Promoter of Cassava MeAHL31 Responds to Diverse Abiotic Stresses and Hormone Signals in Transgenic Arabidopsis.

The AT-hook motif nuclear-localized (AHL) family is pivotal for the abiotic stress response in plants. However, the function of the cassava AHL genes has not been elucidated. Promoters, as important regulatory elements of gene expression, play a crucial role in stress resistance. In this study, the promoter of the cassava MeAHL31 gene was cloned. The MeAHL31 protein was localized to the cytoplasm and the nucleus. qRT-PCR analysis revealed that the MeAHL31 gene was expressed in almost all tissues tested, and the expression in tuber roots was 321.3 times higher than that in petioles. Promoter analysis showed that the MeAHL31 promoter contains drought, methyl jasmonate (MeJA), abscisic acid (ABA), and gibberellin (GA) cis-acting elements. Expression analysis indicated that the MeAHL31 gene is dramatically affected by treatments with salt, drought, MeJA, ABA, and GA3. Histochemical staining in the proMeAHL31-GUS transgenic Arabidopsis corroborated that the GUS staining was found in most tissues and organs, excluding seeds. Beta-glucuronidase (GUS) activity assays showed that the activities in the proMeAHL31-GUS transgenic Arabidopsis were enhanced by different concentrations of NaCl, mannitol (for simulating drought), and MeJA treatments. The integrated findings suggest that the MeAHL31 promoter responds to the abiotic stresses of salt and drought, and its activity is regulated by the MeJA hormone signal.

Synthesis of a Metalla[2]catenane, Metallarectangles and Polynuclear Assemblies from Di(N-Heterocyclic Carbene) Ligands.

The 2,7-fluorenone-linked bis(6-imidazo[1,5-a]pyridinium) salt H2-1(PF6)2 reacts with Ag2O in CH3CN to yield the [2]catenane [Ag4(1)4](PF6)4. The [2]catenane rearranges in DMF to yield two metallamacrocycles [Ag2(1)2](PF6)2. 2,7-Fluorenone-bridged bis-(imidazolium) salts H2-L(PF6)2 (L=2 a, 2 b) react with Ag2O in CH3CN to yield metallamacrocycles [Ag2(L)2](PF6)2 with interplanar distances between the fluorenone rings too small for [2]catenane formation. Intra- and intermolecular π⋅⋅⋅π interactions between the fluorenone groups were observed by X-ray crystallography. The strongly kinked 2,7-fluorenone bridged bis(5-imidazo[1,5-a]pyridinium) salt H2-4(PF6)2 reacts with Ag2O to yield [Ag2(4)(CN)](PF6), while the tetranuclear assembly [Ag4(4)2(CO3)](PF6)2 was obtained in the presence of K2CO3.

Constructing Metal(II)-Sulfate Site Catalysts toward Low Overpotential Carbon Dioxide Electroreduction to Fuel Chemicals.

Precise regulation of the active site structure is an important means to enhance the activity and selectivity of catalysts in CO2 electroreduction. Here, we creatively introduce anionic groups, which can not only stabilize metal sites with strong coordination ability but also have rich interactions with protons at active sites to modify the electronic structure and proton transfer process of catalysts. This strategy helps to convert CO2 into fuel chemicals at low overpotentials. As a typical example, a composite catalyst, CuO/Cu-NSO4/CN, with highly dispersed Cu(II)-SO4 sites has been reported, in which CO2 electroreduction to formate occurs at a low overpotential with a high Faradaic efficiency (-0.5 V vs. RHE, FEformate=87.4 %). Pure HCOOH is produced with an energy conversion efficiency of 44.3 % at a cell voltage of 2.8 V. Theoretical modeling demonstrates that sulfate promotes CO2 transformation into a carboxyl intermediate followed by HCOOH generation, whose mechanism is significantly different from that of the traditional process via a formate intermediate for HCOOH production.

Constructing pH-Responsive and Tunable Azo-Phenol-Based o-Nitrobenzyl Photocages.

Multiple triggered-release strategies are widely utilized to control the release of caged target molecules. Among them, photocages with conditional triggers provide extra layers of control in photorelease. In this work, a series of pH-responsive photocages was designed that could be triggered under irradiation and specific intracellular pH values. pH-sensitive phenolic groups were conjugated with o-nitrobenzyl (oNB) to form azo-phenolic NPX photocages with tunable pKa. These azo-phenol-based oNB photocages showed differentiable photoreleasing profiles at pH 5.0, 7.2 and 9.0. By attaching fluorogenic cargos, it was shown that one of the photocages, NPdiCl, could be used to differentiate between acidic pH 5.0 and neutral pH 7.2 in cells under artificial pH conditions. Finally, NPdiCl was identified as a promising pH-responsive photocage for photoreleasing cargo inside acidic tumor cells.

