bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereocontrolled Electrophilic Additions on Amide Enolates Employing (S,S)‐(+)‐Pseudoephedrine as Chiral Auxiliary
Authors: Anakabe Eneritz , Badia Dolores , Carrillo Luisa , Rodriguez Monica , Vicario Jose L. 
Published: June 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Tubulin glycylation and glutamylation deficiencies in unconventional insect axonemes
Authors: Mencarelli Caterina , Caroti Daniela , Bré Marie‐Hélène , Levilliers Nicolette , Dallai Romano 
Published: June 2005

AbstractThough the 9+2 axonemal organization has generally been conserved throughout metazoan evolution, insect spermatozoa possess a substantial variety in axoneme ultrastructure, displaying different axonemal patterns. Therefore, insects provide a wide range of models that may be useful for the study of the mechanisms of axoneme assembly. We have used antibodies specific for glutamylated, monoglycylated, and polyglycylated tubulin to investigate the tubulin isoform content expressed in the unorthodox sperm axonemes of four insect species belonging to both of the superorders Palaeoptera and Neoptera. Each one of these axonemal models exhibits distinctive structural features, either showing the typical radial organization endowed with a ninefold symmetry or consisting of an helical arrangement with up to 200 microtubular doublets, but in all cases these axonemes share the absence of a microtubule central pair. Our results showed that all these atypical patterns are characterized by a dramatic decrease in both tubulin glycylation and glutamylation levels or even lack of both polymodifications. These data provide the first examples of a simultaneous extreme reduction or even absence of both polymodifications in axonemal tubulin. Given the unrelated positions of the analyzed species in the insect phylogenetic tree, this common feature is probably not due to evolutionary relationships. Therefore, our findings support the hypothesis of the existence of a correlation between the low level of polymodifications and the lack of a microtubule central pair in these peculiar insect flagellar axonemes, similarly as was previously proposed for cilia of Tetrahymena glycylation site mutants. Cell Motil. Cytoskeleton 61:226–236, 2005. © 2005 Wiley‐Liss, Inc.
Shallow site archaeology: Artifact dispersal, stratigraphy, and radiocarbon dating at the Barger Gulch locality B Folsom Site, Middle Park, Colorado
Authors: Surovell Todd A. , Waguespack Nicole M. , Mayer James H. , Kornfeld Marcel , Frison George C. 
Published: June 2005

AbstractShallowly buried archaeological sites are particularly susceptible to surface and subsurface disturbance processes. Yet, because cultural deposition often operates on short time scales relative to geologic deposition, vertical artifact distributions can be used to clarify questions of site formation. In particular, patterns in artifact distributions that cannot be explained by occupation histories must be explained by natural processes that have affected sites. Buried only 10–50 cm beneath the ground surface for 10,450 14C yr, the Folsom component at Barger Gulch Locality B (Middle Park, Colorado) exhibits many signs of post‐depositional disturbance. Through examination of variation in the vertical distribution of the artifact assemblage, we are able to establish that only a Folsom component is present. Using vertical artifact distributions, stratigraphy, and radiocarbon dating, we are able to reconstruct the series of events that have impacted the site. The Folsom occupation (˜10,450 14C yr B.P.) was likely initially buried in a late‐Pleistocene eolian silt loam. Erosion brought the artifacts to rest on a deflation surface at some time prior to 9400 14C yr B.P. A mollic epipedon formed in sediments that accumulated between 9400 and 7000 14C yr B.P. Some time after 5200 14C yr B.P., this soil was partially truncated, and artifacts that had previously dispersed upward created a secondary lag at its upper contact. This surface was buried again and artifact dispersal continued. © 2005 Wiley Periodicals, Inc.
In vitro studies of calcium phosphate glass ceramics with different solubility with the use of human bone marrow cells
Authors: Dias A. G. , Lopes M. A. , Trigo Cabral A. T. , Santos J. D. , Fernandes M. H. 
Published: June 2005

