bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular and Supermolecular Electronics
Authors: Roberts Gareth
Published: October 2009

Historical Review ofLangmuir‐Blodgett Films

The Chemistry and Preparation ofLangmuir Films

Langmuir‐Blodgett Film Deposition

Applications ofLangmuir‐Blodgett Films

Model System in Basic Research

Promising Applied Research Areas

Conclusions

Author's Acknowledgments

Editor's Acknowledgments
Photorefractive Keratectomy (
PRK
)
Authors:   Vision Rx, Inc.
Published: October 2009

PRK
Procedure
Space Microelectronics Technology
Authors:   Jet Propulsion Laboratory
Published: October 2009

Microdevices Laboratory

High‐Performance Computing

Microspacecraft

Management

Programs
Telephony (Telecommunications)
Authors: Hofacker Richard Q.
Published: October 2009

Early History of Telephony

Modern Telephony

Customer Premises Equipment (
CPE
)

Transmission Equipment

Switching Equipment

Global Telephone Networks
Tandem Affinity Purification of Protein Complexes in Mouse Embryonic Stem Cells Using In Vivo Biotinylation
Authors: Wang Jianlong , Cantor Alan B. , Orkin Stuart H.
Published: October 2009

Streptavidin affinity purification of protein complexes, in combination with in vivo biotinylation of critical transcription factors, has contributed to the analysis of the pluripotent state in mouse embryonic stem (ES) cells and made it possible to construct a protein‐protein interaction network.This has facilitated discovery of novel pluripotency factors and a better understanding of stem cell pluripotency. Here we describe detailed procedures for an in vivo biotinylation system setup in mouse ES cells, and affinity purification of multi‐protein complexes using in vivo biotinylation. In addition, we present a protocol employing SDS‐PAGE fractionation to reduce sample complexity prior to submission for mass spectrometry (MS) protein identification. Curr. Protoc. Stem Cell Biol. 11:1B.5.1‐1B.5.17. © 2009 by John Wiley & Sons, Inc.
Endothelial nitric oxide synthase and nitric oxide regulate endothelial tissue factor expression in vivo in the sickle transgenic mouse
Authors: Solovey Anna , Kollander Rahn , Chang Milbauer Liming , Abdulla Fuad , Chen Yingie , Kelm Robert J. , Hebbel Robert P.
Published: October 2009

Activation of the coagulation system is a characteristic feature of sickle cell anemia, which also includes clinical thrombosis. The sickle transgenic mouse abnormally expresses tissue factor (TF) on the pulmonary vein endothelium. Knowing that this aberrancy is stimulated by inflammation, we sought to determine whether nitric oxide (NO) contributes to regulation of endothelial TF expression in the sickle mouse model. We used the NY1DD sickle mouse, which exhibits a low‐TF to high‐TF phenotype switch on exposure to hypoxia/reoxygenation. Manipulations of NO biology, such as breathing NO or addition of arginine or L‐NAME (N‐nitro‐L‐arginine‐methyl‐ester) to the diet, caused significant modulations of TF expression. This was also seen in hBERK1 sickle mice, which have a different genetic background and already have high‐TF even at ambient air. Study of NY1DD animals bred to overexpress endothelial nitric oxide synthase (eNOS; eNOS‐Tg) or to have an eNOS knockout state (one eNOS−/− animal and several eNOS+/− animals) demonstrated that eNOS modulates endothelial TF expression in vivo by down‐regulating it. Thus, the biodeficiency of NO characteristic of patients with sickle cell anemia may heighten risk for activation of the coagulation system. Am. J. Hematol., 2010. © 2009 Wiley‐Liss, Inc.
Chitosan modified with a polydentate crosslinker for metal‐ion adsorption
Authors: Krishnapriya K. R. , Kandaswamy M.
Published: October 2009

The chemical modification on chitosan (CTS) was carried out by cross‐linking it with precursor compound 3,3′‐dimethoxy‐4,4′‐dihydroxy‐5,5′‐bis(N,N′‐ piperazine‐1‐yl methyl benzaldehyde), (PC) in order to improve the metal ion adsorption capacities and selectivity of the product. The resulting crosslinked chitosan derivative (CCTSL) was characterized by elemental analysis, Fourier transform infrared spectrum (FTIR), Differential Scanning calorimetry (DSC), Scanning Electron Microscopy (SEM) and powder X‐ray diffraction (XRD) studies. Adsorption experiments (pH dependency, kinetics, and equilibrium) of CCTSL towards various metal ions (Mn2+, Fe2+, Co2+, Cu2+, Ni2+, Cd2+ and Pb2+) were investigated. The adsorption was dependent on pH of the solution, with a maximum capacity between pH 6.5 and 8.5. The adsorption kinetics data were best fitted with pseudo second‐order model, which gave a correlation coefficient of 0.999. The adsorption process could be described with Langmuir isotherm (R = 0.999), which revealed that the maximum capacity for monolayer saturation was 79 mg Cu(II) per gram of CCTSL (1.24 mmol g−1). From the studies, we also infer that the order of metal adsorption capacities in mmol g−1 for the derivative is Cu2+ > Ni2+ > Co2+ ≥ Fe2+ ≥ Cd2+ ≥ Mn2+ ≥ Pb2+. Hence this material can be used to extract Cu2+ ions from industrial effluents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Reaching the depth of the Chinese hamster ovary cell transcriptome
Authors: Jacob Nitya M. , Kantardjieff Anne , Yusufi Faraaz Noor Khan , Retzel Ernest F. , Mulukutla Bhanu Chandra , Chuah Song Hui , Yap Miranda , Hu Wei‐Shou
Published: October 2009