Antibacterial oxygenated ergostane-type steroids produced by the marine sponge-derived fungus Aspergillus sp.

Two oxygenated ergostane-type steroids including one new compound, 3ß-hydroxy-5α,6ß-methoxyergosta-7,22-dien-15-one (1) along with a known analogue ergosta-6,22-dien-3ß,5α,8α-triol (2) were isolated from the crude extracts of the marine sponge-derived fungus Aspergillus sp. Their structures were elucidated on the basis of combined NMR and MS spectroscopic methods. Compound 1 was a marine ergostane-type steroid with two methoxy groups at C-5 and C-6, respectively. These oxygenated ergostane-type steroids were evaluated for their antibacterial activities against human or aquatic pathogens. Among them, compound 1 exhibited antibacterial activity against Staphylococcus aureus.

Unravelling the Roles of Solvophobic Effects and π⋠⋠⋠π Stacking Interactions in the Formation of [2]Catenanes Featuring Di-(N-Heterocyclic Carbene) Building Blocks.

A series of [2]catenanes has been prepared from di-NHC building blocks by utilizing solvophobic effects and/or π⋅⋅⋅π stacking interactions. The dinickel naphthobiscarbene complex syn-[1] and the kinked biphenyl-bridged bipyridyl ligand L2 yield the [2]catenane [2-IL](OTf)4 by self-assembly. Solvophobic effects are pivotal for the formation of the interlocked species. Substitution of the biphenyl-linker in L2 for a pyromellitic diimide group gave ligand L3 , which yielded in combination with syn-[1] the [2]catenane [3-IL](OTf)4 . This assembly exhibits enhanced stability in diluted solution, aided by additional π⋅⋅⋅π stacking interactions. The π⋅⋅⋅π stacking was augmented by the introduction of a pyrene bridge between two NHC donors in ligand L4 . Di-NHC precursor H2 -L4 (PF6 )2 reacts with Ag2 O to give the [Ag2 L4 2 ]2 [2]catenane [4-IL](PF6 )4 , which shows strong π⋅⋅⋅π stacking interactions between the pyrene groups. This assembly was readily converted into the [Au2 L4 2 ]2 gold species [5-IL](PF6 )4 , which exhibits exceptional stability based on the strong π⋅⋅⋅π stacking interactions and the enhanced stability of the Au-CNHC bonds.

A Tale of Two Sites: Neighboring Atomically Dispersed Pt Sites Cooperatively Remove Trace H2 in CO-Rich Stream.

Single-atom catalysts (SACs) exhibit distinct catalytic behavior compared with nano-catalysts because of their unique atomic coordination environment without the direct bonding between identical metal centers. How these single atom sites interact with each other and influence the catalytic performance remains unveiled as designing densely populated but stable SACs is still an enormous challenge to date. Here, a fabrication strategy for embedding high areal density single-atom Pt sites via a defect engineering approach is demonstrated. Similar to the synergistic mechanism in binuclear homogeneous catalysts, from both experimental and theoretical results, it is proved that electrons would redistribute between the two oxo-bridged paired Pt sites after hydrogen adsorption on one site, which enables the other Pt site to have high CO oxidation activity at mild-temperature. The dynamic electronic interaction between neighboring Pt sites is found to be distance dependent. These new SACs with abundant Pt-O-Pt paired structures can improve the efficiency of CO chemical purification.

Copper(II)-Doped Two-Dimensional Titanium-Based Metal-Organic Frameworks toward Light-Driven CO2 Reduction to Value-Added Products.

