bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mosaic deletion of Rb arrests rod differentiation and stimulates ectopic synaptogenesis in the mouse retina
Authors: Johnson Dianna A. , Donovan Stacy L. , Dyer Michael A. 
Published: July 2006

AbstractThe retinoblastoma gene (Rb) regulates neural progenitor cell proliferation and cell fate specification and differentiation. For the developing mouse retina, two distinct functions of Rb have been described: regulation of retinal progenitor cell proliferation and rod photoreceptor development. Cells that would normally become rods fail to mature and remain as immature cells in the outer nuclear layer in the adult. By using Chx10‐Cre;RbLox/− mice, we generated a chimeric retina with alternating apical‐basal stripes of wild‐type and Rb‐deficient tissue. This provides a unique model with which to study synaptogenesis at the outer plexiform layer within regions that lack differentiated rods. In regions where rods failed to differentiate, the outer plexiform layer (OPL) was disrupted. Horizontal cells formed, and their somata were appropriately aligned, but their neurites did not project laterally. Instead many horizonal cell neurites extended apically, forming ectopic synapses with photoreceptors at all levels of the outer nuclear layer. These ectopic photoreceptor terminals contained synaptic ribbons, horizontal cell processes with synaptic vesicles, and a single mitochrondrion characteristic of rod spherules. Rb‐deficient bipolar cells differentiated normally, extended dendrites to the OPL, and formed synapses that were indistinguishable from adjacent wild‐type cells. In contrast to OPL‐positioned synapses, ectopic synapses did not contain bipolar dendrites. This finding suggests that horizontal cells and photoreceptors can form stable synapses that are devoid of bipolar dendrites outside the normal boundaries of the OPL. Finally, analysis of P4, P7, P12, and P15 retinae suggests that the apical horizontal cell processes result from their failure to establish their normal lateral projections during development. J. Comp. Neurol. 498:112–128, 2006. © 2006 Wiley‐Liss, Inc.
Solid‐State Photodimerization of Guest Molecules in Inclusion Compounds
Authors: Zouev Irena , Lavy Tali , Kaftory Menahem 
Published: July 2006

AbstractPhotochemical dimerization reactions of 1,3‐diphenyl‐1‐propen‐3‐one (chalcone), 9‐acetylanthracene, and 9‐(methoxycarbonyl)anthracene as guest molecules in inclusion compounds with 1,1,6,6‐tetraphenyl‐2,4‐hexadiyne‐1,6‐diol were studied. The irradiation of a single crystal containing chalcone was carried out in a single step and resulted in a single crystal containing the photodimer in full occupancy. In the case of the crystal containing 9‐acetylanthracene, X‐ray diffraction data were collected after irradiation for different periods of time. Only one of the two crystallographically independent pairs of 9‐acetylanthracene underwent solid‐state photodimerization at ca. 11 % conversion to the head‐to‐tail dimer. Photodimerization of the 9‐(methoxycarbonyl)anthracene inclusion compound led, after irradiation for 2.5 h, to ca. 37 % conversion. It was found that the molecules that were arranged in stacks had undergone photodimerization in two different ways, so that on the average it looked as if all the guest molecules had polymerized. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Biogenetically Based Strategy Towards the Polycyclic Core Skeleton of Sarain A
Authors: Ge Cheng Sheng , Hourcade Stéphane , Ferdenzi Antoine , Chiaroni Angèle , Mons Stéphane , Delpech Bernard , Marazano Christian 
Published: July 2006

AbstractAn approach to the polycyclic core of sarain A, based upon a proposed biogenetic route, is presented. Condensation of a protected amino acid with a bromoacrylamide and subsequent addition of malonaldehyde sodium salt and methyl iodide afforded, after stereoselective hydrogenation, a highly functionalized diazabicyclo[4.3.0]nonane system 16. This intermediate possesses the stereochemistry required for the synthesis of the core skeleton of sarain A, a model of which (31) was obtained by an allylsilane strategy previously described by Weinreb and co‐workers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Palladium‐Catalyzed Allylation of Pronucleophiles with Alkynes at 50 °C – Remarkable Effect of 2‐(Dicyclohexylphosphanyl)‐2′‐(dimethylamino)biphenyl as Ligand
Authors: Patil Nitin T. , Song Dschun , Yamamoto Yoshinori 
Published: July 2006

