bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Effects in the Electrodeposition of CdSe Quantum Dots on Mechanically Strained Gold
Authors: Ruach‐Nir I. , Wagner H.D. , Rubinstein I. , Hodes G. 
Published: February 2003

AbstractCdSe nanoparticles were electrodeposited on mechanically strained gold, the latter achieved by controlled bending of gold films evaporated on mica. It is shown that the size and bandgap of the electrodeposited CdSe quantum dots (QDs) can be varied by applying mechanical strain to the Au substrate during deposition. This is attributed to change in the lattice spacing of the strained {111} Au and consequently in the lattice mismatch between the Au and the CdSe. Negative mechanical strain promotes the formation of rocksalt (RS) CdSe nanocrystals, normally existing only at high pressures. This is attributed to surface tension compression in the small crystals, together with enhancement of the phase transition by the CdSe/substrate interface.
Effect of ecdysone agonists on vitellogenesis and the expression of EcR and USP in codling moth (Cydia pomonella)
Authors: Sun Xiaoping , Song Qisheng , Barrett Bruce 
Published: February 2003

AbstractThe effects of tebufenozide and methoxyfenozide on vitellogenin (Vg) synthesis/release in the fat body, translocation in hemolymph, uptake by the ovary, and the expression of the ecdysone receptor (EcR) and its heterodimer partner, ultraspiracle protein (USP) in fat body, were investigated in Cydia pomonella. The results indicated that both ecdysone agonists significantly increased the Vg level in the adult hemolymph when the moths were exposed to agonist‐treated surfaces. However, these agonists did not affect Vg release from the fat body nor Vg deposition in the first batch oocytes. Western blot analysis revealed that the expression of EcR and USP was significantly increased in tebufenozide‐ and methoxyfenozide‐treated samples compared to the control, suggesting that ecdysone agonists regulated the Vg synthesis via the EcR and USP proteins complex. Arch. Insect Biochem. Physiol. 52:115–129, 2003. © 2003 Wiley‐Liss, Inc.
Small GTP binding proteins: Rab GTPases from the brain of Bombyx mori
Authors: Uno Tomohide , Hiragaki Susumu 
Published: February 2003

AbstractFrom a mRNA of the brain of Bombyx mori, we isolated 8 cDNA clones (BRabs), each of which encodes a different member of Rab‐protein family. Four of them have more than 80% amino acid identity to the corresponding members of Drosophila Rab proteins. The other 4 proteins show low sequence similarity to any of the known Rab proteins. However, all of them contain the region conserved in rab protein. Using RACE (Rapid Amplification of cDNA ends), the one full‐length cDNA clone (BRab14) was isolated. The clone was expressed in Escherichia coli as a glutathione S‐transferase (GST) fusion protein. After purification, the fusion protein was cut with protease to remove GST‐Tag and applied to a glutathione S‐Sepharose column. The protein bound [3H]‐GDP with association constant of 1.02 × 1011 M–1. Further, the protein was phosphorylated by protein kinase. This result suggests that Rab protein in the brain of Bombyx mori binds GDP or GTP and its function is regulated by phosphorylation. Arch. Insect Biochem. Physiol. 52:130–138, 2003. © 2003 Wiley‐Liss, Inc.
Organ‐specific distribution of the calcium sensor CaMKII in Locusta migratoria
Authors: Braak Sandra , Fährmann Michael 
Published: February 2003

AbstractThe Ca2+/calmodulin‐dependent kinase CaMKII is a key signaling component in Ca2+‐dependent physiological processes. The expression and function of CaMKII in insect brain is well documented but less investigated for other tissues of insects. The present study demonstrates that in the locust Locusta migratoria CaMKII is widely expressed in various tissues. Relatively high expression levels of CaMKII were found in the brain, upper part of the digestive tract (pharynx, esophagus), and the flight and leg muscles. The different expression patterns of CaMKII in various tissues, as well as different molecular masses of CaMKII between 48 and 60 kDa indicate a tissue‐specific expression of CaMKII variants. The expression was monitored with a polyclonal anti‐(rat)CaMKII antibody. About 60% of total CaMKII activity in flight muscle cells is associated to the myofibril‐rich, particulate fraction suggesting an important role of CaMKII in sarcomeric function. Arch. Insect Biochem. Physiol. 52:155–162, 2003. © 2003 Wiley‐Liss, Inc.
Resolving the source populations that contribute to the X‐ray background: The 2 Ms Chandra Deep Field‐North Survey
Authors: Alexander D. M. , Bauer F. E. , Brandt W. N. , Garmire G. P. , Hornschemeier A. E. , Schneider D. P. , Vignali C. 
Published: February 2003