Recently, metal-organic framework (MOF)-based photocatalysts for an efficient CO2 reduction reaction have drawn wide attention in multidisciplinary fields and sustainable chemistry. In this work, a series of Cu2+-doped two-dimensional Ti-based MOFs were fabricated by a facile in situ solvothermal method. Cu2+ ions were doped in equal proportions and uniformly dispersed in the crystal structure of the MOF matrix. Interestingly, the doping content of Cu2+ ions and the photocatalytic performance displayed an obvious volcanic relationship, the medium-concentration Cu2+-doped sample (T1-2Cu) held the greatest activity with 100% carbonaceous product (CH4 and CO) formation, and the CH4 production rate was 3.7 µmol g-1 h-1 with 93% electron selectivity. The band structure, local electronic structure, carrier separation kinetics, and CO2 adsorption studies demonstrated that the excellent photocatalytic activity of T1-2Cu benefited from the appropriate amount of Cu2+ ion doping: (1) a doping amount of 2 atom % optimized the conduction band position of the MOF substrate and endowed T1-2Cu with strong reduction potential in thermodynamics, (2) doping Cu2+ ions tuned the local electronic environment around titanium oxide clusters and optimized the generation, separation, and migration processes of photoinduced carriers, and (3) the introduction of Cu2+ ions also provided more accessible active sites and more probabilities for the adsorption and activation of CO2 reactants.

Three-dimensional genetic networks among seed oil-related traits, metabolites and genes reveal the genetic foundations of oil synthesis in soybean.

Although the biochemical and genetic basis of lipid metabolism is clear in Arabidopsis, there is limited information concerning the relevant genes in Glycine max (soybean). To address this issue, we constructed three-dimensional genetic networks using six seed oil-related traits, 52 lipid metabolism-related metabolites and 54 294 SNPs in 286 soybean accessions in total. As a result, 284 and 279 candidate genes were found to be significantly associated with seed oil-related traits and metabolites by phenotypic and metabolic genome-wide association studies and multi-omics analyses, respectively. Using minimax concave penalty (MCP) and smoothly clipped absolute deviation (SCAD) analyses, six seed oil-related traits were found to be significantly related to 31 metabolites. Among the above candidate genes, 36 genes were found to be associated with oil synthesis (27 genes), amino acid synthesis (four genes) and the tricarboxylic acid (TCA) cycle (five genes), and four genes (GmFATB1a, GmPDAT, GmPLDα1 and GmDAGAT1) are already known to be related to oil synthesis. Using this information, 133 three-dimensional genetic networks were constructed, 24 of which are known, e.g. pyruvate-GmPDAT-GmFATA2-oil content. Using these networks, GmPDAT, GmAGT and GmACP4 reveal the genetic relationships between pyruvate and the three major nutrients, and GmPDAT, GmZF351 and GmPgs1 reveal the genetic relationships between amino acids and seed oil content. In addition, GmCds1, along with average temperature in July and the rainfall from June to September, influence seed oil content across years. This study provides a new approach for the construction of three-dimensional genetic networks and reveals new information for soybean seed oil improvement and the identification of gene function.

Metal-Organic Framework Membranes Encapsulating Gold Nanoparticles for Direct Plasmonic Photocatalytic Nitrogen Fixation.

Photocatalytic nitrogen fixation reaction can harvest the solar energy to convert the abundant but inert N2 into NH3. Here, utilizing metal-organic framework (MOF) membranes as the ideal assembly of nanoreactors to disperse and confine gold nanoparticles (AuNPs), we realize the direct plasmonic photocatalytic nitrogen fixation under ambient conditions. Upon visible irradiation, the hot electrons generated on the AuNPs can be directly injected into the N2 molecules adsorbed on Au surfaces. Such N2 molecules can be additionally activated by the strong but evanescently localized surface plasmon resonance field, resulting in a supralinear intensity dependence of the ammonia evolution rate with much higher apparent quantum efficiency and lower apparent activation energy under stronger irradiation. Moreover, the gas-permeable Au@MOF membranes, consisting of numerous interconnected nanoreactors, can ensure the dispersity and stability of AuNPs, further facilitate the mass transfer of N2 molecules and (hydrated) protons, and boost the plasmonic photocatalytic reactions at the designed gas-membrane-solution interface. As a result, an ammonia evolution rate of 18.9 mmol gAu-1 h-1 was achieved under visible light (>400 nm, 100 mW cm-2) with an apparent quantum efficiency of 1.54% at 520 nm.

An efficient multi-locus mixed model framework for the detection of small and linked QTLs in F2.