AbstractTwo glass ceramics in the CaOP2O5MgO system with the incorporation of K2O or TiO2 oxides were prepared with the goal of using them as potential bone graft substitutes. The incorporation of TiO2 and K2O led to the preparation of specific crystalline phases in the structure of the glass ceramics, which show different degrees of biodegradation. In fact, the 45CaO45P2O55MgO5K2O has been previously demonstrated to be much more soluble in aqueous solutions than the 45CaO37P2O55MgO13TiO2 glass ceramic. The in vitro biological activity of the two calcium phosphate glass ceramics was studied with the use of human bone marrow osteoblast cell cultures maintained for 28 days, and seeded materials were assessed for cell proliferation and function. The Ti‐containing glass ceramic showed a stable surface throughout the culture time, on macroscopic and SEM observation. Osteoblast cells proliferated gradually, especially during the third week, with a high alkaline phosphatase activity and formation of a mineralized matrix. On SEM observation, attached cells appeared with a spread‐polygonal morphology typical of the osteoblast cells, with extensive cell‐to‐cell contact. Cell behavior on the seeded material was similar to that found on cultures performed on tissue‐culture‐grade polystyrene; except for the presence of lower cell numbers during the first 2 weeks. By contrast, the K‐containing glass ceramic showed a highly instable surface with dissolution/precipitation processes occurring throughout the culture time. Few cells adhered to the material surface, and subsequent proliferation was also hindered, especially from the first week onwards. Cell numbers were significantly lower than those observed in the Ti‐containing glass ceramic during most of the incubation time. Results suggest that the different in vitro biological behavior of these two glass ceramics is mainly due to the significant differences in the surface degradation rate, which is directly correlated to the chemical composition of the mother glass. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Porous scaffolds of gelatin–hydroxyapatite nanocomposites obtained by biomimetic approach: Characterization and antibiotic drug release
Authors: Kim Hae‐Won , Knowles Jonathan C. , Kim Hyoun‐Ee 
Published: June 2005

AbstractGelatin–hydroxyapatite (HA) nanocomposite porous scaffolds were fabricated biomimetically, and their feasibility as a drug‐delivery carrier for tissue‐regeneration and wound‐healing treatments was addressed. The composite sols were prepared by the precipitation of HA up to 30 wt % within a gelatin solution with the use of calcium and phosphate precursors, and the porous scaffold was obtained by casting the sols and further freeze drying. The obtained bodies were crosslinked with carbodiimide derivatives to retain chemical and thermal integrity. The apatite precipitates were observed to be a poorly crystallized carbonate‐substituted HA. The nanocomposite scaffolds had porosities of ∼ 89–92% and exhibited a bimodal pore distribution, that is, the macropores (∼ 300–500 μm) of the framework structure, and micropores (∼ 0.5–1 μm) formed on the framework surface. Transmission electron microscopy (TEM) observation revealed the precipitation of highly elongated HA nanocrystals on the gelatin network. The well‐developed porous structure and organized nanocomposite configurations were in marked contrast to the directly mixed gelatin–HA powder conventional composites. For drug‐release tests, tetracycline, an antibiotic drug, was entrapped within the scaffold, and the drug‐release profile was examined with processing parameters, such as HA amount in gelatin, crosslinking degree, and initial drug addition. The drug entrapment decreased with increasing HA amount, but increased with increasing crosslinking degree and initial drug addition. The crosslinking of the gelatin was the prerequisite to sustaining and controlling the drug releases. Compared to pure gelatin, the gelatin–HA nanocomposites had lower drug releases, because of their lower water uptake and degradation. All the nanocomposite scaffolds released drugs in proportion to the initial drug addition, suggesting their capacity to deliver drugs in a controlled manner. Based on the findings of the well‐developed morphological feature and controlled drug‐release profile, the gelatin–HA nanocomposite porous scaffolds are suggested to be potentially useful for hard‐tissue regeneration. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Angiogenesis, endothelial cell functions, and tumor cell growth in biodegradable and nonbiodegradable devices
Authors: Zhao Xia , Kalliomäki Suzanne , Wang Xiangdong , Kalliomäki Jacob , Andersson Roland 
Published: June 2005

