bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bulky Monodentate Phosphoramidites in Palladium‐Catalyzed Allylic Alkylation Reactions: Aspects of Regioselectivity and Enantioselectivity
Authors: Boele Maarten D. K. , Kamer Paul C. J. , Lutz Martin , Spek Anthony L. , de Vries Johannes G. , van Leeuwen Piet W. N. M. , van Strijdonck Gino P. F. 
Published: November 2004

AbstractA series of bulky monodentate phosphoramidite ligands, based on biphenol, BINOL and TADDOL backbones, have been employed in the Pd‐catalysed allylic alkylation reaction. Reaction of disodium diethyl 2‐methyl malonate with monosubstituted allylic substrates in the presence of palladium complexes of the phosphoramidite ligands proceeds smoothly at room temperature. The regioselectivities observed depend strongly on the leaving group and the geometry of the allylic starting compounds. Mono‐coordination occurs when these ligands are ligated in [Pd(allyl)(X)] complexes (allyl=C3H5, 1‐CH3C3H4, 1‐C6H5C3H4, 1,3‐(C6H5)2C3H3; X=Cl, OAc). The solid‐state structure determined by X‐ray diffraction of [Pd(C3H5)(1)(Cl)] reveals a non‐symmetric coordination of the allyl moiety, caused by the stronger trans influence of the phosphoramidite ligand relative to X−. In all of these complexes, the syn,trans isomer is the major species present in solution. Because of fast isomerisation and high reactivity of the syn,cis complex, the major product formed upon alkylation is the linear product, especially for monosubstituted phenylallyl substrates in the presence of halide counterions. In the case of biphenol‐ and BINOL‐based phosphoramidites, however, a strong memory effect is observed when 1‐phenyl‐2‐propenyl acetate is employed as the substrate. In this case, nucleophilic attack competes effectively with the isomerisation of the transient cinnamylpalladium complexes. The asymmetric allylic alkylation of 1,3‐diphenyl‐2‐propenyl acetate afforded the chiral product in up to 93 % ee. Substrates with smaller substituents gave lower enantioselectivities. The observed stereoselectivity is explained in terms of a preferential rotation mechanism, in which the product is formed by attack on one of the isomers of the intermediate [Pd{1,3‐(C6H5)2C3H3}(L)(OAc)] complex.
Colorectal carcinoma mortality among Appalachian men and women, 1969–1999
Authors: Armstrong Lori R. , Thompson Trevor , Hall H. Irene , Coughlin Steven S. , Steele Brooke , Rogers Joe D. 
Published: November 2004

AbstractBACKGROUNDColorectal carcinoma screening can reduce mortality, but residents of poor or medically underserved areas may face barriers to screening. The current study assessed colorectal carcinoma mortality in Appalachia, a historically underserved area, from 1969 to 1999.METHODSAll counties within the 13‐state Appalachian region, which stretches from southern New York to northern Mississippi, were used to calculate annual death rates for the 31‐year period. Joinpoint regression analysis was used to examine trends by age and race for the Appalachian region and the remainder of the United States. Five‐year rates for 1995–1999 age‐adjusted to the 2000 U.S. standard population were calculated by race and age group for the Appalachian region and elsewhere in the United States.RESULTSTrend analysis showed that colorectal carcinoma death rates among both racial and gender groups studied had declined in recent years. Despite this, the rates for white males and white females were still significantly higher in Appalachia than in the rest of the country at the end of the study period, 1999. Five‐year colorectal carcinoma death rates among white males (ages < 50, 50–59, and 70–79 years) and white females (ages < 50, 50–59, 70–79, ≥ 80 years) were significantly higher in Appalachia than elsewhere in the United States, whereas rates among black females 60–69 and 70–79 years old were significantly lower in Appalachia.CONCLUSIONSThe Appalachian region may benefit from targeted prevention efforts to eliminate disparities in the colorectal carcinoma death rates among subgroups. Further studies are needed to determine whether the higher death rates in specific Appalachian subgroups are related to a higher incidence of the disease, the cancer being at a later stage at diagnosis, poorer treatment, or other factors. Cancer 2004. Published 2004 by the American Cancer Society.
Local and global chemotopic organization: General features of the glomerular representations of aliphatic odorants differing in carbon number
Authors: Johnson Brett A. , Farahbod Haleh , Xu Zhe , Saber Sepideh , Leon Michael 
Published: November 2004

