Showing papers by "Hong Liu published in 2006"
TL;DR: A new class of compounds are revealed as potential drug leads against the SARS virus, and a solid understanding of the mechanism of inhibition against the target enzyme is provided.
224 citations
TL;DR: The technique can be expanded to many material systems, and it provides a general, simple, convenient, and innovative strategy for the synthesis of nanostructures of complex oxides with important scientific and technological applications in ferroelectricity, ferromagnetism, colossal magnetoresistance, fuel cell, optics, and more.
Abstract: We demonstrate a generic approach for the synthesis of single-crystal complex oxide nanostructures of various structure types, such as perovskites, spinels, monoclinic, corundum, CaF(2) structured, tetragonal, and even metal hydroxides. The method is based on a reaction between a metallic salt and a metallic oxide in a solution of composite-hydroxide eutectic at approximately 200 degrees C and normal atmosphere without using an organic dispersant or capping agent. The synthesis technique is cost-effective, one-step, easy to control, and is performed at low temperature and normal atomospheric pressure. The technique can be expanded to many material systems, and it provides a general, simple, convenient, and innovative strategy for the synthesis of nanostructures of complex oxides with important scientific and technological applications in ferroelectricity, ferromagnetism, colossal magnetoresistance, fuel cell, optics, and more.
193 citations
TL;DR: In this article, a new method to directly synthesize single-crystalline CeO2 nanoparticles has been developed, which is rapid synthesis, at normal atmosphere, 100% productive ratio and low cost with a great potential for scale-up.
Abstract: A new method to directly synthesize single-crystalline CeO2 nanoparticles has been developed. The advantages of the method are rapid synthesis, at normal atmosphere, 100% productive ratio and low cost, with a great potential for scale-up. X-ray diffraction (XRD) spectra showed unusual peak width versus particle size, compared with Scherrer equation predictions. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), electron diffraction and ultraviolet (UV) absorption were used to examine the particle size and microstructure to find out the cause. As a result, ultrafine particles with a size less than 6 nm were found to be self-assembled into a 'coherent interface', so that a large group of particles behave like a large single particle in XRD.
154 citations
TL;DR: Findings of thermal comfort are presented and the more sustainable standard for the indoor climate of residential buildings in Shanghai is discussed, which determines the adaptive relationship of neutral temperature with outdoor air temperature.
Abstract: A long-term field investigation was carried out in naturally ventilated residential buildings in Shanghai from April 2003 to November 2004. A total of 1,768 returned questionnaires were collected in the study. This study deals with the thermal sensation of occupants in naturally ventilated buildings and the change in thermal neutral temperature with season. The range of accepted temperature in naturally ventilated buildings is between 14.7 degrees C T(op) and 29.8 degrees C T(op). The results also report the findings of the adaptive comfort model in Shanghai that determines the adaptive relationship of neutral temperature with outdoor air temperature. A long-term field study was carried out in residential buildings in Shanghai to find the relationship between thermal sensation, indoor neutral temperature and outdoor temperature. This paper presents findings of thermal comfort and discusses the more sustainable standard for the indoor climate of residential buildings in Shanghai.
111 citations
TL;DR: Sixteen novel 4-triazole-modified zanamivir analogues were synthesized using the click reactions, and their inhibitory activities against avian influenza virus (AIV, H5N1) were determined.
107 citations
TL;DR: A novel flow-through immunosensing system for performing a multianalyte chemiluminescent determination in a single run and a new analytical strategy of substrate zone-resolved technique were proposed, and the results were in acceptable agreement with the reference values.
