bluuebunny/crossref_metadata_2025_split huggingface dataset:
An in vitro model to evaluate cell adhesion to metals used in implantation shows significant differences between palladium and gold or platinum
Authors: Turner Neill , Armitage Michelle , Butler Ronald , Ireland Grenham 
Published: July 2004

AbstractAdhesion of tissue cells to metallic implants is a major factor that is important for proper tissue integration. Adhesion of Swiss mouse 3T3 fibroblasts to gold, platinum and palladium surfaces was investigated. Immunofluorescence staining for the integrin subunits αv and β1 and the focal contact protein vinculin revealed that cells growing on gold and platinum expressed many focal contacts. In contrast, cells on palladium surfaces had reduced numbers of focal contacts shown by vinculin staining and failed to demonstrate expression of αv and β1 in focal contacts. Spread cell area was also significantly reduced on palladium than on other surfaces suggesting that cells on palladium were more weakly attached. This may be due to either a different molecular composition of focal contacts in cells grown on palladium surfaces or unusual microstructural properties of the palladium surface. This model is useful to evaluate adhesion of cells to different metal surfaces.
2,4,5‐T and 2,4,5‐TCP induce oxidative damage in human erythrocytes: the role of glutathione
Authors: Bukowska Bożena 
Published: July 2004

AbstractThe molecular basis of the toxic properties of phenoxy herbicides in humans and animals has been insufficiently studied. In this study, damage parameters [levels of reduced glutathione (GSH) and total glutathione; activity of glutathione reductase (GR); activities of catalase (CAT) and superoxide dismutase (SOD); levels of adenine nucleotides and adenine energy charge (AEC)] were measured in human erythrocytes exposed in vitro to 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T) and its metabolite 2,4,5‐trichlorophenol (2,4,5‐TCP).Both 2,4,5‐T and 2,4,5‐TCP decreased the level of reduced glutathione (GSH) in erythrocytes in comparison to the control, but did not significantly change the total glutathione (2GSH+GSSG). This suggests that GSH concentration decreases concomitantly with an increase in oxidized glutathione (GSSG). 2,4,5‐TCP at 100 ppm significantly decreased catalase and SOD activities. 2,4,5‐T and 2,4,5‐TCP did not significantly change the activity of glutathione reductase. 2,4,5‐TCP decreased the level of ATP and increased the content of ADP and AMP, indicating a fall in AEC. 2,4,5‐T and 2,4,5‐TCP significantly changed the erythrocyte morphology. All these data are evidence of oxidative stress in erythrocytes incubated with 2,4,5‐T and 2,4,5‐TCP; the stress appears to be more intense in the case of 2,4,5‐TCP.
Patient Satisfaction with Cancer Genetic Counseling: A Psychometric Analysis of the Genetic Counseling Satisfaction Scale
Authors: DeMarco Tiffani A. , Peshkin Beth N. , Mars Bryn D. , Tercyak Kenneth P. 
Published: July 2004

AbstractSatisfaction is an important patient reported outcome of genetic counseling, as it is one of the elements used by professional organizations and healthcare accrediting bodies to determine the quality of professional work. However, empirical research on patient satisfaction with genetic counseling has been limited, partly due to the lack of standardized measures available to assess this construct. The purpose of this study was to conduct a psychometric analysis of a new satisfaction measure, the Genetic Counseling Satisfaction Scale (GCSS), within a sample of women participating in a no‐cost cancer genetic counseling and testing program. The sample consisted of 61 women undergoing counseling and testing for hereditary breast‐ovarian cancer risk (BRCA1/2 testing) who completed the GCSS following pretest counseling. The results suggest that the GCSS was reliable (Cronbach's coefficient alpha = 0.90) and that participants were highly satisfied with the care they received. In addition, there were no differences in satisfaction between cancer genetic counseling and prenatal counseling participants (based on preexisting norms), and satisfaction did not vary by sociodemographic characteristics. Implications and recommendations are discussed.
Infrared Spectra of Sodium and Potassium Cyanide
Authors: Leroi George E. , Klemperer William 
Published: July 2004