The high‐throughput DNA sequencing Illumina Solexa GAII platform was employed to characterize the transcriptome of an antibody‐producing Chinese hamster ovary (CHO) cell line. More than 55 million sequencing reads were generated and mapped to an existing set of CHO unigenes derived from expressed sequence tags (ESTs), as well as several public sequence databases. A very significant fraction of sequencing reads has not been previously seen. The frequency with which fragments of a unigene were sequenced was taken as an estimate of the abundance level of the corresponding transcripts. A wide dynamic range of transcript abundance levels was observed, spanning six orders of magnitude. However, the distribution of coverage across transcript lengths was found to vary, from relatively uniform to highly variable. This observation suggests that more challenges are yet to be resolved before direct sequencing can be used as a true quantitative measure of transcript level and for differential gene expression analysis. With the depth that high‐throughput sequencing methods can reach, one can expect that the entire transcriptome of this industrially important organism will be decoded in the near future. Biotechnol. Bioeng. 2010;105: 1002–1009. © 2009 Wiley Periodicals, Inc.
Simultaneous saccharification and ethanol fermentation at high corn stover solids loading in a helical stirring bioreactor
Authors: Zhang Jian , Chu Deqiang , Huang Juan , Yu Zhanchun , Dai Gance , Bao Jie
Published: October 2009

The higher ethanol titer inevitably requires higher solids loading during the simultaneous enzymatic saccharification and fermentation (SSF) using lignocellulose as the feedstock. The mixing between the solid lignocellulose and the liquid enzyme is crucially important. In this study, a bioreactor with a novel helical impeller was designed and applied to the SSF operation of the steam explosion pretreated corn stover under different solids loadings and different enzyme dosages. The performances using the helical impeller and the common Rushton impeller were compared and analyzed by measuring rheological properties and the mixing energy consumption. The results showed that the new designed stirring system had better performances in the saccharification yield, ethanol titer, and energy cost than those of the Rushton impeller stirring. The mixing energy consumption under different solids loadings and enzyme dosages during SSF operation were analyzed and compared to the thermal energy in the ethanol produced. A balance for achieving the optimal energy cost between the increased mixing energy cost and the reduced distillation energy cost at the high solids loading should be made. The potentials of the new bioreactor were tested under various SSF conditions for obtaining optimal ethanol yield and titer. Biotechnol. Bioeng. 2010. 105: 718–728. © 2009 Wiley Periodicals, Inc.
Identification of genes encoding N‐glycan processing β‐N‐acetylglucosaminidases in Trichoplusia ni and Bombyx mori: Implications for glycoengineering of baculovirus expression systems
Authors: Geisler Christoph , Jarvis Donald L.
Published: October 2009

Glycoproteins produced by non‐engineered insects or insect cell lines characteristically bear truncated, paucimannose N‐glycans in place of the complex N‐glycans produced by mammalian cells. A key reason for this difference is the presence of a highly specific N‐glycan processing β‐N‐acetylglucosaminidase in insect, but not in mammalian systems. Thus, reducing or abolishing this enzyme could enhance the ability of glycoengineered insects or insect cell lines to produce complex N‐glycans. Of the three insect species routinely used for recombinant glycoprotein production, the processing β‐N‐acetylglucosaminidase gene has been isolated only from Spodoptera frugiperda. Thus, the purpose of this study was to isolate and characterize the genes encoding this important processing enzyme from the other two species, Bombyx mori and Trichoplusia ni. Bioinformatic analyses of putative processing β‐N‐acetylglucosaminidase genes isolated from these two species indicated that each encoded a product that was, indeed, more similar to processing β‐N‐acetylglucosaminidases than degradative or chitinolytic β‐N‐acetylglucosaminidases. In addition, over‐expression of each of these genes induced an enzyme activity with the substrate specificity characteristic of processing, but not degradative or chitinolytic enzymes. Together, these results demonstrated that the processing β‐N‐acetylglucosaminidase genes had been successfully isolated from Trichoplusia ni and Bombyx mori. The identification of these genes has the potential to facilitate further glycoengineering of baculovirus‐insect cell expression systems for the production of glycosylated proteins. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Lanthanide(III) Complexes of Tris(amide) PCTA Derivatives as Potential Bimodal Magnetic Resonance and Optical Imaging Agents
Authors: Rojas‐Quijano Federico A. , Benyó Enikő Tircsóné , Tircsó Gyula , Kálmán Ferenc K. , Baranyai Zsolt , Aime Silvio , Sherry A. Dean , Kovács Zoltán
Published: October 2009

Lanthanide complexes of two tris(amide) derivatives of PCTA were synthesized and characterized. The relaxometric and luminescence properties of their lanthanide complexes were investigated as bimodal magnetic resonance (MR) and optical imaging agents. Luminescence studies show that one of the TbIII complexes dimerizes in solution at low millimolar concentrations, whereas the other may have a higher than expected coordination number in solution. The corresponding GdIII complexes display unusually high T1 relaxivities and enhanced kinetic inertness compared to GdPCTA. These features suggest that these new chelates may be suitable for in vivo applications. The fast water‐exchange rates observed for these complexes make them unsuitable as paramagnetic chemical exchange saturation transfer (PARACEST) agents.
In Situ High‐Energy Synchrotron Radiation Study of Boehmite Formation, Growth, and Phase Transformation to Alumina in Sub‐ and Supercritical Water
Authors: Lock Nina , Bremholm Martin , Christensen Mogens , Almer Jonathan , Chen Yu‐Sheng , Iversen Bo B.
Published: October 2009