Abstract: A novel flow-through immunosensing system for performing a multianalyte chemiluminescent determination in a single run was designed. A new analytical strategy of substrate zone-resolved technique was proposed. Using carcinoma antigen 125 (CA 125) and carcinoembryonic antigen (CEA) as model analytes, the capture antibodies for CA 125 and CEA were immobilized on an UltraBind aldehyde-actived membrane to act as an immunoreactor, to which the mixture of CA 125, CEA, and their corresponding tracers, horseradish peroxidase (HRP)-labeled anti-CA 125 and alkaline phosphatase (ALP)-labeled anti-CEA, was introduced for on-line incubation. The substrates for HRP and ALP were then delivered into the detection cell sequentially to perform substrate zone-resolved immunoassay by a sandwich format. Under optimal conditions, CA 125 and CEA could be assayed in the ranges of 5.0−100 units/mL and 1.0−120 ng/mL, respectively. The whole assay process including incubation, wash, detection, and regeneration could be completed in...
97 citations
TL;DR: In this article, a co-precipitation method with ammonium hydrogen carbonate as precipitant, octyl polyoxyethylene sulfate sodium and glycol as secondary surfactant was used to synthesize Yttrium aluminum garnet nano-sized powder.
73 citations
TL;DR: A new inhibitor that abolishes Abeta fibrillation was discovered using virtual screening in conjunction with thioflavin T fluorescence assay and atomic force microscopy determination and revealed some clues to understanding the molecular events involved in Abeta aggregation.
Abstract: Abeta peptides cleaved from the amyloid precursor protein are the main components of senile plaques in Alzheimer's disease. Abeta peptides adopt a conformation mixture of random coil, beta-sheet, and alpha-helix in solution, which makes it difficult to design inhibitors based on the 3D structures of Abeta peptides. By targeting the C-terminal beta-sheet region of an Abeta intermediate structure extracted from molecular dynamics simulations of Abeta conformational transition, a new inhibitor that abolishes Abeta fibrillation was discovered using virtual screening in conjunction with thioflavin T fluorescence assay and atomic force microscopy determination. Circular dichroism spectroscopy demonstrated that the binding of the inhibitor increased the beta-sheet content of Abeta peptides either by stabilizing the C-terminal beta-sheet conformation or by inducing the intermolecular beta-sheet formation. It was proposed that the inhibitor prevented fibrillation by blocking interstrand hydrogen bond formation of the pleated beta-sheet structure commonly found in amyloid fibrils. The study not only provided a strategy for inhibitor design based on the flexible structures of amyloid peptides but also revealed some clues to understanding the molecular events involved in Abeta aggregation.
61 citations
TL;DR: A strain of Pseudomonasputida ZWL73 was isolated from soil contaminated with chloronitrobenzenes and identified by 16S rDNA sequencing, and the phylogenetic analysis suggested that 2A5CPDO may form a new subgroup in class III meta-cleavage dioxygenase with its close homologs.
Abstract: A strain of Pseudomonas putida ZWL73 was isolated from soil contaminated with chloronitrobenzenes and identified by 16S rDNA sequencing. This bacterium released chloride and ammonia into the medium when grown on 4-chloronitrobenzene (4CNB) as the sole source of carbon, nitrogen and energy. A plasmid designated pZWL73 of approximately 100 kb in this strain was found to be responsible for 4CNB degradation. This was based on the fact that the plasmid-cured strains showed 4CNB- phenotype and the 4CNB+ phenotype could be conjugally transferred. The cell-free extracts of strain ZWL73 exhibited chloronitrobenzene nitroreductase and 2-amino-5-chlorophenol 1, 6-dioxygenase (2A5CPDO) activities, but neither activity was found from that of the plasmid-cured strain. We have also cloned a 4.9-kb EcoRI fragment exhibiting 2A5CPDO activity. Sequencing results revealed beta-subunit (cnbCa) and alpha subunit (cnbCb) of a meta-cleavage dioxygenase, which were subsequently expressed in E. coli with 2A5CPDO activity. The phylogenetic analysis suggested that 2A5CPDO may form a new subgroup in class III meta-cleavage dioxygenase with its close homologs.
48 citations
TL;DR: In addition to engineering mammalian cytochromes P450 for enhanced activity, directed evolution can also be used to optimize catalytic tolerance to temperature and organic solvent.