In the genetic system that regulates complex traits, metabolites, gene expression levels, RNA editing levels and DNA methylation, a series of small and linked genes exist. To date, however, little is known about how to design an efficient framework for the detection of these kinds of genes. In this article, we propose a genome-wide composite interval mapping (GCIM) in F2. First, controlling polygenic background via selecting markers in the genome scanning of linkage analysis was replaced by estimating polygenic variance in a genome-wide association study. This can control large, middle and minor polygenic backgrounds in genome scanning. Then, additive and dominant effects for each putative quantitative trait locus (QTL) were separately scanned so that a negative logarithm P-value curve against genome position could be separately obtained for each kind of effect. In each curve, all the peaks were identified as potential QTLs. Thus, almost all the small-effect and linked QTLs are included in a multi-locus model. Finally, adaptive least absolute shrinkage and selection operator (adaptive lasso) was used to estimate all the effects in the multi-locus model, and all the nonzero effects were further identified by likelihood ratio test for true QTL identification. This method was used to reanalyze four rice traits. Among 25 known genes detected in this study, 16 small-effect genes were identified only by GCIM. To further demonstrate GCIM, a series of Monte Carlo simulation experiments was performed. As a result, GCIM is demonstrated to be more powerful than the widely used methods for the detection of closely linked and small-effect QTLs.

Tunable Electronic Metal-Support Interactions on Ceria-Supported Noble-Metal Nanocatalysts in Controlling the Low-Temperature CO Oxidation Activity.

A fundamental study on the metal-support interactions of supported metal catalysts is of great importance for developing heterogeneous catalysts with high performance, is still attracting and challenging in many heterogeneous catalytic reactions. In this work, we report the catalytic performances of CeO2-supported noble-metal catalysts among single atoms, subnanoclusters (∼1 nm), and nanoparticles (2.2-2.7 nm) upon low-temperature CO oxidation reaction between 50 and 250 °C. The subnanoclusters and nanoparticles of Ru, Rh, and Ir showed much higher activities than those of the single atoms, while a Pd single-atom catalyst was more active than Pd subnanoclusters and nanoparticles. According to the results of multiple ex situ and in situ characterizations, the much different activities of Ru, Rh, Ir, and Pd were derived from the alterable electronic metal-support interactions (EMSI), which determine the concurrent reaction pathway including the famous Mars van Krevelen mechanism and carbonate-intermediate route on the most active metal sites of Mδ+ (0 < δ < 1) for Ru, Rh, and Ir and Pd2+ for Pd. Also, the moderate EMSI of CeO2-supported Rh subnanoclusters furthest benefited activation of the adsorbed CO molecule and ensured it the highest activity among CeO2-supported Ru, Rh, and Ir catalysts with similar metal deposit sizes.

pH-sensitive chitosan-deoxycholic acid/alginate nanoparticles for oral insulin delivery.

Oral absorption of peptides/proteins is usually compromised by various gastrointestinal tract barriers. To improve delivery efficiency, chitosan-conjugated deoxycholic acid (CS-DCA) coupled with sodium alginate (ALG) was prepared to load insulin into pH-sensitive nanoparticles. The insulin-loaded chitosan-deoxycholic acid/alginate nanoparticles (CDA NPs) were characterized by size (143.3 ± 10.8 nm), zeta potential (19.5 ± 1.6 mV), entrapment efficiency (61.14 ± 1.67%), and insulin drug loading (3.36 ± 0.09%). The CDA NPs exhibited pH-triggered release characteristics in vitro and protected the wrapped insulin from gastric degradation. Stability of the CDA NPs in enzyme-containing simulated gastrointestinal fluids suggested that the NPs could partially protect the wrapped insulin from enzymatic degradation. Additionally, CS-DCA-modified NPs promoted the permeability of Caco-2 cells and enhanced intracellular absorption of FITC-labeled insulin by 9.4 and 1.2-folds, when compared to insulin solution and unmodified NPs, respectively. The positively charged NPs increased intestinal villi adhesion and enhanced insulin absorption in the intestines of diabetic rat models. Furthermore, the hypoglycemic test showed that CDA NPs prolonged insulin release in vivo and exerted a remarkable hypoglycemic effect on diabetic rats with an oral bioavailability of 15%. In conclusion, CDA NPs is a potential oral insulin delivery system.

A Strategy for the Construction of Triply Interlocked Organometallic Cages by Rational Design of Poly-NHC Precursors.