AbstractThe allylation of various pronucleophiles 1a–i with 1‐phenylprop‐1‐yne (2) proceeded very smoothly at 50 °C in the presence of catalytic amounts of Pd2(dba)3·CHCl3 (5 mol‐%) and 2‐(dicyclohexylphosphanyl)‐2′‐(dimethylamino)biphenyl (I; 20 mol‐%) in toluene, whilst when Pd(PPh3)4 or Pd2(dba)3·CHCl3/PPh3 were used, the reaction needed 100 °C for completion.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Development of capillary electrophoresis methods for quantitative determination of taurine in vehicle system and biological media
Authors: da Silva Dayse. L. P. , Rüttinger Hans H. , Mrestani Yahia , Baum Walter F. , Neubert Reinhard H. H. 
Published: July 2006

AbstractCE methods have been developed for the determination of taurine in pharmaceutical formulation (microemulsion) and in biological media such as sweat. The CE system with end‐column pulsed amperometric detection has been found to be an interesting method in comparison with UV and fluorescence detection for its simplicity and rapidity. A gold‐disk electrode of 100 μm diameter was used as the working electrode. The effects of a field decoupler at the end of the capillary, separation voltage, injection and pressure times were investigated. A detection limit of 4×10−5 mol/L was reached using integrated pulsed amperometric detection, a method successfully applied to taurine analysis of the biological samples such as sweat. For taurine analysis of oil‐in‐water microemulsion, fluorescence detector was the favored method, the detection limit of which was 4×10−11 mol/L.
Preparation and characterization of novel poly[cyclotriphosphazene‐co‐(4,4′‐sulfonyldiphenol)] nanofiber matrices
Authors: Lu Zhu , Weizhong Yuan , Yang Pan , Xiaozhen Tang , Xiaobin Huang 
Published: July 2006

AbstractNovel poly[cyclotriphosphazene‐co‐(4,4′‐sulfonyldiphenol)] nanofiber matrices were synthesized via a facile one‐pot polymerization. The fibers are 20–50 nm in diameter and 500 nm or more in length. Uniform nanoscale fibers linked covalently with each other and formed three‐dimensional matrices. The highly cross‐linked chemical structure of the nanofiber matrices was measured by means of Fourier transform infrared and quantitative solid‐state NMR spectroscopy. Experiments show the pH had an effect on the hydrolytic degradation of the polymer. The hydrolysis of the matrices could be accelerated by alkaline conditions. The as‐synthesized nanofiber matrices have potential applications in tissue engineering materials. Copyright © 2006 Society of Chemical Industry
Prevalence of acute and post‐traumatic stress disorder and comorbid mental disorders in breast cancer patients during primary cancer care: a prospective study
Authors: Mehnert Anja , Koch Uwe 
Published: July 2006

AbstractThis study aimed at the identification of acute and post‐traumatic stress responses, and comorbid mental disorders in breast cancer patients. Structured clinical interviews for DSM‐IV (SCID) were conducted post‐surgery with 127 patients (t1). Screening measures were used to assess post‐traumatic stress responses, anxiety, and depression at t1 and at 6 months follow‐up (t2). Based on the SCID, prevalence rates were 2.4% for both, cancer‐related ASD and PTSD. Experiences most frequently described as traumatic were the cancer diagnosis itself and subsequent feelings of uncertainty. Patients with lifetime PTSD (8.7%) were more likely to meet the criteria for cancer‐related ASD or PTSD (OR=14.1). Prevalence estimates were 7.1% for Adjustment Disorder, 4.7% for Major Depression, 3.1% for Dysthymic Disorder and 6.3% for Generalized Anxiety Disorder. Using the screening instruments, IES‐R, PCL‐C and HADS, we found PTSD in 18.5% at t1 and 11.2–16.3% at t2. The estimates of anxiety and depression reveal rates of 39.6% (t1) and 32.7% (t2) for anxiety, as well as 16.0% (t1) and 13.3% (t2) for depression (t1) (cut‐off⩾8). The diagnosis of a life‐threatening illness has been included as a potential trauma in the DSM‐IV. However, it has to be critically evaluated whether subjective feelings of uncertainty like fears of treatment count among traumatic stressors, and thus, whether the diagnosis of PTSD is appropriate in this group of cancer patients. However, a large number of women with emotional distress illustrate the need for psychosocial counseling and support in this early treatment phase. Copyright © 2006 John Wiley & Sons, Ltd.
Interatomic potential and elastic constants of rare‐gas crystals under pressure
Authors: Zarochentsev E. V. , Varyukhin V. N. , Troitskaya E. P. , Chabanenko Val. V. , Horbenko E. E. 
Published: July 2006