The infrared absorption spectra of sodium cyanide and potassium cyanide vapors have been measured in the region 3500 to 200 cm-1. Two absorptions assigned as fundamental frequencies of the monomeric species were found in each system. The absorption frequencies and their present assignments are: NaCN ν2=238, ν3=2176 cm-1; KCN ν2=207, ν3=2158 cm-1. A third absorption at 2076 cm-1 in sodium cyanide vapor is assigned to the dimer of NaCN.
The bond-stretching force constant of the CN group in XCN molecules is sensibly independent of the electronegativity of X. The angle-bending force constant varies directly with the electronegativity of X.
Structure of the Band Spectrum of CuCl Molecule. I. Additional Knowledge in the Coarse Structure
Authors: Rao P. Ramakoteswara , Brody J. K. 
Published: July 2004

A number of new bands in the A, B, C, D, and E systems of CuCl, recorded in the spectrum of the molecule excited in an electrodeless discharge tube by a microwave oscillator, are reported. Because of the employment of high dispersion and the use of a single isotopic species of CuCl (Cu63Cl35), it has been possible to investigate the phenomenon of formation of head of heads in the Δv=−4 sequence of the E system. This phenomenon has also been detected in the Δv=−3 sequence of the A system.
The weak F system has been photographed for the first time under suitable dispersion so that a satisfactory vibrational analysis of the same could be made. The R heads of this system of the Cu63Cl35 molecule are represented by the formula ν63,35F=25287.0+386.8(v′+12)−1.64(v′+12)2−417.1(v′′+12)2+1.50(v′′+12)2.It has been shown that the lower state of the F system is the same as the common lower state of all the other known band systems, which is also the ground state of the molecule. Data on the A and F systems of the Cu65Cl35 molecule also are given.
Vapor Pressures of the Inert Gases
Authors: Hamrin Charles E. , Thodos George 
Published: July 2004

A single vapor-pressure relationship applicable from the triple point to the critical point has been found to exist for the inert gases argon, krypton, and xenon when the reduced vapor pressure PR is related to TR the reduced temperature. This vapor-pressure function resulted from the Frost-Kalkwarf Eq. (12) and can be expressed as logPR=α+(β/TR)+γ logTR+0.1832 (PR/TR2),where 0.1832 is a universal constant. For these inert gases β=−2.2936 and γ=−2.6786 while α can be calculated from the boundary condition, α+β+0.1832=0.
The vapor-pressure data for helium and neon produced similar reduced-vapor-pressure relationships having different constants. These results are not unexpected in view of the significant quantum effects associated with helium and to a lesser degree with neon. Values calculated with this reduced-vapor-pressure equation have been found to be in excellent agreement with experimental values reported for argon, krypton, and xenon. The average deviation for these gases was 0.63%, for neon 1.51%, and for helium 0.79%.
Excited States of Molecules and the Scattering of Fast Electrons
Authors: Karle J. 
Published: July 2004

When fast electrons are scattered by molecules which undergo excitation in the course of the scattering process, the patterns associated with discrete energy losses show the characteristic molecular-diffraction features associated with interatomic distances. A theory is developed here in agreement with experimental results thus far obtained which describes the possible forms for these diffraction features, and shows that the molecular scattering does not necessarily disappear on averaging over all states of excitation, as has been generally assumed for the ``incoherent'' scattering. In developing the theory, the wave function for the molecule is formed from a linear combination of atomic orbitals assumed to be S functions. By means of group theoretical methods the proper linear combinations of S functions may be composed for the possible types of excited electronic states of the molecule. The theoretical analysis also employs the Franck-Condon principle and the Born scattering theory.
From the theory developed here it is possible to predict and interpret gross features of the molecular scattering from molecules in the process of excitation. The accurate prediction of energy changes and atomic background scattering are interesting problems for future consideration. This new electron-diffraction technique should be a valuable adjunct to the field of photon spectroscopy.
Photo- and Semiconduction in Crystalline Chlorophylls a and b
Authors: Rosenberg Barnett , Camiscoli James F. 
Published: July 2004

