bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Relaxivity Studies of a Gadolinium(III) Complex of ATP‐Conjugated DO3A as a Contrast Enhancing Agent for MRI
Authors: Ratnakar S. James , Alexander Vedhamonickom 
Published: August 2005

AbstractA gadolinium(III) complex of adenosine 5′‐triphosphate (ATP)‐appended DO3A has been synthesized in order to attain higher relaxivity and to reduce the in vivo toxicity. DO3A (2) was synthesized as the exclusive product by a single step direct trialkylation of cyclen with chloroacetic acid in water (pH 10, –4 °C). ATP was then covalently appended to the DO3A framework through a propyl linker. The 3‐bromopropane spacer appended DO3A (3) was synthesized by the reaction of DO3A with 1,3‐dibromopropane in water/DMF in the presence of triethylamine as proton scavenger. The ATP‐appended DO3A (DO3A‐Pr‐ATP) was synthesized by the reaction of 3 with ATP in water at room temperature. [Gd(DO3A‐Pr‐ATP)(H2O)2] (4) was synthesized by the reaction of DO3A‐Pr‐ATP with gadolinium(III) perchlorate hydrate in water. The X‐ and Q‐band EPR spectra of 4 contain a broad band with no hyperfine splitting at both room temperature and liquid nitrogen temperature. The g‐values are 2.167 and 2.033 at X‐ and Q‐band, respectively. The magnetic moment of 4 is 7.45 BM which is close to the value for free GdIII ion. The longitudinal relaxivity, r1p, of [Gd(DO3A‐Pr‐ATP)(H2O)2] is 6.51 mM–1 s–1 (24 MHz and 35 ± 0.1 °C), which is higher than that of [Gd(DOTA)(H2O)]– (r1p = 3.56 mM–1 s–1, 20 MHz, 39 °C, pH 7.3) and [Gd(DO3A)(H2O)2] (r1p = 4.8 mM–1 s–1, 20 MHz, 40 °C). The higher relaxivity of 4 than for other systems with q = 2 is due to the increase in the molecular dimension of the complex by the conjugation of ATP. The relaxivity of 4 at pH 8.4 (TRIS buffer) decreases to 5.64 mM–1 s–1, probably due to a change in the hydration number by the replacement of the coordinated water molecules by TRIS. The r1p relaxivity of 4 in the presence of β‐cyclodextrin is 8.97 mM–1 s–1 due to the increase in the molecular weight and dimension of the inclusion complex formed by the noncovalent host–guest interaction of the ATP pendant arm with the hydrophobic cavity of β‐cyclodextrin. The transverse relaxivity, r2p, of 4 is 7.48 mM–1 s–1 (24 MHz and 35 ± 0.1 °C). The r2p/r1p ratio of 1.16 indicates that 4 is a T1‐weighted contrast agent. The ATP moiety remains as an extended pendant arm and does not bind with the metal ion, nor does it block the coordination sites for the inner‐sphere water molecules. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Intramolecular Heck Couplings and Cycloisomerizations of Bromodienes and Enynes with 1′,1′‐Disubstituted Methylenecyclopropane Terminators: Efficient Syntheses of [3]Dendralenes
Authors: Bräse Stefan , Wertal (nee Nüske) Hanno , Frank Daniel , Vidović Denis , de Meijere Armin 
Published: August 2005

Abstract2‐Bromoalka‐1,n‐dienes such as 9, 30 and 14 (n = 7) with tetrasubstituted methylenecyclopropane end groups, under palladium catalysis, underwent cyclization with cyclopropane‐ring opening to give 2‐ethenyl‐3‐methylene‐1‐cycloalkenes 41 (n = 6), 42 (n = 7), and 43, which are substituted monocyclic [3]dendralenes, in 65, 63 and 70 % yield, respectively. The same cross‐conjugated trienes were isolated in good to excellent yields (77–92 %) from the corresponding 1,6‐ (10‐H, 15) and 1,7‐enynes (28‐H) by a more atom‐economic, palladium‐catalyzed cycloisomerization. The vinylpalladium halide intermediate generated by initial carbopalladation of the 1,6‐enyne 10‐H with in situ generated phenylpalladium iodide also underwent the same cyclization cascade to yield the correspondingly phenyl‐substituted cyclic [3]dendralene 41‐Ph (21 %). The palladium‐catalyzed cycloisomerization of the alk‐1‐ene‐7,12‐diyne 33‐H gave the bicyclic cross‐conjugated tetraene 50‐H (43 %). Key features of the mechanism of the palladium‐catalyzed cycloisomerization were proved using the specially designed model system 20‐H. Like other cyclic [3]dendralenes, the ethenyl(methylene)cycloheptene 42 underwent a domino‐Diels–Alder reaction with N‐phenyltriazoline‐3,5‐dione to give a single diastereomer of the pentacyclic heterocycle 69 (77 % yield). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Cover Picture: Design and Application of Self‐Assembled Low Molecular Weight Hydrogels (Eur. J. Org. Chem. 17/2005)
Authors: de Loos Maaike , Feringa Ben L. , van Esch Jan H. 
Published: August 2005

