bluuebunny/crossref_metadata_2025_split huggingface dataset:
Luminol–silver nitrate chemiluminescence enhancement induced by cobalt ferrite nanoparticles
Authors: Shi Wenbing , Wang Hui , Huang Yuming 
Published: March 2011

ABSTRACTCoFe2O4 nanoparticles (NPs) could stimulate the weak chemiluminescence (CL) system of luminol and AgNO3, resulting in a strong CL emission. The UV–visible spectra, X‐ray photoelectron spectra and TEM images of the investigated system revealed that AgNO3 was reduced by luminol to Ag in the presence of CoFe2O4 NPs and the formed Ag covered the surface of CoFe2O4 NPs, resulting in CoFe2O4–Ag core–shell nanoparticles. Investigation of the CL reaction kinetics demonstrated that the reaction among luminol, AgNO3 and CoFe2O4 NPs was fast at the beginning and slowed down later. The CL spectra of the luminol − AgNO3 − CoFe2O4 NPs system indicated that the luminophor was still an electronically excited 3‐aminophthalate anion. A CL mechanism has been postulated. When the CoFe2O4 NPs were injected into the mixture of luminol and AgNO3, they catalyzed the reduction of AgNO3 by luminol to produce luminol radicals and Ag, which immediately covered the CoFe2O4 NPs to form CoFe2O4–Ag core–shell nanoparticles, and the luminol radicals reacted with the dissolved oxygen, leading to a strong CL emission. With the continuous deposition of Ag on the surface of CoFe2O4 NPs, the catalytic activity of the core–shell nanoparticles was inhibited and a decrease in CL intensity was observed and also a slow growth of shell on the nanoparticles. Copyright © 2011 John Wiley & Sons, Ltd.
Electrochemiluminescence of tris(2,2′‐bipyridyl)ruthenium and its applications in bioanalysis: a review
Authors: Wei Hui , Wang Erkang 
Published: March 2011

ABSTRACTElectrochemiluminescence (ECL) of tris(2,2’‐bipyridyl)ruthenium(II) [Ru(bpy)32+] is an active research area and includes the synthesis of ECL‐active materials, mechanistic studies and broad applications. Extensive research has been focused on this area, due to its scientific and practical importance. In this mini‐review we focus on the bio‐related applications of ECL. After a brief introduction to Ru(bpy)32+ ECL and its mechanisms, its application in constructing an effective bioassay is discussed in detail. Three types of ECL assay are covered: DNA, immunoassay and functional nucleic acid sensors. Finally, future directions for these assays are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Investigating rhodamine B‐labeled peptoids: Scopes and limitations of its applications
Authors: Birtalan Esther , Rudat Birgit , Kölmel Dominik K. , Fritz Daniel , Vollrath Sidonie B. L. , Schepers Ute , Bräse Stefan 
Published: March 2011

AbstractThe fluorophore rhodamine B is often used in biological assays. It is inexpensive, robust under a variety of reaction conditions, can be covalently linked to bioactive molecules, and has suitable spectral properties in terms of absorption and fluorescence wavelength. Nonetheless, there are some drawbacks: it can readily form a spirolactam compound, which is nonfluorescent, and therefore may not be the dye of choice for all fluorescence microscopy applications. Herein this spirolactam formation was observed by purifying such a labeled peptoid with high performance liquid chromatography (HPLC) and monitored in detail by making a series of analytical HPLC runs over time. Additionally, a small library of eight peptoids with rhodamine B as label was synthesized. Analysis of the absorption properties of these molecules demonstrated that the problem of fluorescence loss can be overcome by coupling secondary amines with rhodamine B. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96: 694–701, 2011.
Development and validation of a liquid chromatography method with electrospray ionization tandem mass spectrometry for the determination of brotizolam residues in beef and commercial whole milk
Authors: Cho Hee‐Jung , Jo Kyul , Yi Hee , Cho Soo Min , Abd El‐Aty A. M. , Kim Min Kyung , Han Sang Beom , Oh Jae Ho , Kwon Chan Hyeok , Shim Jae‐Han , Shin Ho‐Chul 
Published: March 2011