Boehmite (AlOOH) nanoparticles have been synthesized in subcritical (300 bar, 350 °C) and supercritical (300 bar, 400 °C) water. The formation and growth of AlOOH nanoparticles were studied in situ by small‐ and wide‐angle X‐ray scattering (SAXS and WAXS) using 80 keV synchrotron radiation. The SAXS/WAXS data were measured simultaneously with a time resolution greater than 10 s and revealed the initial nucleation of amorphous particles takes place within 10 s with subsequent crystallization after 30 s. No diffraction signals were observed from Al(OH)3 within the time resolution of the experiment, which shows that the dehydration step of the reaction is fast and the hydrolysis step rate‐determining. The sizes of the crystalline particles were determined as a function of time. The overall size evolution patterns are similar in sub‐ and supercritical water, but the growth is faster and the final particle size larger under supercritical conditions. After approximately 5 min, the rate of particle growth decreases in both sub‐ and supercritical water. Heating of the boehmite nanoparticle suspension allowed an in situ X‐ray investigation of the phase transformation of boehmite to aluminium oxide. Under the wet conditions used in this work, the transition starts at 530 °C and gives a two‐phase product of hydrated and non‐hydrated aluminium oxide.
Colorimetric Sensing of Adenosine Based on Aptamer Binding Inducing Gold Nanoparticle Aggregation
Authors: Liu Xueping , Zhou Zhenhua , Zhang Liangliang , Tan Zhongyang , Shen Guoli , Yu Ruqin
Published: October 2009

A simple and rapid colorimetric approach for the determination of adenosine has been developed via target inducing aptamer structure switching, thus leading to Au colloidal solution aggregation. In the absence of the analytes, the aptamer/gold nanoparticle (Au NP) solution remained well dispersed under a given high ionic strength condition in that the random‐coil aptamer was readily wrapped on the surface of the Au NPs, which resulted in the enhancement of the repulsive force between the nanoparticles due to the high negative charge density of DNA molecules. While in the presence of adenosine, target‐aptamer complexes were formed and the conformation of the aptamer was changed to a folded structure which disfavored its adsorption on the Au NP surface, thus leading to the reduction of the negative charge density on each Au NP and then the reduced degree of electrostatic repulsion between Au nanoparticles. As a result, the aggregation of the Au colloidal solution occurred. The changes of the absorption spectrum could be easily monitored by a UV‐Vis spectrophotometer. A linear correlation exists between the ratio of the absorbance of the system at 522 to 700 nm (A522 nm/A700 nm) and the concentration of adenosine between 100 nmol·L−1 and 10 µmol·L−1, with a detection limit of 51.5 nmol·L−1.
Preparation of Chiral 4,4′‐Biphenylene‐silica Nanoribbons
Authors: Li Haitao , Li Baozong , Chen Yuanli , Zhang Ming , Wang Sibing , Li Yi , Yang Yonggang
Published: October 2009

A sol‐gel transcription process was carried out using an anionic gelator 12K and TMAPS as the co‐structure‐directing agent, as well as 4,4′‐bis(triethoxysilyl)biphenyl as a hybrid silica source. It is interesting to find that the chirality of the organic self‐assemblies of 12K was successfully transferred to the 4,4′‐biphenylene‐silica nanoribbons which are potentially applied in chiral catalysis.
Theoretical Studies on the Structures, Thermodynamic Properties, Detonation Performance, and Pyrolysis Mechanisms for Six Dinitrate Esters
Authors: Li Miaomiao , Guo Xiaode , Li Fengsheng , Song Hongchang
Published: October 2009

Density functional theory (DFT) has been employed to study the geometric and electronic structures of six dinitrate esters including ethylene glycol dinitrate (EGDN), diethylene glycol dinitrate (Di‐EGDN), triethylene glycol dinitrate (Tri‐EGDN), tetraethylene glycol dinitrate (Tetra‐EGDN), pentaethylene glycol dinitrate (Penta‐EGDN) and hexaethylene glycol dinitrate (Hexa‐EGDN) at the B3LYP/6‐31G* level. Their IR spectra were obtained and assigned by vibrational analysis. Based on the frequencies scaled by 0.96 and the principle of statistic thermodynamics, the thermodynamic properties were evaluated, which were linearly related with the number of CH2CH2O groups as well as the temperature, obviously showing good group additivity. Detonation performances were evaluated by the Kamlet‐Jacobs equations based on the calculated densities and heats of formation. It was found that density, detonation velocity, detonation pressure decreased with the increase of the number of CH2CH2O groups. Thermal stability and the pyrolysis mechanism of the title compounds were investigated by calculating the bond dissociation energies (BDE) at the B3LYP/6‐31G* level. For the nitrate esters, the O‐NO2 bond is a trigger bond during a thermolysis initiation process.
Is Free Cyclooctatetraene Dianion an Aromatic System? A Quantum Chemistry Study
Authors: Cao Tingting , Ma Yipei , Yan Xiuhua , Cheng Jiagao , Luo Youhua , He Liming , Zhu Weiliang
Published: October 2009

To investigate whether free cyclooctatetraene dianion (COT2−) is aromatic, quantum chemistry methods were used to optimize its structure. Based on the optimized structures, the natural population analysis (NPA) charge, bond order, delocalization energy, nucleus‐independent chemical shift (NICS), and harmonic oscillator model of aromaticity (HOMA) values were computed by DFT‐B3LYP method with basis set 6‐311++G**, which shows that COT2− is not aromatic as it is not planar and has different bond lengths and bond orders, smallest delocalization energy and positive NICS values. To further confirm the finding, the changes of NICS and energy against ring distortion angle were scanned. The COT2− has positive NICS values all along the angle from 180° to 120° while other aromatic systems always have negative values. The energy scanning suggests that COT2− should have the weakest capability to maintain its planar structure. All the calculations strongly indicate that COT2− is not aromatic. This study also suggests that NICS scan might be a good approach to judge aromaticity.
Preparation of Polyelectrolyte Nanotubes by a Pressure‐filter‐template Technique Using Microporous Anodic Aluminum Oxide (AAO) as the Template
Authors: Meng Xiuxia , Yang Naitao , Tan Xiaoyao
Published: October 2009

