bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untersuchungen an 1,4‐Naphthochinonen, 10. Mitt. Reaktionen von Methylethern des 1,5‐Dihydroxynaphthalins mit Singulettsauerstoff
Authors: Wurm Gotthard , Geres Uwe 
Published: October 2006

AbstractWährend 1,5‐Dihydroxynaphthalin bei der farbstoffsensibilisierten Photooxidation unter Cycloaddition von 1O2 regiospezifisch Juglon (3) in hoher Ausbeute liefert, entstehen unter gleichen Reaktionsbedingungen aus dem Monomethylether 1 die Verbindungen 2, 3 und 4 und aus dem Dimethylether 5 die Verbindungen 2, 6 und 7. Die Etherspaltungen sind nicht das Ergebnis von 1O2‐Reaktionen im Sinne einer Cycloaddition, sondern Elektronentransferoxidationen über Radikalionenpaare mit O2·− als Anionen.
Kondensation von Indeno[2,1‐c]‐1,2‐dithiolen zu Diindeno‐[2,1‐b: 1′,2′‐e]thiopyran‐Derivaten
Authors: Hartke Klaus , Hoederath Wolfgang , Krampitz Dieter 
Published: October 2006

AbstractIndeno[2,1‐c]‐1,2‐dithiole1„dimerisieren”︁ unter Säurekatalyse und Verlust von zwei Schwefelatomen zu Diindeno‐thiopyranen2I/2II. Eine analoge Reaktion ist vom 3‐Methyl‐5‐phenyl‐1,2‐dithiolylium‐perchlorat (3) bekannt, das mit Pyridin die beiden isomeren Thiopyrane4I/IIliefert. Kondensation von 1‐Acyl‐2‐indanonen13mit Acetanhydrid/Perchlorsäure ergibt die zu2I/2IIstrukturanalogen Sauerstoffverbindungen14und15.
Untersuchungen über die Reaktion von N‐Isopropyl‐N′‐phenylcarbodiimid mit Benzoylchlorid, Oxalsäuredichlorid und Quadratsäuredichlorid
Authors: Grüunefeld Johann , Zinner Gerwalt 
Published: October 2006

AbstractDie Struktur der Additionsprodukte aus N‐Isopropyl‐N‐phenylcarbodiimid (1) und Benzoylchlorid bzw. Quadratsäuredichlorid wird durch spektroskopische Vergleiche mit Referenzsubstanzen bestimmt.
Additionsreaktionen von β‐Ketosulfoxiden und Bis(phenylsulfinyl)methan an Isocyanate
Authors: Messinger Paul , Kunick Conrad 
Published: October 2006

AbstractDie Natriumsalze der β‐Ketosulfoxide 1 reagieren mit Isocyanaten 2 zu α‐Acyl‐α‐sulfinyl‐acetamiden 4, analog entsteht aus Bis(phenylsulfinyl)methan (11) und Phenylisocyanat (2a) 2,2‐Bis‐(phenylsulfinyl)‐N‐phenyl‐acetamid (12). 4a wird zu Benzoylacetanilid (9) und Benzolsulfinsäure (10) hydrolysiert.
Antivirale Wirkstoffe, 27. Mitt. Die Aminomethinylierung von 5‐Oxo‐2‐pyrazolin‐3‐carbonsäurederivaten
Authors: Kreutzberger Alfred , Kolter Karl 
Published: October 2006

AbstractAus der mit s‐Triazin (1) durchgeführten Aminomethinylierung der 5‐Oxo‐2‐pyrazolin‐3‐carbonsäurederivate 2a,b gehen die 4‐Aminomethylen‐5‐oxo‐2‐pyrazolin‐3‐carbonsäurederivat 4a,b und die C‐Rubazonsäuren 5a,b hervor. Bei 4a deuten die spektroskopischen Daten auf das Vorliegen der Z‐Form (Abb. 1), für 5a auf das der Z‐s‐cis‐(OH)‐Form (Abb. 2) hin. Die Strukturtypen 4 und 5 weisen Vertreter mit antiviraler, entzündungshemmender, temperatursenkender und antimykotischer Wirkung auf.
Zur Stereochemie der 3‐Oxo‐5‐phenyl‐1‐cyclopentancarbonsäuren, 9. Mitt. Synthese kernfluorierter stereomerer 3‐Oxo‐5‐phenyl‐1‐cyclopentancarbonsäuren
Authors: Beck Martin , Jaunich Siegfried , Frahm August W. 
Published: October 2006

