bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of conformation and solvation on optical rotation: Substituted epoxides
Authors: Wilson Shaun M. , Wiberg Kenneth B. , Murphy Michael J. , Vaccaro Patrick H. 
Published: July 2007

AbstractThe vapor‐phase optical rotation (or circular birefringence) of (S)‐1,2‐epoxybutane, (S)‐epichlorohydrin, and (S)‐epifluorohydrin has been measured at the nonresonant excitation wavelengths of 355 nm and 633 nm by means of Cavity Ring‐Down Polarimetry (CRDP). Complementary solution‐phase studies were performed in a wide variety of dilute solvent media to highlight the pronounced influence of solute–solvent interactions. Density functional theory calculations of optical activity have been enlisted to unravel the structural and electronic provenance of experimental observations. Three stable, low‐lying conformers have been identified and characterized for each of the targeted chiral species, with thermal (relative population weighted) averaging of their antagonistic chiroptical properties allowing specific rotation values to be predicted under both isolated and solvated conditions. For (S)‐epichlorohydrin and (S)‐epifluorohydrin, a self‐consistent isodensity polarizable continuum model (SCI‐PCM) has been exploited to gain further insight into the underlying nature of solvation effects. Chirality, 2008. © 2007 Wiley‐Liss, Inc.
Chiral NMR discrimination of amines: Analysis of secondary, tertiary, and prochiral amines using (18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid
Authors: Lovely Ann E. , Wenzel Thomas J. 
Published: July 2007

AbstractEnantiomeric discrimination is observed in the 1H and 13C NMR spectra of secondary and tertiary amines in the presence of (−)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid (1). Nonequivalence of the resonances of prochiral nuclei in primary and secondary amines is also observed when they associate with 1. The amines are added in their neutral form and are protonated by the carboxylic acid groups of 1 to produce the corresponding ammonium and carboxylate ions. Secondary amines associate with 1 through two hydrogen bonds and an ion pair interaction. Tertiary amines can only form one hydrogen bond to accompany the ion pairing. Chiral discrimination in the 1H and 13C NMR spectra of a series of aryl‐containing secondary amines is of sufficient magnitude to determine enantiomeric purities. The discrimination in the spectra of tertiary amines with 1 is smaller, but 13C NMR spectra provided enough distinction for the determination of enantiomeric purity. Chirality, 2008. © 2007 Wiley‐Liss, Inc.
Analysis of pD‐Dependent complexation of N‐benzyloxycarbonylaminophosphonic acids by α‐cyclodextrin. Enantiodifferentiation of phosphonic acid pKa values
Authors: Rudzińska Ewa , Berlicki Łukasz , Mucha Artur , Kafarski Paweł 
Published: July 2007

AbstractThe influence of aqueous solution pD on stereoselective complexation of N‐benzyloxycarbonylaminophosphonic acids with α‐cyclodextrin was investigated by means of nuclear magnetic resonance spectroscopy. The highest enantiodiscrimination was achieved at pD close to the pKa of less acidic hydroxyl group of the phosphonic moiety of analytes (6.5–7.5). This effect results from the stereoselective differentiation of pKa (up to 0.28 pD unit) upon complexation with applied chemical shift reagent. Moreover, analysis of 2D‐ROESY spectra proved that the host–guest inclusion mode is strongly influenced by pD. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
Spinnenseidenproteine: Grundlage für neue Materialien
Authors: Römer Lin , Scheibel Thomas 
Published: July 2007

AbstractSpinnenseiden sind sehr stabil und gleichzeitig extrem dehnbar – eine Kombination die es in industriell eingesetzten Fasern in dieser Form nicht gibt. Es wird daher seit langem versucht, das große Potential der Spinnenseide in technische Produkte umzusetzen. Dieser Übersichtsartikel fasst den aktuellen Entwicklungsstand zur Seidenstruktur, biotechnologischen Seidenproduktion, und über den Seidenfaser‐Spinnprozess zusammen. Die neuesten Entwicklungen stellen eine Grundlage für neue technische Produkte auf Basis von Spinnenseide dar, was eine neue Generation umweltverträglicher Polymermaterialien ermöglicht.
Carl Hagemann ...ein Mensch von großer Güte, ein richtiger Chemiker...
Authors: Eiden Fritz 
Published: July 2007

AbstractDer Chemiker Carl Hagemann (1867–1940), der bei den Farbenfabriken Bayer, Cassella und der I.G. Farben A.G. Karriere machte, ist durch eine Sammlung von Bildern Deutscher Expressionisten bekannt geworden. Es handelt sich um denselben Hagemann, der 1893 über eine einfache Methode zur Herstellung von Methyl‐cyclohexenon‐carbonsäureestern berichtete und dessen Name dann mit einem dieser Ester verknüpft wurde. Nach der Strukturaufklärung fand man, dass Hagemanns Ester und viele seiner Derivate sich als Bausteine zur Synthese von Natur‐ und Wirkstoffen eignen. Erstaunlich ist nicht nur, dass die heute hochgeschätzte Hagemannsche Bildersammlung die bösartigen Aktionen der Hitlerdiktatur und die vernichtenden Bombenangriffe der Alliierten überstand, sondern auch, dass das Interesse von Chemikern an Hagemanns Ester bis in unsere Zeit andauert.
Zelloberflächenrezeptor für die Aufnahme von Vitamin A
Authors: Hille‐Rehfeld Annette 
Published: July 2007