Polyelectrolyte nanotubes of poly(sodium 4‐styrene‐sulfonate) (PSS) with cationic poly(diallyl dimethyl ammonium chloride) (PDDA) (PSS/PDDA) were fabricated by a pressure‐filter‐template technique using microporous anodic aluminum oxide (AAO) as the template. UV‐Vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD) and infrared spectroscopy (FT‐IR) were applied to characterize the obtained PSS/PDDA nanotubes. The results have shown that the PSS/PDDA nanotubes exhibit an amorphous structure and have the outer diameter of 200 nm and length of 25 µm respectively, which are in good agreement with the dimensions of the AAO template pores. The wall thickness of the nanotubes may be controlled by the number of the self‐assembled layers. Formation of the nanotubes follows a layer‐by‐layer (LbL) mechanism due to the electrostatic interactions, where the SO−3 groups of PSS are first adsorbed on the Lewis acid sites of AAO template pores.
Synthesis and Characterization of New Thiacalix[4]arenes Bearing Semicarbazide and Thiosemicarbazide Fragments at the Lower Rim
Authors: Omran Abdellah Omran
Published: October 2009

Starting from thiacalixarene tetraacetates, tetraacetohydrazides have been prepared and then used for the introduction of semicarbazide and thiosemicarbazide fragments into the lower rim by the reaction with phenyl isocyanate and phenyl isothiocyanate in dry toluene. The structures of the prepared compounds were investigated by FT‐IR, FAB‐MS, 1H NMR, and X‐ray crystallography, and their receptor properties were examined by liquid liquid extraction of dichromate anions.
Synthesis and Mesophase Behavior of Rod Like Phenylene Thiophene Based Polyhydroxy Amphiphiles
Authors: Luo Zhiwu , Yao Guini , Gao Zhulin , Cheng Xiaohong
Published: October 2009

Novel rod like phenylene thiophene based polyhydroxy amphiphiles, derivatives of gallic acid combining three hydrophilic 2,3‐dihydroxypropyloxy groups and one alkyl chain via central aromatic linking units, have been synthesized by using Ni(II), Pd(0) catalyzed coupling reaction as key steps. The mesophase behavior of such compounds was investigated by POM and DSC. Thereby the influence of the position of the alkyl chains on the mesophase behavior was discussed. All such compounds exhibit smectic A phases. As the alkyl chain moving from the terminal position to the lateral position near the central of the rigid core, the stability of the smectic A phase would be decreased.
Novel 5‐Methyl‐2‐[(un)substituted phenyl]‐4‐{4,5‐dihydro‐ 3‐[(un)substituted phenyl]‐5‐(1,2,3,4‐tetrahydroisoquinoline‐2‐yl)pyrazol‐1‐yl}‐oxazole Derivatives: Synthesis and Anticancer Activity
Authors: Liu Xinhua , Bai Linshan , Pan Chunxiu , Song Baoan , Zhu Hailiang
Published: October 2009

Eleven novel 5‐methyl‐2‐[(un)substituted phenyl]‐4‐{4,5‐dihydro‐3‐[(un)substituted phenyl]‐5‐(1,2,3,4‐tetrahydroisoquinoline‐2‐yl)pyrazol‐1‐yl}‐oxazole derivatives were synthesized and characterized by elemental analysis, ESI‐MS, 1H NMR and 13C NMR. All of the compounds have been screened for their antiproliferative activities against PC‐3 cell (human prostate cancer) and A431 cell (human epidermoid carcinoma cancer) lines in vitro. The results revealed that compounds 4g, 4j and 4k exhibited the strong inhibitory activities against the PC‐3 cell lines (with IC50 values of 2.8±0.11, 3.1±0.10 and 3.0±0.06 μg/mL, respectively).
Ga(OTf)3‐catalyzed Three‐component Mannich Reaction in Water Promoted by Ultrasound Irradiation
Authors: Zhang Guangliang , Huang Zhihao , Zou Jianping
Published: October 2009

Ga(OTf)3‐catalyzed three‐component Mannich reaction of aromatic aldehydes, aromatic amines and cycloketones in water promoted by ultrasound gave the corresponding β‐amino cycloketones in good to excellent yields and good anti selectivities.
Sorption of Pb(II) on Mg‐Fe Layered Double Hydroxide
Authors: Liang Xuefeng , Hou Wanguo , Xu Jie
Published: October 2009

Mg‐Fe layered double hydroxide (LDH) with a Mg/Fe molar ratio of 3:1 was synthesized by using a coprecipitation method and the sorption removal of Pb(II) by the LDH sample from Pb(NO3)2 solution was investigated. It was found that Mg‐Fe LDH showed a good sorption ability for Pb(II) from Pb(NO3)2 solution, indicating that the use of LDH as a promising inorganic sorbent for the removal of heavy metal ions is possible. The sorption kinetics and the sorption isotherm of Pb(II) on the LDH sample obeyed the pseudo‐second order kinetic model and Aranovich‐Donohue equation, respectively. The sorption mechanism of Pb(II) on the LDH may be attributed to the surface‐induced precipitation and the chemical binding adsorption, and the removal ability arising from the surface‐induced precipitation is much higher than that from the chemical binding adsorption.
Homo‐coupling of Aryl Iodide and Bromide Catalyzed by Immobilized Palladium with a Bidentate Nitrogen Ligand
Authors: Chen Xiaofang , Wang Lei
Published: October 2009