AbstractEs wird die stereoselektive Synthese der kernfluorierten cis‐ und trans‐5‐Phenyl‐3‐oxo‐cyclopentan‐carbonsäuren 5a‐d/6a‐d durch kombinierte Michael‐ und Dieckmannreaktion aus Ethantricarbonsäuretrimethylester und den fluorierten Zimtsäuremethylestern 1a‐d beschrieben. Der saure bzw. basische Abbau der 5‐Phenyl‐3‐oxo‐cyclopentan‐1.1.t‐4‐tricarbonsäure‐trimethylester 2a‐d führt über die 5‐Phenyl‐c‐1‐methoxycarbonyl‐3‐oxo‐cyclopentan‐t‐1‐carbonsäuren 3a‐d und die 5‐Phenyl‐3‐oxo‐cyclopentan‐1.1‐dicarbonsäuren 4a‐d. Zum Strukturbeweis werden 5a‐d zu 7a‐d, 6a‐d zu 8a‐d, sowie 3a‐d und 4a‐d zu 9a‐d mit Diazomethan verestert.
Basisch substituierte Pyrrolidin‐2,5‐dione, 2. Mitt. Konfiguration der Enantiomere
Authors: Knabe Joachim , Konrad Horst 
Published: October 2006

AbstractAus den ORD‐ und CD‐Spektren der in Ethanol rechtsdrehenden Enantiomere der Pyrrolidindione 1a‐1c ergibt sich, daß sie gleiche Konfiguration besitzen. Der chemische Abbau von (+)1c führt zu R(+)‐3‐Ethyl‐1‐methyl‐3‐phenylpyrrolidin‐2,5‐dion [R(+)‐1i]. Hieraus läßt sich für (+)1a ‐ (+)1c R‐Konfiguration ableiten. (+)3a und (+)3b, durch katalytische Hydrierung von (+)1a und (+)1b gewonnen, besitzen ebenfalls R‐Konfiguration. Die ORD‐ und CD‐Spektren der 3‐(2‐Thienyl)pyrrolidindione (+)2a und (+)2b zeigen, daß beide Verbindungen gleich konfiguriert sind.
Umsetzung von 1,2‐Dihydro‐3‐indazolon mit ω‐Dialkylaminoalkylhalogeniden und α,ω‐Dihalogenalkanen
Authors: Oelschläger Herbert , Matthiesen Uwe , Shaik Mohammed Al 
Published: October 2006

AbstractWährend das K‐Salz des 1,2‐Dihydro‐3‐indazolons in trockenem Dioxan mit ω‐Dialkylaminoalkylhalogeniden zu den analgetisch wirkenden basischen Lactimethern reagiert, entstehen bei der Umsetzung mit α, ω‐Dihalogenpropanen zwei basische Verbindungen, die als 3,4‐Dihydro‐2H‐(1,3)oxazino[2,2‐b]indazol (1) und 2,3‐Dihydro‐1H‐pyrazolo[1,2‐a]indazol‐9‐on (2) identifiziert wurden. 2 läßt sich mit LiAlH4 zu 2,3‐Dihydro‐1H, 9H‐pyrazolo [1, 2‐a] indazol (5) reduzieren.
P‐Glycoprotein Effects of Cyclic Urea HIV Protease Inhibitor DMP 323 in Competitional Absorption Studies
Authors: Richter Martin , Gyémánt Nóra , Molnár Joséf , Hilgeroth Andreas 
Published: October 2006