AbstractIn this work, a liquid chromatography–tandem mass spectrometric detection technique was developed and validated for the determination of brotizolam residues in beef muscle and commercial whole milk. This procedure involves the extraction of the analyte from the samples via liquid–solid extraction, and caffeine was used as an internal standard. The analyte was successfully separated on an XTerra‐C18 column, with a mobile phase composed of 0.01% formic acid in acetonitrile and 1 mm ammonium formate–0.01% formic acid in water. The one‐step extraction method evidenced good selectivity, precision (RSD = 9.87–26.47%), and the recovery of the extractable analyte was 92.61–115.98% in the matrices. The limits of quantification ranged between 0.4 and 0.5 µg/kg. The developed method is simple since it requires no additional cleanup procedures. Copyright © 2011 John Wiley & Sons, Ltd.
Anatomical and dynamic volume spline model applied to facial soft tissue
Authors: Ulusoy Ilkay , Akagunduz Erdem , Yirci Murat 
Published: March 2011

ABSTRACTBiomechanical modeling of soft tissue is a complex problem for achieving realistic surgical simulations, surgical planning, and scientific analysis. In the literature, three categories of biomechanical models: spline based models, spring models, and finite element models (FEMs) are mainly used for dealing with this problem. Among these, spline based models offer relatively fast and realistic soft tissue simulations by utilizing both the spring and FEMs. In this paper, a new dynamic volume spline model for human face skin is proposed and the performance of our model is discussed by estimating the results of facial surgery of three different patients. Face models of the patients are obtained from 3D CT/MR scans by segmenting the skull, muscle, and skin layers. In these face models, the skull and the muscle layers are considered as the rigid boundary for the skin layer and the skin layer is modeled by our dynamic volume spline. The control points of the dynamic volume spline are localized masses with viscoelastic material properties (stiffness, damping, and mass). These parameters are computed from the skin material properties that were published in the literature. Once the face models are generated, facial surgery plannings are simulated. Infact, the pre‐surgery face models are modified according to the surgical plans and the estimated post‐surgery face models are compared with the actual post‐surgery face models. Moreover, in order to discuss the performance of our dynamic volume spline model, the same analyses are performed on the post‐surgery estimations of a conventional tool. Copyright © 2011 John Wiley & Sons, Ltd.
New Pregnane Glycosides from Brucea javanica and Their Antifeedant Activity
Authors: Chen Yue‐Yuan , Pan Qiao‐Dan , Li Dian‐Peng , Liu Jin‐Lei , Wen Yong‐Xin , Huang Yong‐Lin , Lu Feng‐Lai 
Published: March 2011

AbstractThree new pregnane glycosides, 3‐O‐β‐D‐glucopyranosyl‐(1→2)‐α‐L‐arabinopyranosyl‐(20R)‐pregn‐5‐ene‐3β,20‐diol (1), 3‐O‐α‐L‐arabinopyranosyl‐(20R)‐pregn‐5‐ene‐3β,20‐diol‐20‐O‐β‐D‐glucopyranoside (2), 3‐O‐α‐L‐arabinopyranosyl‐(20R)‐pregn‐5‐ene‐3β,20‐diol‐20‐O‐β‐D‐glucopyranosyl‐(1→2)‐β‐D‐glucopyranoside (3) were isolated along with four known compounds, 4–7, from the leaves and stems of Brucea javanica. Their structures were determined by detailed analyses of 1D‐ and 2D‐NMR spectroscopic data. All of the compounds isolated from Brucea javanica were tested for the antifeedant activities against the larva of Pieris rapae. Compounds 1, 3, and 5 showed significant antifeedant activities after 72 h incubation.
Correlation between Environmental Factors, Chemical Composition, and Antioxidative Properties of Caper Species Growing Wild in Calabria (South Italy)
Authors: Conforti Filomena , Modesto Silvia , Menichini Federica , Statti Giancarlo A. , Uzunov Dimitar , Solimene Umberto , Duez Pierre , Menichini Francesco 
Published: March 2011