AbstractThe cover picture shows a transmission electron micrograph revealing the three‐dimensional entangled network of fibers found in aqueous solutions of a bis‐urea cyclohexane hydrogelator. What these and many other low molecular weight hydrogelators have in common is that they effectively self‐assemble into elongated fibers, which in turn form a three‐dimensional network that leads to the formation of a gel. The reversible formation of these gels and their unique visco‐elastic properties are currently attracting much interest because of potential applications in, for example, drug delivery, and because the supramolecular chemical approach towards the design of novel hydrogelators has led to gels with tailor‐made properties. The recent developments in this rapidly emerging field of research are discussed in the Microreview by M. de Loos, B. L. Feringa, and J. H. van Esch on p. 3615 ff.
A sensitive biochemical assay for the detection of uracil
Authors: Cabelof Diane C. , Nakamura Jun , Heydari Ahmad R. 
Published: August 2005

AbstractWe have developed a sensitive new assay for the detection of uracil in DNA. The assay described here is an adaptation to the highly sensitive aldehydic slot blot (ASB) assay developed by Nakamura et al. (Nakamura et al. 1998: Cancer Res 58:222–225) in which aldehydic DNA lesions (ADLs) are detected through binding of a biotinylated aldehydic reactive probe to DNA. The uracil DNA glycosylase (UDG)‐coupled ASB assay uses uracil‐DNA glycosylase to generate an abasic site, which is subsequently detected by the ASB methodology. The ability to modify this technique for the detection of uracil has these advantages: small quantities of DNA are required (4 μg of DNA); the assay is adaptable to DNA from both cells and tissues; sensitivity is as good as that achieved by less accessible methodologies, like gas chromatography–mass spectroscopy (GC–MS); DNA strand breaks are not a confounding variable; preexisting aldehydic lesions are blocked through the use of methoxyamine; variation is very low (<3%); radioactive isotopes are not required; and the assay is easy to establish and involves only equipment and reagents that are inexpensive and readily available. This assay is conceivably adaptable to the detection of other DNA base lesions through the use of a variety of DNA glycosylases. Environ. Mol. Mutagen., 2006. © 2005 Wiley‐Liss, Inc.
Biases of submerged bulk and freeze‐core samples
Authors: Zimmermann André , Coulombe‐Pontbriand Moise , Lapointe Michel 
Published: August 2005

AbstractFreeze‐coring and bulk sampling are routine methods used to sample subsurface spawning gravel under shallow water. Both methods have limitations. Freeze‐coring is not believed to representatively sample coarse grain sizes and the sample volumes are relatively small. Conversely, when bulk sampling, even within an enclosure, some fine sediment is suspended and washed away from the sample. This paper assesses the biases in sampling performance between the two methods and determines whether the loss of fines that occurs when bulk sampling could be predicted and thus corrected for.At six riffles the spawning substrate was sampled under approximately 50 cm of water with a bulk sample and three adjacent freeze‐cores. For each riffle, data from the two samples were combined using the method of Fripp and Diplas (1993) and the resultant composite sample was compared with the original freeze‐core and bulk samples to assess the relative precision and biases of the two techniques.On average, the D50 of the bulk samples was 4 mm larger and a one‐third loss of the <2 mm fraction occurred compared with the composite samples. In contrast, freeze‐core samples contain on average 32% more sediment >16 mm compared with composite samples. Based on six samples, taken from six riffles, the amount of sediment finer than 0·5 mm lost using our bulk sampling technique with an enclosure appears to be predictable and correctable. Copyright © 2005 John Wiley & Sons, Ltd.
The Potential of Angiogenesis Soluble Markers in Chronic Hepatitis C *
Authors: Salcedo Xamila , Medina Jesús , Sanz-Cameno Paloma , García-Buey Luisa , Martín-Vilchez Samuel , Borque María J. , López-Cabrera Manuel , Moreno-Otero Ricardo 
Published: August 2005