AbstractCyclic ureas form a perspective class of non‐peptidic HIV‐1 protease inhibitors with major bioavailability problems. Low absorption rates of DMP 323 as one of the first representatives led to investigations whether transport efflux pump P‐glycoprotein (P‐gp) within the intestine may be partly responsible for the low absorption rates. DMP 323 proved to be a P‐gp substrate in competition studies with P‐gp inhibitor ritonavir and H17 as a representative of another class of non‐peptidic HIV‐1 protease inhibitors. Intestinal DMP 323 absorption was mainly increased under co‐application of both ritonavir and H17. DMP 323 used as a membrane efflux pump inhibitor itself showed little affinities to P‐gp compared to H17 as strong P‐gp inhibitor. So P‐gp proved to play a decisive role in the low intestinal absorption of the cyclic urea representative DMP 323.
Clinician reviewers in birth defects surveillance programs: Survey of the National Birth Defects Prevention Network
Authors: Lin Angela E. , Forrester Mathias B. , Cunniff Christopher , Higgins Cathleen A. , Anderka Marlene 
Published: October 2006

AbstractBACKGROUND: Some birth defects surveillance programs utilize a clinician reviewer (“Clinician”) to assist the multidisciplinary staff in the process of case review, coding and classification. The untested assumption is that expertise in the evaluation of individuals with birth defects and genetic syndromes in clinical practice, usually clinical genetics, is useful in reviewing medical records. METHODS: We conducted an exploratory survey of the 50 functioning birth defects surveillance programs that participated in the National Birth Defects Prevention Network in 2004. The survey was mailed electronically to program coordinators and included 10 questions with check‐off option replies. Open‐ended comments were also solicited. RESULTS: Responses were received from 31 of 50 (62%) programs, 21 (68%) which used a Clinician. In addition to the 9 centers that identified themselves as participants in the National Birth Defects Prevention Study (NBDPS), there were 12 non‐NBDPS programs using a Clinician, 2 of whom were not clinical geneticists (1 nurse genetic counselor and 1 primary pediatrician). A total of 86% (18/21) of Clinicians were employed part‐time or as consultants; 1 was full‐time, and 2 were volunteers. In addition to the core activities of classifying defects and reviewing cases to determine if a syndrome was present, over one‐half of the Clinicians participated in education of birth defects surveillance programs staff, research, and program development. Most (86%; 18/21) Clinicians had been trained informally for their roles. Only 1 had received a formal performance review. CONCLUSIONS: Aside from the 9 centers in the NBDPS in which the position of Clinician is funded by the Centers for Disease Control and Prevention (CDC), about one‐half of the remaining respondent birth defects surveillance programs used a Clinician. Future research is needed to determine why a birth defects surveillance program hires or refrains from using a Clinician, and whether a Clinician accomplishes the desired goals. This survey reveals a lack of formal training for the Clinicians in their roles in the surveillance programs, and a lack of quality monitors, which might be addressed in the future. Birth Defects Research (Part A), 2006. © 2006 Wiley‐Liss, Inc.
The Water‐Exchange Mechanism of the [UO2(OH2)5]2+ Ion Revisited: The Importance of a Proper Treatment of Electron Correlation
Authors: Rotzinger François P. 
Published: October 2006

AbstractThe water‐exchange mechanism of [UO2(OH2)5]2+ has been reinvestigated by using ab initio molecular orbital (MO) methods. The geometries and the vibrational frequencies were computed with CAS‐SCF(12/11)‐SCRF and CAS‐SCF(12/11)‐PCM methods, which take into account static electron correlation (using the complete active space self‐consistent field (CAS‐SCF) technique, based on an active space of 12 electrons in 11 orbitals) and hydration (using the self‐consistent reaction field (SCRF) and polarizable continuum model (PCM) techniques). The total energies were computed with multiconfiguration quasi‐degenerate second‐order perturbation theory, the MCQDPT2(12/11)‐PCM method, which treats static and dynamic electron correlation as well as hydration. The adequacies of other currently used quantum chemical methods, MP2, CCSD(T), B3 LYP, and BLYP, are discussed. For the associative and dissociative pathways, thermodynamic activation parameters (ΔH≠, ΔS≠, and ΔG≠) were computed. For the associative mechanism, the calculated ΔH≠ and ΔG≠ values agree with experiment, whereas for the dissociative mechanism, they are higher by ≈20 kJ mol−1. The dissociative mechanism is preferred for substitution reactions of uranyl(VI) complexes with ligands that are stronger electron donors than water. The question of whether a concerted (Ia or Id) or a stepwise (A or D) mechanism operates is discussed on the basis of the computed lifetime of the respective intermediate, and the duration of the vibration with which the intermediate is transformed into the product.
Theoretical Investigation of the Second‐Order Nonlinear Optical Properties of Helical Pyridine–Pyrimidine Oligomers
Authors: Botek Edith , Castet Frédéric , Champagne Benoît 
Published: October 2006