AbstractWith ≈ 2 Ms of exposure, the Chandra Deep Field‐North (CDF‐N) survey provides the deepest view of the Universe in the 0.5–8.0 keV band. Five hundred and three (503) X‐ray sources are detected down to on‐axis 0.5–2.0 keV and 2–8 keV flux limits of ≈ 1.5 × 10–17 erg cm–2 s–1 and ≈ 1.0 × 10–16 erg cm–2 s–1, respectively. These flux limits correspond to L0.5–8.0 keV≈ 3 × 1041 erg s–1 at z = 1 and L0.5–8.0 keV≈ 2 × 1043 erg s–1 at z = 6; thus this survey is sensitive enough to detect starburst galaxies out to moderate redshift and Seyfert galaxies out to high redshift.We present the X‐ray observations, describe the broad diversity of X‐ray selected sources, and review the prospects for deeper exposures.
Chandra Deep Field South: the optically faint population
Authors: Mainieri V. , Rosati P. , Nonino M. , Szokoly G. , Bergeron J. , Hasinger G. , Lehmann I. , Tozzi P. , CDFS Team  
Published: February 2003

AbstractA not negligible fraction (∼15%) of X‐ray sources detected in the 1 Msec observation of the Chandra Deep Field South (CDFS) are not detected down to R ≃ 27, however they are registered in deep near‐IR imaging.We use deep multicolor photometry from the VLT (FORS+ISAAC instruments), covering a broad wavelength range, to discuss the adequacy of such techniques for X‐ray selected sources and to constrain the nature of this optically faint population.
XMM‐Newton view of the Hubble Deep Field‐North and Groth‐Westphal strip regions
Authors: Miyaji T. , Griffiths R.E. , Lumb D. , Sarajedini V. , Siddiqui H. 
Published: February 2003

AbstractWe report the progress on our analysis of two deep XMM observations in the areas of Hubble Deep Field‐North and the Groth‐Westphal Strip field. We present the source detection method, Monte‐Carlo simulation on source detection, and our preliminary Log N – Log S relations. Comparing these two fields and other fields in literature, we find up to ∼30% variations in number counts near our flux limits, which are most likely to be due to cosmic variance. This serves as a pilot study for a more systematic investigation. The nature of the X‐ray sources in the Groth‐Westphal field is also discussed in terms of hardness ratios, morphology and spectroscopic properties.
Unconventional AGN in hard X‐ray surveys
Authors: Comastri A. , Brusa M. , Mignoli M. , The Hellas2xmm Team  
Published: February 2003

AbstractExtensive programs of follow–up observations of hard X–ray selected sources have unambiguously revealed that the sources of the X–ray background are characterized by an extremely large dispersion in their optical magnitude and spectroscopic classification. Here we present the results of an attempt to understand the nature of the observed variety using a simple prescription for their optical to X–ray energy distribution.
The hard X‐ray luminosity function from ASCA surveys
Authors: Ueda Y. , Akiyama M. , Ohta K. , Miyaji T. 
Published: February 2003

AbstractWe summarize the nature of hard X‐ray populations at “bright” fluxes > 10–13 erg cm–2 s–1 (2–10 keV) from optical identification of ASCA surveys, and present results of the hard X‐ray luminosity function (HXLF) of Active Galactic Nuclei (AGN). Combined with HEAO1 and Chandra surveys we construct a hard‐band selected sample with extremely high degree of completeness (>95%), consisting of 228 AGNs over the flux range 10–11 ≈ 3 × 10–15 erg cm–2 s–1 (2–10 keV). We find evidence that the percentage of “type‐II” AGNs decreases with the intrinsic luminosity. The intrinsic HXLF of the whole AGNs (including type‐II AGNs) is well described with the pure luminosity evolution (PLE) model up to redshift of 3. Our results directly constrain the evolution of AGNs that produce a major part of the hard X‐ray background.
Chandra multi‐wavelength plane (ChaMPlane) survey: design and initial results
Authors: Grindlay J. , Zhao P. , Hong J.S. , Jenkins J. , Kim Dong‐Woo , Schlegel E. , Drake J. , Kashyap V. , Edmonds P. , Cohn H. , Lugger P. , Cool A. 
Published: February 2003

