bluuebunny/crossref_metadata_2025_split huggingface dataset:
Update in Osteoporosis and Metabolic Bone Disorders
Authors: Shoback Dolores 
Published: March 2007

Abstract
Considerable progress has been made in the development and testing of agents to treat osteoporosis. Most impressive are reports on new antiresorptive agents—both bisphosphonates (ibandronate and zoledronic acid) and monoclonal antibodies (MAbs) (denosumab) directed against receptor activator of nuclear factor κB-ligand, a key molecule in the control of commitment and activation of osteoclasts. Bisphosphonates promise convenience and potency at slowing bone loss, whereas denosumab offers powerful suppression of resorption and rapid offset of action. Attention is also shifting from the osteoclast as a target for new therapies to the osteoblast and the osteocyte, with its complex network within the depths of bone. Wnt signaling through the frizzled receptor and its coreceptor, the low-density lipoprotein receptor related protein-5, appears from both molecular and in vivo evidence to be a pivotal pathway for modulating osteoblastic activity, bone formation, and bone strength. The recently identified product of the SOST gene or sclerostin has also been shown to block Wnt signaling. Sclerostin is produced by the osteocytes buried in the bone and is a new target to treat bone loss. Clinical trial reports indicate that the calcimimetic cinacalcet can effectively treat PTH hypersecretion due to primary and secondary hyperparathyroidism and parathyroid carcinoma. Lastly, it is now recognized that the matrix protein dentin matrix protein-1 enhances the release of the phosphate-regulating factor fibroblast growth factor 23 and that mutations in dentin matrix protein-1 play a causative role in a form of hypophosphatemic rickets.
Natural Selection on Fecundity Variance in Subdivided Populations: Kin Selection Meets Bet Hedging
Authors: Lehmann Laurent , Balloux François 
Published: March 2007

Abstract
In a series of seminal articles in 1974, 1975, and 1977, J. H. Gillespie challenged the notion that the “fittest” individuals are those that produce on average the highest number of offspring. He showed that in small populations, the variance in fecundity can determine fitness as much as mean fecundity. One likely reason why Gillespie's concept of within-generation bet hedging has been largely ignored is the general consensus that natural populations are of large size. As a consequence, essentially no work has investigated the role of the fecundity variance on the evolutionary stable state of life-history strategies. While typically large, natural populations also tend to be subdivided in local demes connected by migration. Here, we integrate Gillespie's measure of selection for within-generation bet hedging into the inclusive fitness and game theoretic measure of selection for structured populations. The resulting framework demonstrates that selection against high variance in offspring number is a potent force in large, but structured populations. More generally, the results highlight that variance in offspring number will directly affect various life-history strategies, especially those involving kin interaction. The selective pressures on three key traits are directly investigated here, namely within-generation bet hedging, helping behaviors, and the evolutionary stable dispersal rate. The evolutionary dynamics of all three traits are markedly affected by variance in offspring number, although to a different extent and under different demographic conditions.
Meiotic Recombination in Drosophila Msh6 Mutants Yields Discontinuous Gene Conversion Tracts
Authors: Radford Sarah J , Sabourin Mathilde M , McMahan Susan , Sekelsky Jeff 
Published: March 2007

Abstract
Crossovers (COs) generated through meiotic recombination are important for the correct segregation of homologous chromosomes during meiosis. Several models describing the molecular mechanism of meiotic recombination have been proposed. These models differ in the arrangement of heteroduplex DNA (hDNA) in recombination intermediates. Heterologies in hDNA are usually repaired prior to the recovery of recombination products, thereby obscuring information about the arrangement of hDNA. To examine hDNA in meiotic recombination in Drosophila melanogaster, we sought to block hDNA repair by conducting recombination assays in a mutant defective in mismatch repair (MMR). We generated mutations in the MMR gene Msh6 and analyzed recombination between highly polymorphic homologous chromosomes. We found that hDNA often goes unrepaired during meiotic recombination in an Msh6 mutant, leading to high levels of postmeiotic segregation; however, hDNA and gene conversion tracts are frequently discontinuous, with multiple transitions between gene conversion, restoration, and unrepaired hDNA. We suggest that these discontinuities reflect the activity of a short-patch repair system that operates when canonical MMR is defective.
A Soybean Transcript Map: Gene Distribution, Haplotype and Single-Nucleotide Polymorphism Analysis
Authors: Choi Ik-Young , Hyten David L , Matukumalli Lakshmi K , Song Qijian , Chaky Julian M , Quigley Charles V , Chase Kevin , Lark K Gordon , Reiter Robert S , Yoon Mun-Sup , Hwang Eun-Young , Yi Seung-In , Young Nevin D , Shoemaker Randy C , van Tassell Curtis P , Specht James E , Cregan Perry B 
Published: March 2007

