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Strong Affinity (strong + affinity)
Selected AbstractsTriassic metasedimentary successions across the boundary between the southern Apennines and the Calabrian Arc (northern Calabria, Italy)GEOLOGICAL JOURNAL, Issue 2 2005A. Iannace Abstract The boundary area between the Apenninic fold-and-thrust belt and the crystalline Calabrian Arc, located around Sangineto in northern Calabria, has been investigated. New geological mapping in the Sant'Agata area has been performed on the Triassic successions traditionally attributed to the metasedimentary San Donato Unit. This, coupled with a reappraisal of the stratigraphy and tectonics of coeval successions present more to the south in the Cetraro Unit, results in a new reconstruction of the Triassic evolution of all the metasedimentary successions found in the region. Four informal stratigraphic units have been distinguished in the S. Agata area. The lowest one (Unit A) consists of well-bedded metalimestones and bioturbated marly limestones that correlate with Ladinian,Carnian carbonates in nearby areas. A second unit (Unit B), never recognized before, contains a complex alternation of dolomites, phyllites and some meta-arenites containing several beds of Cavernoso facies, attributed to the Carnian. They grade upward to platform and platform-margin dolomites of Norian,Rhaetian age (Unit C) that in turn are replaced upward and laterally by a fourth unit (Unit D) consisting of well-bedded, dark dolomites and metalimestones with marly interlayers locally found as resedimented large blocks in slope conglomerates. Unit D correlates with Rhaetian,Liassic beds in nearby areas. Several pieces of evidence of post-metamorphic contractional tectonics, with 140°N and 30°N trends, are found together with evidence of SW-directed extension. The siliciclastic Carnian beds of Unit B are correlated with the phyllites of Cetraro, formerly believed to be Middle Triassic; moreover, it is suggested that in the Cetraro area Unit C is almost totally replaced by Unit D. This demonstrates that the former distinction between the two tectonic units in the whole area has to be discarded. We have made a general palaeoenvironmental reconstruction which progresses laterally, during Ladinian,Carnian times, from (i) a coastal, mixed siliciclastic,carbonate,evaporitic area at Cetraro to (ii) a transitional carbonate shelf where siliciclastic input was only episodic, and finally to (iii) a bioconstructed margin which was later replaced by a steepened margin created by tectonic instability. Starting from the Norian, subsidence shifted toward the former coastal area where an intraplatform, restricted basin developed. The proposed stratigraphy corresponds closely to the Alpujarride units of the Betic Cordillera, Spain. Moreover, it is shown that strong affinities also exist, in terms of the structural framework, with the metamorphic units of Tuscany and Liguria. Copyright © 2005 John Wiley & Sons, Ltd. [source] Results of longterm hospital based cytological screening in asymptomatic womenDIAGNOSTIC CYTOPATHOLOGY, Issue 3 2006Jata S. Misra Ph.D., M.I.A.C. Abstract Routine cytological screening has been carried out in 27,062 asymptomatic women attending Gynaec and Family Planning O.P.D. of Queen Mary's Hospital, Lucknow, India (April 1971,December 2004). Incidence of squamous intraepithelial lesion (SIL) was found to be 5.9% in the series, while cervical malignancy was seen in 0.6% of cases. The study highlighted the immense utility of cytological screening in minimizing the incidence of carcinoma cervix in the segment of the urban population screened, as the incidence dropped down to 0.5% in the second half from 1.1% noticed in the first half of the screening period. The study also emphasized the utility of clinically downstaging the cervical cancer as 7,316 women showing clinical lesions of cervix were found to harbor SIL in 15.3% and carcinoma cervix in 1.3% of cases as against the incidence of 2.5% for SIL and 0.6% for frank cancer in women with normal cervix. The investigation into different risk factors involved in cervical carcinogenesis revealed that the incidence of SIL and cancer cervix showed a rise with increasing age and parity and prolonged sexual period. The incidences of both cervical cytopathologies were also higher in women of low socio-economic status while religion was found to have no bearing on the occurrence of the disease. Among the four sexually transmitted diseases (STDs) diagnosed in the cervical smears, Trichomonas vaginalis was found to be more prevalent (2.6%), while human papillomavirus (HPV) and Herpes simplex was seen in 0.4 and 0.2% of cases, respectively Herpes simplex was found to have strong affinity with both SIL and carcinoma cervix, while only SIL incidence was high with HPV infection. The study emphasizes need of proper education to women of low socio-economic class for creating awareness regarding hazards and risk factors of cervical cancer as well as management and cure of the disease. Diagn. Cytopathol. 