AbstractDevelopment of tissue engineering creates multiple potentials for clinical treatment and scientific research. Biodegradable collagen matrices have been found to support simultaneous autotransplantation of hepatocytes after major liver resection. Dynamic angiogenesis in biodegradable devices (BDD) and nondegradable devices (NDD) transplanted into the renal subcapsule and subcutaneous tissue was measured by the distribution of radiolabeled red blood cells and serum albumin. The circulation, microvascular integrity, and capacities of endothelial cells (adhesion, proliferation, and migration) were investigated within 2 weeks after subcutaneous transplantation of both devices. Patterns of tumor cell growth in both devices were morphologically studied. After subcutaneous transplantation, significant angiogenesis was noted at 1 week in BDD implants and from 2 weeks and on in NDD implants, with an increase in implant blood and plasma volumes. Leakage index of radiolabeled albumin in NDD implants was significantly higher than in BDD implants, while the leakage index 2 weeks after BDD implant was similar to that in subcutaneous tissues. Adhesion, proliferation and migration rates of endothelial cells isolated from both devices were higher than from subcutaneous tissues. Endothelial proliferation and migration rates in BDD implants were significantly higher at 1 week, while in NDD at 2 weeks. Tumor cells migrated and grew on the top surface of NDD with a flattened shape, while growing within the BDD forming a round mass. Endothelial capacities, angiogenetic procedure, and biological and physical characteristics of the device contribute to patterns of tumor cell growth in the device. Biodegradable collagen matrix with three‐dimensional structure is suitable for simultaneous transplantation with cells without prevascularization. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Simultaneous activation of JAK1 and JAK2 confers IL‐3 independent growth on Ba/F3 pro‐B cells
Authors: Huang Huei‐Mei , Lin Yi‐Li , Chen Cheng‐Hsien , Chang Ting‐Wei 
Published: June 2005

AbstractJAK1 and JAK2 are tyrosine kinases involved in the regulation of cell proliferation, differentiation, and survival. These proteins may play a key role in mediating the effects of the cytokine IL‐3 on hematopoietic cells. IL‐3 induces tyrosine phosphorylation of both JAK1 and JAK2. However, it is not clear whether the activation of JAK1, JAK2, or both is sufficient to confer factor‐independent growth in IL‐3 dependent cells. To address this issue, fusion proteins CD16/CD7/JAK (CDJAK), comprised of a CD16 extracellular domain, a CD7 transmembrane domain, and a JAK cytoplasmic region (either a wild‐type JAK or a dominant negative mutant of JAK) were constructed. We established several Ba/F3 derivatives that stably overexpress the conditionally active forms of either CDJAK1, CDJAK2, or both these fusion proteins. In this study, the autophosphorylation of CDJAK1 or CDJAK2 was induced by crosslinking with anti‐CD16 antibody. We demonstrated that, like their wild‐type counterparts, CDJAK1 and CDJAK2 were preassociated with the IL‐3 receptor beta and alpha subunits, respectively. Furthermore, the simultaneous activation of both CDJAK1 and CDJAK2 fusion proteins, but not either one alone, led to the tyrosine phosphorylation of the IL‐3 receptor beta subunit, the activation of downstream signaling molecules, including STAT5, Akt, and MAPK, and the conferring of factor‐independent growth to IL‐3‐dependent Ba/F3 cells. Coexpression of dominant negative mutants CDJAK1KE or CDJAK2KE with wild type CDJAK2 or CDJAK1, respectively, inhibited these activation activities. These results suggest that JAK1 and JAK2 must work cooperatively and not independently and that their actions are dependent on having normal kinase activity to trigger downstream signals leading to IL‐3 independent proliferation and survival of Ba/F3 cells. © 2005 Wiley‐Liss, Inc.
A paradigm for the treatment of prostate cancer bone metastases based on an understanding of tumor cell–microenvironment interactions
Authors: Loberg Robert D. , Gayed Bishoy A. , Olson Karin B. , Pienta Kenneth J. 
Published: June 2005