AbstractFettlösliche Vitamine können durch Zellmembranen frei diffundieren, dennoch erfolgt ihre Aufnahme am Wirkort und in Speicherorgane hochselektiv. Über im Serum zirkulierende Transportproteine binden sie an spezifische Zelloberflächenrezeptoren.
Platensimycin hemmt Bakterienmembran‐Synthese
Authors: Jaenicke Lothar 
Published: July 2007

AbstractDie bisherigen Antibiotika greifen in die Bildung der Bakterienhülle oder in die DNA‐Verdoppelung ein. Bisher hat sich noch immer rasch eine Resistenz gegen neu eingeführte Bakterienhemmstoffe ausgebildet. Man diskutiert daher, gleichzeitig zwei unterschiedlich wirkende Antibiotika einzusetzen, da simultane Doppelresistenz sehr unwahrscheinlich ist. Man sucht aber eifrig nach neuen und neuartig wirkenden Natur‐ und Synthesestoffen, allerdings meist mit den alten Rezepten (wie in der Politik und allgemein im Leben).
Schloss Oranienburg in Brandenburg
Authors: Schwedt Georg 
Published: July 2007

AbstractIn der ersten Hälfte des 19. Jahrhunderts arbeitete der Chemiker Friedlieb Ferdinand Runge in einem Seitenflügel des Schlosses Oranienburg etwa 30 km nördlich des Standzentrums von Berlin und entdeckte dort u.a. Anilin, Chinolin, Pyrrol und Phenol im Steinkohlenteer. Von ihm stammen auch die berühmten “Professoren‐Kleckse”, Farbstoff‐Trennungen auf Papier nach einer Vorläufer‐Methode der Papier‐Chromatographie.
Improving colorectal cancer screening by using community volunteers
Authors: Katz Mira L. , Tatum Cathy , Dickinson Stephanie L. , Murray David M. , Long‐Foley Kristie , Cooper M. Robert , Daven Morgan , Paskett Electra D. 
Published: July 2007

AbstractBACKGROUND.The goal of the Carolinas Cancer Education and Screening (CARES) Project was to improve colorectal cancer (CRC) screening among low‐income women in subsidized housing communities in 11 cities in North and South Carolina who were traditionally underserved by cancer control efforts.METHODS.Cross‐sectional samples were randomly selected from housing authority lists at 5 timepoints in this nonrandomized community‐based intervention study. Face‐to‐face interviews focused on CRC knowledge, beliefs, barriers to screening, and screening behaviors. The intervention components were based on a previous evidence‐based program.RESULTS.A total of 2098 surveys were completed. Seventy‐eight percent of the respondents were African American, 62% were 65+ years, and 4% were married. At baseline, the rate of CRC screening within guidelines was 49.3% and physician recommendation was the strongest predictor (odds ratio [OR] = 21.9) of being within guidelines. There was an increase in positive beliefs about CRC screening (P = .010) and in the intention to complete CRC screening in the next 12 months (P = .053) after the intervention. The odds of being within CRC screening guidelines for women living in a city that had received the intervention were not significantly different from women living in a city that had not received the intervention (P = .496).CONCLUSIONS.Although CRC screening rates were not significantly better after the intervention, there was a positive change in beliefs about screening and intention to be screened. The results suggest that the dissemination of an evidence‐based behavioral intervention may require a longer duration to engage hard‐to‐reach populations and change behaviors. Cancer 2007. © 2007 American Cancer Society.
Inverse correlation between body mass index and clinical outcomes in men with advanced castration–recurrent prostate cancer
Authors: Halabi Susan , Ou San‐San , Vogelzang Nicholas J. , Small Eric J. 
Published: July 2007

