bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flavone–Nitrogen Heterocycle Conjugate Formation by 1,3‐Dipolar Cycloadditions
Authors: Sousa Regina M. S. , Pinto Diana C. G. A. , Silva Artur M. S. , Serra Vanda Vaz , Barros Ana I. R. N. A. , Faustino Maria A. F. , Neves Maria G. P. M. S. , Cavaleiro José A. S. 
Published: November 2011

AbstractAzomethine ylides generated in situ from the reaction of N‐[2‐, 3‐ and 4‐(chromon‐2‐yl)phenyl]glycine and paraformaldehyde can be trapped with dipolarophiles in 1,3‐dipolar cycloaddition reactions to yield flavone–nitrogen heterocycle dyads. These azomethine ylides proved to be reactive with electron‐poor dipolarophiles, affording the expected adducts. The use of microwave irradiation as an alternative source of heating has significant advantages and allows a reduction of both reaction time and temperature. The use of benzaldehydes as dipolarophiles afforded flavone–oxazolidine dyads, and the results indicate that electron‐withdrawing groups in the para position of the benzaldehyde increases the dipolarophile reactivity. This work was also extended to the use of meso‐tetrakis(pentafluorophenyl)porphyrin as a dipolarophile, allowing new flavone–dihydroporphyrin conjugates to be prepared.
Selective Determination of p‐Nitrophenol Based on Its Unique Voltammetric Behavior on Nanoporous Gold
Authors: Liu Zhaona , Zhang Huacheng , Ma Houyi , Hou Shifeng 
Published: November 2011

AbstractIn this paper, an unsupported nanoporous gold (us‐NPG) was applied as a novel electrochemical sensor material for the selective detection of p‐nitrophenol (p‐NP) among its isomers in acid solution based on the distinct cyclic voltammetric behavior. To ascertain the ascription of each peak in cyclic voltammograms (CVs) of three nitrophenol isomers (NPs) on the us‐NPG, contrast voltammetric studies of NPs were conducted at an ultrathin NPG film supported on glassy carbon substrate (NPG/GC) and a well‐defined Au(111) electrode, respectively. Effects of potential scan rate and rotation speed of the electrode on the redox reaction of NPs were investigated to further confirm the reaction mechanisms. Interestingly, unlike those obtained on NPG/GC and Au(111) electrodes, the CVs of both o‐nitrophenol (o‐NP) and m‐nitrophenol (m‐NP) on us‐NPG presented a new pair of redox waves separated very well from the redox waves of p‐NP, indicating an obviously different mechanism involved in the redox process. Based on the voltammetric behavior, trace level determination of p‐NP can be achieved on us‐NPG electrode in the presence of o‐NP and m‐NP. Thus, the fast electron transfer, high selectivity and good sensitivity make us‐NPG act as an ideal electrochemical sensor material in the selective determination of p‐NP in aqueous solutions.
Methods for Estimation of Generalized Diffusion Parameter at Membrane–Solution Interface
Authors: Egorov Vladimir V. , Zdrachek Elena A. , Nazarov Valentine A. 
Published: November 2011

AbstractTwo methods for direct experimental estimation of the generalized diffusion parameter q which is equal to the ratio of the diffusion coefficients in membrane and aqueous phase multiplied by the reversed ratio of the corresponding diffusion layer thicknesses have been described. The first method is based on the peculiarities of pH response of ion‐selective electrodes reversible to sufficiently lipophilic amine cations and the second one is based on the comparison of data obtained by separate solution and modified separate solution techniques used for selectivity coefficients determination. The values of the q parameter calculated by both methods conform to each other.
Semipreparative enantioseparation of methamidophos by HPLC-UV and preliminary in vitro study of butyrylcholinesterase inhibition
Authors: Emerick Guilherme L. , Oliveira Regina V. , Belaz Kátia Roberta A. , Gonçalves Monique , DeOliveira Georgino H. 
Published: November 2011

