bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copolymerization kinetics of dental dimethacrylate resins initiated by a benzoyl peroxide/amine redox system
Authors: Sideridou Irini D. , Achilias Dimitris S. , Kostidou Nikoleta C. 
Published: March 2008

AbstractThe copolymerization of four dental dimethacrylates initiated by a benzoyl peroxide/4‐N,N‐dimethylamino phenethyl alcohol redox system at 37°C was studied with differential scanning calorimetry. The studied dimethacrylates were viscous bisphenol A glycidyl dimethacrylate (Bis‐GMA), bisphenol A ethoxylated dimethacrylate (Bis‐EMA), and urethane dimethacrylate (UDMA), which were characterized as base monomers, and low‐viscosity triethylene glycol dimethacrylate (TEGDMA), which was characterized as a diluent. Also, three series of dimethacrylate copolymers were prepared by incremental additions (12.5 wt %) of TEGDMA to a base comonomer (Bis‐GMA, UDMA or Bis‐EMA). The maximum rate of homopolymerization of the dimethacrylates followed the order of Bis‐GMA > UDMA > TEGDMA > Bis‐EMA, and the final degree of conversion of the corresponding homopolymers followed the order of TEGDMA > UDMA > Bis‐EMA > Bis‐GMA. A reaction–diffusion‐controlled termination region was clear in all monomers and started earlier in bulky and rigid Bis‐GMA and Bis‐EMA (followed by the more flexible UDMA and TEGDMA) but lasted longer in the Bis‐EMA polymerization. The maximum rate of copolymerization and degree of conversion of copolymers of a base monomer with TEGDMA changed monotonically with an increase in the TEGDMA content in the initial comonomer mixture. A synergistic effect was clear only in the final double‐bond conversion of Bis‐GMA/TEGDMA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Cell penetrating peptide‐modified pharmaceutical nanocarriers for intracellular drug and gene delivery
Authors: Torchilin Vladimir P. 
Published: March 2008

AbstractCell‐penetrating peptides (CPPs) including TAT peptide (TATp) have been successfully used for intracellular delivery of a broad variety of cargos including various nanoparticulate pharmaceutical carriers (liposomes, micelles, nanoparticles). Here, we will consider the main results in this area, with a special emphasis on TATp‐mediated delivery of liposomes and DNA. We will also address the development of “smart” stimuli‐sensitive nanocarriers, where cell‐penetrating function can be activated by the decreased pH only inside the biological target minimizing thus the interaction of drug‐loaded nanocarriers with nontarget cells. © 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 604–610, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Type 1 diabetes: can exercise impair the autoimmune event? TheL‐arginine/glutamine coupling hypothesis
Authors: da Silva Krause Maurício , de Bittencourt Paulo Ivo Homem 
Published: March 2008

AbstractPrevention of type 1 diabetes mellitus (T1DM) requires early intervention in the autoimmune process directed against β‐cells of the pancreatic islets of Langerhans, which is believed to result from a disorder of immunoregulation. According to this concept, a T‐helper lymphocyte of type 1 (Th1) subset of T‐lymphocytes and their cytokine products, the type 1 cytokines [e.g.interleukin 2 (IL‐2), interferon gamma (IFN‐γ) and tumour necrosis factor beta (TNF‐β)] prevail over immunoregulatory (anti‐inflammatory) Th2 subset and its cytokine products,i.e. type 2 cytokines (e.g. IL‐4, IL‐6 and IL‐10). This allows type 1 cytokines to initiate a cascade of immune/inflammatory processes in the islet (insulitis), culminating in β‐cell destruction. Activation of sympathetic‐corticotropin‐releasing hormone (CRH) axis by psychological stress induces specifically Th1 cell overactivity that determines enhanced glutamine utilization and consequent poorL‐arginine supply for nitric oxide (NO)‐assisted insulin secretion. This determines the shift of intraislet glutamate metabolism from the synthesis of glutathione (GSH) to that ofL‐arginine, leading to a redox imbalance that activates nuclear factor κB exacerbating inflammation and NO‐mediated cytotoxicity. Physical exercise is capable of inducing changes in the pattern of cytokine production and release towards type 2 class and to normalize the glutamine supply to the circulation, which reduces the need for glutamate, whose metabolic fate may be restored in the direction of GSH synthesis and antioxidant defence. Also, the 70‐kDa heat shock protein (hsp70), which is immunoregulatory, may modulate exercise‐induced anti‐inflammation. In this work, we envisage how exercise can intervene in the mechanisms involved in the autoimmune process against β‐cells and how novel therapeutic approaches may be inferred from these observations. Copyright © 2008 John Wiley & Sons, Ltd.
Probing the Hydrophobic Pocket of the Active Site in the Particulate Methane Monooxygenase (pMMO) from Methylococcus capsulatus (Bath) by Variable Stereoselective Alkane Hydroxylation and Olefin Epoxidation
Authors: Ng Kok‐Yaoh , Tu Li‐Chun , Wang Yane‐Shih , Chan Sunney I. , Yu Steve S.‐F. 
Published: March 2008