AbstractTo determine whether there is a general strategy used by the olfactory system to represent odorants differing in carbon chain length, rats were exposed to homologous series of straight‐chained, saturated aliphatic aldehydes, ethyl esters, acetates, ketones, primary alcohols, and secondary alcohols (32 odorants total). Neural activity across the entire glomerular layer of the olfactory bulb was mapped quantitatively by measuring uptake of [14C]2‐deoxyglucose evoked by each odorant. Uptake was observed both in dorsal glomerular modules previously associated with the particular odorant functional groups and in more ventral and posterior modules. Aldehyde‐evoked activity patterns were dominated by ventral modules that included the area receiving projections from octanal‐responsive sensory neurons expressing the I7 odorant receptor. The dorsal area that has been the focus of optical imaging studies of aldehyde responses contained only minor activity. For all functional groups except for ketones, uptake within functional group‐sensitive modules displayed local chemotopy, with longer odorants stimulating more ventral and rostral glomeruli. In more posterior regions, chemotopy was observed for all functional groups, again with uptake shifting ventrally and rostrally with increasing chain length. In addition to these local shifts in activity, correlations analysis of entire activity patterns revealed a global chemotopic organization for all odorant series, with each odorant evoking a pattern most similar to odorants possessing the same functional group but differing by only one carbon in length. Thus, global chemotopy and local modular chemotopy appear to be fundamental principles underlying the representation of odorants differing in carbon chain length. J. Comp. Neurol. 480:234–249, 2004. © 2004 Wiley‐Liss, Inc.
Experimental study of the connections of the telencephalon in the rainbow trout (Oncorhynchus mykiss). II: Dorsal area and preoptic region
Authors: Folgueira Mónica , Anadón Ramón , Yáñez Julián 
Published: November 2004

AbstractIn this study and the accompanying article (Folgueira et al., 2004a), the fluorescent carbocyanine dye 1,1′‐dioctadecyl 3,3,3′,3′‐tetramethylindocarbocyanine perchlorate (DiI) was used in fixed tissue to comprehensively analyze the connections of the different regions of the telencephalic lobes and the preoptic region of the rainbow trout. Here, we analyze the connections of the dorsal area (D; pallium) of the telencephalon, and the preoptic region, as well as the telencephalic connections of several structures in the diencephalon and brainstem of juvenile trout. The dorsal plus dorsolateral pallial zone of D (Dd+Dl‐d) receives afferents from contralateral Dd+Dl‐d, the ventral area of the telencephalon, preoptic nucleus, suprachiasmatic nucleus, medial thalamus, preglomerular complex, anterior and lateral tuberal nuclei, posterior tuberal nucleus, posterior hypothalamic lobe, superior raphe nucleus, and the rhombencephalic central gray and reticular formation, and projects to the central zone of D (Dc), medial thalamus, and some caudomedial hypothalamic regions. The medial zone of D (Dm) maintains reciprocal connections with the preglomerular complex and also receives afferents from the preoptic nucleus, suprachiasmatic nucleus, anterior tuberal nucleus, preglomerular tertiary gustatory nucleus, posterior tubercle, superior raphe nucleus, locus coeruleus, and the rhombencephalic central gray, and reticular formation. Dc receives fibers mainly from Dd+Dl‐d, preoptic nucleus, preglomerular complex, and torus semicircularis and projects to several extratelencephalic centers, including the paracommissural nucleus, optic tectum, torus semicircularis, thalamus, preglomerular complex, posterior tubercle nuclei, and inferior hypothalamic lobes. The posterior zone of D (Dp) is mainly connected with the olfactory bulbs, the ventral and supracommissural nuclei of the ventral area (subpallium), the preoptic nucleus, and the preglomerular complex and projects to wide hypothalamic and posterior tubercular regions. The preoptic nucleus projects to the olfactory bulb, to most regions of the telencephalic lobes, and to several diencephalic and brainstem structures. These results reveal complex and specialized connectional patterns in the rainbow trout dorsal telencephalon and preoptic region. Most of these connections have not been described previously in salmonids. These connections indicate that the salmonid telencephalon is involved in multisensorial processing and modulation of brain activity. J. Comp. Neurol. 480:204–233, 2004. © 2004 Wiley‐Liss, Inc.
Urocortinergic neurons respond in a differentiated manner to various acute stressors in the Edinger‐Westphal nucleus in the rat
Authors: Gaszner Balázs , Csernus Valér , Kozicz Tamás 
Published: November 2004