Abstract: The previously laboratory-evolved cytochrome P450 2B1 quadruple mutant V183L/F202L/L209A/S334P (QM), which showed enhanced H(2)O(2)-mediated substrate oxidation, has now been shown to exhibit a >3.0-fold decrease in K(m,HOOH) for 7-ethoxy-4-trifluoromethylcoumarin (7-EFC) O-deethylation compared with the parental enzyme L209A. Subsequently, a streamlined random mutagenesis and a high-throughput screening method were developed using QM to screen and select mutants with enhanced tolerance of catalytic activity to temperature and dimethyl sulfoxide (DMSO). Upon screening >3000 colonies, we identified QM/L295H and QM/K236I/D257N with enhanced catalytic tolerance to temperature and DMSO. QM/L295H exhibited higher activity than QM at a broad range of temperatures (35-55 degrees C) and maintained approximately 1.4-fold higher activity than QM at 45 degrees C for 6 h. In addition, QM/L295H showed a significant increase in T(m,app) compared with L209A. QM/L295H and QM/K236I/D257N exhibited higher activity than QM at a broad range of DMSO concentrations (2.5-15%). Furthermore, QM/K236I/D257N/L295H was constructed by combining QM/K236I/D257N with L295H using site-directed mutagenesis and exhibited a >2-fold higher activity than QM at nearly the entire range of DMSO concentrations. In conclusion, in addition to engineering mammalian cytochromes P450 for enhanced activity, directed evolution can also be used to optimize catalytic tolerance to temperature and organic solvent.
47 citations
TL;DR: Investigation of the effect of connective tissue growth factor antisense oligonucleotide (CTGF-AS) on angiotensin II (Ang II)-induced tubular cell epithelial mesenchymal transition (EMT) in human proximal tubular epithelial cells (PTC) provides further evidence that CTGF might be involved in Ang II-induced EMT in PTC.
Abstract: Influence of connective tissue growth factor antisense oligonucleotide on angiotensin II-induced epithelial mesenchymal transition in HK2 cells 1
TL;DR: A series of novel small molecular CypA inhibitors have been discovered by using structure-based virtual screening in conjunction with chemical synthesis and bioassay, and four of which showed high CypA PPIase inhibition activities with IC50s of 2.5–6.2μM.
TL;DR: A combination of random and site-directed mutagenesis approaches yielded CYP3A4 enzymes with enhanced peroxide-supported metabolism of several substrates.
Abstract: CYP3A4 has been subjected to random and site-directed mutagenesis to enhance peroxide-supported metabolism of several substrates. Initially, a high-throughput screening method using whole cell suspensions was developed for H 2 O 2 -supported oxidation of 7-benzyloxyquinoline. Random mutagenesis by error-prone polymerase chain reaction and activity screening yielded several CYP3A4 mutants with enhanced activity. L216W and F228I showed a 3-fold decrease in K m, HOOH and a 2.5-fold increase in k cat / K m, HOOH compared with CYP3A4. Subsequently, T309V and T309A were created based on the observation that T309V in CYP2D6 has enhanced cumene hydroperoxide (CuOOH)-supported activity. T309V and T309A showed a >6- and 5-fold higher k cat / K m, CuOOH than CYP3A4, respectively. Interestingly, L216W and F228I also exhibited, respectively, a >4- and a >3-fold higher k cat / K m, CuOOH than CYP3A4. Therefore, several multiple mutants were constructed from rationally designed and randomly isolated mutants; among them, F228I/T309A showed an 11-fold higher k cat / K m, CuOOH than CYP3A4. Addition of cytochrome b 5 , which is known to stimulate peroxide-supported activity, enhanced the k cat / K m, CuOOH of CYP3A4 by 4- to 7-fold. When the mutants were tested with other substrates, T309V and T433S showed enhanced k cat / K m, CuOOH with 7-benzyloxy-4-(trifluoromethyl)coumarin and testosterone, respectively, compared with CYP3A4. In addition, in the presence of cytochrome b 5 , T433S has the potential to produce milligram quantities of 6β-hydroxytestosterone through peroxide-supported oxidation. In conclusion, a combination of random and site-directed mutagenesis approaches yielded CYP3A4 enzymes with enhanced peroxide-supported metabolism of several substrates.