Measurements are reported on some characteristics of photo-conduction and semiconduction in pure crystalline chlorophylls a and b. The semiconduction activation energy is 1.12 ev in chlorophyll a and 1.44 ev in chlorophyll b (E/2kT). The latter value is in excellent agreement with the triplet state energy of 1.43 ev measured by the phosphorescence method in chlorophyll b. The former value suggests that a possible cause of the lack of detectable phosphorescence in chlorophyll a is that it occurs in the infrared at about 11 000 A. The evidence indicates that the mobility of the predominant charge carriers (positive holes) is the same in both crystals. Photoconduction is easily measured in chlorophyll b and less easily in chlorophyll a, because of the much larger dark current. The photoconduction activation energy in chlorophyll b is 0.36 ev. This supports Rabinowitch's view that photoconduction in chlorophyll is not involved in the primary act of photosynthesis.
The oxygen adsorbed on the surface of the crystals forms an oxygen-chlorophyll complex. This leads to an increase in both the dark current and the photocurrent probably by increasing the mobility of the surface charge carriers. There is no detectable effect of oxygen upon the semiconduction activation energy, since the increase of the magnitude of the current is small (a factor of 4 to 10). The binding energy of the oxygen-chlorophyll a complex is about 1.4 ev; that of the oxygen-chlorophyll b complex 0.63 ev. There is no detectable activation energy for the formation of the complex. It is not a photo-oxidation process. Some evidence suggests that a more tightly bound oxygen complex exists which has no effect on electronic conductivity. This more stable complex is converted by light into the weakly bound complex described above (probably by photoreduction of chlorophyll in the complex). These results are similar to those of Arnold and Sherwood's work on dried chloroplasts. They favor their alternative explanation—that of an oxygen compound being responsible for thermoluminescence and a thermal spike in conductivity—rather than their first assumption, that of electron trapping and recombination in chlorophyll itself.
Microwave Spectrum, Dipole Moment, Structure, and Internal Rotation of Dimethyl Sulfide
Authors: Pierce Louis , Hayashi Michiro 
Published: July 2004

The microwave spectra of five isotopic species of dimethyl sulfide are reported. Changes in rotational constants with isotopic substitution yield the following structural parameters: CS 1.802 A; CSC=98°52′; CH 1.901 A; HCH=109°34′; 2θ=104°22′, where 2θ is the angle between the symmetry axes of the methyl groups. The equilibrium conformation of both methyl groups is the staggered one, i.e., staggered with respect to the adjacent CS bond axis. From Stark effect measurements the dipole moment of dimethyl sulfide is found to be 1.50±0.01 debye.
Fine structure in the ground-state rotational spectrum of (CH3)2S and an excited torsional state of CH3SCD3 has been resolved and analyzed. This fine structure results from coupling of internal and over-all rotation and is affected by top-top coupling terms in the kinetic and potential energy portions of the Hamiltonian. Neglecting only the potential energy coupling terms, the (CH3)2S and CH3SCD3 splittings yield as the barrier to internal rotation 2132±6 and 2118±3 cal/mole, respectively. Estimates of the potential energy coupling parameters are made. They are found to be an order of magnitude smaller than the main term of ∼2100 cal/mole in the Fourier expansion of the potential energy.
Homopolar Dipole
Authors: Coulson C. A. , Rogers Max T. 
Published: July 2004

Numerical tables for the homopolar dipole or overlap moment μh.d. associated with various molecular orbitals (MO's) are presented. The present tables include values of μh.d./R for the common MO's constructed from linear combinations of atomic orbitals (the LCAO approximation), one of which is an 1s, 2s, 2pσ, 2pπ, 3s, or 3pσ orbital. The calculations employ approximate atomic orbitals of the Slater type. Formulas for x̄AB, the x coordinate of the centroid of negative charge for an electron in an MO, are given as functions of the parameters p=12R(ζA+ζB) and t=(ζA−ζB)/(ζA+ζB), where R is the internuclear distance, ζ (n—δ) is the effective nuclear charge found by the Slater rules, and (n—δ) is an effective quantum number. Values of μh.d./R are also given for some MO's in which one AO is a hybrid. The variation of μh.d. with the parameters p and t is shown graphically for certain MO's. The overlap moment μh.d. has been computed for various chemical bonds by use of the tables.
Overlap integrals for the AO combinations 1s—3dσ, 2s—5s, 2s—5pσ, 2pπ—3dπ, and 3s—3s were computed since these were not available in the literature over the necessary range of the variables.
Green Light Stimulates Early Stem Elongation, Antagonizing Light-Mediated Growth Inhibition
Authors: Folta Kevin M. 
Published: July 2004