Abstract
The first genetic transcript map of the soybean genome was created by mapping one SNP in each of 1141 genes in one or more of three recombinant inbred line mapping populations, thus providing a picture of the distribution of genic sequences across the mapped portion of the genome. Single-nucleotide polymorphisms (SNPs) were discovered via the resequencing of sequence-tagged sites (STSs) developed from expressed sequence tag (EST) sequence. From an initial set of 9459 polymerase chain reaction primer sets designed to a diverse set of genes, 4240 STSs were amplified and sequenced in each of six diverse soybean genotypes. In the resulting 2.44 Mbp of aligned sequence, a total of 5551 SNPs were discovered, including 4712 single-base changes and 839 indels for an average nucleotide diversity of θ = 0.000997. The analysis of the observed genetic distances between adjacent genes vs. the theoretical distribution based upon the assumption of a random distribution of genes across the 20 soybean linkage groups clearly indicated that genes were clustered. Of the 1141 genes, 291 mapped to 72 of the 112 gaps of 5–10 cM in the preexisting simple sequence repeat (SSR)-based map, while 111 genes mapped in 19 of the 26 gaps &gt;10 cM. The addition of 1141 sequence-based genic markers to the soybean genome map will provide an important resource to soybean geneticists for quantitative trait locus discovery and map-based cloning, as well as to soybean breeders who increasingly depend upon marker-assisted selection in cultivar improvement.
Transcriptional Control of Gluconeogenesis in Aspergillus nidulans
Authors: Hynes Michael J , Szewczyk Edyta , Murray Sandra L , Suzuki Yumi , Davis Meryl A , Sealy-Lewis Heather M 
Published: March 2007

Abstract
Aspergillus nidulans can utilize carbon sources that result in the production of TCA cycle intermediates, thereby requiring gluconeogenesis. We have cloned the acuG gene encoding fructose-1,6 bisphosphatase and found that expression of this gene is regulated by carbon catabolite repression as well as by induction by a TCA cycle intermediate similar to the induction of the previously studied acuF gene encoding phosphoenolpyruvate carboxykinase. The acuN356 mutation results in loss of growth on gluconeogenic carbon sources. Cloning of acuN has shown that it encodes enolase, an enzyme involved in both glycolysis and gluconeogenesis. The acuN356 mutation is a translocation with a breakpoint in the 5′ untranslated region resulting in loss of expression in response to gluconeogenic but not glycolytic carbon sources. Mutations in the acuK and acuM genes affect growth on carbon sources requiring gluconeogenesis and result in loss of induction of the acuF, acuN, and acuG genes by sources of TCA cycle intermediates. Isolation and sequencing of these genes has shown that they encode proteins with similar but distinct Zn(2) Cys(6) DNA-binding domains, suggesting a direct role in transcriptional control of gluconeogenic genes. These genes are conserved in other filamentous ascomycetes, indicating their significance for the regulation of carbon source utilization.
Differential Epigenetic Regulation Within an Arabidopsis Retroposon Family
Authors: Rangwala Sanjida H , Richards Eric J 
Published: March 2007

Abstract
We previously reported a novel family of Arabidopsis thaliana nonautonomous retroposons, Sadhu, showing epigenetic variation in natural populations. Here, we show that transcripts corresponding to Sadhu elements accumulate in a subset of mutants carrying disruptions in genes encoding chromatin modification enzymes, but are not significantly expressed in mutants defective in RNA silencing pathways, indicating that RNA-directed processes are not necessary to maintain transcriptional suppression of this class of retroelements. We focused our analysis on three representative elements showing differential responses to ddm1, met1, and hda6 mutations. These mutations had differing effects on cytosine methylation depending on the element and the sequence context. Curiously, the Sadhu6-1 element with the strongest CpHpG methylation is expressed in a met1 CpG methyltransferase mutant, but is not expressed in ddm1 or cmt3 mutants. Regardless of the mutant background, H3meK9 was found at silenced loci, while H3meK4 was restricted to expressed alleles. We discuss the different modes of regulation within this family and the potential impact of this regulation on the stability of silencing in natural populations.
Preterm Birth–Associated Cost of Early Intervention Services: An Analysis by Gestational Age
Authors: Clements Karen M. , Barfield Wanda D. , Ayadi M. Femi , Wilber Nancy 
Published: March 2007