TL;DR: The genes encoding enzymes involved in the initial reactions during degradation of 4-chloronitrobenzene (4CNB) were characterized from the 4CNB utilizer Pseudomonas putida ZWL73, in which a partial reductive pathway was adopted.
Abstract: The genes encoding enzymes involved in the initial reactions during degradation of 4-chloronitrobenzene (4CNB) were characterized from the 4CNB utilizer Pseudomonas putida ZWL73, in which a partial reductive pathway was adopted. A DNA fragment containing genes coding for chloronitrobenzene nitroreductase (CnbA) and hydroxylaminobenzene mutase (CnbB) were PCR-amplified and subsequently sequenced. These two genes were actively expressed in Escherichia coli, and recombinant E. coli cells catalyzed the conversion of 4CNB to 2-amino-5-chlorophenol, which is the ring-cleavage substrate in the degradation of 4CNB. Phylogenetic analyses on sequences of chloronitrobenzene nitroreductase and hydroxylaminobenzene mutase revealed that these two enzymes are closely related to the functionally identified nitrobenzene nitroreductase and hydroxylaminobenzene mutase from Pseudomonas strains JS45 and HS12. The nitroreductase from strain ZWL73 showed a higher specific activity toward 4CNB than nitrobenzene (approximately at a ratio of 1.6:1 for the recombinant or 2:1 for the wild type), which is in contrast to the case where the nitroreductase from nitrobenzene utilizers Pseudomonas pseudoalcaligenes JS45 with an apparently lower specific activity against 4CNB than nitrobenzene (0.16:1) [Kadiyala et al. Appl Environ Microbiol 69:6520-6526, 2003]. This suggests that the nitroreductase from 4-chloronitrobenzene utilizer P. putida ZWL73 may have evolved to prefer chloronitrobenzene to nitrobenzene as its substrate.
TL;DR: A series of novel small molecular CypA inhibitors have been discovered using a strategy integrating focused combinatorial library design, virtual screening, chemical synthesis, and bioassay, demonstrating the efficiency of the strategy for focused library design and screening.
Abstract: The discovery of cyclophilin A (CypA) inhibitor is now of special interest in the treatment of immunological disorders. In this work, using a strategy integrating focused combinatorial library design, virtual screening, chemical synthesis, and bioassay, a series of novel small molecular CypA inhibitors have been discovered. First, using the fragments taken from our previously discovered CypA inhibitors (Bioorg. Med. Chem. 2006, 14, 2209−2224) as building blocks, we designed a focused combinatorial library containing 255 molecules employing the LD1.0 program (J. Comb. Chem. 2005, 7, 398−406) developed by us. Sixteen compounds (1a−e, 2a−b, 3a−b, and 4a−g) were selected by using virtual screening against the X-ray crystal structure of CypA as well as druglike analysis for further synthesis and bioassay. All these sixteen molecules are CypA binders with binding affinities (KD values) ranging from 0.076 to 41.0 μM, and five of them (4a, 4c, and 4e−g) are potent CypA inhibitors with PPIase inhibitory activities...
TL;DR: The gene cassette (camA+ camB+ camC) encoding a cytochrome P-450cam variant was integrated into the nonessential gene pcpM of the pentachlorophenol degrader Sphingobium chlorophenolicum ATCC 39723 by homologous recombination.
Abstract: The gene cassette (camA+ camB+ camC) encoding a cytochrome P-450cam variant was integrated into the nonessential gene pcpM of the pentachlorophenol degrader Sphingobium chlorophenolicum ATCC 39723 by homologous recombination. The recombinant strain could degrade hexachlorobenzene at a rate of 0.67 nmol · mg (dry weight)−1 · h−1, and intermediate pentachlorophenol was also identified.