Abstract

Angiogenesis, the formation of new vessels, has been reported to play a significant pathogenic role in liver damage–associated hepatitis C virus infection. Most of our current knowledge derives from immunohistochemical studies of hepatic biopsy samples obtained from chronic hepatitis C (CHC) patients. We evaluated whether CHC is associated with elevated serum levels of angiogenesis markers and whether these are modulated by therapy. Vascular endothelial growth factor (VEGF), angiopoietin-2 (Ang-2), and soluble Tie-2 (sTie-2) were determined in the serum of 36 CHC patients, before and after receiving antiviral combination therapy with pegylated interferon alpha-2b plus ribavirin, and in 15 healthy controls. CHC patients showed elevated baseline VEGF and Ang-2 levels. After treatment, both factors were decreased, whereas antiangiogenic sTie-2 was increased, indicating a shift toward an “anti-angiogenic” profile of serum markers in CHC patients.
In conclusion,
this suggests that serum VEGF, Ang-2, and sTie-2 levels could be useful as noninvasive, mechanistically based markers of response to therapy and disease progression in CHC. (Hepatology 2005.)
Differential expression of TGFβ‐stimulated clone 22 in normal prostate and prostate cancer
Authors: Rentsch Cyrill A. , Cecchini Marco G. , Schwaninger Ruth , Germann Markus , Markwalder Regula , Heller Manfred , van der Pluijm Gabri , Thalmann George N. , Wetterwald Antoinette 
Published: August 2005

AbstractThe transforming growth factor‐β (TGFβ) superfamily and its downstream effector genes are key regulators of epithelial homeostasis. Altered expression of these genes may be associated with malignant transformation of the prostate gland. The cDNA array analysis of differential expression of the TGFβ superfamily and functionally related genes between patient‐matched noncancerous prostate (NP) and prostate cancer (PC) bulk tissue specimens highlighted two genes, namely TGFβ‐stimulated clone‐22 (TSC‐22) and Id4. Verification of their mRNA expression by real‐time PCR in patient‐matched NP and PC bulk tissue, in laser‐captured pure epithelial and cancer cells and in NP and PC cell lines confirmed TSC‐22 underexpression, but not Id4 overexpression, in PC and in human PC cell lines. Immunohistochemical analysis showed that TSC‐22 protein expression in NP is restricted to the basal cells and colocalizes with the basal cell marker cytokeratin 5. In contrast, all matched PC samples lack TSC‐22 immunoreactivity. Likewise, PC cell lines do not show detectable TSC‐22 protein expression as shown by immunoblotting. TSC‐22 should be considered as a novel basal cell marker, potentially useful for studying lineage determination within the epithelial compartment of the prostate. Conversely, lack of TSC‐22 seems to be a hallmark of malignant transformation of the prostate epithelium. Accordingly, TSC‐22 immunohistochemistry may prove to be a diagnostic tool for discriminating benign lesions from malignant ones of the prostate. The suggested tumour suppressor function of TSC‐22 warrants further investigation on its role in prostate carcinogenesis and on the TSC‐22 pathway as a candidate therapeutic target in PC. © 2005 Wiley‐Liss, Inc.
Scaled interfacial activity of proteins at a hydrophobic solid/aqueous‐buffer interface
Authors: Krishnan Anandi , Liu Yi‐Hsiu , Cha Paul , Allara David , Vogler Erwin A. 
Published: August 2005