2006;34: 184,187. © 2006 Wiley-Liss, Inc. [source] Protein-based electrochemical biosensor for detection of silver(I) ions,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2010Sona Krizkova Abstract Silver(I) ions are extremely toxic to aquatic animals. Hence, monitoring of these ions in the environment is needed. The aim of the present study was to suggest a simple biosensor for silver(I) ions detection. The suggested biosensor is based on the modification of a hanging mercury drop electrode (HMDE) by the heavy metal binding protein metallothionein (MT) for silver(I) ions detection. Metallothionein accumulated for 120 s onto the HMDE surface. After rinsing the electrode, the biosensor (MT modified HMDE) was prepared prior to detection of silver(I) ions. The biosensor was immersed in a solution containing silver(I) ions. These ions were bound to the MT structure. Furthermore, the electrode was rinsed and transferred to a pure supporting electrolyte solution, in which no interference was present. Under these experimental conditions, other signals relating to heavy metals naturally occurring in MT were not detected. This phenomenon confirms the strong affinity of silver(I) ions for MT. The suggested biosensor responded well to higher silver(I) ion concentrations. The relative standard deviation for measurements of concentrations higher than 50,µM was approximately 2% (n,=,8). In the case of concentrations lower than 10,µM, the relative standard deviation increased to 10% (n,=,8). The detection limit (3,signal/noise) for silver(I) ions was estimated as 500,nM. Environ. Toxicol. Chem. 2010;29:492,496. © 2009 SETAC [source] Phase distribution of synthetic pyrethroids in runoff and stream waterENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2004Weiping Liu Abstract Synthetic pyrethroids (SPs) are a group of hydrophobic compounds with significant aquatic toxicity. Their strong affinity to suspended solids and humic materials suggests that SPs in natural surface water are distributed in solid-adsorbed, dissolved organic matter (DOM)-adsorbed, and freely dissolved phases. The freely dissolved phase is of particular importance because of its mobility and bioavailability. In the present study, we used solid-phase microextraction to detect the freely dissolved phase, and we evaluated the phase distribution of bifenthrin and permethrin in stream and runoff waters. In stream water, most SPs were associated with the suspended solids and, to a lesser extent, with DOM. The freely dissolved phase contributed only 0.4% to 1.0%. In runoff effluents, the freely dissolved concentration was 10% to 27% of the overall concentration. The predominant partitioning into the adsorbed phases implies that the toxicity of SPs in surface water is reduced because of decreased bioavailability. This also suggests that monitoring protocols that do not selectively define the freely dissolved phase can lead to significant overestimation of toxicity or water-quality impacts by SPs. [source] Partitioning of metals (Cd, Co, Cu, Ni, Pb, Zn) in soils: concepts, methodologies, prediction and applications , a reviewEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2009F. Degryse Summary Prediction of the fate of metals in soil requires knowledge of their solid,liquid partitioning. This paper reviews analytical methods and models for measuring or predicting the solid,liquid partitioning of metals in aerobic soils, and collates experimental data. The partitioning is often expressed with an empirical distribution coefficient or Kd, which gives the ratio of the concentration in the solid phase to that in the solution phase. The Kd value of a metal reflects the net effect of various reactions in the solid and liquid phases and varies by orders of magnitude among soils. The Kd value can be derived from the solid,liquid distribution of added metal or that of the soil-borne metal. Only part of the solid-phase metal is