TL;DR: The results show that Fe(3+) ions have been successfully incorporated into the framework of HMS, and Fe-HMS has a uniform mesoporous structure with about 2.7 nm pore diameter.
Abstract: The iron-incorporated mesoporous silica material Fe-HMS was successfully synthesized at ambient temperature by using dodecylamine as the template agent, and it was characterized by XRD, SEM, FT–IR, UV–vis, ESR and N2 adsorption measurements. Its catalytic performance was studied for phenol hydroxylation with H2O2 in a fixed-bed reactor. The results show that Fe3+ ions have been successfully incorporated into the framework of HMS, and Fe-HMS has a uniform mesoporous structure with about 2.7 nm pore diameter. After Fe-HMS is calcined, most of the Fe3+ ions remain in the tetrahedral coordinated framework, and only a small part of Fe species migrate to the extraframework. Fe-HMS has high catalytic activity and very high selectivity to dihydroxybenzene for the hydroxylation of phenol. Over the Fe-HMS catalyst, the product distribution of phenol hydroxylation is different from that over the microporous TS-1 zeolite. The solvents have great influence on the catalytic activity of Fe-HMS, and water is the best solvent.
TL;DR: The chemical kinetics of hydroxylation of phenol with 30% H 2 O 2 over the TS-1/diatomite catalyst in a fixed-bed reactor system was studied in this paper.
TL;DR: A novel quinoxaline derivative, 2,3-di(furan-2-yl)-6-(3-N,N-diethylcarbamoyl-piperidino)carbonylamino quin oxaline (DC838, 3), which was confirmed to be a potent inhibitor against human CypA, and elucidated the specific DC838 binding to CypA at the atomic level.
TL;DR: In this paper, nano-sized YAG powders were synthesized using the co-precipitation method with ammonium hydrogen carbonate as precipitant, nonionic, anionic and cationic surfactant as dispersant, respectively.
TL;DR: A novel class of protein tyrosine kinase inhibitors, featuring the N-(2-oxo-1,2-dihydroquinolin-3-yl-methyl)-thiourea framework is designed and synthesized, providing a promising new template with potential antitumor activity.
Abstract: Design, synthesis and antitumor evaluation of a new series of N -substituted-thiourea derivatives
TL;DR: Both the docking simulations and QSAR analyses suggest that new potent dual inhibitors should share a structural feature with a moderately bulky group at R2 position and a rather negatively charged group around the position of the carbonyl group of DHDMBFs.
TL;DR: Investigation of the quantitative structure–activity relationship for 126 NA inhibitors with great structural diversities and wide range of bioactivities against influenza A virus shows clearly how steric, electrostatic, hydrophobicity, and individual fragments affect the potency of NA inhibitors.
Abstract: The recent wide spreading of the H5N1 avian influenza virus (AIV) in Asia, Europe and Africa and its ability to cause fatal infections in human has raised serious concerns about a pending global flu pandemic. Neuraminidase (NA) inhibitors are currently the only option for treatment or prophylaxis in humans infected with this strain. However, drugs currently on the market often meet with rapidly emerging resistant mutants and only have limited application as inadequate supply of synthetic material. To dig out helpful information for designing potent inhibitors with novel structures against the NA, we used automated docking, CoMFA, CoMSIA, and HQSAR methods to investigate the quantitative structure–activity relationship for 126 NA inhibitors (NIs) with great structural diversities and wide range of bioactivities against influenza A virus. Based on the binding conformations discovered via molecular docking into the crystal structure of NA, CoMFA and CoMSIA models were successfully built with the cross-validated q
2 of 0.813 and 0.771, respectively. HQSAR was also carried out as a complementary study in that HQSAR technique does not require 3D information of these compounds and could provide a detailed molecular fragment contribution to the inhibitory activity. These models also show clearly how steric, electrostatic, hydrophobicity, and individual fragments affect the potency of NA inhibitors. In addition, CoMFA and CoMSIA field distributions are found to be in well agreement with the structural characteristics of the corresponding binding sites. Therefore, the final 3D-QSAR models and the information of the inhibitor–enzyme interaction should be useful in developing novel potent NA inhibitors.