Abstract
Many chiral pesticides are introduced into the environment as racemates, although their pesticidal activity is usually the result of preferential reactivity of only one enantiomer, while the other enantiomer may have toxic effects against nontarget organisms. Methamidophos (O,S-dimethyl phosphoramidothioate), a chiral compound, is an insecticide widely used in agriculture in both developed and developing countries. However, this pesticide has a high toxicity not only to targeted insects but also to human and animals. In the present study, the enantiomers of methamidophos were enantiomerically separated by a semipreparative chiral liquid chromatography at the multimilligram scale on a polysaccharide-based chiral stationary phase and a preliminary evaluation of their in vitro inhibition of plasma butyrylcholinesterase (BChE) of hens was performed. In the present study, our first effort was to resolve the racemic mixture of methamidophos and to that end reversed-phase, normal-phase, and polar organic elution conditions were investigated in four different polysaccharide-based chiral phases. The best performance was achieved on a cellulose tris(3,5-dimethylphenylcarbamate) phase under normal phase. This chromatographic condition allowed the separation of 225 mg of methamidophos enantiomers with a high degree of chiral purity (&gt;98%) in a short analysis time. Significant differences were found between the concentration that causes 50% of enzyme inhibition (IC50) of the three isoforms of methamidophos. (−)-Methamidophos showed an IC50 approximately three times larger than the (+)-enantiomer for plasma BChE of hens. Environ. Toxicol. Chem. 2012;31:239–245. © 2011 SETAC
RNA‐directed epigenomic reprogramming—an emerging principle of a more targeted cancer therapy?
Authors: Moskalev Evgeny A. , Schubert Mario , Hoheisel Jörg D. 
Published: November 2011

AbstractEpigenetic aberrations are recognized as an early and common event during carcinogenesis. This provides a strong rationale for a therapeutic intervention at the epigenetic level. Current epigenetically active drugs, however, lack specificity for particular genomic loci. Better processes for a more targeted manipulation of the cancer epigenome are needed. One option could be the ability of long noncoding RNAs (lncRNAs) to recruit the chromatin modification complexes to particular genomic loci. In consequence, epigenetic variations would not be stochastic but controlled by a directed programme, through which specific groups of genes are regulated by promoter methylation and(or) histone marks, even if located on different chromosomes. lncRNAs are known to be functionally involved in cell fate specification and carcinogenesis. Depleting lncRNAs with oncogenic potential or replacing scarce molecules with tumor suppressor activity could therefore be employed for a specific reprogramming of the epigenome of cancer cells. Apart from the targeted manner and thus specificity, the mode of action by itself could be an advantage of lncRNA‐associated therapy. Similar to what happens naturally during cell fate decisions, the whole developmental programme of a cell or particular parts of it could be reset. In consideration of the early onset of epigenetic aberrations, such an approach could even be useful for cancer prevention. © 2011 Wiley Periodicals, Inc.
Determining the extent of lateral neck dissection necessary to establish regional disease control and avoid reoperation after previous total thyroidectomy and radioactive iodine for papillary thyroid cancer
Authors: Wu Gaosong , Fraser Shannon , Pai Sara I. , Farrag Tarik Y. , Ladenson Paul W. , Tufano Ralph P. 
Published: November 2011

AbstractBackgroundThe purpose of this study was to evaluate patients who underwent lateral neck dissection for fine‐needle aspiration (FNA)‐confirmed disease after total thyroidectomy and radioactive iodine (RAI) to determine the appropriate extent of resection necessary to avoid reoperation.MethodsThis study was conducted with a retrospective review of medical charts of 100 consecutive patients.ResultsSeventy‐seven percent of initial lateral neck dissection specimens and 64% of reoperative lateral neck dissection specimens had more than 1 nodal level of involvement. The sensitivity and negative predictive value of preoperative ultrasound to determine whether a specific nodal level was involved were: level 2: 54% and 66.2%; level 3: 47% and 49.4%; level 4: 60% and 55.4%; and level 5: 42% and 88.5%, respectively.ConclusionPatients undergoing lateral neck dissection after previous total thyroidectomy and RAI tend to have multiple involved nodes within multiple neck levels. Preoperative ultrasound is not sensitive enough to account for all of these involved nodes, therefore, a compartmental lateral neck dissection is recommended to minimize the risk of persistence and reoperation. © 2011 Wiley Periodicals, Inc. Head Neck, 2011
Local delivery of antimicrobial peptides using self‐organized TiO2 nanotube arrays for peri‐implant infections
Authors: Ma Menghan , Kazemzadeh‐Narbat Mehdi , Hui Yu , Lu Shanshan , Ding Chuanfan , Chen David D. Y. , Hancock Robert E. W. , Wang Rizhi 
Published: November 2011