AbstractThe Chandra Multiwavength Plane (ChaMPlane) Survey of the galactic plane incorporates serendipitous sources from selected Chandra pointings in or near the galactic plane (b < 12°; ≥20 ksec; lack of bright diffuse or point sources) to measure or constrain the luminosity function of low‐luminosity accretion sources in the Galaxy. The primary goal is to detect and identify accreting white dwarfs (cataclysmic variables, with space density still uncertain by a factor of >10‐100), neutron stars and black holes (quiescent low mass X‐ray binaries) to constrain their space densities and thus origin and evolution. Secondary objectives are to identify Be stars in high mass X‐ray binaries and constrain their space densities, and to survey the H‐R diagram for stellar coronal sources. A parallel optical imaging under the NOAO Long Term Survey program provides deep optical images using the Mosaic imager on the CTIO and KPNO 4‐m telescopes. The 36′ × 36′ optical images (Hα, R, V and I) cover ∼ 5× the area of each enclosed Chandra ACIS FOV, providing an extended survey of emission line objects for comparison with Chandra. Spectroscopic followup of optical counterparts is then conducted, thus far with WIYN and Magellan. The X‐ray preliminary results from both the Chandra and optical surveys will be presented, including logN‐logS vs. galactic position (l,b) and optical identifications.
The source content of low galactic latitude XMM‐Newton surveys
Authors: Motch C. , Herent O. , Guillout P. 
Published: February 2003

AbstractWe present results from a project conducted by the Survey Science Center of the XMM‐Newton satellite and aiming at the identification and characterisation of serendipitous EPIC sources at low galactic latitudes. Deep multi‐colour optical imaging and spectroscopic observations have been obtained in the framework of several observing campaigns carried out at ING, CFHT and ESO. These observations have lead to a number of optical identifications, mostly with active stars. We describe the identified source content at low galactic latitudes and compare stellar populations properties at low and high galactic latitudes with those expected from stellar X‐ray count models.
The Chandra Multi‐wavelength Project (ChaMP): Results and prospects
Authors: Green Paul J. , Cameron Rob , Ghosh Himel , Grimes John , Kim Dong‐Woo , Morris David , Mossman Amy , Silverman John , Wilkes Belinda , Baldwin Jack , Jannuzi Buell , Harnden Rick , Kashyap Vinay , LaCluyzé Aaron , Maksym Peter , Schlegel Eric , Tananbaum Harvey , Vikhlinin Alexey , Smith Chris , Smith Malcolm , The Champ Collaboration  
Published: February 2003

AbstractThe cosmic diffuse X‐ray background radiation has been almost completely resolved into point sources by Chandra and XMM. However, the nature and evolution of those sources are just beginning to be investigated. The answers are key to our understanding of the inter‐relationship over cosmic time of (a) the formation and growth of black holes, (b) star formation, and (c) hierarchical structure formation. This requires multiwavelength followup of Chandra sources over a large area. The Chandra Multiwavelength Project (ChaMP) is a serendipitous survey of the X‐ray sky, covering about 14 deg2 of sky in the X‐ray flux range of ‐13 to ‐16 (log 0.5‐2 keV flux, cgs) and will include about 8000 sources, 70% of which are expected to be active galactic nuclei (AGN). Using Chandra archival data, we span flux limits between those reached by previous satellites and those of the deepest small‐area Chandra and XMM surveys, allowing study of larger samples of rare objects like luminous absorbed AGN, groups and clusters of galaxies, and their spatial correlations. Optical imaging and spectroscopy of the ChaMP fields are underway at a variety of telescopes using Sloan g′, r′, and i′ filters to a flux limit matched to the X‐ray such that about 75% of the X‐ray sources will be optically identified.We also plan for radio and near‐IR observations of subsets of the ChaMP sample to expand our multi‐wavelength coverage and increase the fraction of sources identified.
Optical spectroscopic followup of serendipitous Chandra sources: the Chandra Multiwavelength Project (ChaMP)
Authors: Silverman J. , Green P. , Wilkes B. , Foltz C. , Smith P. , Smith C. , Kim Dong‐Woo , Morris D. , Mossman A. , Cameron R. , Adelberger K. , The Champ Collaboration  
Published: February 2003