AbstractThe structure and second‐order nonlinear optical properties of a series of helical pyridine–pyrimidine oligomers recently synthesized by Barboiu and Lehn have been investigated theoretically by combining molecular mechanics and quantum chemistry approaches. In the absence of substituents, the hyper‐Rayleigh scattering response (βHRS) and the projection of the first hyperpolarizability on the dipole moment (β∥) exhibit periodic variations with chain length, but these nonlinear optical responses remain small. The first hyperpolarizabilities can, however, be enhanced by adding substituents. The greatest enhancement is obtained by substituting the pyrimidine groups by donor groups. Moreover, regular distributions of the donor groups around the helices enable the design of supramolecular structures exhibiting dipolar, octupolar or Λ‐shaped nonlinear optical characters, evident from the values of the depolarization ratios in hyper‐Rayleigh scattering. Therefore this theoretical investigation demonstrates the potential of helical structures for the organization of chromophores in such a way that they exhibit large and specific second‐order nonlinear optical responses.
Combined AFM and Two‐Focus SFCS Study of Raft‐Exhibiting Model Membranes
Authors: Chiantia Salvatore , Ries Jonas , Kahya Nicoletta , Schwille Petra 
Published: October 2006

AbstractDioleoylphosphatidylcholine/sphingomyelin/cholesterol (DOPC/SM/cholesterol) model membranes exhibit liquid–liquid phase separation and therefore provide a physical model for the putative liquid‐ordered domains present in cells. Here we present a combination of atomic force microscopy (AFM) imaging, force measurements, confocal fluorescence imaging and two‐focus scanning fluorescence correlation spectroscopy (two‐focus SFCS) to obtain structural and dynamical information about this model membrane system. Partition coefficients and diffusion coefficients in the different phases were measured with two‐focus SFCS for numerous fluorescent lipid analogues and proteins, while being directly related to the lateral organization of the membrane and its mechanical properties probed by AFM. Moreover we show how the combination of these different approaches is effective in reducing artifacts resulting from the use of a single technique.
Nucleus image properties assessed by video image analysis in mouse hepatocytes under a short lysis for extended chromatin fiber formation
Authors: Vidal Benedicto C. , Moraes Alberto S. , Mello Maria Luiza S. 
Published: October 2006

AbstractBackground:How much DNA remains in mouse hepatocyte nuclei after extended chromatin fiber (ECF) formation or whether this content varies within the nuclear population is not known. This information could be relevant to understanding chromatin extensibility as related to chromatin organization, possibly associated with variable nuclear activities in hepatocytes.Methods:A protocol for ECF formation under the gravity action, image analysis of Feulgen‐stained unfixed mouse hepatocyte remnants, and DAPI fluorescence were used.Results:Areas, shape, Feulgen‐DNA amounts, and chromatin texture were affected in unfixed, lysed nuclei. The Feulgen‐DNA values in nuclear remnants represented ∼37% of the content in fixed, nonlysed nuclei in terms of median values; the coefficient of variation of Feulgen‐DNA values in the nuclear remnants was much higher than those in controls. Enhancement in DAPI fluorescence was evident in chromocenters of the fixed nuclei and in remnants and some ECF granules of the unfixed, lysed nuclei.Conclusions:The DNA content of the nuclear remnants was much more variable than that assumed from known variability in hepatocyte ploidy degrees. The variable constraint to chromatin extrusion from hepatocyte nuclei is hypothesized to depend on variable chromatin organization with possible involvement of nuclear matrix association, transcriptional activities, and AT‐rich DNA‐containing heterochromatin. © 2006 International Society for Analytical Cytology
Cell behaviors associated with somite segmentation and rotation in Xenopus laevis
Authors: Afonin Bonnie , Ho Minh , Gustin Jean K. , Meloty‐Kapella Caroline , Domingo Carmen R. 
Published: October 2006