AbstractPeri‐implant infections have been reported as one of the major complications that lead to the failure of orthopedic implants. An ideal solution to the peri‐implant infection is to locally deliver antimicrobial agents through the implant surface. The rising problem of infections caused by multiple antibiotic‐resistant bacteria makes traditional antibiotics less desirable for the prevention of peri‐implant infections. One of the promising alternatives is the family of antimicrobial peptides (AMPs). In this study, we report the local delivery of AMPs through the nanotubular structure processed on titanium surface. Self‐organized and vertically oriented TiO2 nanotubes, about 80 nm in diameter and 7 μm thick, were prepared by the anodization technique. HHC‐36 (KRWWKWWRR), one of the most potent broad‐spectrum AMPs, was loaded onto the TiO2 nanotubes via a simple vacuum‐assisted physical adsorption method. Antimicrobial activity testing against Gram‐positive bacterium, Staphylococcus aureus, demonstrated that this AMP‐loaded nanotubular surface could effectively kill the bacteria (˜99.9% killing) and reduce the total bacterial number adhered to the surface after 4 h of culture. In vitro AMP elution from the nanotubes was investigated using liquid chromatography‐mass spectrometry (LC‐MS). The release profiles strongly depended on the crystallinity of the TiO2 nanotubes. Anatase TiO2 nanotubes released significantly higher amounts of AMP than amorphous nanotubes during the initial burst release stage. Both followed almost the same slow release profile from 4 h up to 7 days. Despite the differences in release kinetics, no significant difference was observed between these two groups in bactericidal efficiency. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
In vitro and in vivo evaluations on osteogenesis and biodegradability of a β‐tricalcium phosphate coated magnesium alloy
Authors: Chai Hongwei , Guo Lei , Wang Xiantao , Gao Xiaoyu , Liu Kui , Fu Yuping , Guan Junlin , Tan Lili , Yang Ke 
Published: November 2011

AbstractMagnesium (Mg) alloys have been demonstrated to be potential orthopedic implants due to their biodegradability in vivo. To enhance its corrosion resistance and improve its osteogenesis, β‐tricalcium phosphate (β‐TCP) was coated on a Mg alloy (Mg‐3AI‐1Zn) by phosphating process. In vitro, the human osteosarcoma cell line (SaOS‐2) showed significantly good adherence and proliferation on the surface of the β‐TCP coated Mg alloy after 24‐h incubation. The growth factor bone morphogenetic protein 2 (BMP‐2) was highly expressed in SaOS‐2 cultured with the β‐TCP coated Mg alloy by Western blot analysis (p < 0.05). In vivo, the newborn bone at the implant/bone interface was formed at week 1 and matured at week 4 postimplantation. Villous tissue was found at the implant/bone interface at week 12 postimplantation. The contents of phosphorus and calcium on the surface of the β‐TCP coated Mg alloy were decreased at week 4 and week 12 postimplantation, respectively. Immunohistochemical analysis of the experiment results demonstrated that the β‐TCP coated Mg alloy implants provided a high BMP‐2 expression during the first 4 weeks postimplantation. Compared with the naked Mg alloy which was degraded for 33% in vivo, only 17% of the β‐TCP coated Mg alloy was degraded at week 12 postimplantation (p < 0.05). The in vitro cell tests showed that the β‐TCP coating provided the Mg alloy with a significantly better surface cytocompatibility, and in vivo results also confirmed that the β‐TCP coating exhibited greatly improved osteoconductivity and osteogenesis in the early 12 weeks postoperation period. Moreover, in vivo experiment demonstrated that the β‐TCP coating layer could slow down the degradation of the naked Mg alloy at the early stage of implantation. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Osteoderm histology of the Pampatheriidae (Cingulata, Xenarthra, Mammalia): Implications for systematics, osteoderm growth, and biomechanical adaptation
Authors: Wolf Dominik , Kalthoff Daniela C. , Sander P. Martin 
Published: November 2011