Abstract
During the transition from darkness to light, the rate of hypocotyl elongation is determined from the integration of light signals sensed through the phototropin, cryptochrome, and phytochrome signaling pathways. In all light conditions studied, from UV to far-red, early hypocotyl growth is rapidly and robustly suppressed within minutes of illumination in a manner dependent upon light quality and quantity. In this study, it is shown that green light (GL) irradiation leads to a rapid increase in the growth rate of etiolated Arabidopsis seedlings. GL-mediated growth promotion was detected in response to constant irradiation or a short, single pulse of light with a similar time course. The response has a threshold between 10−1 and 100 μmol m−2, is saturated before 102 μmol m−2 and obeys reciprocity. Genetic analyses indicate that the cryptochrome or phototropin photoreceptors do not participate in the response. The major phytochrome receptors influence the normal amplitude and timing of the GL response, yet the GL response is normal in seedlings grown for hours under constant dim-red light. Therefore, phytochrome activation enhances, but is not required for, the GL response. Seedlings grown under green, red, and blue light together are longer than those grown under red and blue alone. These data indicate that a novel GL-activated light sensor promotes early stem elongation that antagonizes growth inhibition.
Cloning and Characterization of Two NAD Kinases from Arabidopsis. Identification of a Calmodulin Binding Isoform
Authors: Turner William L. , Waller Jeffrey C. , Vanderbeld Barb , Snedden Wayne A. 
Published: July 2004

Abstract
NAD kinase (NADK; ATP:NAD 2′-phosphotransferase, EC 2.7.1.23), an enzyme found in both prokaryotes and eukaryotes, generates the important pyridine nucleotide NADP from substrates ATP and NAD. The role of NADKs in plants is poorly understood, and cDNAs encoding plant NADKs have not previously been described to our knowledge. We have cloned two cDNAs from Arabidopsis predicted to encode NADK isoforms, designated NADK1 and NADK2, respectively. Expressed as recombinant proteins in bacteria, both NADK1 and NADK2 were catalytically active, thereby confirming their identity as NADKs. Transcripts for both isoforms were detected in all tissues examined and throughout development. Although the predicted catalytic regions for NADK1 and NADK2 show sequence similarity to NADKs from other organisms, NADK2 possesses a large N-terminal extension that appears to be unique to plants. Using recombinant glutathione-S-transferase fusion proteins and calmodulin (CaM)-affinity chromatography, we delineated a Ca2+-dependent CaM-binding domain to a 45-residue region within the N-terminal extension of NADK2. Although recombinant NADK2 was not responsive to CaM in vitro, immunoblot analysis suggests that native NADK2 is a CaM-binding protein. In Arabidopsis crude extracts, CaM-dependent NADK activity was much greater than CaM-independent activity throughout development, particularly in young seedlings. A native CaM-dependent NADK was partially purified from Arabidopsis seedlings (K m NAD=0.20 mM, K m Mg2+−ATP=0.17 mM). The enzyme was fully activated by conserved CaM (S 0.5 = 2.2 nm) in the presence of calcium but displayed differential responsiveness to eight CaM-like Arabidopsis proteins. Possible roles for NADKs in plants are discussed in light of our observations.
Signal Peptide-Dependent Targeting of a Riceα-Amylase and Cargo Proteins to Plastids and Extracellular Compartments of Plant Cells
Authors: Chen Min-Huei , Huang Li-Fen , Li Hsou-min , Chen Yung-Reui , Yu Su-May 
Published: July 2004

Abstractα-Amylases are important enzymes for starch degradation in plants. However, it has been a long-running debate as to whether α-amylases are localized in plastids where starch is stored. To study the subcellular localization of α-amylases in plant cells, a rice (Oryza sativa) α-amylase, αAmy3, with or without its own signal peptide (SP) was expressed in transgenic tobacco (Nicotiana tabacum) and analyzed. Loss-of-function analyses revealed that SP was required for targeting of αAmy3 to chloroplasts and/or amyloplasts and cell walls and/or extracellular compartments of leaves and suspension cells. SP was also required for in vitro transcribed and/or translated αAmy3 to be cotranslationally imported and processed in canine microsomes. αAmy3, present in chloroplasts of transgenic tobacco leaves, was processed to a product with M r similar to αAmy3 minus its SP. Amino acid sequence analysis revealed that the SP of chloroplast localized αAmy3 was cleaved at a site only one amino acid preceding the predicted cleavage site. Function of the αAmy3 SP was further studied by gain-of-function analyses. β-Glucuronidase (GUS) and green fluorescence protein fused with or without the αAmy3 SP was expressed in transgenic tobacco or rice. The αAmy3 SP directed translocation of GUS and green fluorescence protein to chloroplasts and/or amyloplasts and cell walls in tobacco leaves and rice suspension cells. The SP of another rice α-amylase, αAmy8, similarly directed the dual localizations of GUS in transgenic tobacco leaves. This study is the first evidence of SP-dependent dual translocations of proteins to plastids and extracellular compartments, which provides new insights into the role of SP in protein targeting and the pathways of SP-dependent protein translocation in plants.
Critical Roles of Bacterioferritins in Iron Storage and Proliferation of Cyanobacteria
Authors: Keren Nir , Aurora Rajeev , Pakrasi Himadri B. 
Published: July 2004