AbstractCorticotropin‐releasing factor (CRF) was implicated as being a major contributor to the neurochemically mediated central regulation of stress response; however, an increasing body of evidence suggests that, besides CRF, other members of this neuropeptide family, such as urocortin (Ucn), may also play a role in modifying the efferent components of immune, endocrine, and behavioral responses to stress. Ucn's distribution in the rat brain has been demonstrated, with the most abundant Ucn‐immunoreactive perikarya present in the Edinger‐Westphal nucleus (E‐WN). Acute pain and immobilization stresses recruit E‐WN neurons, however, the activation pattern of E‐WN Ucn neurons in response to various acute systemic and neurogenic challenges has not been compared in a single study. We therefore combined quantitative Fos imaging as a marker for neuronal activation with urocortin immunohistochemistry to visualize neurons induced by intravenous lipopolysaccharide (LPS; 100 μg/kg), ether inhalation, restraint, hyperosmotic (1.5 M NaCl i.p.), and hypotensive hemorrhage challenges. Neurons in the E‐WN responded with the strongest Fos induction to LPS, but ether and restraint stress also resulted in massive Fos immunoreactivity 2 hours after stress. Unexpectedly, hyperosmotic and hypotensive hemorrhage stresses did not induce urocortinergic perikarya in this brain area 2 hours poststress. This challenge‐specific recruitment of E‐WN neurons was independent of stress‐induced adrenal response. The biological significance and the stress‐specific activation of E‐WN urocortinergic neurons will be discussed. J. Comp. Neurol. 480:170–179, 2004. © 2004 Wiley‐Liss, Inc.
Dispersive analysis of charge transfer models
Authors: Rodnianski I. , Schlag W. , Soffer A. 
Published: November 2004

AbstractWe prove dispersive estimates for the time‐dependent Schrödinger equation with a charge transfer Hamiltonian. As a by‐product we also obtain another proof of asymptotic completeness of the wave operators for a charge transfer model established earlier by K. Yajima and J. M. Graf. We also consider a more general matrix non‐self‐adjoint charge transfer problem. This model appears naturally in the study of nonlinear multisoliton systems and is specifically motivated by the problem of asymptotic stability of multisoliton states of a nonlinear Schrödinger equation. © 2004 Wiley Periodicals, Inc.
Directing pluripotent cell differentiation using “diced RNA” in transient transfection
Authors: Carpenter Lee , Zernicka‐Goetz Magdalena 
Published: November 2004

AbstractEmbryonic stem (ES) and embryonic carcinoma (EC) cells are pluripotent and have the capacity to differentiate into many cell types. The ability to direct their differentiation should have considerable practical applications. Here, we first report the use of diced short interfering RNAi against Oct4 in a transient approach, to direct differentiation of ES towards the trophectoderm lineage. We then apply this approach to downregulate Smad4 in mouse P19 EC cells. We have found that this leads to an increase in the levels of Pax6 (a neuroectoderm marker), reduction in the levels of Brachyury (a mesoderm marker), and a 3‐fold increase in the number of βIII tubulin‐positive colonies when these cells were allowed to differentiate. This indicates a redirection of cell fate towards the neuroectoderm lineage. Thus, transient RNAi could provide a valuable tool to direct pluripotent cells along specific pathways of differentiation while circumventing permanent genetic changes. genesis 40:157–163, 2004. © 2004 Wiley‐Liss, Inc.
Positional cloning and characterization of mouse mei8, a disrupted allele of the meiotic cohesin Rec8
Authors: Bannister Laura A. , Reinholdt Laura G. , Munroe Robert J. , Schimenti John C. 
Published: November 2004