The immobilized palladium onto organic‐inorganic hybrid material, which contains bidentate nitrogen ligands, was a very effective catalyst for homo‐coupling of aryl iodide and bromide. The protocol involved the use of N,N‐dimethylacetamide as a solvent, and n‐tributylamine as a base. The reaction generated the corresponding homo‐coupling products in good to excellent yields at low catalyst loading (0.20 mol%). Furthermore, the silica‐supported palladium catalyst could be recovered and recycled by a simple filtration of the reaction solution and used for five consecutive trials without loss of its activity.
Synthesis of 1,4‐Benzothiazine Compounds Containing Isatin Hydrazone Moiety as Antimicrobial Agent
Authors: Sonawane Atul E. , Pawar Yogesh A. , Nagle Pramod S. , Mahulikar Pramod P. , More Dhananjay H.
Published: October 2009

A series of novel 3‐methyl‐N"‐(2‐oxoindolin‐3‐ylidene)‐4H‐benzo[b][1,4]thiazine‐2‐carbohyrazides have been synthesized and studied on their in vitro antimicrobial activity potency to establish structure‐activity relationship. Several compounds demonstrated promising antifungal and antibacterial activity; however, other tested compounds exhibited moderate to poor antimicrobial activity with respect to the reference drug against the test strains.
Determination of Copper and Zinc Ions by Flame‐AAS After Preconcentraction Using Sodium Dodecyl Sulfate Coated Alumina Modified with 3‐((1H‐Indol‐3‐yl)‐3,4,5‐trimethyl)‐1H‐indole
Authors: Ghaedi Mehrorang , Tavallali Hossein , Keshavarz M. , Niknam K.
Published: October 2009

A sensitive and simple method for the simultaneous preconcentration of trace amount Cu2+ and Zn2+ ions in some real samples has been established, which is based on the sorption of Cu2+ and Zn2+ on 3‐((1H‐indol‐3‐yl)‐3,4,5‐trimethyl)‐1H‐indole (ITMI) loaded on sodium dodecyl sulfate (SDS) coated alumina. The metal absorbed on the complexes was eluted using 3 mol/L nitric acid. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally higher than 95% with a low RSD. The method has been successfully applied to content evaluation of these metals in real samples.
Synthesis of Novel Bromo‐substituted Flavone‐like Troponoid Compounds from Oxidation Cyclization of 3‐Cinnamoyl‐5,7‐dibromotropolones Using I2/DMSO/H2SO4 System
Authors: Li Yang , Chang Mingqin , Sun Mingchun , Li Wei , Gao Wentao
Published: October 2009

A convenient method to obtain a series of bromo‐substituted flavone‐like troponoid compounds 6,8‐dibromo‐2‐arylcyclohepta[b]pyran‐4,9‐diones 3a–3s by oxidation cyclization of the readily available intermediates 3‐cinnamoyl‐5,7‐dibromotropolones 2a–2s using I2/DMSO/H2SO4 system was realized. Compounds 2a–2s were obtained from the aldol reaction of 3‐acetyl‐5,7‐dibromotropolone 1 with various benzaldehydes. Compounds 2a–2s and 3a–3s are novel and their structures were supported by IR, 1H NMR, MS and elemental analyses.
Homology Modeling of Cyt2Ca1 of Bacillus thuringiensis and Its Molecular Docking with Inositol Monophosphate
Authors: Zhao Xinming , Xia Liqiu , Ding Xuezhi , Yu Ziquan , LÜ Yuan , Tao Wenna
Published: October 2009

Cyt2Ca1 is an insecticidal crystal protein produced by Bacillus thuringiensis ET29 during its stationary phase, and this δ‐endotoxin demonstrates remarkable insecticidal activity against not only insects of the order Coleoptera, but also against fleas, and in particular the larvae of the cat flea, Ctenocephalides felis. The first theoretical model of the three‐dimensional structure of Cyt2Ca1 was predicted and compared with Cyt2Aa, which is lethal to insect larvae. The three‐dimensional structure of the Cyt2Ca1 was obtained by homology modeling on the structures of the Cyt2Aa protein. The deduced model resembles previously reported Cyt2Aa toxin. A binding mode of inositol monophosphate as a polar head group of the putative membrane phospholipid ligand to Cyt2Ca1 was presented using molecular docking. The residues of Leu9, Glu21, Tyr23 and Gln110 of the Cyt2Ca1 toxin are responsible for the interactions with inositol monophosphate via eight hydrogen bonds. Those residues could be important for receptor recognition. This binding simulation will be helpful for the design of mutagenesis experiments aimed at the improvement of toxicity, and lead to a deep understanding of the mechanism of action of Cyt toxins.
Synthesis and Photosensitive Properties of Poly(aryl imino) Containing Azobenzene Group (PAI‐A)
Authors: Chen Xiaoquan , Chang Guanjun
Published: October 2009

Using 4,4′‐dibromobenzophenone and 4,4′‐diaminoazobenzene as monomers, poly(aryl imino) containing azobenzene unit (PAI‐A) was synthesized via palladium‐catalyzed amination, and structurally characterized by means of FT‐IR, 1H NMR spectra and elemental analysis, the results of which show an agreement with the proposed structure. The UV absorption spectra were tested under different conditions. Additionally, differential scanning calorimetry (DSC) and thermogravimetric (TG) measurements show that PAI‐A possesses high glass transition temperature (Tg>176°C) and good thermal stability with high decomposition temperatures in nitrogen atmosphere (TD>410°C).
Crystal Structure of β‐Cyclodextrin‐Felbinac Inclusion Complex
Authors: Wang Enju , Chen Guangying , Liu Hong
Published: October 2009

The crystal structure of the inclusion complex of β‐cyclodextrin (β‐CD) synthesized with felbinac (4‐biphenylacetic acid) was determined by single crystal X‐ray diffraction at 150 K. The complex contains two β‐CDs, two felbinac molecules, twenty‐two water molecules in the asymmetric unit, and could be formulated as (C42H70O35)2·(C14H12O2)2·22(H2O). In the crystal lattice, the two β‐CD moieties form a head‐to‐head dimer jointed through hydrogen bonds, and the felbinacs that interact by face‐to‐face Π‐Π stacking are included in the β‐CD dimer cavity with their carboxyl groups protruding out from cavity opening. In crystals the dimer units of β‐CD are stacked in an intermediate type (IM) that consists of closely packed β‐CD dimer layers.
Thermodynamics of Carbon Dioxide Adsorption on the Protonic Zeolite H‐ZSM‐5
Authors: Armandi Marco , Garrone Edoardo , Areán Carlos O. , Bonelli Barbara
Published: October 2009