Abstract
Cyanobacteria are key contributors to global photosynthetic productivity, and iron availability is essential for cyanobacterial proliferation. While iron is abundant in the earth's crust, its unique chemical properties render it a limiting factor for photoautotrophic growth. As compared to other nonphotosynthetic organisms, oxygenic photosynthetic organisms such as cyanobacteria, algae, and green plants need large amounts of iron to maintain functional PSI complexes in their photosynthetic apparatus. Ferritins and bacterioferritins are ubiquitously present iron-storage proteins. We have found that in the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis 6803), bacterioferritins are responsible for the storage of as much as 50% of cellular iron. Synechocystis 6803, as well as many other cyanobacterial species, have two bacterioferritins, BfrA and BfrB, in which either the heme binding or di-iron center ligating residues are absent. Purified bacterioferritin complex from Synechocystis 6803 has both BfrA and BfrB proteins. Targeted mutagenesis of each of the two bacterioferritin genes resulted in poor growth under iron-deprived conditions. Inactivation of both genes did not result in a more severe phenotype. These results support the presence of a heteromultimeric structure of Synechocystis bacterioferritin, in which one subunit ligates a di-iron center while the other accommodates heme binding. Notably, the reduced internal iron concentrations in the mutant cells resulted in a lower content of PSI. In addition, they triggered iron starvation responses even in the presence of normal levels of external iron, thus demonstrating a central role of bacterioferritins in iron homeostasis in these photosynthetic organisms.
Novel Biosynthetic Pathway of Castasterone from Cholesterol in Tomato
Authors: Kim Tae-Wuk , Chang Soo Chul , Lee June Seung , Takatsuto Suguru , Yokota Takao , Kim Seong-Ki 
Published: July 2004

AbstractEndogenous brassinosteroids (BRs) in tomato (Lycopersicon esculentum) seedlings are known to be composed of C27- and C28-BRs. The biosynthetic pathways of C27-BRs were examined using a cell-free enzyme solution prepared from tomato seedlings that yielded the biosynthetic sequences cholesterol → cholestanol and 6-deoxo-28-norteasterone ↔ 6-deoxo-28-nor-3-dehydroteasterone ↔ 6-deoxo-28-nortyphasterol → 6-deoxo-28-norcastasterone → 28-norcastasterone (28-norCS). Arabidopsis CYP85A1 that was heterologously expressed in yeast mediated the conversion of 6-deoxo-28-norCS to 28-norCS. The same reaction was catalyzed by an enzyme solution from wild-type tomato but not by an extract derived from a tomato dwarf mutant with a defect in CYP85. Furthermore, exogenously applied 28-norCS restored the abnormal growth of the dwarf mutant. These findings indicate that the C-6 oxidation of 6-deoxo-28-norCS to 28-norCS in tomato seedlings is catalyzed by CYP85, just as in the conversion of 6-deoxoCS to CS. Additionally, the cell-free solution also catalyzed the C-24 methylation of 28-norCS to CS in the presence of NADPH and S-adenosylmethionine (SAM), a reaction that was clearly retarded in the absence of NADPH and SAM. Thus it seems that C27-BRs, in addition to C28-BRs, are important in the production of more active C28-BRs and CS, where a SAM-dependent sterol methyltransferase appears to biosynthetically connect C27-BRs to C28-BRs. Moreover, the tomato cell-free solution converted CS to 26-norCS and [2H6]CS to [2H3]28-norCS, suggesting that C-28 demethylation is an artifact due to an isotope effect. Although previous feeding experiments employing [2H6]CS suggested that 28-norCS was synthesized from CS in certain plant species, this is not supported in planta. Altogether, this study demonstrated for the first time, to our knowledge, that 28-norCS is not synthesized from CS but from cholesterol. In addition, CS and [2H6]CS were not converted into BL and [2H6]BL, respectively, confirming an earlier finding that the active BR in tomato seedlings is not BL but CS. In conclusion, the biosynthesis of 28-norBRs appears to play a physiologically important role in maintaining homeostatic levels of CS in tomato seedlings.