AbstractTwenty samples of two caper species were collected from various natural habitats of Calabria (South Italy). A sample program was designed in order to cover all taxa and morphotypes present in the studied area, trying to correlate ecological conditions, phytochemical content, and biological activities. These species were characterized through the detection, isolation, and capillary GC‐GC/MS quantitative evaluation of chemical markers (phytosterols and vitamin E). The antioxidant activity of MeOH caper extracts was assayed using 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and β‐carotene bleaching tests. The chemical investigation showed a different composition according to the species and the populations. The best free radical (DPPH) scavenging activity was exerted by Capparis orientalis sample C4 (collected near Copanello village, granodiorite sea cliff) and Capparis sicula ssp. sicula sample C5 (collected near Tarsia village, clay soil). Sample C2 (Galatrella Valley, clay soil) showed the highest inhibition of linoleic acid oxidation with more efficacy than propyl gallate, the reference drug.
Characterization of Dihydrofolate Reductases from Multiple Strains of Plasmodium falciparum Using Mathematical Descriptors of Their Inhibitors
Authors: Basak Subhash C. , Mills Denise , Hawkins Douglas M. 
Published: March 2011

AbstractTwo classes of graph‐theoretic molecular descriptors, viz., topological indices (TIs) and atom pairs (APs), have been used to derive high‐quality quantitative structureactivity relationships (QSARs) for inhibitors of dihydrofolate reductases (DHFRs) isolated from the wild and four mutant strains of Plasmodium falciparum. Of the three methods used for QSAR formulation, viz., principal‐components regression (PCR), partial least squares (PLS), and ridge regression (RR), the RR method outperformed the other two. Cohen's kappa values, based on the overlap of significant and insignificant structural descriptors calculated for the QSAR development, show that DHFR from the wild strain is substantially different from the four mutant strains. The differential QSAR approach reported in this study can be used in protocols for the development of drugs to combat drug‐resistant pathogens arising continuously in nature due to mutations. The pairwise kappa values in conjunction with appropriate drug targets and their corresponding set of ligands may be a useful tool in gauging the evolving mutual similarities and dissimilarities of pathogenic organisms from purely computed mathematical descriptors of the ligands.
Phytochemical Constituents and Inhibitory Activity towards Methicillin‐Resistant Staphylococcus aureus Strains of Eryngium Species (Apiaceae)
Authors: Çelik Ali , Aydınlık Nilüfer , Arslan Idris 
Published: March 2011

AbstractThe chemical composition of the essential oils of Eryngium campestre, E. thorifolium, and E. creticum (Apiaceae), growing in the Aegean region of Turkey (Mount Sandras, Denizli), was determined by direct thermal desorption (DTD)‐GC/MS analyses. A total of 49 components were identified in the oils, α‐pinene and hexanal being the major compounds. The three essential oils were also tested for their inhibitory activity of nine different methicillin‐resistant Staphylococcus aureus (MRSA) strains by the agar disc diffusion method. The anti‐MRSA activity of E. thorifolium oil, the most active of the three oils, was comparable with those of the reference antibiotic vancomycin and oregano oil, although somewhat lower.
Evaluation of the in vitro Activity of Dermaseptin 01, a Cationic Antimicrobial Peptide, against Schistosoma mansoni
Authors: de Moraes Josué , Nascimento Carlos , Miura Leiz M. C. V. , Leite José R. S. A. , Nakano Eliana , Kawano Toshie 
Published: March 2011