rapidly exchangeable with the solution phase. Various methods have been developed to quantify this ,labile' phase, and Kd values based on this phase often correlate better with soil properties than Kd values based on total concentration, and are more appropriate to express metal ion buffering in solute transport models. The in situ soil solution is the preferred solution phase for Kd determinations. Alternatively, water or dilute-salt extracts can be used, but these may underestimate in situ concentrations of dissolved metals because of dilution of metal-complexing ligands such as dissolved organic matter. Multi-surface models and empirical models have been proposed to predict metal partitioning from soil properties. Though soil pH is the most important soil property determining the retention of the free metal ion, Kd values based on total dissolved metal in solution may show little pH dependence for metal ions that have strong affinity for dissolved organic matter. The Kd coefficient is used as an equilibrium constant in risk assessment models. However, slow dissociation of metal complexes in solution and slow exchange of metals between labile and non-labile pools in the solid phase may invalidate this equilibrium assumption. [source] Zinc ion adsorption on montmorillonite,Al hydroxide polymer systemsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2003R. P. T. Janssen Summary Clay,Al hydroxide polymers (CAlHO) can bind heavy metals effectively and may play an important role in the adsorption behaviour and metal binding capacity of soils. We studied the dependence of Al loading and pH on the adsorption of Zn on Na-saturated montmorillonite,Al hydroxide polymer systems. The available binding sites on Al hydroxide polymers (AlHO) had a very strong affinity for Zn ions. Zinc binding on the clay surface became important when the binding sites on the AlHO were nearly all occupied. The pH had a very strong effect on the Zn binding. At pH 6.6 much more Zn could be adsorbed to the AlHO than at pH 5.0. The effect of the Al:clay ratio on Zn binding was influenced by pH. At pH 6.6, Zn binding to the AlHO, expressed per mole AlHO, was independent of the Al:clay ratio, whereas at pH 5.0 this relation was dependent. This is related to the constant charge of the AlHO at pH 6.6, whereas at pH 5.0 the charge decreases with increasing Al:clay ratio. If clay,Al hydroxide polymers are present in the soil their Zn binding to the AlHO will strongly influence the availability of the Zn. [source] Interaction of copper and zinc with allophane and organic matter in the B horizon of an AndosolEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2003C. Latrille Summary Andosols developed on basaltic material are naturally rich in metals. Organic matter and allophane, the key colloids of these soils, have a strong affinity for trace metals, but are intimately mixed so that speciation of trace metal is difficult to determine. We used three complementary approaches, namely physical fractionation, chemical extraction and potentiometric measurement, to distinguish them. Physical particle-size separations and chemical selective dissolution of allophanes and organic matter were combined to demonstrate relations between the occurrence of colloids and contents of Cu and Zn in an andic B horizon. About 22% of total soil Cu and 7% of total soil Zn were present in the < 5-,m fraction, associated with organic or amorphous mineral constituents. To support this association further, the affinity of soil colloids for Cu and Zn in a mimicked system was demonstrated. An Al-rich allophane was synthesized, and a portion of the organic matter was extracted from the clay fraction, and their reactivities towards Cu2+ or Zn2+ were studied by potentiometry. The two metallic cations displayed specific affinity towards allophane or soluble organic matter. Furthermore, the behaviour of copper and zinc in the ternary system, allophane + soluble organic matter + trace element, revealed a synergy in the surface complexation. The use of these three speciation approaches highlighted the linkage between metals and constituents, and showed how important the colloidal constituents are in the behaviour of Cu and Zn in Andosols. [source] Cross-species divergence of the major recognition pathways of ubiquitylated substrates for ubiquitin/26S proteasome-mediated proteolysisFEBS JOURNAL, Issue 3 2010Antony S. Fatimababy The recognition of ubiquitylated substrates is an essential element of ubiquitin/26S