compounds by capillary electrophoresis with indirect laser-induced fluorescence detection.

A capillary zone electrophoresis (CZE) with indirect laser-induced fluorescence detection (ILIFD) method is described for the simultaneous determination of esculin, esculetin, isofraxidin, genistein, naringin and sophoricoside. The baseline separation was achieved within 5 min with running buffer (pH 9.4) composed of 5mM borate, 20% methanol (v/v) as organic modifier, 10(-7)M fluorescein sodium as background fluorophore and 20 kV of applied voltage at 30 degrees C of cartridge temperature. Good linearity relationships (correlation coefficients >0.9900) between the second-order derivative peak-heights (RFU) and concentrations of the analytes (mol L(-1)) were obtained. The detection limits for all analytes in second-order derivative electrophoregrams were in the range of 3.8-15 microM. The RSD data of intra-day for migration times and second-order derivative peak-height were less than 0.95 and 5.02%, respectively. This developed method was applied to the analysis of the courmin compounds in herb plants with recoveries in the range of 94.7-102.1%. In this work, although the detection sensitivity was lower than that of direct LIF, yet the method would extend the application range of LIF detection.

Enantioseparation of palonosetron hydrochloride by micellar electrokinetic chromatography with sodium cholate as chiral selector.

The enantioseparation of four stereoisomers of palonosetron hydrochloride by micellar electrokinetic chromatography using sodium cholate as chiral surfactant was described. Sodium cholate was shown to be effective in separating palonosetron hydrochloride stereoisomers. For method optimization, several parameters such as sodium cholate concentration, buffer pH and concentration, the types and concentration of organic modifiers and applied voltage, on the enantioseparation were evaluated and the optimum conditions were obtained as follows: 30 mM borate buffer (pH 9.40) containing 70 mM sodium cholate and 20% (v/v) methanol with an applied voltage of 20 kV. Under these conditions, baseline separation of palonosetron hydrochloride stereoisomers was achieved within 18 min.

Analysis of baicalein, baicalin and wogonin in Scutellariae radix and its preparation by microemulsion electrokinetic chromatography with 1-butyl-3-methylimizolium tetrafluoborate ionic liquid as additive.

Microemulsion electrokinetic chromatography (MEEKC) using 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4) ionic liquid (IL) as additive was developed for the analysis of baicalin, wogonin and baicalein in Scutellariae radix and its preparation. After conducting a series of optimizations, baseline separation was obtained for the analytes within 5min under the optimum conditions (sodium dodecyl sulfate (SDS) 0.88% (m/v) ethyl acetate 0.8% (v/v) butan-1-ol 0.2% (v/v) and the buffer composition were 25% acetonitrile (v/v), 7.5 mM BMIM-BF4 and 10 mM NaH2PO4, pH 8.2, applied voltage 17.5 kV and detection at 254 nm), the method has been successfully applied to the determination and quantification of the analytes in the extracts of S. radix (cooked), S. radix (raw) and Qingfeiyihuowan which was the preparation including S. radix.

Comparison of the characterization on binding of alpinetin and cardamonin to lysozyme by spectroscopic methods.

Studies on the binding affinity of protein to the active components of herbs are novel in biochemistry and are valuable for the information about speciation of drugs and exchange in biological systems. Alpinetin and cardamonin, two of the main constituents from the seeds of Alpinia katsumadai Hayata, have been used in traditional herbs as antibacterial, anti-inflammatory, and other important therapeutic activities of significant potency and low systemic toxicity. The interactions between two flavonoids analogs and lysozyme have been studied for the first time by spectroscopic method including Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) and UV-absorption spectroscopy in combination with Fluorescence quenching study. Both molecules showed high affinities to lysozyme under the experimental condition with drug concentrations from 3.33 x 10(-6) to 2.67 x 10(-5)molL(-1) for alpinetin and 1.67 x 10(-6) to 13.33 x 10(-6)molL(-1) for cardamonin. The alterations of protein secondary structure in the presence of drugs in aqueous solution were quantitatively estimated by the evidences from CD and FT-IR spectroscopy. The thermodynamic parameters obtained and the results of spectroscopic measurements suggest that hydrophobic and electrostatic interactions are the predominant intermolecular forces stabilizing two coordination compounds. The quenching mechanism and the number of binding site (n approximately 1) were obtained by fluorescence titration data. The efficiency of energy transfer provided the binding distances of 4.04 and 5.90 nm for alpinetin-LYSO and cardamonin-LYSO systems, respectively.

Binding analysis of glycyrrhetinic acid to human serum albumin: fluorescence spectroscopy, FTIR, and molecular modeling.

Fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), and molecular modeling methods were employed to analyze the binding of glycyrrhetinic acid (GEA) to human serum albumin (HSA) under physiological conditions with GEA concentrations from 4.0x10(-6) to 4.5x10(-5) mol L(-1). The binding of GEA to HSA was via two types of sites: the numbers of binding site for the first type was near 0.45 and for the second type it was approximately 0.75. The binding constants of the second type binding site were lower than those of the first type binding site at corresponding temperatures, the results suggesting that the first type of binding site had high affinity and the second binding site involved other sites with lower binding affinity and selectivity. The fluorescence titration results indicated that GEA quenched the fluorescence intensity of HSA through static mechanism. The FTIR spectra evidence showed that the protein secondary structure changed with reduction of alpha-helices about 26.2% at the drug to protein molar ratio of 3. Thermodynamic analysis showed that hydrogen bonds were the mainly binding force in the first type of binding site, and hydrophobic interactions might play a main role in the second type of binding site. Furthermore, the study of computational modeling indicated that GEA could bind to the site I of HSA and hydrophobic interaction was the major acting force for the second type of binding site, which was in agreement with the thermodynamic analysis.

Binding of the bioactive compound 5,7,4'-trihydroxy-6,3',5'-trimethoxyflavone to human serum albumin.

5,7,4'-trihydroxy-6,3',5'-trimethoxyflavone is one of the bioactive components isolated from Artemisia plants possessing antitumor therapeutic activities. In this paper, its binding properties and binding sites located on human serum albumin (HSA) have been studied using UV absorption spectroscopy, fluorescence spectroscopy and Fourier transform infrared (FT-IR) spectra. The results of fluorescence titration revealed that 5,7,4'-trihydroxy-6,3',5'-trimethoxyflavone could strongly quench the intrinsic fluorescence of HSA by static quenching and there was only one class of binding sites on HSA for this drug. The binding constants at four different temperatures (289, 298, 310, and 318 K) were 1.93, 1.56, 1.22, and 0.93x10(5) L mol-1, respectively. The FT-IR spectra evidence showed that the protein secondary structure changed with reduction of alpha-helices about 27.6% at the drug to protein molar ratio of 3. The thermodynamic functions standard enthalpy change (DeltaH0) and standard entropy change (DeltaS0) for the reaction were calculated to be -18.70 kJ mol-1 and 36.62 J mol-1 K-1 according to the van't Hoff equation. These results and the molecular modeling study suggested that hydrophobic interaction was the predominant intermolecular force stabilizing the complex, and 5,7,4'-trihydroxy-6,3',5'-trimethoxyflavone could bind to the site I of HSA (the Warfarin Binding site).