AbstractSchistosomiasis is a neglected tropical disease that remains a considerable public health problem worldwide. Since the mainstay of schistosomiasis control is chemotherapy with a single drug, praziquantel, drug resistance is a concern. Here, we examined the in vitro effects of dermaseptin 01 (DS 01), an antimicrobial peptide found in the skin secretion of frogs of the genus Phyllomedusa, on Schistosoma mansoni adult worms. DS 01 at a concentration of 100 μg/ml reduced the worm motor activity and caused the death of all worms within 48 h in RPMI 1640 medium. At the highest sublethal concentration of antimicrobial peptide (75 μg/ml), a 100% reduction in egg output of paired female worms was observed. Additionally, DS 01 induced morphological alterations on the tegument of S. mansoni, and a quantitative analysis carried out by confocal microscopy revealed extensive destruction of the tubercles in a dose‐dependent manner over the concentration range of 50–200 μg/ml. It was the first time that an anthelmintic activity towards schistosomes has been reported for a dermaseptin.
Chemical Composition and Antibacterial Activity of the Essential Oil of Drimys granadensis L.f. Leaves from Colombia
Authors: Gaviria Mauricio , Quijano Clara , Pino Jorge , Madriñán Santiago 
Published: March 2011

AbstractDrimys granadensis L.f., a native plant from Colombia, has been included in the Vademecum de Plantas Medicinales de Colombia by the Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, due to its widespread use in the folk medicine for the treatment of gastrointestinal ailments. The chemical composition of the essential oil of Drimys granadensis obtained by hydrodistillation of the leaves was analyzed by GC and GC/MS analyses. A total of 85 components were identified, with the major compounds germacrene D (1, 14.7%), sclarene (9.5%), α‐cadinol (7.3%), longiborneol acetate (2, 6.3%), drimenol (4.2%), (Z)‐β‐ocimene (3, 4.2%), α‐pinene (4, 3.2%), and β‐elemene (5, 2.7%). The essential oil was also tested against eight bacteria using the KirbyBauer disk‐diffusion method. Most of the Gram‐positive bacteria tested were susceptible to the D. granadensis essential oil, while the Gram‐negative bacteria tested were not.
A Novel Non‐phenolic Dibenzazecine Derivative with Nanomolar Affinities for Dopamine Receptors
Authors: Robaa Dina , ElDin AbulAzm Shams , Lehmann Jochen , Enzensperger Christoph 
Published: March 2011

AbstractDibenzazecines are a novel class of dopamine receptor antagonists, characterized by their high affinities as well as their tendency for D1 selectivity. Hitherto, the most active dibenzazecines were phenolic in nature; a 3‐OH substituent was found to result in the highest affinities. However, the phenolic nature of these compounds mostly renders them unsuitable for in vivo application, due to the poor pharmacokinetic profile, imparted by the phenolic group. A novel dibenzazecine derivative was prepared, with methylenedioxy moiety, connecting C(2) amd C(3), instead of the 3‐OH group. The newly synthesized derivative 3 showed high affinities similar to the lead LE404, displaying nanomolar affinities for all dopamine receptor subtypes. Its dibrominated derivative 4, though exhibiting almost a fivefold decrease in affinities, still displayed nanomolar ones for all dopamine receptors, except for D4. In a functional Ca2+ assay, both compounds 3 and 4 were found to possess antagonistic properties towards the dopamine receptors.
Derivatives of Pheophorbide‐a and Pheophorbide‐b from Photocytotoxic Piper penangense Extract
Authors: Adzhar Kamarulzaman Fadzly , Shaari Khozirah , Siong Hock Ho Anthony , Haji Lajis Nordin , Hwang Teo Soo , Boon Lee Hong 
Published: March 2011