AbstractIn previous papers, the authors have ab initio constructed a nonempirical pair interatomic potential of rare‐gas crystals. It was constructed for the case of high pressures (strong compression). The equations of state are solved and the elastic constants responsible for the propagation of sound in strongly compressed crystals of rare gases are calculated in the next‐nearest‐neighbor approximation using the interatomic potential proposed by the authors. The results of calculations are in satisfactory agreement with the experimental data. The shear modulus ℬ︁12 is described somewhat less well. The last experiment data show that Cauchy relation is satisfied in krypton consequently the interatomic interaction in the rare‐gas crystals has a central character. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge transfer in single‐ and double‐strand DNAs: Theoretical analysis based on molecular orbital method
Authors: Dedachi Kenichi , Natsume Takayuki , Nakatsu Taisuke , Ishikawa Yasuyuki , Kurita Noriyuki 
Published: July 2006

AbstractElectrochemical DNA chips determine the sequence of DNA bases by detecting the change in charge conductivity through single‐ or double‐strand DNA. Experimentally, double‐strand DNAs were found to conduct much greater electric current than single‐strand DNAs. To gain insight into the underlying mechanism leading to such a disparity in charge conductivity, the hole/electron conductivities in single‐ and double‐strand DNAs were examined theoretically by molecular dynamics and molecular orbital (MO) calculations. The hole/electron transfer integrals between the neighboring DNA bases were estimated from the frontier MO energy levels. The current‐voltage characteristics of single‐ and double‐strand DNAs, derived from the transfer integrals and the site energy of each DNA base, are qualitatively in agreement with experiment. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Structures and G3X energies of C3H3N+ intermediates
Authors: Elkner Kenneth , Binning R. C. , Bacelo Daniel E. 
Published: July 2006

AbstractGeometries and energies of 15 stable C3H3N+ structures, potential intermediates in ion–molecule reactions that occur on the C3H3N+ potential energy surface (PES), have been calculated with G3X theory. Accurate energy ordering of the intermediates is needed to understand the initial stage of the reactions. The reactions of N(2D) with cyclopropenyl cation and of HCN and HNC with acetylene cation radical are of interest because they may lead to the formation of cyanoacetylene or some of its isomers in dense interstellar dust clouds. The energetics of the initial phases of these reactions are discussed in light of the calculated energies of reactants and intermediates. The variety of high‐energy intermediates optimized makes it likely that the reactions discussed involve long‐lived complexes and multiple rearrangements. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Prospective, Blinded Comparison of Helical CT and CT Arterial Portography in the Assessment of Hepatic Metastasis from Colorectal Carcinoma
Authors: Schwartz L. , Brody L. , Brown K. , Covey A. , Tuorto S. , Mazumdar M. , Riedel E. , Jarnagin W. , Getrajdman G. , Fong Y. 
Published: July 2006

AbstractObjectiveThis prospective blinded comparison of helical CT and helical CT arterial portography aimed to detect liver metastasis from colorectal carcinoma.Methods and Materials50 patients with colorectal carcinoma were evaluated comparing helical CT with helical CT arterial portography. Each imaging study was evaluated on a 5‐point ROC scale by radiologists blinded to the other imaging findings, and the results were compared, with the surgical and pathologic findings as the gold standard.ResultsOf the 127 lesions found at pathology identified as metastatic colorectal cancer, helical CT correctly identified 85 (69%) and CT portography 96 (76%). When subgroups with lesions <3 cm (48 patients) and patients with maximum tumor size <3 cm (18 patients) were considered, CT portography was always better than helical CT in terms of sensitivity, specificity, positive predictive value, and negative predictive value. ROC analysis adjusting for multiple lesions per patient revealed significantly greater area under the curve (AUC) for the subgroup of lesions <3 cm (CT‐AUC of 77% and CT portography AUC of 81%; P = 0.002).ConclusionsFor identification of large metastases, helical CT and CT portography have similar yield. However, for detection of small liver metastases, CT portography remains superior for lesion detectability.
Laparoscopic Treatment of Benign Insulinomas Localized in the Body and Tail of the Pancreas: A Single‐center Experience
Authors: Toniato Antonio , Meduri Francesco , Foletto Mirto , Avogaro Angelo , Pelizzo MariaRosa 
Published: July 2006