OBJECTIVES. Characterizing the cost of preterm birth is important in assessing the impact of increasing prematurity rates and evaluating the cost-effectiveness of therapies to prevent preterm delivery. To assess early intervention costs that are associated with preterm births, we estimated the program cost of early intervention services for children who were born in Massachusetts, by gestational age at birth.
METHODS. Using the Pregnancy to Early Life Longitudinal Data Set, birth certificates for infants who were born in Massachusetts between July 1999 and June 2000 were linked to early intervention claims through 2003. We determined total program costs, in 2003 dollars, of early intervention and mean cost per surviving infant by gestational age. Costs by plurality, eligibility criteria, provider discipline, and annual costs for children's first 3 years also were examined.
RESULTS. Overall, 14033 of 76901 surviving infants received early intervention services. Program costs totaled almost $66 million, with mean cost per surviving infant of $857. Mean cost per infant was highest for children who were 24 to 31 weeks' gestational age ($5393) and higher for infants who were 32 to 36 weeks' gestational age ($1578) compared with those who were born at term ($725). Cost per surviving infant generally decreased with increasing gestational age. Among children in early intervention, mean cost per child was higher for preterm infants than for term infants. At each gestational age, mean cost per surviving infant was higher for multiples than for singletons, and annual early intervention costs were higher for toddlers than for infants.
CONCLUSIONS. Compared with their term counterparts, preterm infants incurred higher early intervention costs. This information along with data on birth trends will inform budget forecasting for early intervention programs. Costs that are associated with early childhood developmental services must be included when considering the long-term costs of prematurity.
Transcriptional profiling of lymphoblast lines from subjects with panic disorder
Authors: Philibert Robert A. , Crowe Raymond , Ryu Gi‐Yung , Yoon Jae‐Geun , Secrest Dianna , Sandhu Harinder , Madan Anup 
Published: March 2007

AbstractIn attempts to isolate genetic vulnerability factors for panic disorder (PD), a number of investigators have used genome‐wide linkage or association analyses. But these attempts have been only modestly successful which suggests that alternative approaches may be needed to define the biology of PD. Therefore, using recently developed genome‐wide gene expression profiling, we explored whether transcriptional signatures associated with PD are present in lymphoblast cell line. The expression of 2,469 transcripts in lymphoblast cell lines from 16 subjects was arithmetically increased in every line and significantly increased overall and 354 transcripts was arithmetically decreased in every cell line and significantly decreased overall as compared to those lymphoblast lines from 17 subjects without a history of behavioral illness. Further sex specific analyses showed that in those 10 lines derived from female probands, the expression of a further 67 transcripts was arithmetically increased in every line and significantly increased overall and a further 332 transcripts was arithmetically decreased in every cell line and significantly decreased. Conversely, in cell lines from the six male probands, the expression of an additional 212 was arithmetically increased in every line and significantly increased overall and a further 332 transcripts was arithmetically decreased in every cell line. We conclude that lymphoblast cell lines derived from subjects with PD have significant, partially sex dependent changes in gene transcription. Further studies are necessary to correlate these changes in these hemopoetically derived cells with those changes postulated to occur in the CNS in association with PD. © 2007 Wiley‐Liss, Inc.
Dicarbonylrhodium(I) complexes of aminophenols and their catalytic carbonylation reaction
Authors: Sharma Manab , Sarmah Bhaskar J. , Bhattacharyya Pradip , Deka Ramesh C. , Dutta Dipak K. 
Published: March 2007

AbstractThe complexes [Rh(CO)2ClL](1), where L = 2‐aminophenol (a), 3‐aminophenol (b) and 4‐aminophenol (c), have been synthesized and characterized. The ligands are coordinated to the metal centre through an N‐donor site. The complexes 1 undergo oxidative addition (OA) reactions with various alkyl halides (RX) like CH3I, C2H5I and C6H5CH2Cl to produce Rh(III) complexes of the type [Rh(CO)(COR)XClL], where R = CH3(2), C2H5(3), X = I; R = C6H5CH2 and X = Cl (4). The OA reaction with CH3I follows a two‐stage kinetics and shows the order of reactivity as 1b > 1c > 1a. The minimum energy structure and Fukui function values of the complexes 1a–1c were calculated theoretically using a DND basis set with the help of Dmol3 program to substantiate the observed local reactivity trend. The catalytic activity of the complexes 1 in carbonylation of methanol, in general, is higher (TON 1189–1456) than the species [Rh(CO)2I2]− (TON 1159). Copyright © 2007 John Wiley & Sons, Ltd.
Solvent effects on complexation of thallium(I) with guanosine 5′‐monophosphate in methanol–water mixtures
Authors: Gharib Farrokh , Sadeghi Fatemeh 
Published: March 2007