AbstractIn our screening program for new photosensitizers from Malaysian biodiversity for photodynamic therapy (PDT) of cancer, MeOH extracts of ten terrestrial plants from Cameron Highlands in Pahang, Peninsular Malaysia, were tested. In a short‐term 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay, 20 μg/ml each of these extracts were incubated in a pro‐myelocytic leukemia cell‐line, HL60, with or without irradiation with 9.6 J/cm2 of a broad spectrum light. Three samples, Labisia longistyla, Dichroa febrifuga, and Piper penangense, were photocytotoxic by having at least twofold lower cell viability when irradiated compared to the unirradiated assay. The extract of the leaves of Piper penangense, a shrub belonging to the family Piperaceae and widely distributed in the tropical and subtropical regions in the world, was subsequently subjected to bioassay‐guided fractionation using standard chromatography methods. Eight derivatives of pheophorbide‐a and ‐b were identified from the fractions that exhibited strong photocytotoxicity. By spectroscopic analysis, these compounds were identified as pheophorbide‐a methyl ester (1), (R,S)‐132‐hydroxypheophorbide‐a methyl ester (2 and 3), pheophorbide‐b methyl ester (4), 132‐hydroxypheophorbide‐b methyl ester (5), 152‐hydroxylactone pheophorbide‐a methyl ester (6), 152‐methoxylactone pheophorbide‐a methyl ester (7), 152‐methoxylactone pheophorbide‐b methyl ester (8).
Coupling Proteomics and Transcriptomics for the Identification of Novel and Variant Forms of Mollusk Shell Proteins: A Study with P. margaritifera
Authors: Berland Sophie , Marie Arul , Duplat Denis , Milet Christian , Sire Jean Yves , Bédouet Laurent 
Published: March 2011

AbstractShell matrix proteins from Pinctada margaritifera were characterized by combining proteomics analysis of shell organic extracts and transcript sequences, both obtained from the shell‐forming cell by using the suppression subtractive hybridization method (SSH) and from an expressed sequence tag (EST) database available from Pinctada maxima mantle tissue. Some of the identified proteins were homologues to proteins reported in other mollusk shells, namely lysine‐rich matrix proteins (KRMPs), shematrins and molluscan prismatic and nacreous layer 88 kDa (MPN88). Sequence comparison within and among Pinctada species pointed to intra‐ and interspecies variations relevant to polymorphism and to evolutionary distance, respectively. In addition, a novel shell matrix protein, linkine was identified. BLAST analysis of the peptide sequences obtained from the shell of P. margaritifera against the EST database revealed the presence of additional proteins: two proteins similar to the Pif97 protein that was identified in the shell of P. fucata, a chitinase‐like protein previously identified in Crassostrea gigas, two chitin‐binding proteins, and two incomplete sequences of proteins unknown so far in mollusk shells. Combining proteomics and transcriptomics analysis we demonstrate that all these proteins, including linkine, are addressed to the shell. Retrieval of motif‐forming sequences, such as chitin‐binding, with functional annotation from several peptides nested in the shell could indicate protein involvement in shell patterning.
Photoinduced Nitric Oxide Release from a Nitrobenzene Derivative in Mitochondria
Authors: Horinouchi Taeko , Nakagawa Hidehiko , Suzuki Takayoshi , Fukuhara Kiyoshi , Miyata Naoki 
Published: March 2011

AbstractWe report a novel NO donor (RpNO), containing a 2,6‐dimethylnitrobenzene moiety for photocontrollable NO release and a rhodamine moiety for targeting to mitochondria. Photorelease of NO from RpNO in aqueous solution was confirmed by means of ESR analysis. Cellular release of NO from RpNO was confirmed with the aid of DAF‐FM DA, an NO‐specific fluorescence probe. RpNO was colocalized with MitoTracker Green FM, a mitochondrial stain, in HCT116 colon cancer cells and exhibited photodependent cytotoxicity. Our results indicate that RpNO is an effective NO donor for time‐controlled, mitochondria‐specific NO treatment.
Self‐Assembly of Chiral trans‐Cyclobutane‐Containing β‐Dipeptides into Ordered Aggregates
Authors: Gorrea Esther , Nolis Pau , Torres Elisabeth , Da Silva Eric , Amabilino David B. , Branchadell Vicenç , Ortuño Rosa M. 
Published: March 2011