AbstractPampatheres are extinct, large‐bodied cingulates, which share morphological characters with both armadillos and glyptodonts but are considered to be more closely related to the latter. The osteoderm histology of six pampathere taxa was examined and compared to the histology of other cingulate osteoderms. This study investigates the development and functional adaptation of pampathere osteoderms as well as the phylogenetic relationships of the Pampatheriidae within the Cingulata. We found that pampathere osteoderms share a uniform histological organization based on a basic diploe‐like structure. After initial stages of intramembranous growth, metaplastic ossification, that is, the direct incorporation and mineralization of pre‐existing protein fibers, plays an important role in osteoderm development and provides information on various kinds of soft tissue otherwise not preserved. The latest stages of osteoderm growth are dominated by periosteal bone formation especially in the superficial cortex. Movable band osteoderms show regular arrangements of incorporated fibers that may increase the resistance of particularly weak areas against strain. The histological composition of pampathere osteoderms is plesiomorphic in its basic structure but shows a number of derived features. A unique array of Sharpey's fibers that are incorporated into the bone matrix at sutured osteoderm margins is interpreted as a synapomorphy of pampatheres. The arrangement of dermal fibers in the deep and superficial cortexes supports the close relationship between pampatheres and glyptodonts. J. Morphol., 2012. © 2011 Wiley Periodicals, Inc.
Reduction of molybdate to molybdenum blue by Klebsiella sp. strain hkeem
Authors: Lim H. K. , Syed M. A. , Shukor M. Y. 
Published: November 2011

AbstractA novel molybdate‐reducing bacterium, tentatively identified as Klebsiella sp. strain hkeem and based on partial 16s rDNA gene sequencing and phylogenetic analysis, has been isolated. Strain hkeem produced 3 times more molybdenum blue than Serratia sp. strain Dr.Y8; the most potent Mo‐reducing bacterium isolated to date. Molybdate was optimally reduced to molybdenum blue using 4.5 mM phosphate, 80 mM molybdate and using 1% (w/v) fructose as a carbon source. Molybdate reduction was optimum at 30 °C and at pH 7.3. The molybdenum blue produced from cellular reduction exhibited absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Inhibitors of electron transport system such as antimycin A, rotenone, sodium azide, and potassium cyanide did not inhibit the molybdenum‐reducing enzyme. Mercury, silver, and copper at 1 ppm inhibited molybdenum blue formation in whole cells of strain hkeem. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of inhibitory efficacy of short interfering RNAs targeting different genes on Measles virus replication
Authors: Shi Junyan , Wang Meilian , Wang Jian , Wang Si , Luo Enjie 
Published: November 2011

AbstractRNA interference (RNAi)‐based short interfering RNAs (siRNAs) targeting the viral genes and the host cellular genes have been used to suppress Measles virus (MV) replication in vitro. In order to select suitable target genes and highly effective target sites for developing effective RNAi‐mediated anti‐MV therapy, in this study, nine short hairpin RNA (shRNA) expression vectors, which expressed siRNAs targeting the host celluar Rab9 GTPase gene, the viral large protein (L) gene and nucleoprotein (N) gene, respectively, were constructed and used to compare their ability to inhibit MV replication in Vero‐E6 cells. The results showed that nine siRNAs targeting different genes exhibited different inhibitory efficacy on MV replication in vitro (about 23–94%), which could last at least 168 h post‐infection. Of the nine siRNAs, R2, L1 and N2 more effectively decreased MV replication by over 90%. Furthermore, inhibitory efficacy on MV replication were increased and reached almost 100% when cells were transfected with pR2, pL1 and pN2 together. These results emphasis the importance of selecting suitable siRNA target sites for developing siRNAs‐based drug therapy for MV, and demonstrate the potential of combination of siRNAs targeting different genes as a therapeutic approach to treat MV infection. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cloning and characterization of a phosphate transporter gene in Dunaliella salina
Authors: Li Shao‐He , Xia Bing‐Bing , Zhang Chi , Cao Jiao , Bai Lin‐Han 
Published: November 2011

AbstractThe full‐length cDNA of a Na+‐dependent Pi transport gene (DsSPT1) in Dunaliella salina was cloned by 3′ and 5′ Rapid Amplification of cDNA Ends (RACE), with an open reading frame (ORF) encoding 716 predicted amino acids, which exhibited 60.5% identity to that of Na+‐dependent Pi transport 1 (DvSPT1) from Dunaliella viridis. Hydrophobicity and secondary structure prediction revealed 11 conserved transmembrane domains similar to those found in DvSPT1 from D. viridis and PHO89 from Saccharomyces cerevisiae. The result of real‐time quantitative PCR showed that expression level of DsSPT1 was enhanced at first and reached its peak at 90 min after salt stress; however, D. salina cells rapidly absorbed extracellular inorganic phosphorus which was determined by Inductively Coupled Plasma Mass Spectrometry (ICP‐MS) during the first 5 min under salt stress. It suggested that D. salina on the absorption of inorganic phosphorus was regulated at DsSPTI posttranslational level. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A product formula for semigroups of Lipschitz operators associated with abstract quasilinear evolution equations
Authors: Tanaka Naoki 
Published: November 2011