proteasome-mediated proteolysis (UPP), which is mediated directly by the proteasome subunit RPN10 and/or RPN13, or indirectly by ubiquitin receptors containing ubiquitin-like and ubiquitin-associated domains. By pull-down and mutagenesis assays, we detected cross-species divergence of the major recognition pathways. RPN10 plays a major role in direct recognition in Arabidopsis and yeast based on the strong affinity for the long and K48-linked ubiquitin chains. In contrast, both the RPN10 and RPN13 homologs play major roles in humans. For indirect recognition, the RAD23 and DSK2 homologs (except for the human DSK2 homolog) are major receptors. The human RAD23 homolog is targeted to the 26S proteasome by the RPN10 and RPN13 homologs. In comparison, Arabidopsis uses UIM1 and UIM3 of RPN10 to bind DSK2 and RAD23, respectively. Yeast uses UIM in RPN10 and LRR in RPN1. Overall, multiple proteasome subunits are responsible for the direct and/or indirect recognition of ubiquitylated substrates in yeast and humans. In contrast, a single proteasome subunit, RPN10, is critical for both the direct and indirect recognition pathways in Arabidopsis. In agreement with these results, the accumulation of ubiquitylated substrates and severe pleiotropic phenotypes of vegetative and reproductive growth are associated with the loss of RPN10 function in an Arabidopsis T-DNA insertion mutant. This implies that the targeting and proteolysis of the critical regulators involved are affected. These results support a cross-species mechanistic and functional divergence of the major recognition pathways for ubiquitylated substrates of UPP. Structured digital abstract ,,A list of the large number of protein-protein interactions described in this article is available via the MINT article ID MINT-7307429 [source] The role of interface framework residues in determining antibody VH/VL interaction strength and antigen-binding affinityFEBS JOURNAL, Issue 10 2006Kenji Masuda While many antibodies with strong antigen-binding affinity have stable variable regions with a strong antibody heavy chain variable region fragment (VH)/antibody light chain variable region fragment (VL) interaction, the anti-lysozyme IgG HyHEL-10 has a fairly strong affinity, yet a very weak VH/VL interaction strength, in the absence of antigen. To investigate the possible relationship between antigen-binding affinity and VH/VL interaction strength, a novel phage display system that can switch two display modes was employed. We focused on the two framework region 2 regions of the HyHEL-10 VH and VL, facing each other at the domain interface, and a combinatorial library was made in which each framework region 2 residue was mixed with that of D1.3, which has a far stronger VH/VL interaction. The phagemid library, encoding VH gene 7 and VL amber codon gene 9, was used to transform TG-1 (sup+), and the phages displaying functional variable regions were selected. The selected phages were then used to infect a nonsuppressing strain, and the culture supernatant containing VH -displaying phages and soluble VL fragment was used to evaluate the VH/VL interaction strength. The results clearly showed the existence of a key framework region 2 residue (H39) that strongly affects VH/VL interaction strength, and a marked positive correlation between the antigen-binding affinity and the VH/VL interaction, especially in the presence of a set of particular VL residues. The effect of the H39 mutation on the wild-type variable region was also confirmed by a SPR biosensor as a several-fold increase in antigen-binding affinity owing to an increased association rate, while a slight decrease was observed for the single-chain variable region. [source] Growth and albitization of K-feldspar in crystalline rocks in the shallow crust: a tracer for fluid circulation during exhumation?GEOFLUIDS (ELECTRONIC), Issue 2 2003M. B. Holness Abstract A general feature of medium- to coarse-grained, sheet-silicate bearing, quartzo-feldspathic rocks of either metamorphic or igneous affinity is the retrograde development of lenses of pure K-feldspar at the grain boundaries between sheet silicate (0 0 1) faces and original feldspar grains. The growth of these lenses acts to displace and deform the sheet silicate grain by a force of crystallization, although the substrate feldspar and adjacent quartz are not deformed. Subsequent to the growth of the lenses they are replaced to variable degrees by pure albite, which grows into the lens from the