AbstractpMMO from M. capsulatus (Bath) oxidizes straight‐chain C1–C5 alkanes and alkenes to form their corresponding 2‐alcohols and epoxides. According to experiments performed with cryptically chiral ethane and D,L‐[2‐2H1,3‐2H1]butane, the reactions proceed through the concerted O‐atom insertion mechanism. However, when propene and but‐1‐ene are used as epoxidation substrates, the enantiomeric excesses (ees) of the enzymatic products are only 18 and 37 %, respectively. This relatively poor stereoselectivity in the enzymatic epoxidation presumably reflects low stereochemical differentiation between the re and si faces in the hydrophobic pocket of the active site. Further insights into the reaction mechanism are now provided by studies on trans‐but‐2‐ene, which reveal only the D,L‐2,3‐dimethyloxirane products, and on cis‐but‐2‐ene, which yield only the meso product. These observations indicate that the enzymatic epoxidation indeed proceeds through electrophilic syn addition. To achieve better facial selectivity, we have also used 3,3,3‐trifluoroprop‐1‐ene as the substrate. The products obtained are 90 % (2S)‐oxirane. When 1,1,1‐trifluoropropane is the substrate, the hydroxylation at the 2‐carbon exhibits an inverse chiral selectivity relative to that seen with normal butane, if we consider the size of the CF3 group in the fluorinated propane to be comparable to one of the ethyl groups in butane. These experiments are beginning to delineate the factors that influence the orientations of various substrates in the hydrophobic cavity of the active site in the enzyme.
Dynorphin and stress‐related peptides in rat locus coeruleus: Contribution of amygdalar efferents
Authors: Reyes B.A.S. , Drolet G. , Van Bockstaele E.J. 
Published: March 2008

AbstractThe interaction between the stress axis and endogenous opioid systems has gained substantial attention, because it is increasingly recognized that stress alters individual sensitivity to opiates. One site at which opiates and stress substrates may interact to have global effects on behavior is within the locus coeruleus (LC). We have previously described interactions of several opioid peptides [e.g., proopiomelanocortin, enkephalin (ENK)] with the stress‐related peptide corticotropin‐releasing factor (CRF) in the LC. To examine further the interactions among dynorphin (DYN), ENK, and CRF in the LC, sections were processed for detection of DYN and CRF or DYN and ENK in rat brain. DYN‐ and CRF‐containing axon terminals overlapped noradrenergic dendrites in this region. Dual immunoelectron microscopy showed coexistence of DYN and CRF; 35% of axon terminals containing DYN were also immunoreactive for CRF. In contrast, few axon terminals contained both DYN and ENK. A potential DYN/CRF afferent is the central nucleus of the amygdala (CeA). Dual in situ hybridization showed that, in CeA neurons, 31% of DYN mRNA‐positive cells colocalized with CRF mRNA, whereas 53% of CRF mRNA‐containing cells colocalized with DYN mRNA. Finally, to determine whether limbic DYN afferents target the LC, the CeA was electrolytically lesioned. Light‐level densitometry of DYN labeling in the LC showed a significant decrease in immunoreactivity on the side of the lesion. Taken together, these data indicate that DYN‐ and CRF‐labeled axon terminals, most likely arising from amygdalar sources, are positioned dually to affect LC function, whereas DYN and ENK function in parallel. J. Comp. Neurol. 508:663–675, 2008. © 2008 Wiley‐Liss, Inc.
The Antimalarial Artemisone is an Efficient Heme Alkylating Agent
Authors: Bousejra‐El Garah Fatima , Meunier Bernard , Robert Anne 
Published: March 2008

AbstractThe reductive activation by iron(II)‐heme of artemisone, a C‐10 substituted derivative of the antimalarial artemisinin, generates covalent heme‐drug adducts in high yields. This result confirms that the substitution at C‐10 of artemisinin does not alter the alkylating ability of artemisinin derivatives when activated by a redox‐active metal center. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Loss prediction in switched reluctance motors using finite element method
Authors: Faiz J. , Ganji B. , Carstensen C. E. , De Doncker R. W. 
Published: March 2008