AbstractA primary goal of the Chandra Multiwavelength Project (ChaMP) is to investigate the evolution of Active Galactic Nuclei (AGN) and quasars by measuring the luminosity function out to z ≥ 4 including obscured AGN that have been missed by previous surveys. To do so, we are acquiring spectra of optical counterparts to serendipitious X‐ray sources detected by Chandra for classification and redshift determination. We have amassed about 200 spectra using the FLWO 1.5m, WIYN 3.5m, CTIO/4m, Magellan and the MMT 6.5m. We have classified the majority of optical counterparts as 65% broad line AGN, 14% narrow emission line galaxies and 12% absorption line galaxies. The remaining counterparts are either stars (8%) or galaxy clusters (1%). We have acquired a sample of 120 AGN in 12 Chandra fields.With a limiting magnitude of r′ = 22 for spectroscopic followup, we are able to detect quasars out to z ∼ 5 and galaxies out to z ∼ 0.7. This preliminary sample forms the foundation for our measurement of the X‐ray luminosity function of AGNs out to z ∼ 4.
High cell density cultivation of probiotics and lactic acid production
Authors: Schiraldi Chiara , Adduci Vincenzo , Valli Vivien , Maresca Carmelina , Giuliano Mariateresa , Lamberti Monica , Cartenì Maria , De Rosa Mario 
Published: February 2003

AbstractThe commercial interest in functional foods that contain live microorganisms, also named probiotics, is paralleled by the increasing scientific attention to their functionality in the digestive tract. This is especially true of yogurts that contain strains of lactic‐acid bacteria of intestinal origin, among these, Lactobacillus delbrueckii ssp. bulgaricus is extensively used in the dairy industry and it has been demonstrated to be a probiotic strain. In this work we describe high cell density cultivations of this microorganism also focusing on the stereospecific production of lactic acid. Key parameters such as medium composition (bactocasitone concentration) and diverse aeration conditions were explored. The results showed that the final concentration of biomass in anaerobic fermentation was lower than the one obtained in microaerophilic conditions, while it gave a very high productivity of lactic acid which was present as a racemic mixture in the permeate. Fermentation experiments carried out with air sparging, even at very low flow‐rate, led to the production of the sole L(+) lactic acid giving sevenfold increase in biomass yield in respect to the batch cultivation. Finally, a mathematical model was developed to describe the microfiltration bioprocess applied in this research considering an inhibition kinetic and enucleating a suitable mathematical description for the decrease of the transmembrane flux. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 213–222, 2003.
A light distribution model for an internally radiating photobioreactor
Authors: Suh In Soo , Lee Sun Bok 
Published: February 2003

AbstractAnalysis of light energy distribution in culture is important for maximizing the growth efficiency of photosynthetic cells and the productivity of a photobioreactor. To characterize the irradiance conditions in a photobioreactor, we developed a light distribution model for a single‐radiator system and then extended the model to multiple radiators using the concept of parallel translation. Mathematical expressions for the local light intensity and the average light intensity were derived for a cylindrical photobioreactor with multiple internal radiators. The proposed model was used to predict the irradiance levels inside an internally radiating photobioreactor using Synechococcus sp. PCC 6301 as a model photosynthetic microorganism. The effects of cell density and radiator number were interpreted through photographic and model simulation studies. The predicted light intensity values were found to be very close to those obtained experimentally, which suggests that the proposed model is capable of accurately interpreting the local light energy profiles inside the photobioreactor system. Due to the simplicity and flexibility of the proposed model, it was also possible to predict the light conditions in other complex photobioreactors, including optical‐fiber and pond‐type photobioreactors. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 180–189, 2003.
The annotation of RNA motifs
Authors: Leontis Neocles B. , Westhof Eric 
Published: February 2003

AbstractThe recent deluge of new RNA structures, including complete atomic‐resolution views of both subunits of the ribosome, has on the one hand literally overwhelmed our individual abilities to comprehend the diversity of RNA structure, and on the other hand presented us with new opportunities for comprehensive use of RNA sequences for comparative genetic, evolutionary and phylogenetic studies. Two concepts are key to understanding RNA structure: hierarchical organization of global structure and isostericity of local interactions. Global structure changes extremely slowly, as it relies on conserved long‐range tertiary interactions. Tertiary RNA–RNA and quaternary RNA–protein interactions are mediated by RNA motifs, defined as recurrent and ordered arrays of non‐Watson–Crick base‐pairs. A single RNA motif comprises a family of sequences, all of which can fold into the same three‐dimensional structure and can mediate the same interaction(s). The chemistry and geometry of base pairing constrain the evolution of motifs in such a way that random mutations that occur within motifs are accepted or rejected insofar as they can mediate a similar ordered array of interactions. The steps involved in the analysis and annotation of RNA motifs in 3D structures are: (a) decomposition of each motif into non‐Watson–Crick base‐pairs; (b) geometric classification of each basepair; (c) identification of isosteric substitutions for each basepair by comparison to isostericity matrices; (d) alignment of homologous sequences using the isostericity matrices to identify corresponding positions in the crystal structure; (e) acceptance or rejection of the null hypothesis that the motif is conserved. Copyright © 2002 John Wiley & Sons, Ltd.
Endogenous retroviruses and human evolution
Authors: Khodosevich Konstantin , Lebedev Yuri , Sverdlov Eugene 
Published: February 2003