substrate feldspar behind an irregular replacement front. The composition and texture of both K-feldspar and replacive albite suggest a strong affinity with authigenic feldspars, although it is considered likely that the K-feldspar of the lenses is derived from low-temperature biotite-breakdown reactions. A model is proposed whereby the lenses grow into open pores at dilatant sites in response to infiltration of aqueous fluids as the crystalline rocks are exhumed under brittle conditions. Continued circulation of infiltrating fluids in a temperature gradient results in the replacement of K-feldspar by albite via an alkali exchange process. The lenses point to a significant grain-scale permeability in crystalline rock at shallow levels in the crust. [source] Functional Hydrogel Surfaces: Binding Kinesin-Based Molecular Motor Proteins to Selected Patterned Sites,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2005T. Yu Abstract Hydrogel microstructures with micrometer-scale topography and controllable functionality have great potential for numerous nanobiotechnology applications including, for example, three-dimensional structures that exhibit controlled interactions with proteins and cells. Taking advantage of the strong affinity of histidine (His) residues for metal-ion,nitrilotriacetic acid (NTA) complexes, we have chemically modified hydrogels to enable protein immobilization with retention of activity by incorporating 2-methacrylamidobutyl nitrilotriacetic acid, an NTA-containing monomer that can be copolymerized with a series of monomers to form NTA-containing hydrogels. By varying the NTA-monomer composition in the hydrogels, it is possible to control the amount of protein bound to the hydrogel surface. The retention of biological activity was demonstrated by microtubule gliding assays. Normally, hydrogels are resistant to protein binding, but we have selected these materials because of their porous nature. Bringing together hydrogel functionalization and soft-lithography patterning techniques, it was possible to create a hybrid hydrogel superstructure that possesses binding specificity to His-tagged protein in selected sites. This type of surface and microstructure is not only advantageous for motor protein integration, but it can also be generally applied to the formation of His-tagged molecules for sensors and biochip applications. [source] On open-set lattices and some of their applications in semanticsINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 12 2003Mouw-Ching Tjiok In this article, we present the theory of Kripke semantics, along with the mathematical framework and applications of Kripke semantics. We take the Kripke-Sato approach to define the knowledge operator in relation to Hintikka's possible worlds model, which is an application of the semantics of intuitionistic logic and modal logic. The applications are interesting from the viewpoint of agent interactives and process interaction. We propose (i) an application of possible worlds semantics, which enables the evaluation of the truth value of a conditional sentence without explicitly defining the operator "," (implication), through clustering on the space of events (worlds) using the notion of neighborhood; and (ii) a semantical approach to treat discrete dynamic process using Kripke-Beth semantics. Starting from the topological approach, we define the measure-theoretical machinery, in particular, we adopt the methods developed in stochastic process,mainly the martingale,to our semantics; this involves some Boolean algebraic (BA) manipulations. The clustering on the space of events (worlds), using the notion of neighborhood, enables us to define an accessibility relation that is necessary for the evaluation of the conditional sentence. Our approach is by taking the neighborhood as an open set and looking at topological properties using metric space, in particular, the so-called ,-ball; then, we can perform the implication by computing Euclidean distance, whenever we introduce a certain enumerative scheme to transform the semantic objects into mathematical objects. Thus, this method provides an approach to quantify semantic notions. Combining with modal operators Ki operating on E set, it provides a more-computable way to recognize the "indistinguishability" in some applications, e.g., electronic catalogue. Because semantics used in this context is a local matter, we also propose the application of sheaf theory for passing local information to global