AbstractA novel mutation, mei8, was isolated in a forward genetic screen for infertility mutations induced by chemical mutagenesis of ES cells. Homozygous mutant mice are sterile. Mutant females exhibit ovarian dysgenesis and lack ovarian follicles at reproductive maturity. Affected males have small testes due to arrest of spermatogenesis during meiotic prophase I. Genetic mapping and positional cloning of mei8 led to the identification of a mutation in Rec8, a homolog of the yeast meiosis‐specific cohesin gene REC8. Analysis of meiosis in Rec8mei8/Rec8mei8 spermatocytes showed that, while initiation of recombination and synapsis occurs, REC8 is required for the completion and/or maintenance of synapsis, cohesion of sister chromatids, and the formation of chiasmata, as it is in other organisms. However, unlike yeast and Caenorhabditis elegans, localization of REC8 on meiotic chromosomes is not required for the assembly of axial elements. genesis 40:184–194, 2004. © 2004 Wiley‐Liss, Inc.
A convenient route to pyridones, pyrazolo[2,3‐a]pyrimidines and pyrazolo[5,1‐c]triazines incorporating antipyrine moiety
Authors: Farag Ahmad M. , Dawood Kamal M. , Elmenoufy Hanan A. 
Published: November 2004

AbstractCondensation of 4‐aminoantipyrine with ethyl acetoacetate, ethyl benzoylacetate, and ethyl cyanoacetate furnished the corresponding ethyl 3‐(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)aminoacrylate and 2‐cyano‐N‐[(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)]acetamide derivatives. The aminoacrylates derivatives react with acetonitrile and sodium hydride to give 2‐amino‐6‐methyl‐1‐(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)‐4‐pyridone. Reaction of the cyanoacetamide derivative with dimethylformamide‐dimethylacetal (DMF‐DMA) afforded 2‐cyano‐N‐[1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐pyrazol‐4‐yl]‐2‐(N,N‐dimethylamino)methylene acetamide in high yield. Treatment of the latter with 5‐aminopyrazole derivatives afforded the corresponding pyrazolo[2,3‐a]pyrimidines. 2‐cyano‐N‐[(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)]acetamide also reacts with heterocyclic diazonium salts to give the corresponding pyrazolo[5,1‐c]‐1,2,4‐triazine derivatives. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:508–514, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20046
A new approach to synthesis of 3,3‐dialkyl‐3,4‐dihydroisoquinoline derivatives
Authors: Shklyaev Yu. V. , Yeltsov M. A. , Rozhkova Yu. S. , Tolstikov A. G. , Dembitsky V. M. 
Published: November 2004

AbstractThe synthesis of 3,3‐dialkyl‐3,4‐dihydroisoquinolines via heterocyclization in three‐component reaction of an activated arene with isobutyraldehyde and nitriles is described. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:486–493, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20049
Michael adducts‐synthons for pyrazolidinediones, isoxazolidinediones, pyrimidinetriones, and thioxopyrimidinediones
Authors: Padmavathi V. , Subbaiah D. R. C. Venkata , Sarma M. Rajagopala , Balaiah A. 
Published: November 2004

Abstract4‐Substituted pyrazolidinediones, isoxazolidinediones, and 5‐substituted pyrimidinetriones, thioxopyrimidinediones were obtained by exploiting gem‐diester functionality in mono‐ and di‐substituted dimethyl malonates. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:477–481, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20053
Crystal structures and molecular modeling of 1,8 chalcogenide‐substituted naphthalenes
Authors: Aucott Stephen M. , Milton Heather L. , Robertson Stuart D. , Slawin Alexandra M. Z. , Woollins J. Derek 
Published: November 2004

AbstractThe molecular structures of naphtho[1,8‐cd][1,2]dithiole, naphtho[1,8‐cd][1,2]diselenole, naphtho[1,8‐cd][1,2]ditellurole, naphtho[1,8‐cd]‐ [1,2]dithiole 1‐oxide, naphtho[1,8‐cd][1,2]dithiole 1,1‐dioxide, and naphtho[1,8‐cd][1,2]dithiole 1,1,2‐trioxideand naphtho[1,8‐cd][1,2]dithiole 1,1,2,2‐tetroxide are compared. The E–E distance varies, broadly reflecting the degree of distortion imposed by the rigid naphthalene backbone as well as the degree of oxidation at sulfur.Index Entry:
magnified imageThe naphthalene backbone imposes shortening of E–E bond lengths when E = S and Se compared to PhEEPh systems but is itself subject to distortion as a consequence of the steric bulk of the E atoms. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:530–542, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20055
Repeated in vivo electrochemical activation and the biological effects of microelectromechanical systems drug delivery device
Authors: Shawgo Rebecca S. , Voskerician Gabriela , Duc Hong Linh Ho , Li Yawen , Lynn Aaron , MacEwan Matthew , Langer Robert , Anderson James M. , Cima Michael J. 
Published: November 2004