AbstractThe interaction of guanosine 5′‐monophosphate, GMP, with the thallium(I) ion was studied by UV–vis and potentiometric titration methods and 31P NMR spectroscopy. Both NMR spectra and UV–vis titration data have shown that GMP coordinates via guanine to the thallium(I) ion in the pH range 1.5–10. Our study of the system Tl(I) + GMP was performed in water–methanol mixtures with different volume ratios of methanol. The complexation equilibrium in the pH range of study led to the following mononuclear species: TlH2(GMP)+, TlH(GMP) and Tl(GMP)−, where (GMP)2− represents the fully dissociated ligand. The formation constants of the species were calculated in the various media at constant temperature (25 °C) and constant ionic strength of sodium perchlorate (0.1 mol dm−3) using a suitable computer program. The formation constants were analyzed in terms of Kamlet and Taft's parameters. A single‐parameter correlation of the formation constants, β121, β111 and β101 vs α (hydrogen‐bond donor acidity), β (hydrogen‐bond acceptor basicity) and for π* (dipolarity/polarizability) are relatively poor in all solutions, but multi‐parameter correlations represent significant improvements with regard to the single‐parameter model. In this work, we have also used the normalized polarity parameter, ETN, alone and in combination with some of the Kamlet–Taft parameters to find a better correlation of the formation constants in different methanol–water mixtures. Copyright © 2007 John Wiley & Sons, Ltd.
Development of an animal model for ovotoxicity using 4‐vinylcyclohexene: a case study
Authors: Hoyer Patricia B. , Sipes I. Glenn 
Published: March 2007

AbstractBACKGROUNDThe occupational chemical 4‐vinylcyclohexene (VCH) has been shown to cause destruction of small pre‐antral follicles in ovaries of mice. Further, its monoepoxide metabolites, 1,2‐VCH epoxide, 7,8‐VCH epoxide, and the diepoxide, VCD, have been shown to cause pre‐antral follicle loss in rats as well as mice. Chemicals that destroy small pre‐antral follicles are of concern to women because exposure can result in premature ovarian failure (early menopause).METHODSStudies working with these chemicals over the past decade have determined a number of aspects of the mechanism(s) of small pre‐antral destruction, and a variety of questions have been answered.RESULTSSpecifically, it has been determined that the diepoxide (VCD) is the bioactive form and it directly targets the ovary in mice and rats. Mice are more susceptible to VCH than rats because they are capable of its metabolic bioactivation. Follicle destruction by VCD is selective for primordial and primary follicles. Mechanistic studies in rats have determined that VCD causes ovotoxicity by accelerating the natural process of atresia (apoptosis) and this requires repeated exposures. Pro‐apoptotic signaling events in the Bcl‐2 and mitogen activated protein kinase families have been shown to be selectively activated in fractions of small pre‐antral follicles (targets for VCD). Finally, a whole ovarian culture system using neonatal mouse and rat ovaries has been developed to expand the potential for more in depth investigations into ovotoxicity caused by VCD.CONCLUSIONSThis article provides an overview of the questions asked and the approaches taken in studying VCH and VCD to support these conclusions.Birth Defects Res (Part B), 2007. © 2007 Wiley‐Liss, Inc.
Stereoselective Ring‐Opening Polymerization of a Racemic Lactide by Using Achiral Salen– and Homosalen–Aluminum Complexes
Authors: Nomura Nobuyoshi , Ishii Ryohei , Yamamoto Yoshihiko , Kondo Tadao 
Published: March 2007