AbstractThe pliability of cancer cells to mutate into several different phenotypes in an attempt to find one that will survive and colonize at the metastatic site is a tremendous “hurdle” to overcome in designing novel cancer therapeutics. New targets of therapy are essential if we are to effectively overcome the evasiveness of cancer. The interaction between the tumor cell and the surrounding microenvironment creates a vicious cycle that perpetuates disease survival and progression. The future of cancer therapy resides in the ability to focus on the recruited and exploited relationships of the cancer cell with the host environment. These therapies target cancer cell growth early and interrupt the vicious cycle that is created by the tumor cells interacting with bone components by inhibiting osteoclasts, osteoblasts, stromal cells, and endothelial cells. They alter the bone microenvironment, creating a hostile “soil” that prevents the “seed” from developing into bone metastases and represent a potential new platform for the development of prostate cancer therapeutics. © 2005 Wiley‐Liss, Inc.
Solute transport in non‐aqueous nanofiltration: effect of membrane material
Authors: Geens Jeroen , Hillen An , Bettens Ben , Van der Bruggen Bart , Vandecasteele Carlo 
Published: June 2005

AbstractNanofiltration experiments in methanol and ethanol were carried out for six reference components with different molecular weights (MW 228–880) and polarities (logP 0–12). The contribution of diffusion to solute transport, calculations based on results from cell diffusion experiments, was found to be only 1–7%; solute transport occurs mainly by convection. Furthermore, it was found that solute transport is influenced by solute–solvent–membrane interactions. Solvent–solute interactions (solvation) cause a different effective solute diameter in each solvent: it is smaller in ethanol than in methanol, resulting in lower rejections in ethanol than in methanol. Solute rejection increases with increasing molecular size (for components with similar polarity). Solute–membrane interactions were expressed in polarity terms and charge effects. A decrease of the rejection with decreasing solute polarity (for components with similar MW) was observed. Since non‐polar components (high logP) are exposed to smaller repulsion forces from the polymeric membrane material, the resistance against solute permeation is lower for these components. The solvent–membrane interactions were found to result in solvation of the pore wall; the degree of membrane solvation is different for each solvent. It is determined by the affinity between the solvent and the membrane, and by the molecular size of the solvent. In ethanol, hydrophilic membranes show a larger drop in solute rejection than hydrophobic membranes. The differences in solvent–membrane affinity (measured by contact angle) are much smaller for the first membranes, and therefore pore wall solvation decreases with increasing solvent size. Hydrophobic membranes have a much larger affinity for ethanol than for methanol, leading to stronger interactions, but undergo competitive forces due to the larger solvent size. Therefore, the difference in degree of solvation and effective pore diameter is less pronounced. Based on these three observed or postulated interactions, rejections of all six reference solutes in methanol and ethanol could be explained. Copyright © 2005 Society of Chemical Industry
Screen‐printed biosensor for allergens
Authors: Sarkar P , Ghosh D , Bhattacharya D , Kataky R , Setford SJ , White SF , Turner APF 
Published: June 2005

AbstractAllergen levels in indoor environments, leading to many diseases, eg asthma, rhinitis and conjunctivitis, affect a large and increasing fraction of the population. A quite effective and inexpensive method of a rough but very rapid overall assessment of total allergen level in the environment has been developed. The method involved estimation of protein in allergen extracts by screen‐printed electrodes using two different techniques. The biosensor comprised a rhodinised carbon working electrode, a silver/silver chloride reference electrode and a carbon counter electrode. In the first method the enzyme protease reacted with allergen protein to release amino acid, which produced hydrogen peroxide in the presence of amino acid oxidase. This was detected amperometrically. The second method used potassium bromide as electrolyte and the electrode was subjected to dual potential. Bromine, released due to electrolysis at higher potential, was consumed by the allergen protein at lower potential. In the first method, a unique technique was used to microencapsulate the enzyme protease and immobilise it on the surface of the electrode by in‐situ polymerisation to avoid contact with the amino acid oxidase. A total of seven allergens were tested and the results gave a good correlation with the standard protein measurement method. Environmental specimens from indoors, schools and workplaces can be evaluated for the aeroallergens produced by dust mites, animal hairs, cockroach debris, pollens, etc as a means of determining the exposure risk. Copyright © 2005 Society of Chemical Industry
Hyperbranched polymers generated from oxyanionic vinyl polymerization of commercially available methacrylate inimers
Authors: Jia Zhifeng , Yan Deyue 
Published: June 2005