AbstractThe repeated activation of a microelectromechanical systems (MEMS) drug delivery device was studied in vivo in rats to examine the effect of implantation on the device operation and the effect of electrochemical activation on the inflammatory and wound‐healing response. The MEMS devices were fabricated from a silicon wafer into which reservoirs were etched and covered with gold membranes. The membranes were electrochemically removed when an anodic voltage was applied. Devices were implanted subcutaneously both with and without stainless steel mesh cages for 4, 7, 14, 21, or 28 days before activation. Devices were activated every other day for five activations. Leukocyte concentrations indicated that both the application of voltage and the gold corrosion products elevated the inflammatory response which was resolved within 48 h after each activation. The efficiency of gold membrane removal was not impaired throughout the implantation, although a bimodal distribution of background current densities was observed after long implantation times. The thickness of the fibrous capsule surrounding the MEMS devices was similar between activated and control devices explanted at each time point. It was concluded that the repeated activation of MEMS drug delivery devices was successful and the activation produced an acceptable biological response that resolved promptly. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 559–568, 2004
Structure formation in injectable poly(lactide‐co‐glycolide) depots. II. Nature of the gel
Authors: Wang Liwei , Venkatraman Subbu , Gan Leong Huat , Kleiner Lothar 
Published: November 2004

AbstractThe benzyl benzoate solutions of poly(D,L‐lactide‐co‐glycolide), a random oriented synthesized copolymer with L/G ratio of 50:50, have been shown to form gels during aging and upon injection into buffer or water. The gelation properties influence drug release kinetics for these injectable, depot‐forming solutions. In this article, we report on the mechanism of gelation. We find that only polymers that have a certain average block length of glycolide units form gels during aging as well as depots upon in vitro. Thus, gel formation is likely due to the formation of ordered solvated aggregates of blocky glycolide units. Rheometry, differential scanning calorimetry, and nuclear magnetic resonance were used to investigate the gelation kinetics and the polymer molecular parameters. Of all the polymers used, poly(lactide‐co‐glycolide)s with glycolide average block length <2.9 did not show any gelation behavior. The details of the gelation process are also solvent dependent. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 215–222, 2005
Use of the fertilized hen's egg in the evaluation of embryotoxicity of dental alloys
Authors: Durmus Ercan , Inan Özgür , Çelik Ilhami , Sur Emrah , Özkan Yasemin , Acar Asli , Aydin Mehmet Faruk 
Published: November 2004

AbstractIn this study, embryotoxic effects of five commercially available dental alloys were investigated by using fertilized hens' eggs. One sample of each alloy was conditioned in one of the conditioning media, physiological saline (PS), 0.1 M phosphate‐buffered saline (PBS, pH 7.4), and 0.1 M protein (3% bovine serum albumin, BSA) containing PBS (pH 6.8), respectively. The test solutions were injected into the fertilized hen's eggs via air sac at the beginning of the incubation. Various concentrations of a highly embryotoxic substance, AFB1, was also used as positive control test material. Mortality of the AFB1 treatment groups increased with increasing concentrations of AFB1 and the mortality values were significantly (p < 0.05) higher than those of the controls and eluent injected groups. The eluents of five commercially available dental alloys tested in the study did not have significant embryotoxic effects. Cu‐ and Pd‐containing alloys displayed relatively high but statistically insignificant embryotoxic effects. Chick embryo might be used in determination of the embryotoxic effects of the dental alloys with its several advantages. Nevertheless, the test should be further standardized and new methods such as micronucleus test showing possible genotoxic effects of the materials should be used. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 322–327, 2005