AbstractHighly isotactic polylactide or poly(lactic acid) is synthesized in a ring‐opening polymerization (ROP) of racemic lactide with achiral salen– and homosalen–aluminum complexes (salenH2=N,N′‐bis(salicylidene)ethylene‐1,2‐diamine; homosalenH2=N,N′‐bis(salicylidene)trimethylene‐1,3‐diamine). A systematic exploration of ligands demonstrates the importance of the steric influence of the Schiff base moiety on the degree of isotacticity and the backbone for high activity. The complexes prepared in situ are pure enough to apply to the polymerizations without purification. The crystal structures of the key complexes are elucidated by X‐ray diffraction, which confirms that they are chiral. However, analysis of the 1H and 13C NMR spectra unambiguously demonstrates that their conformations are so flexible that the chiral environment of the complexes cannot be maintained in solution at 25 °C and that the complexes are achiral under the polymerization conditions. The flexibility of the backbone in the propagation steps is also documented. Hence, the isotacticity of the polymer occurs due to a chain‐end control mechanism. The highest reactivity in the present system is obtained with the homosalen ligand with 2,2‐dimethyl substituents in the backbone (ArCHNCH2CMe2CH2NCHAr), whereas tBuMe2Si substituents at the 3‐positions of the salicylidene moieties lead to the highest selectivity (Pmeso=0.98; Tm=210 °C). The ratio of the rate constants in the ROPs of racemic lactide and L‐lactide is found to correlate with the stereoselectivity in the present system. The complex can be utilized in bulk polymerization, which is the most attractive in industry, although with some loss of stereoselectivity at high temperature, and the afforded polymer shows a higher melting temperature (Pmeso=0.92, Tm up to 189 °C) than that of homochiral poly(L‐lactide) (Tm=162–180 °C). The “livingness” of the bulk polymerization at 130 °C is maintained even at a high conversion (97–98 %) and for an extended polymerization time (1–2 h).
Fat and water differentiation by nuclear magnetic resonance imaging
Authors: Kaldoudi Eleni , Williams Steve C. R. 
Published: March 2007

AbstractFollowing our article entitled „Fat and Water Differentiation by Nuclear Magnetic Resonance Imaging”︁ (1), it was suggested that it would be helpful to summarize our findings in tabular form. The table presented here highlights the advantages and disadvantages of numerous techniques that have been used in MRI for fat and water differentiation. Our „title”︁ for each subcategory is followed by the original references relating to that method. This table is intended to be used as a quick reference guide. For a more elaborate treatment of the subject, we suggest that the reader refer to the full paper.
Parameterized description of NMR signal reception systems. Part II: S/N of NMR signal reception systems
Authors: Cho Shin‐Il , Sullivan Neil S. 
Published: March 2007

AbstractThe mathematical tools that were developed in Part I are used to show quantitatively how the signal‐to‐noise ratio and the ringing time depend on Q factors, and thus how overall performance can be improved. The noise factor of a model preamplifier also is considered, and the minimum noise factor is derived in terms of the impedances of the probe and of the preamplifier. The optimization of the noise factor in realistic signal reception systems is discussed.
NMR rotating‐frame relaxation measurements of conformational exchanges on the microsecond time scale. Part II: Verification of the T1p method and analysis of experimental results
Authors: Wang Yu‐Sen 
Published: March 2007

AbstractPart I of this paper describes an on‐resonance, rotating‐frame relaxation method and proposes a procedure for the accurate evaluation of the contribution of chemical exchange to rotating‐frame spin‐lattice relaxation (T1p). Dynamic information, such as exchange lifetimes and chemical shift differences between exchange sites, can be extracted from the exchange contribution. The procedure extends the T1p method to medium‐sized and large molecules. Part II presents a verification of the T1p method and an analysis of experimental results. The accuracy of these dynamic parameters has been examined using simple, well‐characterized conformational exchange systems. The examination shows that T1p is convenient for studying molecular dynamics on the microsecond time scale. The application of the method to peptides and to right‐ and left‐handed DNA oligomers gives unique dynamic information on the conformational exchange processes in these molecules.
Rotational resonance NMR of biological membranes
Authors: Peersen Olve B. , Smith Steven O. 
Published: March 2007

AbstractRotational resonance (RR) NMR is a magic angle spinning‐based method for measuring internuclear distances through homonuclear dipolar couplings. RR NMR data obtained from crystals of a hydrophobic α‐helical peptide are used to illustrate general experimental considerations in generating RR magnetization exchange curves and in translating the observed exchange rates into internuclear distances. The extension of RR methods to structural studies of membranes is demonstrated by intramolecular measurements within the transmembrane domain of glycophorin A and between 13C‐labeled sites in lipid bilayers.