AbstractHyperbranched polymethacrylates were prepared by means of oxyanionic vinyl polymerization of commercially available monomers, including hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) methacrylate (PEG‐MA). Hyperbranched polymethacrylates with high molecular weight were obtained with the complex of potassium hydride and 18‐crown‐6 as the initiator. The effect of 18‐crown‐6 is very important, and only oligomer can be obtained in the polymerization without 18‐crown‐6. The molecular structure of the hyperbranched polymers was confirmed with 1H NMR and 13C NMR spectra. The ratio of initiator to monomer significantly affects the architecture of the resultant polymers. When the ratio of initiator to monomer equals 1 in the oxyanionic vinyl polymerization of HEMA, the degree of branching of the resulting polymer was calculated to be around 0.49. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3502–3509, 2005
Hydrogen bonding in peptide secondary structures
Authors: Varga Zoltán , Kovács Attila 
Published: June 2005

AbstractHydrogen bonding interactions in various peptide secondary structures (β‐sheet, 27‐ribbon, 310‐helix, α‐helix, π‐helix, β‐turn II, and γ‐turn) have been investigated in small oligopeptides by quantum chemical calculations at the B3LYP/6‐31G** level. Besides the primary O…HN interactions, the optimized structures revealed the importance of N…HN hydrogen bonding in several structures. The effect of substitution on the energy and structural properties was investigated comparing the properties of glycine, alanine, valine, and serine. The aliphatic substituents generally weaken the hydrogen bonds, the strongest effects being observed in crowded valine conformers. Additional hydrogen bonding interactions introduced by the OH group of serine can both strengthen (by polarizing the amide moiety through N…H interaction) and weaken (constraining the CO oxygen by O…HO interaction) the backbone hydrogen bonds. The effect of water as a polarizable medium on the energy properties was assessed by the COSMO model. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
An evaluation of the utility of in vacuo methylation for mass‐spectrometry‐based analyses of peptides
Authors: Laremore Tatiana N. , Weber David M. , Choma Christin T. 
Published: June 2005

AbstractIn vacuo trimethylation of the N‐terminus of a lyophilized peptide with methyl iodide was previously reported to enhance the peptide's signal in matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) and to suppress alkali adduct formation in electrospray ionization mass spectrometry (ESI‐MS). Both the signal enhancement and alkali adduct suppression observed for methylated peptides are believed to be due to the permanent positive charge on the N‐terminus of the peptide resulting from the formation of a quaternary ammonium moiety. The present work evaluates the general utility of the in vacuo methylation procedure for the MS analysis of peptides, and specifically addresses the issue of whether the methylation of nucleophilic sites other than the N‐terminal amine affects the MALDI signal of modified peptides. This work establishes that, although certain side‐chain modifications are inevitable using present reaction conditions, the derivatization leads to significant MALDI‐MS signal improvement. The experimental results demonstrate that the N‐terminal trimethylammonium derivatives of peptides exhibit MALDI signals comparable to or exceeding those of arginine‐containing standards such as angiotensin I. The advantages and limitations of the in vacuo methylation procedure are discussed. Copyright © 2005 John Wiley & Sons, Ltd.
Enhancement of phosphoprotein analysis using a fluorescent affinity tag and mass spectrometry
Authors: Stevens Stanley M. , Chung Alfred Y. , Chow Marjorie C. , McClung Scott H. , Strachan Camille N. , Harmon Alice C. , Denslow Nancy D. , Prokai Laszlo 
Published: June 2005

AbstractA fluorescent affinity tag (FAT) was synthesized and was utilized to selectively modify phosphorylated serine and threonine residues via beta‐elimination and Michael addition chemistries in a ‘one‐step’ reaction. This labeling technique was used for covalent modification of both phosphoproteins and phosphopeptides, allowing identification of these molecular species by fluorescence imaging after solution‐ or gel‐based separation methods. In addition to the strong fluorescence of the rhodamine tag, a commercially available antibody can be used to enrich low‐abundance post‐labeled phosphopeptides present in complex mixtures. Application of this methodology to phosphorylation‐site mapping has been evaluated for a phosphoprotein standard, bovine beta‐casein. Initial results demonstrated low femtomole detection limits after fluorescence image analysis of FAT‐labeled proteins or peptides. Copyright © 2005 John Wiley & Sons, Ltd.