AbstractIn the present paper, a core loss model for switched reluctance motor (SRM) is developed using ANSYS finite element package. In this model, the flux waveform in one part of the magnetic circuit of the motor is predicted by analysis of the motor with finite element method (FEM), and then the flux waveforms in other sections of the motor are determined using this predicted flux waveform. To validate the obtained flux waveforms, they are compared with those predicted solely by analysis of the motor with FEM. Since the flux waveforms are completely non‐sinusoidal, three different methods based on the Steinmetz equation are utilized to estimate the core loss, and the estimated loss are compared with measured data. For the measurement, an experimental set‐up is introduced and various aspects of the core loss measurement of SRM are discussed. Copyright © 2008 John Wiley & Sons, Ltd.
A BAC transgenic mouse model to analyze the function of astroglial SPARCL1 (SC1) in the central nervous system
Authors: Weimer Jill M. , Stanco Amelia , Cheng Jr‐Gang , Vargo Ana C. , Voora Santhi , Anton E. S. 
Published: March 2008

AbstractExtracellular matrix associated Sparc‐like 1 (SC1/SPARCL1) can influence the function of astroglial cells in the developing and mature central nervous system (CNS). To examine SC1's significance in the CNS, we generated a BAC transgenic mouse model in which Sc1 is expressed in radial glia and their astrocyte derivatives using the astroglial‐specific Blbp (Brain‐lipid binding protein; [Feng et al., (1994) Neuron 12:895–908]) regulatory elements. Characterization of these Blbf‐Sc1 transgenic mice show elevated Sc1 transcript and protein in an astroglial selective pattern throughout the CNS. This model provides a novel in vivo system for evaluating the role of SC1 in brain development and function, in general, and for understanding SC1's significance in the fate and function of astroglial cells, in particular. © 2008 Wiley‐Liss, Inc.
Monitoring of FLT3 phosphorylation status and its response to drugs by flow cytometry in AML blast cells
Authors: Grafone Tiziana , Palmisano Michela , Nicci Chiara , Martelli Alberto Maria , Emanuela Ottaviani , Storti Sergio , Baccarani Michele , Martinelli Giovanni 
Published: March 2008

AbstractFLT3 mutation and overexpression in most acute myeloid leukaemia (AML) patients make this tyrosine kinase receptor an attractive therapeutic target. FLT3 kinase inhibitors are actually in clinical trials, thus it is critical to develop a reproducible and standardized method for screening of FLT3 activation and for monitoring its inhibition in response to drug in AML patients. We developed a flow cytometry method to analyse phosphorylated FLT3 (P‐FLT3) in samples with <105 cells. The method was first validated in FLT3 wild‐type (HL60/WT) and mutant (MV4‐11/ITD+) as well as FLT3 negative (K562) cell lines. The method also proved to be reproducible in AML patient samples. Analysis was performed after exposure to drugs (CEP‐701 and SU11657), in vitro and in vivo. In response to increasing drug concentrations, there was a linear reduction in P‐FLT3. Intracellular flow cytometry analysis correlated with Western blot and XTT assays; flow cytometry data also correlated with FLT3 mutational status. The results highlight a rapid method to detect P‐FLT3 protein at the single cell level by flow cytometry which enables an accurate assessment of FLT3 kinase activity in blast cells in response to novel tyrosine kinase inhibitors. Copyright © 2008 John Wiley & Sons, Ltd.
Long‐term evaluation of a calcium phosphate bone cement with carboxymethyl cellulose in a vertebral defect model
Authors: Kobayashi Hideo , Fujishiro Takaaki , Belkoff Stephen M. , Kobayashi Naomi , Turner A. Simon , Seim Howard B. , Zitelli Joseph , Hawkins Monica , Bauer Thomas W. 
Published: March 2008