AbstractBackgroundThe increasingly widespread use of minimally invasive surgery has allowed surgeons to exploit this approach for complex procedures, such as pancreatic resections, though its actual role outside simple operations remains debated.MethodsThis is a study of 12 consecutive patients, 5 men and 7 women, with pancreatic insulinoma who were treated at our institution from 2000 to September 2005. All patients presented with typical symptoms and laboratory findings of hyperinsulinism and were good candidates for laparoscopic surgery. Preoperative diagnostic work‐up, operating time, postoperative complication rate, length of hospital stayd and clinical outcome were assessed.ResultsSuccessful laparoscopic resection was performed in 11 out of 12 patients: 4 had tumor enucleation, and 7 had distal pancreatectomy; among these latter 5 had spleen‐preserving distal pancreatectomy. In 1 case conversion to open surgery was necessary. Mean operative time was 170 minutes. The median tumor size was 18 mm, and all the insulinomas were benign. Four complications were observed in this group, and the median hospital stay was 8 days.ConclusionsThe laparoscopic approach proved to be feasible and safe, although the average operative time was longer and demanded good surgical skills as well as precise localization of the tumor and definition of its nature. Tumors located in the body or tail of the pancreas that are benign in nature can better benefit of laparoscopic approach.
A Transfer Function for Estimating Paleoceanographic Conditions Based on Deep-Sea Surface Sediment Distribution of Radiolarian Assemblages in the South Atlantic
Authors: Morley Joseph J. 
Published: July 2006

A quantitative analysis of radiolarian species in 57 deep-sea surface sediment samples from the South Atlantic Ocean produced four geographically distinct assemblages (tropical, polar, gyre margin, and subtropical). The distributions of these assemblages or factors coincide with present-day patterns of sea-surface temperatures or water masses.These four assemblages were used to construct a transfer function relating radiolarian distribution in the surface sediments to present-day winter and summer temperatures using standard regression techniques. As a test of the quality of this transfer function, temperatures were estimated on surface sediment samples from the eastern South Pacific. The temperatures produced by the transfer function compared favorably with the observed (present-day) winter and summer sea-surface temperatures at these sites.
Sedimentology and Palynology of Middle Wisconsinan Deposits in the Pecatonica River Valley, Wisconsin and Illinois
Authors: Whittecar G. Richard , Davis Anthony M. 
Published: July 2006

AbstractThe bedrock valley of the Pecatonica River north of Freeport, Illinois, contains a thick valley-fill complex of alluvium and drift. Within the valley, loess-capped benches surround hills of silty Illinoian drift. Beneath these benches lie thick deposits of poorly sorted stony silt interbedded with thin lenses of silt, sand, and organic-rich loam. Channel deposits and peat cap the diamicton in places. We interpret the stony silts as solifluction debris shed from silty slopes within the valley-fill during the Early or Middle Wisconsinan (Altonian). Top and bottom radiocarbon dates from a 2.5-m section of peat overlying the diamicton are 26,820 ± 200 and 40,500 ± 1700 yr B.P., respectively. We informally refer to the stony silts, channel sediments, and peat as the “Martintown unit.” Geomorphic position, sediment input, and macrofossils suggest that the dated peat was deposited in a floodplain pond (oxbow?). The pollen record from the peat indicates that a boreal forest dominated this area during the Middle Wisconsinan (late Altonian and Farmdalian). Two pollen zones are recognized: a basal Zone I with Pinus slightly more abundant than Picea and with few herbs and shrubs, and an upper Zone II dominated by Picea and with a larger representation of herbaceous and shrub taxa. Little displacement of vegetation zones is indicated, even though ice advanced to within 100 km of the site during the time of peat accumulation. Because of the problems involved in clearly defining Middle Wisconsinan forest-tundra in mid-latitudes by using analogs of Holocene forest-tundra in high latitudes, caution is required in making geomorphic inferences solely from vegetation data. Together, though, pollen and sediment data indicate that during the Middle Wisconsinan, Pecatonica hillslopes progressed through a sequence of instability-stability-instability related to climatic fluctuations.
Comparison of Two Indicators of Climatic Change: Tree Growth and Lake Superior Water Supplies
Authors: Brinkmann W.A.R. 
Published: July 2006