AbstractTwo chiral synthetic β‐dipeptides have been constructed, one with two trans‐cyclobutane residues and the other with one trans and one cis fragment, 1 and 2, respectively, and investigated to get insight into the non‐covalent interactions responsible for their self‐assembly to form ordered aggregates, as well into parameters such as their morphology and size. Experimental evidence of the formation of these assemblies was provided by spectroscopy, microscopy and X‐ray diffraction experiments that suggest the formation of nanoscale helical aggregates. This process involves a conformational change in the molecules of each dipeptide with respect to the preferred conformation of the isolated molecules in solution. A high‐resolution NMR spectroscopy study allowed the determination of the dynamics of the gelation process in [D8]toluene and the sol–gel transition temperature, which was around 270 K in this solvent at a concentration of 15 mM. NMR spectroscopy experiments also provided some information about conformational changes involved in the sol–gel transition and also suggested a different gel packing for each dipeptide. These observations have been nicely explained by computational studies. The self‐assembly of the molecules has been modelled and suggested a head‐to‐head molecular arrangement for 1 and a head‐to‐tail arrangement for 2 to give helical structures corresponding to hydrogen‐bonded single chains. These chains interact with one another in an antiparallel way to afford bundles, the significant geometry parameters of which fit well to the main peaks observed in wide‐angle X‐ray diffraction spectra of the aggregates in the solid state.
Selective Synthesis of β‐Alkylpyrroles
Authors: Tsuchimoto Teruhisa 
Published: March 2011

Abstractβ‐Alkylpyrroles are key structural motifs found in many natural products and biologically active compounds as well as functional organic materials. For this reason, synthetic chemists continue to be interested in construction of the framework of β‐alkylpyrroles. Due to sufficient aromaticity and π‐excessive nature of pyrroles, a straightforward approach to β‐alkylpyrroles should be electrophilic aromatic substitution (SEAr) toward the pyrrole ring. However, since a primary nucleophilic site of pyrroles is an α‐position, some “trick” is required to direct incoming alkyl electrophiles toward a β‐position. This Concept article focuses on presenting previous efforts that have been devoted to the synthesis of β‐alkylpyrroles, mainly through the SEAr route.
Addition and Redox Reactivity of Hydrogen Sulfides (H2S/HS−) with Nitroprusside: New Chemistry of Nitrososulfide Ligands
Authors: Quiroga Sandra L. , Almaraz Alejandra E. , Amorebieta Valentín T. , Perissinotti Laura L. , Olabe José A. 
Published: March 2011

AbstractThe nitroprusside ion [Fe(CN)5NO]2− (NP) reacts with excess HS− in the pH range 8.5–12.5, in anaerobic medium (“Gmelin” reaction). The progress of the addition process of HS− into the bound NO+ ligand was monitored by stopped‐flow UV/Vis/EPR and FTIR spectroscopy, mass spectrometry, and chemical analysis. Theoretical calculations were employed for the characterization of the initial adducts and reaction intermediates. The shapes of the absorbance–time curves at 535–575 nm depend on the pH and concentration ratio of the reactants, R=[HS−]/[NP]. The initial adduct [Fe(CN)5N(O)SH]3− (AH, λmax≈570 nm) forms in the course of a reversible process, with kad=190±20 M−1 s−1, k‐ad=0.3±0.05 s−1. Deprotonation of AH (pKa=10.5±0.1, at 25.0 °C, I=1 M), leads to [Fe(CN)5N(O)S]4− (A, λmax=535 nm, ε=6000±300 M−1 cm−1). [Fe(CN)5NO].3− and HS2.2− radicals form through the spontaneous decomposition of AH and A. The minor formation of the [Fe(CN)5NO]3− ion equilibrates with [Fe(CN)4NO]2− through cyanide labilization, and generates the “g=2.03” iron–dinitrosyl, [Fe(NO)2(SH)2]−, which is labile toward NO release. Alternative nucleophilic attack of HS− on AH and A generates the reactive intermediates [Fe(CN)5N(OH)(SH)2]3− and [Fe(CN)5N(OH)(S)(SH)]4−, respectively, which decompose through multielectronic nitrosyl reductions, leading to NH3 and hydrogen disulfide, HS2−. N2O is also produced at pH≥11. Biological relevance relates to the role of NO, NO−, and other bound intermediates, eventually able to be released to the medium and rapidly trapped by substrates. Structure and reactivity comparisons of the new nitrososulfide ligands with free and bound nitrosothiolates are provided.