AbstractDuring vertebrate development the formation of somites is a critical step, as these structures will give rise to the vertebrae, muscle, and dermis. In Xenopus laevis, somitogenesis consists of the partitioning of the presomitic mesoderm into somites, which undergo a 90‐degree rotation to become aligned parallel to the notochord. Using a membrane‐targeted green fluorescent protein to visualize cell outlines, we examined the individual cell shape changes occurring during somitogenesis. We show that this process is the result of specific, coordinated cell behaviors beginning with the mediolateral elongation of cells in the anterior presomitic mesoderm and then the subsequent bending of these elongated cells to become oriented parallel with the notochord. By labeling a clonal population of paraxial mesoderm cells, we show that cells bend around their dorsoventral axis. Moreover, this cell bending correlates with an increase in the number of filopodial protrusions, which appear to be posteriorly directed toward the newly formed segmental boundary. By examining the formation of somites at various positions along the anteroposterior axis, we show that the general sequence of cell behaviors is the same; however, somite rotation in anterior somites is slower than in posterior somites. Lastly, this coordinated set of cell behaviors occurs in a dorsal‐to‐ventral progression within each somite such that cells in the dorsal aspect of the somite become aligned along the anteroposterior axis before cells in other regions of the same somite. Together, our data further define how these cell behaviors are temporally and spatially coordinated during somite segmentation and rotation. Developmental Dynamics 235:3268–3279, 2006. © 2006 Wiley‐Liss, Inc.
Improvement of search performance in genetic algorithms with fitness prediction
Authors: Tanaka Masaharu , Mizoguchi Masanobu , Takami Isao 
Published: October 2006

AbstractWhen genetic algorithm (GA) is applied to actual engineering problems, for example, optimization of design parameters, the searching time is usually huge because the fitness is calculated by repetitive simulation or analysis, which requires a large amount of calculation time. In order to shorten the searching time, a method called fitness prediction GA has been proposed. It reduces the calculation time by predicting fitness instead of actually calculating it, and eventually shortens the searching time. In this paper, we propose a new method, Dual Population GA (DPGA), which employs both real and virtual populations. Real populations have actual fitness value, and virtual ones have predicted ones. DPGA can prevent the decline of performance caused by prediction errors, which may occur in fitness prediction GA, by appropriately migrating virtual populations into real ones and accelerating evolution. A fitness predictor based on a neural network is also proposed in this paper. Through computer simulations, DPGA is demonstrated to improve the searching performance of fitness prediction GA. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(1): 60–68, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20205
Cross‐priming with an epicutaneously introduced soluble protein antigen generates Tc1 cells
Authors: Wang Li‐Fang , Hsu Chih‐Jung , Miaw Shi‐Chuen , Chiu Hsien‐Ching , Liu Ching‐Yi , Yu Hsin‐Su 
Published: October 2006

AbstractEpicutaneous sensitization with a protein antigen was demonstrated to induce a predominant type 2 CD4 T cell response with high IgE production in mice. On the other hand, its CD8 T cell responses have not been addressed probably partly because of the generally accepted concept that cross‐priming of soluble protein is an inefficient process. Here, we used an established patch‐applied murine model to demonstrate that cross‐priming with an epicutaneously introduced soluble protein antigen, though inefficient, generated mainly Tc1 cells, but not Tc2 cells. In the presence of an irritant or hapten, the efficiency of this cross‐priming process could be enhanced and more Tc1 cells were generated. CpG oligonucleotides also promote the generation of Tc1 cells. In contrast, lipopolysaccharide and poly (inosinic‐cytidylic) acid [poly (I:C)] have no effect. Together, these results provide supportive evidence of the epicutaneous sensitization of human cutaneous lymphocyte‐associated antigen‐positive CD8 T cells found in the peripheral blood or tissues of patients. The surprising observation of the type 1 character of the generated CD8 T cells will also help us to better understand the complicated pathogenesis of atopic and cutaneous inflammatory diseases.
In vitro generated human memory‐like T cells are CD95 type II cells and resistant towards CD95‐mediated apoptosis
Authors: Fas Stefanie C. , Baumann Sven , Krueger Andreas , Frey Christian R. , Schulze‐Bergkamen Henning , Brenner Dirk , Stumpf Christine , Kappes Kathrin , Krammer Peter H. 
Published: October 2006