Adsorption of carbon dioxide on H‐ZSM‐5 zeolite (Si:Al=11.5:1) was studied by means of variable‐temperature FT‐IR spectroscopy, in the temperature range of 310–365 K. The adsorbed CO2 molecules interact with the zeolite Brønsted‐acid OH groups bringing about a characteristic red‐shift of the OH stretching band from 3610 cm−1 to 3480 cm−1. Simultaneously, the ν3 mode of adsorbed CO2 is observed at 2345 cm−1. From the variation of integrated intensity of the IR absorption bands at both 3610 and 2345 cm−1, upon changing temperature (and CO2 equilibrium pressure), the standard adsorption enthalpy of CO2 on H‐ZSM‐5 is ΔH0=−31.2(±1) kJ mol−1 and the corresponding entropy change is ΔS0=−140(±10) J mol−1 K−1. These results are discussed in the context of available data for carbon dioxide adsorption on other protonic, and also alkali‐metal exchanged, zeolites.
Rational Design of Ag/TiO2 Nanosystems by a Combined RF‐Sputtering/Sol‐Gel Approach
Authors: Armelao Lidia , Barreca Davide , Bottaro Gregorio , Gasparotto Alberto , Maccato Chiara , Tondello Eugenio , Lebedev Oleg I. , Turner Stuart , Van Tendeloo Gustaaf , Sada Cinzia , Štangar Urška Lavrenčič
Published: October 2009

The present work is devoted to the preparation of Ag/TiO2 nanosystems by an original synthetic strategy, based on the radio‐frequency (RF) sputtering of silver particles on titania‐based xerogels prepared by the sol–gel (SG) route. This approach takes advantage of the synergy between the microporous xerogel structure and the infiltration power characterizing RF‐sputtering, whose combination enables the obtainment of a tailored dispersion of Ag‐containing particles into the titania matrix. In addition, the system′s chemico‐physical features can be tuned further through proper ex situ thermal treatments in air at 400 and 600 °C. The synthesized composites are extensively characterized by the joint use of complementary techniques, that is, X‐ray photoelectron and X‐ray excited Auger electron spectroscopies (XPS, XE‐AES), secondary ion mass spectrometry (SIMS), glancing incidence X‐ray diffraction (GIXRD), field emission scanning electron microscopy (FE–SEM), transmission electron microscopy (TEM), electron diffraction (ED), high‐angle annular dark field scanning TEM (HAADF–STEM), energy‐filtered TEM (EF–TEM) and optical absorption spectroscopy. Finally, the photocatalytic performances of selected samples in the decomposition of the azo‐dye Plasmocorinth B are preliminarily investigated. The obtained results highlight the possibility of tailoring the system characteristics over a broad range, directly influencing their eventual functional properties.
Preparation and characterization of monodispersed PbSe nanocubes
Authors: Wang Xinjun , Li Ke , Dong Yutao , Jiang Kai
Published: October 2009

Monodispersed PbSe nanocubes were synthesized through a simple hydrothermal method by using Pb2+‐EDTA complex and Na2SeSO3. Composition and morphology of the samples were characterized by means of XRD, TEM and SEM. The gradually releasing of Pb2+ from Pb2+‐EDTA complex, and the adopting of PVP can adjust the growth rate in <100> and <111> directions of PbSe. Both Pb2+‐EDTA complex and PVP played important roles in the crystal growth of the monodispersed PbSe nanocubes. In addition, UV‐vis and photoluminescence properties were characterized. Eg of the PbSe nanocubes is 1.5 eV approximately, which is much larger than that of bulk PbSe. Under PL excitation at 406 nm, a red emission peak at 696 nm is observed, showing that the synthesized PbSe is luminescent nanomaterials. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Robust marking of photoreceptor cells and pinealocytes with several reporters under control of the Crx gene
Authors: Samson Maria , Emerson Mark M. , Cepko Constance L.
Published: October 2009

Crx is a member of the Otx family of homeobox genes with expression restricted to vertebrate retinal photoreceptor and bipolar cells as well as the pinealocytes of the pineal organ. To facilitate the visualization of Crx‐expressing cells, we generated transgenic mice expressing several reporters under the control of the Crx regulatory sequences present within a bacterial artificial chromosome (BAC). These mice expand the transgenic mouse collection, which uses photoreceptor regulatory elements for reporter gene expression by providing a broader repertoire of reporter genes. In addition, because Crx is expressed very soon after a cell fated to be a photoreceptor cell becomes postmitotic, they provide a means for early identification of immature photoreceptor cells. Developmental Dynamics 238:3218–3225, 2009. © 2009 Wiley‐Liss, Inc.
The evolution of gnathostome development: Insight from chondrichthyan embryology
Authors: Gillis J. Andrew , Shubin Neil H.
Published: October 2009