Three-dimensional (3D) triply interlocked catenanes are a family of chemical topologies that consist of two identical, mechanically interlocked coordination cage components with intriguingly complex structures. Although only a few successful constructions of 3D interlocked catenanes have been achieved to date via metal-mediated assembly, these complex structures have thus far only been targeted by metal-nitrogen/oxygen coordination techniques. Here, taking advantage of rational ligand design, we report the efficient construction of a series of 3D triply interlocked [2]catenanes of the formula [Ag3L2]2, wherein the metal ions exclusively form bonds to N-heterocyclic carbene (NHC) units, and their subsequent transmetalation to the corresponding [Au3L2]2 gold analogues. The formation and transmetalation reactions proceed under mild conditions and are generally applicable. A series of characterization techniques were applied to confirm the formation and structure of the desired 3D triply interlocked architectures: multinuclear NMR spectroscopy, ESI-MS, and single-crystal X-ray diffraction analysis. The solid-state structure of [Ag3(1a)2]2(PF6)6 unambiguously confirms the existence of a 3D catenane that consists of two identical, mechanically interlocked trinuclear hexacarbene cage components. The interlocking of two 3D cages into a [2]catenane is driven by the efficient π···π stacking of triazine-triazine stacks with cooperative interactions between imidazo[1,5-a]pyridine subunits. Notably, the triply interlocked organometallic cages exhibit good stability toward various organic solvents, concentrations, and temperatures, and no disassembly occurred in the presence of coronene or pyrene. The future construction of mechanically interlocked architectures using metal-carbene bonds rather than metal-nitrogen bonds may provide assemblies with interesting properties for as-yet-unimagined applications in fields such as sensors and molecular electrical conductors.

An evolutionary population structure model reveals pleiotropic effects of GmPDAT for traits related to seed size and oil content in soybean.

Seed oil traits in soybean that are of benefit to human nutrition and health have been selected for during crop domestication. However, these domesticated traits have significant differences across various evolutionary types. In this study, we found that the integration of evolutionary population structure (evolutionary types) with genome-wide association studies increased the power of gene detection, and it identified one locus for traits related to seed size and oil content on chromosome 13. This domestication locus, together with another one in a 200-kb region, was confirmed by the GEMMA and EMMAX software. The candidate gene, GmPDAT, had higher expressional levels in high-oil and large-seed accessions than in low-oil and small-seed accessions. Overexpression lines had increased seed size and oil content, whereas RNAi lines had decreased seed size and oil content. The molecular mechanism of GmPDAT was deduced based on results from linkage analysis for triacylglycerols and on histocytological comparisons of transgenic soybean seeds. Our results illustrate a new approach for identifying domestication genes with pleiotropic effects.

[Value of anti-neutrophil cytoplasmic antibody in assessing the severity of bronchiolitis obliterans in children].

OBJECTIVE: To study the value of anti-neutrophil cytoplasmic antibody (ANCA) in assessing the severity of bronchiolitis obliterans (BO) in children. METHODS: A prospective analysis was performed on 59 children who were diagnosed with BO from June 2009 to October 2014. ELISA was used to measure the concentrations of myeloperoxidase (MPO)-ANCA and proteinase 3 (PR3)-ANCA in serum. According to the results of ELISA, the children were divided into three groups: double-negative ANCA (n=22), single-positive ANCA (n=17), and double-positive ANCA (n=20). The three groups were compared in terms of the scores of BO risk factors, clinical symptoms, chest high-resolution computed tomography (HRCT), and lung pathology on admission, as well as the changes in the expression level of ANCA and the scores of clinical symptoms and chest HRCT over time. RESULTS: Compared with the double-negative ANCA group, the double-positive ANCA group had a significantly higher score of BO risk factors (P<0.05), and the single-positive ANCA group and the double-positive ANCA group had significantly higher scores of clinical symptoms, chest HRCT, and lung pathology (P<0.05). The children were followed up for 6 months after discharge, and there were significant reductions in MPO-ANCA and PR3-ANCA titers from admission and discharge to the end of follow-up (P<0.05), as well as a significant reduction in the score of clinical symptoms from admission to the end of follow-up (P<0.05), while there was no significant change in the score of chest HRCT from admission to the end of follow-up (P>0.05). The single-positive ANCA and double-positive ANCA groups still had a significantly higher score of clinical symptoms than the double-negative ANCA group (P<0.05). CONCLUSIONS: The expression level of ANCA is correlated with the severity of BO in children and thus has certain clinical significance in disease evaluation.

Synthesis, Characterization, and Properties of Organometallic Molecular Cylinders Bearing Bulky Imidazo[1,5-a]pyridine-Based N-Heterocyclic Carbene Ligands.