information. By looking at Kripke interpretation as a function with values in an open-set lattice ,,U, which is formed by stepwise verification process, we obtain a topological space structure. Now, using the measure-theoretical approach by taking the Borel set and Borel function in defining measurable functions, this can be extended to treat the dynamical aspect of processes; from the stochastic process, considered as a family of random variables over a measure space (the probability space triple), we draw two strong parallels between Kripke semantics and stochastic process (mainly martingales): first, the strong affinity of Kripke-Beth path semantics and time path of the process; and second, the treatment of time as parametrization to the dynamic process using the technique of filtration, adapted process, and progressive process. The technique provides very effective manipulation of BA in the form of random variables and ,-subalgebra under the cover of measurable functions. This enables us to adopt the computational algorithms obtained for stochastic processes to path semantics. Besides, using the technique of measurable functions, we indeed obtain an intrinsic way to introduce the notion of time sequence. © 2003 Wiley Periodicals, Inc. [source] Development of a 1-Methylcyclopropene (1-MCP) Sachet Release SystemJOURNAL OF FOOD SCIENCE, Issue 1 2006Younsuk S. Lee ABSTRACT The partitioning of 1-methylcyclopropene (1-MCP) between the gas/polymer matrix was determined for 2 adsorbing agents and 4 sachet materials to estimate the adsorption potential of 1-MCP at 23°C. The release study was performed using a closed system under 2 different environmental conditions, dry air (0% RH) and 90% RH. Sachets made from Tyvek®, paper, low-density polyethylene (LDPE), and polyvinyl acetate (PVA) materials were fabricated to contain silica gel and activated carbon. Activated carbon sachets did not release 1-MCP at either testing condition. Activated carbon had a very strong affinity for 1-MCP. The permeability coefficients of 1-MCP and water in polyethylene and polyvinyl acetate films were determined using a quasi-isostatic method. LDPE sachets containing silica gel had similar 1-MCP release rates at both 0% and 90% RH. PVA sachets containing silica gel had slow release of 1-MCP. The amount of 1-MCP released from PVA sachets containing silica gel at 90% RH was larger than the amount of 1-MCP released at 0% RH. Release of 1-MCP from paper and Tyvek sachets was largely dependent on the sorbate-absorbing ability of the adsorbing agents. [source] Bayesian mixture models for complex high dimensional count data in phage display experimentsJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 2 2007Yuan Ji Summary., Phage display is a biological process that is used to screen random peptide libraries for ligands that bind to a target of interest with high affinity. On the basis of a count data set from an innovative multistage phage display experiment, we propose a class of Bayesian mixture models to cluster peptide counts into three groups that exhibit different display patterns across stages. Among the three groups, the investigators are particularly interested in that with an ascending display pattern in the counts, which implies that the peptides are likely to bind to the target with strong affinity. We apply a Bayesian false discovery rate approach to identify the peptides with the strongest affinity within the group. A list of peptides is obtained, among which important ones with meaningful functions are further validated by biologists. To examine the performance of the Bayesian model, we conduct a simulation study and obtain desirable results. [source] Biological significance and development of practical synthesis of biotinMEDICINAL RESEARCH REVIEWS, Issue 4 2006Masahiko Seki Abstract Biotin (1), a water-soluble B series vitamin, distributes widely in microorganisms, plants, and animals. Biosynthesis of 1 involves five steps sequence starting from pimelic acid. The last step, a transformation from dethiobiotin (DTB) to 1, includes an iron clusters-mediated radical process. The compound 1 is a cofactor of carboxylation enzymes and plays crucial roles in the metabolism of fatty acids, sugars, and ,-amino acids. In addition to the increasing application to feed additives, recent reports have revealed that 1 enhances insulin secretion in animals, suggesting it for a promising therapeutic candidate for an anti-diabetes drug. The remarkably strong affinity of 1 with