AbstractWe investigated histological and compressive properties of a calcium phosphate bone cement (BoneSource® (CPC); Stryker Orthopaedics, Mahwah, New Jersey) plus carboxymethyl cellulose (CMC) using a sheep vertebral bone void model. Bone voids were surgically created in L3 and L5 in each of 40 sheep, and the voids were filled with the cement. Histological and radiographic evaluations were performed on one vertebral body from each animal at either: 0, 3, 6, 12, 24, or 36 months after surgery; mechanical testing was performed on operated and non‐operated vertebral bodies from 35 sheep. Undecalcified sections were digitized, and the area of the original defect, new bone formation, empty space, fibrous tissue, and residual cement were quantified with histomorphometry. Decalcified sections were evaluated qualitatively. The cement was biocompatible, extremely osteoconductive and underwent steady resorption and replacement by bone and bone marrow. Histomorphometry showed variations in the rate of cement remodeling among animals in each time group, but on average, at 36 months the original defect area was occupied by ∼14% bone, 82% cement, and 4% bone marrow. Even in animals that had greater resorption of cement, there was good bone ingrowth with no fibrous tissue. Compressive testing did not reveal a significant difference in the mechanical properties between vertebral bodies augmented with cement and non‐augmented controls, irrespective of the postoperative time. BoneSource mixed with CMC had adequate osteoconductivity, biocompatibility, and adequate compressive strength. There was variability among animals, but histology suggests that considerable cement was still present in most samples after 36 months. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Do crocodilians get the flu? Looking for influenza A in captive crocodilians
Authors: Davis Lisa Marie , Spackman Erica 
Published: March 2008

AbstractIt is well established that several wild aquatic bird species serve as reservoirs for the influenza A virus. It has also been shown that the influenza A virus can be transmitted to mammalian species such as tigers and domestic cats and dogs through ingestion of infected birds. Another group of animals that should also be considered as potential hosts for the influenza A virus are the crocodilians. Many crocodilian species share aquatic environments with wild birds that are known to harbor influenza viruses. In addition, many large crocodilians utilize birds as a significant food source. Given these factors in addition to the close taxonomic proximity of aves to the crocodilians, it is feasible to ask whether crocodilian species may also harbor the influenza A virus. Here we analyzed 37 captive crocodilians from two locations in Florida (plus 5 wild bird fecal‐samples from their habitat) to detect the presence of influenza A virus. Several sample types were examined. Real‐time RT‐PCR tests targeting the influenza A matrix gene were positive for four individual crocodilians—Alligator sinensis, Paleosuchus trigonatus, Caiman latirostris and Crocodylus niloticus. Of the seven serum samples tested with the avian influenza virus agar gel immunodiffusion assay, three showed a nonspecific reaction to the avian influenza virus antigen—A. sinensis, P. trigonatus and C. niloticus (C. latirostris was not tested). Viable virus could not be recovered from RT‐PCR‐positive samples, although this is consistent with previous attempts at viral isolation in embryonated chicken eggs with crocodilian viruses. J. Exp. Zool. 309A:571–580, 2008. © 2008 Wiley‐Liss, Inc.
The daguerreotype surface as a SERS substrate: characterization of image deterioration in plates from the 19th century studio of Southworth & Hawes
Authors: Centeno Silvia A. , Meller Taina , Kennedy Nora , Wypyski Mark 
Published: March 2008

AbstractDramatic condition changes were noted in a group of daguerreotypes during a 10 month‐long exhibition featuring masterworks of the prominent Boston‐based studio of Southworth & Hawes. The changes took the form of a hazy, extended white surface layer and of white spots that partially obscured the images after between four weeks and 10 months of exhibition. Raman spectroscopy, complemented by in situ scanning electron microscopy–energy dispersive X‐ray spectrometry (SEM–EDS), was used to nondestructively characterize this form of image deterioration in eight representative daguerreotypes from the studio. Raman proved to be a sensitive technique to noninvasively identify the compounds on the plates due to the fact that their Ag surfaces behave as surface‐enhanced Raman scattering (SERS) substrates. A band at ca 242 cm−1 assigned to the AgCl stretching mode was observed in the areas where a white surface layer or white spots are present. In some of the areas probed, substituted aromatic compounds were also detected. The presence of AgCl bonds on daguerreotype surfaces has profound implications for their exhibition and preservation due to the photosensitivity of silver chloride in the ultraviolet–visible range, which can generate metallic silver that would redeposit on the surfaces. The possible sources of the compounds detected on the surfaces of the plates are discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Evaluation of three different mobile Raman microscopes employed to study deteriorated civil building stones
Authors: Martínez‐Arkarazo I. , Smith D. C. , Zuloaga O. , Olazabal M. A. , Madariaga J. M. 
Published: March 2008