Chondrichthyans (cartilaginous fishes) represent one of the two lineages of gnathostomes, the other being the osteicthyans (bony fishes). Classical studies on chondrichthyan embryology have strongly impacted our views of vertebrate body plan evolution, while recent studies highlight oviparous chondrichthyans as emerging vertebrate model systems that are amenable to experimental embryological manipulation. Here, we review three particular areas of interest in the field of chondrichthyan developmental biology—gastrulation, neural development, and appendage patterning—and we discuss recentfindings within a broader chondrichthyan‐osteichthyan comparative framework. In some cases, comparative studies of chondrichthyan and osteichthyan development reveal conserved patterns of gene expression in common developmental contexts. Studies of chondrichthyan gastrulation reveal conserved patterns of developmental gene expression, despite highly divergent modes of mesendoderm internalization, while molecular characterization of chondrichthyan neurogenic placodes indicates a conservation of placode transcription factor expression across gnathostome phylogeny. In other cases, comparative studies of chondrichthyan and osteichthyan development yield evidence of shared patterning mechanisms functioning in different developmental contexts. This is exemplified by studies on the development of chondrichthyan appendages—paired fins, median fins, and gill rays. These have demonstrated that a retinoic acid‐responsive Shh‐expressing signaling center functions to pattern the endoskeleton of gnathostome paired fins and chondrichthyan gill rays, while expression patterns of Tbx18 and HoxD family members are shared by gnathostome paired fins and chondrichthyan median fins. These findings fuel novel hypotheses of developmental genetic homology, and demonstrate how comparative studies of gnathostome development can provide insight into the evolutionary processes that underlie morphological diversity. genesis 47:825–841, 2009. © 2009 Wiley‐Liss, Inc.
Textpresso site‐specific recombinases: A text‐mining server for the recombinase literature including Cre mice and conditional alleles
Authors: Urbanski William M. , Condie Brian G.
Published: October 2009

Textpresso Site Specific Recombinases (http://ssrc.genetics.uga.edu/) is a text‐mining web server for searching a database of more than 9,000 full‐text publications. The papers and abstracts in this database represent a wide range of topics related to site‐specific recombinase (SSR) research tools. Included in the database are most of the papers that report the characterization or use of mouse strains that express Cre recombinase as well as papers that describe or analyze mouse lines that carry conditional (floxed) alleles or SSR‐activated transgenes/knockins. The database also includes reports describing SSR‐based cloning methods such as the Gateway or the Creator systems, papers reporting the development or use of SSR‐based tools in systems such as Drosophila, bacteria, parasites, stem cells, yeast, plants, zebrafish, and Xenopus as well as publications that describe the biochemistry, genetics, or molecular structure of the SSRs themselves. Textpresso Site Specific Recombinases is the only comprehensive text‐mining resource available for the literature describing the biology and technical applications of SSRs. genesis 47:842–846, 2009. © 2009 Wiley‐Liss, Inc.
Apoptosis of glomerular mesangial cells induced by sublytic C5b‐9 complexes in rats with Thy‐1 nephritis is dependent on Gadd45γ upregulation
Authors: Qiu Wen , Che Nan , Feng Xuefeng , Xia Mei , Wang Hui , Zhao Dan , Wang Yingwei
Published: October 2009

The complement C5b‐9 complexes can result in cell apoptosis, but the mechanism of sublytic C5b‐9‐mediated glomerular mesangial cell (GMC) apoptosis in Thy‐1 nephritis (Thy‐1N) remains largely unclear. The Gadd45 gene is involved in the cellular response to DNA damage and can promote cell apoptosis. In this study, both Gadd45γ expression patterns and pathologic changes of renal tissue were examined in rat Thy‐1N. Both Gadd45γ expression and GMC apoptosis were significantly decreased in Thy‐1N rats upon the depletion of complement with cobra venom factor. Our in vitro studies showed that Gadd45γ over‐expression increased sublytic C5b‐9‐induced GMC apoptosis, while Gadd45γ gene knockdown by siRNA greatly reduced GMC apoptosis. Moreover, Gadd45γ gene silencing in vivo markedly inhibited the pathologic changes in the renal tissue of Thy‐1N rats. These data suggest that Gadd45γ gene expression is involved in regulating GMC apoptosis mediated by sublytic C5b‐9 in Thy‐1N.
Synthesis and Physical Chemistry of s‐Tetrazines: Which Ones are Fluorescent and Why?
Authors: Gong Yong‐Hua , Miomandre Fabien , Méallet‐Renault Rachel , Badré Sophie , Galmiche Laurent , Tang Jie , Audebert Pierre , Clavier Gilles
Published: October 2009

New fluorescent tetrazines have been prepared and their electrochemistry and fluorescence efficiency evaluated. The occurrence of fluorescence as well as the wavelength were found to be strongly dependent on the substituents, which have to be electronegative heteroatoms. This has been rationalized through a computational study that showed that the crucial factor is the nature of the HOMO, which determines the existence or not of fluorescence. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Neural correlates of the spacing effect in explicit verbal semantic encoding support the deficient‐processing theory
Authors: Callan Daniel E. , Schweighofer Nicolas
Published: October 2009

Spaced presentations of to‐be‐learned items during encoding leads to superior long‐term retention over massed presentations. Despite over a century of research, the psychological and neural basis of this spacing effect however is still under investigation. To test the hypotheses that the spacing effect results either from reduction in encoding‐related verbal maintenance rehearsal in massed relative to spaced presentations (deficient processing hypothesis) or from greater encoding‐related elaborative rehearsal of relational information in spaced relative to massed presentations (encoding variability hypothesis), we designed a vocabulary learning experiment in which subjects encoded paired‐associates, each composed of a known word paired with a novel word, in both spaced and massed conditions during functional magnetic resonance imaging. As expected, recall performance in delayed cued‐recall tests was significantly better for spaced over massed conditions. Analysis of brain activity during encoding revealed that the left frontal operculum, known to be involved in encoding via verbal maintenance rehearsal, was associated with greater performance‐related increased activity in the spaced relative to massed condition. Consistent with the deficient processing hypothesis, a significant decrease in activity with subsequent episodes of presentation was found in the frontal operculum for the massed but not the spaced condition. Our results suggest that the spacing effect is mediated by activity in the frontal operculum, presumably by encoding‐related increased verbal maintenance rehearsal, which facilitates binding of phonological and word level verbal information for transfer into long‐term memory. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
The neural origin of the priming distance effect: Distance‐dependent recovery of parietal activation using symbolic magnitudes
Authors: Notebaert Karolien , Pesenti Mauro , Reynvoet Bert
Published: October 2009