TL;DR: The use of nonionic surfactants help to avoid the precipitation of extra framework TiO2, decrease the crystal size of TS-1, increase the amount of Ti incorporated into framework and increase the surface area as discussed by the authors.
TL;DR: The results suggest that the 4-CPI-bound 2B4dH/H226Y crystal structure is an appropriate model for predicting enzyme catalysis and docking into three-dimensional models of selected mutants suggested a re-positioning of residues 363 and 477 to yield products.
TL;DR: In this paper, a variety of 2-substituted-4-nitroquinolines were treated with concentrated hydrochloric acid in ethanol at 70°C for 2-4h.
TL;DR: Aqueous polymer isocyanate (API), which has good adhesive properties at ambient temperature and excellent resistance to warm/boiling water, is widely used in the timber-processing industry as mentioned in this paper.
Abstract: Aqueous polymer isocyanate (API), which has good adhesive properties at ambient temperature and excellent resistance to warm/boiling water, and is friendly to the environment, is widely used in the timber-processing industry. To prepare high performance API, vinyl acetate homopolymer and copolymer emulsion were respectively cross-linked by three types of polymeric methylene diisocyanate (p-MDI). The potlife, curing time, bonding strength, and water resistance of API adhesives were tested with different cross-linkers and varying loadings (5–20%). Also the effect of polyvinyl alcohol (PVOH) content of aqueous vinyl latex on the performance of API was investigated. It was shown that the potlife and curing time of API were obviously influenced by the types of cross-linker and its loading. Correct loadings of p-MDI as crosslinker can remarkably improve the adhesive performance of aqueous polymer emulsion at ambient temperature. Excess cross-linker cannot maintain such an effect of strengthening and ma...
TL;DR: According to the alignment result, four highly conserved histidine residues in GDO from Klebsiella pneumoniae M5a1 and Ralstonia sp.
TL;DR: In this paper, an analytical expression for the energy release rate of adhesively-bonded three-point bending specimens has been derived from linear elastic fracture mechanics (LEFM) and energy release rates of nine API samples are evaluated.
Abstract: In order to investigate the fracture performance of aqueous polymer isocyanates (APIs), an analytical expression for the energy release rate of adhesively-bonded three-point bending specimens has been derived from linear elastic fracture mechanics (LEFM) and the energy release rates of nine API samples are evaluated. Experimental results show that a proper loading of polymeric diphenylmethane-4,4′-diisocyanate (p-MDI) as cross-linker can improve the resistance of aqueous polymer latex adhesive layer to cracking. Excess cross-linker cannot maintain such an effect of strengthening and may decrease considerably the energy release rate of API polymer. When the loading of polyisocyanate is less than the critical value, the polymer cross-linked by aqueous emulsified p-MDI has a higher resistance to cracking. In contrast, polymers modified by p-MDI blended with an organic solvent have much better performance.
18 Sep 2006
TL;DR: This paper compares the development detail in the Abacus environment with that in the manual deployment environment, and evaluates the deployment approach accordingly.
Abstract: This paper presents a language-based approach to service deployment. The language is called Abacus, which is a service-oriented programming language for grid applications. In Abacus, a service is abstracted as a basic language construct, and service deployment is expressed by a deployment statement. This approach allows an Abacus application to automatically deploy a service at runtime without any configuration information. This paper compares the development detail in the Abacus environment with that in the manual deployment environment, and evaluates our deployment approach accordingly. On the one hand, this approach frees maintainers from annoying deployment work at low-level, which helps to enhance the productivity in building grid applications. On the other hand, this approach allows services to be deployed according to the application logic, helping to improve the utilization and the management of various grid resources.