AbstractThree different Raman spectrometers were used to analyse the original composition and the degradation products formed on natural outcrops and building materials under influences of urban and industrial pollutants and a marine environment. A Renishaw portable Raman instrument was used to check the efficiency of two ultramobile instruments for the identification of the products of decay of diverse carbonaceous stones taken from three areas located at different distances from the coast. Satisfactory results were obtained in measurements of original compounds such as quartz and calcium carbonate. Differentiation between the polymorphic forms calcite and aragonite was possible with the Renishaw RA100 and BWTEK BWS415 i‐Raman instruments, the ones provided with higher spectral resolutions. Concerning the degradation products, gypsum (CaSO4· 2H2O) and amorphous carbon (soot) were detected in samples from three locations, but the most damaged stones are those of Aixerrota, which show higher amounts of both decay products, identified by the three Raman instruments, as the main agent responsible for stone decay. Some nitrate compounds were determined in a mortar sample from the location of the highest impacted environment (Aixerrota), and whewellite (CaC2O4· H2O) and weddellite (CaC2O4· 2H2O) appeared in some sandstones from Arriluze and joint mortars from Aixerrota derived from micro‐organism activity. However, the ultramobile equipments were not capable of detecting the presence of nitrates and oxalates, due to high fluorescence (DeltaNu) and thermo‐decomposition (BWTEK) problems. Copyright © 2008 John Wiley & Sons, Ltd.
Thiol‐immobilized silver nanoparticle aggregate films for surface enhanced Raman scattering
Authors: Caro Carlos , López‐Cartes Carlos , Zaderenko Paula , Mejías José A. 
Published: March 2008

AbstractWe report a novel method for the fabrication of films of silver nanoparticle aggregates that are strongly attached to Si substrates (Thiol‐immobilized silver nanoparticle aggregates or TISNA). The attachment is achieved by chemically modifying the surface of a Si(100) surface in order to provide SH groups covalently linked to the substrate and then aggregating silver nanoparticles on these thiol covered surfaces. The transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterization show a high coverage with single nanoparticles or small clusters and a partial coverage with fractal aggregates that provide potential hot spots for surface enhanced Raman scattering (SERS). We have confirmed the SERS activity of these films by adsorbing rhodamine 6G and recording the Raman spectra at several concentrations. By using the silver‐chloride stretching band as an internal standard, the adsorbate bands can be normalized in order to correct for the effects of focusing and aggregate size, which determine the number of SERS active sites in the focal area. This allows a quantitative use of SERS to be done. The adsorption–desorption of rhodamine 6G on TISNA films is reversible. These features make our TISNA films potential candidates for their use in chemical sensors based on the SERS effect. Copyright © 2008 John Wiley & Sons, Ltd.
Vibrational and surface‐enhanced Raman spectra of vanillic acid
Authors: Clavijo E. , Menéndez J. R. , Aroca R. 
Published: March 2008

AbstractThe 3‐methoxy‐4‐hydroxybenzoic acid or vanillic acid (VA) is a naturally occurring molecule important in winemaking. The spectral fingerprints of VA observed in the infrared and Raman spectra are assigned to fundamental vibrational wavenumbers supported by quantum chemical computations. The surface‐enhanced Raman scattering (SERS) of the VA has been obtained in silver colloidal solutions making possible analytical applications for detection of VA at picomole concentrations. Copyright © 2008 John Wiley & Sons, Ltd.
Genetic variants in germline TP53 and MDM2 SNP309 are not associated with early onset colorectal cancer
Authors: Khan Sajid A. , Idrees Kamran , Forslund Ann , Zeng Zhaoshi , Rosenberg Shoshana , Pincas Hanna , Barany Francis , Offit Kenneth , LaQuaglia Michael P. , Paty Philip B. 
Published: March 2008

AbstractBackground and ObjectivesColorectal cancer (CRC) arising in patients under age 30 is a rare disease, and few cases have been reported within Li‐Fraumeni kindreds. To determine how often alterations in the p53 pathway genes contribute to disease susceptibility, we have evaluated patients with early onset CRC for the presence of germline variants in the p53 gene and MDM2 SNP309.MethodsThirty‐five patients with CRC diagnosed before age 30 were included in this study‐based on tissue availability. DNA samples from peripheral blood leukocytes were analyzed for constitutional mutations and polymorphisms in p53 as well as polymorphisms in MDM2 SNP309.ResultsNo mutations were found in exons 4–10 of the p53 gene. The frequencies of polymorphisms in p53 and in MDM2 SNP309 did not differ from rates previously reported for normal control populations, and no polymorphism in either gene could be associated with early onset CRC.ConclusionsNeither germline variants in p53 nor MDM2 SNP309 play an underlying role in the development of very early onset CRC. For the large majority of cases, the genetic basis of this disease remains unknown. J. Surg. Oncol. 2008;97:621–625. © 2008 Wiley‐Liss, Inc.