Numerical magnitudes are known to be processed in areas around the intraparietal sulci of the brain. We used an fMRI‐adaptation paradigm to investigate how they are actually coded at the neural level. In a number identification task, we manipulated the numerical distance between prime and target numbers (same, close, and far pairs) and their symbolic notation (Arabic and verbal numerals). We show that bilateral parietal activations present a distance‐dependent recovery of activation positively correlated with the distance between primes and targets: the larger the prime‐target distance, the higher the recovery of activation. Importantly, this effect is only present for trials where an Arabic numeral precedes a verbal numeral and not the reverse. Together, these findings reveal the neural origin of the behavioral priming distance effect and demonstrate that the relative importance of the semantic and nonsemantic pathways in a dual‐route model of number processing is modulated by symbolic notation. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Glycogen synthase kinases‐3β controls differentiation of malignant glioma cells
Authors: Li Yan , Lu Huimin , Huang Yijun , Xiao Ru , Cai Xiaofeng , He Songmin , Yan Guangmei
Published: October 2009

Malignant gliomas persist as a major disease of morbidity and mortality in adult. Differentiation therapy has emerged as a promising candidate modality. However, the mechanism related is unknown. Here, we show that glycogen synthase kinase‐3β (GSK‐3β) is highly expressed and activated during the cholera toxin‐induced differentiation in sensitive C6 and U87‐MG malignant glioma cells, whereas the GSK‐3α activity remains stable. GSK‐3β inhibitors or small interfering RNA suppress the induced‐differentiation in sensitive C6 cells. Conversely, overexpression of a constitutively active form of human GSK‐3β (pcDNA3‐GSK‐3β‐S9A) mutant in resistant U251 glioma cells restores their differentiation capabilities. In addition, GSK‐3β triggers cyclin D1 nuclear export and subsequent degradation, which is necessary for differentiation in C6 and U251 glioma cells. Analysis of human glioma tissues further revealed overexpression of active GSK‐3β. These findings suggest that GSK‐3β is a differentiation fate determinant, and shed new lights on the mechanism by which GSK‐3β regulates cyclin D1 degradation and cellular differentiation in gliomas.
Averaging forecasts from VARs with uncertain instabilities
Authors: Clark Todd E. , McCracken Michael W.
Published: October 2009

Recent work suggests VAR models of output, inflation, and interest rates may be prone to instabilities. In the face of such instabilities, a variety of estimation or forecasting methods might be used to improve the accuracy of forecasts from a VAR. The uncertainty inherent in any single representation of instability could mean that combining forecasts from a range of approaches will improve forecast accuracy. Focusing on models of US output, prices, and interest rates, this paper examines the effectiveness of combining various models of instability in improving VAR forecasts made with real‐time data. Copyright © 2009 John Wiley & Sons, Ltd.
Barrier heights for H‐atom abstraction by HȮ2 from n‐butanol—A simple yet exacting test for model chemistries?
Authors: Black Gráinne , Simmie John M.
Published: October 2009

The barrier heights involved in the abstraction of a hydrogen atom from n‐butanol by the hydroperoxyl radical have been computed with both compound (CBS‐QB3, CBS‐APNO, G3) and coupled cluster methods. In particular, the benchmark computations CCSD(T)/cc‐pVTZ//MP2/6‐311G(d,p) were used to determine that the barrier heights increase in the order α <γ < β < δ < OH. Two prereaction hydrogen‐bonded complexes are formed, one of which connects the TGt conformer of n‐butanol to the α and β transition states and the other connects to the γ and OH channels from the TGg conformer. Four postreaction complexes were also found which link the transition states to the products, hydrogen peroxide + C4H9O radical. Abstraction from the terminal δ carbon atom does not involve either a pre or postreaction complex. A number of DFT functionals—B3LYP, BMK, MPWB1K, BB1K, MPW1K, and M05‐2X—were tested to see whether the correct ranking could be obtained with computationally less expensive methods. Only the later functional predicts the correct order but requires a basis set of 6‐311++G(df,pd) to achieve this. However, the absolute values obtained do not agree that well with the benchmarks; the composite G3 method predicts the correct order and comes closest (≤ 2 kJ, mol −1) in absolute numerical terms for H‐abstraction from carbon. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Ab initio prediction of the structure and vibration‐rotation spectroscopic properties of Na2OH and K2OH
Authors: Gertych Artur , Koput Jacek
Published: October 2009

The equilibrium structures and potential energy surfaces of the Na2OH and K2OH radicals and the corresponding cations in their electronic ground states have been determined from accurate ab initio calculations. The vibration‐rotation energy levels and spectroscopic constants of various isotopic species were calculated by a perturbational approach. The predicted spectroscopic constants may serve as a useful guide for detecting these species by vibration‐rotation spectroscopy and for assigning their spectra. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Cigarettes labeled with [11C]nicotine: formulation and administration for PET inhalation
Authors: Apana S. M. , Berridge M. S.
Published: October 2009

The ultimate goal of this work was to relate nicotine kinetics in the brain after cigarette smoking to a feature of sensitization in drug addiction. To do this required a positron emission tomography study to measure the regional cerebral biodistribution kinetics of cigarette‐smoked nicotine. This in turn required a cigarette formulated with carbon‐11 labeled nicotine suitable for administration by single bolus inhalation. Here we report the development and validation of cigarettes formulated with [11C]nicotine that were successfully used for single bolus administration by smoking. We also report measurements of nicotine delivery from smoked cigarettes. Copyright © 2009 John Wiley & Sons, Ltd.