AbstractAn adaptive immune response implies expansion of activated T cells and subsequent elimination to maintain homeostasis in a process called activation‐induced cell death. Some cells, however, differentiate into memory cells and ensure a strong secondary immune response. To analyze the apoptosis phenotype of memory T cells on a cellular and molecular level, we have established an in vitro model of T cell activation and generation of cells phenotypically and functionally similar to memory cells. These long‐term cultured T cells show a CD95‐resistant phenotype, although they are still sensitive towards TCR/CD3‐mediated apoptosis. Biochemical analysis revealed that these cells shift from CD95 type I (direct signaling from the receptor) during the effector phase to CD95 type II cells (dependent on the mitochondrial amplification loop). Moreover, their mitochondria are protected, probably due to high expression levels of Bcl‐xL and Bcl‐2. Thus, our data suggest a mechanism how memory T cells acquire resistance towards bystander cell death via the CD95 system.
An important role of Tyk2 in APC function of dendritic cells for priming CD8+ T cells producing IFN‐γ
Authors: Aizu Keiji , Li Wei , Yajima Toshiki , Arai Toshiyuki , Shimoda Kazuya , Nimura Yuji , Yoshikai Yasunobu 
Published: October 2006

AbstractTyrosine kinase 2 (Tyk2) contributes to the signals triggered by IL‐12 for IFN‐γ production by NK cells and T cells. We found in this study that Tyk2‐deficient (–/–) mice showed increased susceptibility at the early stage after an i.p. infection with Listeria monocytogenes, accompanied by impaired IFN‐γ production. The numbers of both MHC class Ib (H2‐M3)‐ or MHC class Ia (Kb)‐restricted CD8+ T cells producing IFN‐γ and exhibiting cytotoxicity were significantly decreased in Tyk2–/– mice after infection with L. monocytogenes. Using an adoptive transfer system of OT‐I cells expressing OVA257–264/Kb‐specific TCR into Tyk2–/– mice followed by challenge with recombinant L. monocytogenes expressing OVA, we found that the defective Tyk2 signaling in the host environment was at least partially responsible for the impaired CD8+ T cytotoxic‐1 (Tc1) cell responses in Tyk2–/– mice following the infection. Adoptive transfer with MHC class Ib‐ or MHC class Ia‐binding peptide‐pulsed BM‐derived DC from Tyk2–/– mice induced lower levels of the Ag‐specific CD8+ Tc1 cells producing IFN‐γ. These results suggest that Tyk2 signaling is also important for DC function in the induction of MHC class Ia‐ and class Ib‐restricted CD8+ Tc1 cells following L. monocytogenes infection.
CD4+CD25+ regulatory T cells suppress contact hypersensitivity reactions by blocking influx of effector T cells into inflamed tissue
Authors: Ring Sabine , Schäfer Stephan C. , Mahnke Karsten , Lehr Hans‐Anton , Enk Alexander H. 
Published: October 2006

AbstractCD4+CD25+ regulatory T cells (Treg) exert suppressive functions on effector T cells in vitro and in vivo. However, the exact cellular events that mediate this inhibitory action remain largely unclear. To elucidate these events, we used intravital microscopy in a model of contact hypersensitivity (CHS) and visualized the leukocyte‐endothelium interaction at the site of antigen challenge in awake C57BL/6 mice. Injection of Treg i.v. into sensitized mice at the time of local hapten challenge significantly inhibited rolling and adhesion of endogenous leukocytes to the endothelium. A similar inhibition of leukocyte recruitment could be recorded after injection of Treg‐derived tissue culture supernatant. Thus, these data indicate that soluble factors may account for the suppressive effects. Accordingly we found that IL‐10, but not TGF‐β, was produced by Treg upon stimulation and that addition of anti‐IL‐10 antibodies abrogated the suppressive effects of Treg and tissue culture supernatant in CHS reactions. Moreover, CD4+CD25+ T cells isolated from IL‐10–/– mice were not able to suppress the immune response induced by hapten treatment in C57BL/6 mice. In conclusion, our data suggest that cytokine‐dependent rather than cell‐cell contact‐dependent mechanisms play a pivotal role in the suppression of CHS reactions by Treg in vivo.