AbstractContact‐angle goniometry confirms that interfacial energetics of protein adsorption to the hydrophobic solid/aqueous‐buffer (solid–liquid, SL) surface is not fundamentally different than adsorption to the aqueous‐buffer/air (liquid–vapor, LV) interface measured by pendant‐drop tensiometry. Adsorption isotherms of 9 globular blood proteins with molecular weight (MW) spanning from 10 to 1000 kDa on methyl‐terminated self‐assembled monolayer surfaces demonstrate that (i) proteins are weak surfactants, reducing contact angles by no more than about 15° at maximum solution concentrations (∼10 mg/mL); (ii) the corresponding dynamic range of spreading pressure Πa < 20 mN/m; and (iii) the maximum spreading pressure Π for these diverse proteins falls within a relatively narrow 5 mN/m band. As with adsorption to the LV interface, we find that concentration scaling substantially alters perception of protein interfacial activity measured by Πa. Proteins appear more similar than dissimilar on a weight/volume basis whereas molarity scaling reveals a systematic ordering by MW, suggesting that adsorption is substantially driven by solution concentration rather than diversity in protein amphilicity. Scaling as a ratio‐to‐physiological‐concentration demonstrates that certain proteins exhibit Π at‐and‐well‐below physiological concentration whereas others require substantially higher solution concentration to attain Π. Important among this latter category of proteins is blood factor XII, assumed by the classical biochemical mechanism of plasma coagulation to be highly surface active, even in the presence of overwhelming concentrations of other blood constituents such as albumin and immunoglobulin that are shown by this work to be among the class of highly surface‐active proteins at physiologic concentration. The overarching interpretation of this work is that water plays a dominant, controlling role in the adsorption of globular‐blood proteins to hydrophobic surfaces and that energetics of hydration control the amount of protein adsorbed to poorly water‐wettable biomaterials. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Interfacial chemistry of class II composite restoration: Structure analysis
Authors: Wang Yong , Spencer Paulette 
Published: August 2005

AbstractThe gingival margins of class II composite restorations are particularly vulnerable to marginal leakage and secondary caries. In identifying the factors contributing to caries development, the molecular structure and differences in the structure at the proximal and gingival margins have been largely overlooked. The purpose of this study was to compare the molecular structure at the adhesive/dentin interface of the proximal and gingival walls of class II composite restorations. Class II preparations were cut in 12 unerupted third molars with a water‐cooled high‐speed dental handpiece. The prepared teeth were randomly selected for treatment with Single Bond (SB) + Z100 (3M). Teeth were restored, per manufacturer's directions, under humidity and temperature characteristic of the oral cavity. Restored teeth were kept in sterile Delbecco's phosphate saline for 48 h. The samples were sectioned occluso‐gingivally and micro‐Raman spectra were acquired at ∼1.5‐μm spatial resolution across the composite/adhesive/dentin interfaces. Samples were wet throughout spectral acquisition. Raman spectral characteristics at the proximal and gingival margins were distinctly different; the depth of demineralized dentin was 6–7 μm at proximal margin, 12–13 μm at gingival margin. SB adhesive penetrated the depth of demineralized dentin in a gradient at the proximal margin. The “single bottle” adhesive used in this study, gradually penetrated the depth of the demineralized dentin at the proximal margin but failed to infiltrate the depth at the gingival margin, leaving a thick exposed collagen layer. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
The effect of limited lateral resolution in the measurement of implant surface roughness: A computer simulation
Authors: Hansson S. , Hansson K. N. 
Published: August 2005

AbstractThe surface roughness of dental implants affects the bone response elicited. Surface roughness is generally described by a range of surface texture parameters. The aim of the present study was to use computerized simulation to investigate the extent to which the lateral resolution of an instrument/method limits the accuracy of certain surface roughness parameters. The lateral resolution was defined as the pixel size of a profiling system. A surface roughness was simulated by a trigonometric function with random periodicity and amplitude. The function was divided into an array of pixels simulating the pixels of the profiling system. The mean height value for each pixel was used to calculate the surface roughness parameters. It was found that the accuracy of all the surface roughness parameters investigated decreased with increasing pixel size. This tendency was most pronounced for mean slope and developed length ratio; amounting to about 80% of their true values for a pixel size of 20% of the true mean high‐spot spacing. It was concluded that the lateral resolution of an instrument/method severely compromises the precision of surface roughness parameters measured for roughness features with a mean high‐spot spacing less than five times the lateral resolution. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Fault tolerant forwarding and optical indexes: A design theory approach
Authors: Gupta Arvind , Maňuch Ján , Stacho Ladislav 
Published: August 2005

AbstractWe study the problem of designing fault tolerant routings in both complete and complete bipartite optical networks. We show that this problem has strong connections to various fundamental problems in design theory. Using a design theory approach, we find optimal f‐fault tolerant arc‐forwarding indexes for all complete networks and all complete balanced bipartite networks. Similarly, we find almost exact values for f‐fault tolerant optical indexes for these networks. © 2005 Wiley Periodicals, Inc. J Combin Designs
Steiner triple systems with two disjoint subsystems
Authors: Bryant Darryn , Horsley Daniel 
Published: August 2005