AbstractMany proxy indicators of past climate integrate the effects of temperature and precipitation, and not all indicators integrate these effects in the same way. This poses a problem in the reconstruction of past climate. A study of the response of tree growth around Lake Superior and the water supplies to that lake to summer climate shows differences and similarities in response. Tree growth is positively correlated with precipitation—although the response is reduced when conditions are very wet—and negatively correlated with temperature. In contrast, the water supplied to the lake are positively correlated with both precipitation and temperature; the correlation with temperature is, however, not very strong. Multiple regression models developed to assess the relative magnitudes of the similarities and differences show that the similarity in response to precipitation accounts for about 30% of the variance in water supplies, the nonlinear response of trees—represented by a log transformation—accounts for an additional 15%, and the difference in response to temperature is equivalent to about 30% of the variance in water supplies.
A Last Interglacial Fauna from the Eastern Sahara
Authors: Kowalski Kazimierz , Neer Wim van , Bocheński Zygmunt , Młynarski Marian , Rzebik-Kowalska Barbara , Szyndlar Zbigniew , Gautier Achilles , Schild Romuald , Close Angela E. , Wendorf Fred 
Published: July 2006

AbstractRecent work on the middle Paleolithic at Bir Tarfawi, in the hyperarid Eastern Sahara (<1 mm of rain per annum), has yielded a rich faunal assemblage, including several thousand remains of fish, amphibians, reptiles, birds, and small mammals. They are derived from the sediments of two consecutive lakes dated by several techniques to about 135,000 yr B.P. Fifty-nine taxa have been identified and indicate that at times during the Last Interglaciation the area received at least 500 mm of rainfall as a result of the northward shift of the monsoon belt, and that, on several occasions, there may have been water connections between Bir Tarfawi and unidentified but permanent bodies of water elsewhere.
U-Series Dating of Last Interglacial High Sea Stands: Barbados Revisited
Authors: Ku Teh-Lung , Ivanovich M. , Luo Shangde 
Published: July 2006

AbstractU-series chronologies of the emerged coral limestone terraces on Barbados, West Indies, together with those of the terraces from New Guinea, have formed the basis for most late Pleistocene eustatic models. The so-called “Barbados sea level model” has been challenged in recent years, however. A major issue is whether during oxygen isotope stage 5e, when Rendezvous Hill reef complex on Barbados Island formed, the sea rose above the present position for one relatively brief period of <10,000 yr, or for two or more periods spanning approximately from 140,000 to 115,000 yr B.P. Evidence for the latter scenario has not come from initial studies of Barbados but from elsewhere; it is also inconclusive because of the dating uncertainties involved. We have carried out careful redeterminations of U-series ages on a suite of 29 Acropora palmata samples systematically collected from four of the lowest terraces on the island. Diagenetic disturbance may have caused the age spreads at some sampling outcrops. A model for the diagenetic exchange of uranium isotopes in coral samples with those in groundwater explains the anomalous 234U/238U ratios in samples with apparently unaltered mineralogy (aragonite) and trace element (Mg and Sr) chemistry. It shows that age dispersions of 5–10% can be engendered by a U exchange coefficient of the order of 10−6 yr−1. The lower-limit terrace ages, estimated from averaging the multiple measurements, are 81,000 ± 2000 yr (Worthing), 105,000 ± 1000 yr (Ventnor), 120,000 ± 2000 yr (Maxwell), and 117,000 ± 3000 yr (Rendezvous Hill). No evidence was found of previously inferred bipartite sea levels centering around 118,000 and 135,000 yr ago. This study documents the need of dating coral with the high precision/sensitivity mass-spectrometric techniques for future resolution of the temporal relationships among sea level changes, climate oscillations, and astronomical forcing—relationships originally addressed by the Barbados sea level model.
Discordant 14C Ages from Buried Tidal-Marsh Soils in the Cascadia Subduction Zone, Southern Oregon Coast
Authors: Nelson Alan R. 
Published: July 2006

AbstractPeaty, tidal-marsh soils interbedded with estuarine mud in late Holocene stratigraphic sequences near Coos Bay, Oregon, may have been submerged and buried during great (M > 8) subduction earthquakes, smaller localized earthquakes, or by nontectonic processes. Radiocarbon dating might help distinguish among these alternatives by showing that soils at different sites were submerged at different times along this part of the Cascadia subduction zone. But comparison of conventional 14C ages for different materials from the same buried soils shows that they contain materials that differ in age by many hundreds of years. Errors in calibrated soil ages represent about the same length of time as recurrence times for submergence events (150–500 yr)—this similarity precludes using conventional 14C ages to distinguish buried soils along the southern Oregon coast. Accelerator mass spectrometer 14C ages of carefully selected macrofossils from the tops of peaty soils should provide more precise estimates of the times of submergence events.