AbstractThe notion of semigroups of Lipschitz operators associated with abstract quasilinear evolution equations is introduced and a product formula for such semigroups is established. The product formula obtained in the paper is applied to the solvability of the Cauchy problem for a first order quasilinear system through a finite difference scheme of the Lax‐Friedrichs type.
The challenge of urban policy
Authors: Glaeser Edward L. 
Published: November 2011

AbstractUrbanization almost invariably accompanies development, and the cities of India and China are experiencing spectacular increases in population. The concentration of millions of people in a small mass creates challenges for public policy, especially in the areas of basic infrastructure, public health, traffic congestion, and often law enforcement as well. In this essay, I discuss five core debates in urban policy, including the optimal degree of federalism, private versus public provision of urban services, optimal land use regulation, appropriate spatial policies, and the use of engineering and economics approaches to reducing the negative consequences of density. None of these debates are close to being resolved, but researchers have managed to generate a number of useful insights in these areas. © 2011 by the Association for Public Policy Analysis and Management.
Study on mechanical and thermal properties of composites of cis‐ and trans‐polyisoprene blends filled with polyaniline
Authors: Baboo Mahesh , Sharma Kananbala , Saxena N.S. 
Published: November 2011

AbstractIn this study, the effect of polyaniline (PANI) as filler has been investigated on the mechanical and thermal properties of blends of cis‐polyisoprene (CPI) and trans‐polyisoprene (TPI) by dynamic mechanical analyzer and transient plane source technique, respectively. The samples blend composites with different concentration of PANI have been prepared by solution casting method and characterized through X‐ray diffraction. Experimental results from mechanical and thermal measurements show that incorporation of PANI in CPI/TPI blends increases glass transition temperature, mechanical properties and thermal properties whereas decreases damping property. This increase in different properties is only upto a certain amount of PANI and over this amount an entirely apposite behavior is observed. This observed behavior of mechanical and thermal properties is explained on the basis of crystallinity and crosslink density. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Polarisation analysis of luminescence for the characterisation of defects in silicon wafer solar cells
Authors: Peloso Matthew P. , Lew Jen Sern , Chaturvedi Pooja , Hoex Bram , Aberle Armin G. 
Published: November 2011

ABSTRACTPhotoluminescence and electroluminescence imaging has progressed significantly in recent years and is now routinely used to extract spatially resolved characteristics of silicon wafer solar cells and other electronic devices. In this paper, we report on the expansion of the luminescence imaging technique by the application of spatially resolved polarisation analysis. Luminescence imaging of silicon wafer solar cells is extended to yield the partial polarisation of luminescence. It is hypothesised, and then shown experimentally, that certain defects in silicon wafer solar cells generate strongly polarised electroluminescence. In particular, extended crystalline defects in silicon wafers are shown to exhibit a partial polarisation of electroluminescence as high as 60%. The linear polarisation is found to be oriented to the dislocations in the multicrystalline silicon wafer solar cells. The luminescence polarisation effect is discussed in relation to internal charge anisotropy of defects in silicon wafer solar cells. These results may be used to advance the characterisation of solar cells, to understand the electrical properties of defects in silicon wafer solar cells, to study the formation of defects during crystal growth, or to probe the Bloch band anisotropy at regions of a high dislocation density. Copyright © 2011 John Wiley & Sons, Ltd.
Ein Plasmonenlineal vermisst Proteine
Authors: Giessen Harald 
Published: November 2011

AbstractDie Faltung von Proteinen ist einer der Schlüsselmechanismen zum Verständnis des Lebens. Seit Jahrzehnten versuchen Wissenschaftler, Struktur und Faltungsdynamik dieser Makromoleküle aufzuklären (Phys. Unserer Zeit 2006, 37 (2), 73; 2004, 35 (6), 274). Einer internationalen Forschergruppe mit Beteiligung der Universität Stuttgart ist es kürzlich gelungen, ein “Nanolineal” herzustellen, das hierbei wertvolle Dienste leisten kann.