The metal-controlled self-assembly of organometallic molecular cylinders from a series of imidazo[1,5-a]pyridine-based tris-NHC ligands is described in this report. The imidazo[1,5-a]pyridinium salts H3 -L(PF6 )3 (L=4 a-4 c) were treated with 1.5 equivalents of Ag2 O to yield the trinuclear AgI hexacarbene cages [Ag3 (L)2 ](PF6 )3 (L=4 a-4 c), in which three AgI are sandwiched between the two tricarbene ligands. The silver(I) complexes [Ag3 (L)2 ](PF6 )3 underwent a facile transmetalation reaction in the presence of 3 equivalents of [AuCl(tht)] (tht=tetrahydrothiophene) to furnish the trinuclear AuI cylinder-like cages [Au3 (L)2 ](PF6 )3 (L=4 a-4 c) without destruction of the metallosupramolecular structure. The new hexacarbene assemblies feature a large cavity that can easily accommodate a molecule of dimethyl sulfoxide as molecular guest. This is the first study of a unique "host-guest" system containing an organometallic cylinder-like cage derived exclusively from poly-NHC ligands.

Boosting Electrochemical Reduction of CO2 at a Low Overpotential by Amorphous Ag-Bi-S-O Decorated Bi0 Nanocrystals.

Bimetal-S-O composites have been rarely researched in electrochemical reduction of CO2 . Now, an amorphous Ag-Bi-S-O decorated Bi0 catalyst derived from Ag0.95 BiS0.75 O3.1 nanorods by electrochemical pre-treatment was used for catalyzing eCO2 RR, which exhibited a formate FE of 94.3 % with a formate partial current density of 12.52 mA cm-2 at an overpotential of only 450 mV. This superior performance was attributed to the attached amorphous Ag-Bi-S-O substance. S could be retained in the amorphous region after electrochemical pre-treatment only in samples derived from metal-S-O composites, and it would greatly enhance the formate selectivity by accelerating the dissociation of H2 O. The existence of Ag would increase the current density, resulting in a higher local pH, which made the role of S in activating H2 O more significantly and suppressed H2 evolution more effectively, thus endowing the catalyst with a higher formate FE at low overpotentials.

Chemical Insights into the Design and Development of Face-Centered Cubic Ruthenium Catalysts for Fischer-Tropsch Synthesis.

Ruthenium is a promising low-temperature catalyst for Fischer-Tropsch synthesis (FTS). However, its scarcity and modest specific activity limit its widespread industrialization. We demonstrate here a strategy for tuning the crystal phase of catalysts to expose denser and active sites for a higher mass-specific activity. Density functional theory calculations show that upon CO dissociation there are a number of open facets with modest barrier available on the face-centered cubic (fcc) Ru but only a few step edges with a lower barrier on conventional hexagonal-closest packed (hcp) Ru. Guided by theoretical calculations, water-dispersible fcc Ru catalysts containing abundant open facets were synthesized and showed an unprecedented mass-specific activity in the aqueous-phase FTS, 37.8 molCO·molRu-1·h-1 at 433 K. The mass-specific activity of the fcc Ru catalysts with an average size of 6.8 nm is about three times larger than the previous best hcp catalyst with a smaller size of 1.9 nm and a higher specific surface area. The origin of the higher mass-specific activity of the fcc Ru catalysts is identified experimentally from the 2 orders of magnitude higher density of the active sites, despite its slightly higher apparent barrier. Experimental results are in excellent agreement with prediction of theory. The great influence of the crystal phases on site distribution and their intrinsic activities revealed here provides a rationale design of catalysts for higher mass-specific activity without decrease of the particle size.

[Oral absorption of asiatic acid nanoparticles modified with PEG].

A solvent diffusion method was used to prepare pegylated asiatic acid (AA) loaded nanostructured lipid carriers (p-AA-NLC), and the ligated intestinal circulation model was established to observe the absorption and distribution in small intestine. The concentration of AA in bile after oral administration of p-AA-NLC was detected by HPLC in healthy SD rats to indirectly evaluate the oral absorption promoting effect of PEG-modified namoparticles. The results showed that the penetration of p-AA-NLC was enhanced significantly and the transport capacity was increased greatly in small intestinal after PEG modification. As compared with the normal nanoparticles (AA-NLC), the Cmax of the drug excretion was increased by 76%, the time to reach the peak (tmax ) was decreased and the elimination half-life t1/2 was doubled in the rats after oral administration of p-AA-NLC, and the AUC0→t was 1.5 times of the AA-NLC group, indicating that the oral bioavailability of AA-NLC was significantly improved by hydrophilic modification of PEG.