avidin and streptavidin has been extensively applied for such technologies as photoaffinity labeling. Among the number of approaches to 1 so far developed in 50 years, a synthesis using L -cysteine and thiolactone as a starting material and a key intermediate, respectively, represents one of the best routes leading to 1, because of short steps, high yield, use of inexpensive reagents, and ease of operation. © 2006 Wiley Periodicals, Inc. Med Res Rev, 26, No. 4, 434,482, 2006 [source] Petrography, mineralogy, and trace element geochemistry of lunar meteorite Dhofar 1180METEORITICS & PLANETARY SCIENCE, Issue 9 2009Aicheng Zhang Dhofar 1180 is predominantly composed of fine-grained matrix with abundant mineral fragments and a few lithic and glassy clasts. Lithic clasts show a variety of textures including cataclastic, gabbroic, granulitic, ophitic/subophitic, and microporphyritic. Both feldspathic and mafic lithic clasts are present. Most feldspathic lithic clasts have a strong affinity to ferroan anorthositic suite rocks and one to magnesian suite rocks. Mafic lithic clasts are moderately to extremely Fe-rich. The Ti/[Ti+Cr]-Fe/[Fe+Mg] compositional trend of pyroxenes in mafic lithic clasts is consistent with that of low-Ti mare basalts. Glasses display a wide chemical variation from mafic to feldspathic. Some glasses are very similar to those from Apollo 16 soils. KREEP components are essentially absent in Dhofar 1180. One glassy clast is rich in K, REE and P, but its Mg/[Mg+Fe] is very low (0.25). It is probably a last-stage differentiation product of mare basalt. Molar Fe/Mn ratios of both olivine and pyroxene are essentially consistent with a lunar origin. Dhofar 1180 has a LREE-enriched (La 18 × CI, Sm 14 × CI) pattern with a small positive Eu anomaly (Eu 15 × CI). Th concentration is 0.7 ppm in Dhofar 1180. Petrography, mineralogy, and trace element geochemistry of Dhofar 1180 are different from those of other lunar meteorites, indicating that Dhofar 1180 represents a unique mingled lunar breccia derived from an area on the lunar nearside but far away from the center of the Imbrium Basin. [source] Molecular-selective adsorption property of chemically surface modified nanoporous alumina membrane by di(1-naphthyl)silanediol to anthracenesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2010Kenji Kakiage Abstract Nano-porous alumina membrane (NPAM) formed by the anodic oxidation of aluminum is an attractive composite as the base material for a functional filter, because of its honeycombed ordered structure with large surface area per weight and also high shape stability. In this work, we investigated the adsorption properties of the NPAM possessing ,-electron systems on the surface, which were produced through chemical surface modification by di(1-naphthyl)silanediol, to aromatic compounds using anthracenes as typical aromatic compounds. The chemically surface-modified NPAM exhibited strong affinity to anthracene molecules and the affinity was observed to be weakened remarkably with the introduction of methyl and phenyl substituents to anthracene, indicating a molecular-selective adsorption property of the NPAM. Copyright © 2009 John Wiley & Sons, Ltd. [source] Structure of human transthyretin complexed with bromophenols: a new mode of bindingACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2000Minakshi Ghosh The binding of two organohalogen substances, pentabromophenol (PBP) and 2,4,6-tribromophenol (TBP), to human transthyretin (TTR), a thyroid hormone transport protein, has been studied by in vitro competitive binding assays and by X-ray crystallography. Both compounds bind to TTR with high affinity, in competition with the natural ligand thyroxine (T4). The crystal structures of the TTR,PBP and TTR,TBP complexes show some unusual binding patterns for the ligands. They bind exclusively in the `reversed' mode, with their hydroxyl group pointing towards the mouth of the binding channel and in planes approximately perpendicular to that adopted by the T4 phenolic ring in a TTR,T4 complex, a feature not observed before. The hydroxyl group in the ligands, which was previously thought to be a key ingredient for a strong binding to TTR, does not seem to play an important role in the binding of these compounds to TTR. In the TTR,PBP complex, it is primarily the halogens which interact with the TTR molecule and therefore must account for the strong affinity of binding. The interactions with the halogens are smaller in number in TTR,TBP