AbstractIt is shown that there exists a triangle decomposition of the graph obtained from the complete graph of ordervby removing the edges of two vertex disjoint complete subgraphs of ordersuandwif and only ifu,w, andvare odd,${{v}\choose 2}-{u\choose 2}- {w\choose 2}\equiv 0$(mod 3), and${v}\ge w + u +{\rm max} \{ u,w\}$. Such decompositions are equivalent to group divisible designs with block size 3, one group of sizeu, one group of sizew, andv–u–wgroups of size 1. This result settles the existence problem for Steiner triple systems having two disjoint specified subsystems, thereby generalizing the well‐known theorem of Doyen and Wilson on the existence of Steiner triple systems with a single specified subsystem. © 2005 Wiley Periodicals, Inc. J Combin Designs
Bioleaching of acid‐consuming low‐grade nickel ore with elemental sulfur addition and subsequent acid generation
Authors: Salo‐Zieman Virpi LA , Kinnunen Päivi H‐M , Puhakka Jaakko A 
Published: August 2005

AbstractThe bioleaching of a nickel concentrate and an acid‐consuming nickel ore was studied using a co‐culture of Acidithiobacillus ferrooxidans and A. thiooxidans, as well as a thermophilic enrichment culture, VS2. The VS2 was dominated by a Sulfolobus species related to Sulfolobus metallicus. Nickel concentrate was readily solubilized with A. ferrooxidans and the VS2, resulting in nickel yields of 56% and 100%, respectively. Low‐grade nickel ore required 350 g H2SO4 kg−1 ore for maintaining the pH of the leaching solution below 3. To overcome the high acid demand, biological elemental sulfur oxidation was combined with the ore leaching. Leaching of a 2% (wt/vol) nickel ore with a co‐culture of A. thiooxidans and A. ferrooxidans resulted in nickel yield of up to 86% with acid supplementation of 290 g H2SO4 kg−1 ore. When coupled with biological sulfur oxidation, an 86% nickel recovery was achieved with 0.5% (wt/vol) ore concentration without further sulfuric acid addition. The VS2 oxidized sulfur at a rate of 0.063 g L−1 d−1 and the simultaneous nickel ore leaching resulted in 100% nickel yield. In summary, the potential of using elemental sulfur addition and subsequent biological acid generation to maintain the low pH during bioleaching of an acid‐consuming nickel ore was demonstrated. Copyright © 2005 Society of Chemical Industry
Phenoxymethylpenicillin–intercalated hydrotalcite as a bacteria inhibitor
Authors: Li Wen‐Zhuo , Lu Jun , Chen Jie‐Sheng , Li Guo‐Dong , Jiang Yu‐Sheng , Li Lian‐Sheng , Huang Bai‐Qu 
Published: August 2005

AbstractPhenoxymethylpenicillin (PMP) has been reversibly intercalated into a layered double hydroxide, and the resulting composite exhibits effective anti‐bacterial activity. Powder X‐ray diffraction studies indicate that the PMP molecules are interdigitated between the inorganic layers, and under mild acidic media, the molecules are released gradually. Therefore a sustained‐release anti‐bacterial medication is envisioned on the basis of this inorganic–drug composite. Copyright © 2005 Society of Chemical Industry
Extraction of essential oil from geranium (Pelargonium graveolens) with supercritical carbon dioxide
Authors: Peterson Amelia , Machmudah Siti , Roy Bhupesh C , Goto Motonobu , Sasaki Mitsuru , Hirose Tsutomu 
Published: August 2005

AbstractThis study investigated the supercritical fluid extraction (SFE) of geranium essential oil from geranium (Pelargonium graveolens) using supercritical carbon dioxide solvent. The extraction yield was measured as a function of pressure, temperature and carbon dioxide flow rate. At low pressure (10 MPa) and high temperature (343 K), waxes were co‐extracted with the essential oil, resulting in artificially elevated essential oil extraction yields as no method was available with the SFE apparatus used to separate co‐extracted waxes and oil. At high pressure (30 MPa) and low temperature (313 K), the amount of wax co‐extracted decreased. Under these ‘optimum’ conditions, the extraction yield increased with decrease in flow rate giving a maximum extraction yield of 2.53%. All samples were analyzed by gas chromatography–mass spectrometry and the effect of pressure and extraction time on oil composition was studied. The percentage compositions of terpene hydrocarbons, terpenols, geraniol and geranyl esters were significantly affected by pressure and extraction time. The oil samples obtained by SFE were also compared with commercially obtained steam distilled samples. All major components of the commercially obtained oils were present in the SFE‐obtained oils; however, the percentage composition of the major components differed greatly between steam distilled and SFE oils. Copyright © 2005 Society of Chemical Industry