AbstractHumans share about 99% of their genomic DNA with chimpanzees and bonobos; thus, the differences between these species are unlikely to be in gene content but could be caused by inherited changes in regulatory systems. Endogenous retroviruses (ERVs) comprise ∼ 5% of the human genome. The LTRs of ERVs contain many regulatory sequences, such as promoters, enhancers, polyadenylation signals and factor‐binding sites. Thus, they can influence the expression of nearby human genes. All known human‐specific LTRs belong to the HERV‐K (human ERV) family, the most active family in the human genome. It is likely that some of these ERVs could have integrated into regulatory regions of the human genome, and therefore could have had an impact on the expression of adjacent genes, which have consequently contributed to human evolution. This review discusses possible functional consequences of ERV integration in active coding regions. Copyright © 2002 John Wiley & Sons, Ltd.
Learning about gene regulatory networks from gene deletion experiments
Authors: Schlitt Thomas , Brazma Alvis 
Published: February 2003

AbstractGene regulatory networks are a major focus of interest in molecular biology. A crucial question is how complex regulatory systems are encoded and controlled by the genome. Three recent publications have raised the question of what can be learned about gene regulatory networks from microarray experiments on gene deletion mutants. Using this indirect approach, topological features such as connectivity and modularity have been studied. Copyright © 2002 John Wiley & Sons, Ltd.
The evolution of light stress proteins in photosynthetic organisms
Authors: Heddad Mounia , Adamska Iwona 
Published: February 2003

AbstractThe Elip (early light‐inducible protein) family in pro‐ and eukaryotic photosynthetic organisms consists of more than 100 different stress proteins. These proteins accumulate in photosynthetic membranes in response to light stress and have photoprotective functions. At the amino acid level, members of the Elip family are closely related to light‐harvesting chlorophyll a/b‐binding (Cab) antenna proteins of photosystem I and II, present in higher plants and some algae. Based on their predicted secondary structure, members of the Elip family are divided into three groups: (a) one‐helix Hlips (high light‐induced proteins), also called Scps (small Cab‐like proteins) or Ohps (one‐helix proteins); (b) two‐helix Seps (stress‐enhanced proteins); and (c) three‐helix Elips and related proteins. Despite having different physiological functions it is believed that eukaryotic three‐helix Cab proteins evolved from the prokaryotic Hlips through a series of duplications and fusions. In this review we analyse the occurrence of Elip family members in various photosynthetic prokaryotic and eukaryotic organisms and discuss their evolutionary relationship with Cab proteins. Copyright © 2002 John Wiley & Sons, Ltd.
Meeting Highlights: International Summer School, ‘From Genome to Life’
Authors: Wixon Jo 
Published: February 2003

AbstractThis report from the International Summer School ‘From Genome to Life’, held at the Institute d'Etudes Scientifiques de Cargèse in Corsica in July 2002, covers the talks of the invited speakers. The topics of the talks can be broadly grouped into the areas of genome annotation, comparative and evolutionary genomics, functional genomics, proteomics, structural genomics, pharmacogenomics, and organelle genomes, epigenetics and RNA. Copyright © 2002 John Wiley & Sons, Ltd.
Flowering buds of globular proteins: transpiring simplicity of protein organization
Authors: Berezovsky Igor N. , Trifonov Edward N. 
Published: February 2003

AbstractStructural and functional complexity of proteins is dramatically reduced to a simple linear picture when the laws of polymer physics are considered. A basic unit of the protein structure is a nearly standard closed loop of 25–35 amino acid residues, and every globular protein is built of consecutively connected closed loops. The physical necessity of the closed loops had been apparently imposed on the early stages of protein evolution. Indeed, the most frequent prototype sequence motifs in prokaryotic proteins have the same sequence size, and their high match representatives are found as closed loops in crystallized proteins. Thus, the linear organization of the closed loop elements is a quintessence of protein evolution, structure and folding. Copyright © 2002 John Wiley & Sons, Ltd.