and there is a decrease in affinity, even though the interaction with the hydroxyl group is stronger than that in the TTR,PBP complex. [source] Study of nobiletin binding to bovine serum albumin by capillary electrophoresis,frontal analysis and circular dichroismBIOMEDICAL CHROMATOGRAPHY, Issue 9 2010Lian Yi Abstract A very recent epidemiological study provided strong support for nobiletin (NOB) as a potential candidate chemopreventive agent against cancer. From the pharmacology point of view, drug,protein interactions are determining factors in therapeutic, pharmacodynamic and toxicological drug properties. In this work, for the first time, detection of NOB at near-physiological conditions was accomplished by means of capillary electrophoresis,frontal analysis (CE-FA), and then the binding constants of NOB with bovine serum albumin (BSA) at the same conditions were determined. Complexation of NOB,BSA led to a decrease of the height for free NOB with increasing concentration of BSA. These results revealed the presence of a single class of binding site on BSA, and provided the binding constant of 103/m, showing the strong affinity of NOB for BSA. Furthermore, circular dichroism spectra showed that, when the molar ratio of NOB to BSA was up to 2:1, NOB did not affect the overall protein conformation significantly and the protein thus retained a native-like structure. These results may provide important information for preclinical studies of nobiletin in pharmaceutical research. Copyright © 2010 John Wiley & Sons, Ltd. [source] Thiophilic interaction chromatography of Alzheimer's , -amyloid peptidesCHEMICAL BIOLOGY & DRUG DESIGN, Issue 2005S. Parry Abstract:, Alzheimer's disease is characterized by a progressive formation of senile plaques in the brain, the major constituent of which is , -amyloid (A,) peptide, a proteolytic product of the transmembrane , -amyloid precursor protein (APP). Prior to the measurement of levels of the A, peptide for diagnostic purposes, this peptide must be isolated from the myriad of proteins resident in the human serum. Thiophilic interaction chromatography is an effective method for the isolation of proteins and peptides containing clusters of aromatic residues such as tryptophan, phenylalanine and tyrosine. The purpose of the present study was to develop a protocol for binding and recovery of A, peptides (1,38), (1,40) and (1,42) to T-gels by varying T-gel type and elution conditions such as the salt concentration and type of eluent. We established the minimal salt concentration necessary for the binding of the A,(1,40) peptide to the 3S-gel; binding at that concentration was subsequently compared with that of model proteins, lysozyme and , -chymotrypsin and this methodology was extended to 2S-gels and PyS. , -Amyloid peptide (1,40) showed a remarkably strong affinity for all three types of T-gels in comparison to lysozyme and , -chymotrypsin and was found to bind best to 2S-gel. [source] Use of Selenium to Detect Mercury in Water and Cells: An Enhancement of the Sensitivity and Specificity of a Seleno Fluorescent ProbeCHEMISTRY - A EUROPEAN JOURNAL, Issue 13 2009Bo Tang Prof. Abstract Seleno fluorescent probe: An organoselenium fluorescent probe (FSe-1) for mercury was designed based on the irreversible deselenation mechanism. FSe-1 exhibits an ultrahigh selectivity and sensitivity for Hg2+ detection only for reactive selenium atom sites, due the strong affinity between Se and Hg. Furthermore, the new probe has been successfully used for imaging mercury ions in RAW,264.7 cells (a mouse macrophage cell line; see figure). Inspired by the antitoxic function of selenium towards heavy-metal ions, we designed an organoselenium fluorescent probe (FSe-1) for mercury. The reaction of FSe-1 and Hg2+ is an irreversible deselenation mechanism based on the selenophilic character of mercury. FSe-1 exhibits an ultrahigh selectivity and sensitivity for Hg2+ detection only for reactive selenium atom sites due to the strong affinity between Se and Hg. The experimental results proved that FSe-1 was selective for Hg2+ ions over other relevant metal ions and bioanalytes, and also showed an enhancement in sensitivity of up to 1.0,nM, which is lower than the current Environmental Protection Agency standard for drinking water. Furthermore, the new probe has been successfully applied to the imaging of mercury ions in RAW,264.7 cells (a mouse macrophage cell line) with high sensitivity and selectivity. [source] | |||||||||||||||||||