AbstractBACKGROUND.Obesity has a variety of adverse health outcomes, but to the authors' knowledge, the effect of obesity on outcome in patients with advanced prostate cancer is not known. For this reason, the correlation between an elevated body mass index (BMI) and clinical outcomes in patients with metastatic, castration–recurrent prostate cancer (CRPC) was evaluated.METHODS.A total of 1226 men with CRPC who were enrolled in 9 prospective clinical trials conducted by the Cancer and Leukemia Group B (CALGB) for the treatment of metastatic disease were considered. Eligible patients had progressive prostate cancer during androgen deprivation therapy (with documented castrate levels of testosterone); an Eastern Cooperative Oncology Group performance status of 0 to 2; and adequate hematologic, renal, and hepatic function. Patients were classified based on BMI as normal (18.5–24.9 kg/m2), overweight (25–29.9 kg/m2), and mildly to severely obese (≥30 kg/m2).RESULTS.Approximately 24% of the patients had a normal BMI, 43% were overweight, and 33% were mildly to severely obese. On multivariable analysis, BMI was found to be a statistically significant predictor of overall survival and prostate cancer–specific mortality. Compared with men with normal BMIs, the hazard ratios for death for overweight men and mildly to severely obese men were 0.80 (95% confidence interval [95% CI], 0.68–0.93; P = .001) and 0.80 (95% CI, 0.68–0.94; P = .010), respectively.CONCLUSIONS.In patients with metastatic CRPC, obesity (as defined by an elevated BMI) appears to have a protective effect against overall mortality and prostate cancer–specific mortality. Alternatively, a higher BMI may reflect different cancer biology (ie, the lack of cachexia–producing substances). Further studies to gain a more comprehensive understanding of the mechanisms behind these clinical observations are needed. Cancer 2007. © 2007 American Cancer Society.
Synaptic and cognitive abnormalities in mouse models of down syndrome: Exploring genotype‐phenotype relationships
Authors: Belichenko Pavel V. , Kleschevnikov Alexander M. , Salehi Ahmad , Epstein Charles J. , Mobley William C. 
Published: July 2007

AbstractDown syndrome (DS) is caused by trisomy of human chromosome 21. Because Ts65Dn and Ts1Cje mice are segmentally trisomic for a region of mouse chromosome 16, they genetically model DS and are used to study pathogenic mechanisms. Previously, we provided evidence for changes in both the structure and function of pre‐ and postsynaptic elements in the Ts65Dn mouse. Striking changes were evident in the size of the dendritic spines and in the ability to induce long‐term potentiation (LTP) in the fascia dentata (FD). To explore the genetic basis for these changes, we examined Ts1Cje mice, which are trisomic for a completely overlapping but smaller segment of mouse chromosome 16. As in the Ts65Dn mouse, there was a regionally selective decrease in the density of dendritic spines (∼12%), an increase in the size of spine heads (∼26%), a decrease in the length of spine necks (∼26%), and reorganization of inhibitory inputs with a relative decrease in inputs to dendrite shafts and spine heads and a significant increase to the necks of spines (6.4%). Thus, all of the Ts65Dn phenotypes were present, but they were significantly less severe. In contrast, and just as was the case for the Ts65Dn mouse, LTP could not be induced unless the selective γ‐aminobutyric acid (GABA)A receptor antagonist picrotoxin was applied. Therefore, there was conservation of important synaptic phenotypes in the Ts1Cje mice. The analysis of data from this and earlier studies points to genotype‐phenotype linkages in DS whose complexity ranges from relatively simple to quite complex. J. Comp. Neurol. 504:329–345, 2007. © 2007 Wiley‐Liss, Inc.
Nav1.7 and Nav1.3 are the only tetrodotoxin‐sensitive sodium channels expressed by the adult guinea pig enteric nervous system
Authors: Sage D. , Salin P. , Alcaraz G. , Castets F. , Giraud P. , Crest M. , Mazet B. , Clerc N. 
Published: July 2007

AbstractThe types of sodium channels that are expressed by neurons shape the rising phase of action potentials and influence patterns of action potential discharge. With regard to the enteric nervous system (ENS), there is uncertainty about which channels are expressed, and in particular it is unknown whether Nav1.7 is present. We designed specific probes for the guinea pig Nav1.7 α subunit as well as for the other tetrodotoxin (TTX)‐sensitive α subunits (Nav1.1, Nav1.2, Nav1.3, and Nav1.6) in order to perform in situ hybridization (ISH) histochemistry on guinea pig myenteric ganglia. We established that only Nav1.7 mRNA and Nav1.3 mRNA are expressed in these ganglia. The ISH signal for Nav1.7 transcripts was found in seemingly all the myenteric neurons. The expression of the Nav1.3 α subunit was confirmed by immunohistochemistry in a large proportion (62%) of the myenteric neuron population. This population included enteric sensory neurons. Nav1.6 immunoreactivity, absent from myenteric neurons, was detected in glial cells only when a high anti‐Nav1.6 antibody concentration was used. This suggests that the Nav1.6 α subunit and mRNA are present only at low levels, which is consistent with the fact that no Nav1.6 mRNA could be detected in the ENS by ISH. The fact that adult myenteric neurons are endowed with only two TTX‐sensitive α subunits, namely, Nav1.3 and Nav1.7, emphasizes the singularity of the ENS. Both these subunits, known to have slow‐inactivation kinetics, are well adapted for generating action potentials from slow excitatory postsynaptic potentials, a mode of synaptic transmission that applies to all ENS neuron types. J. Comp. Neurol. 504:363–378, 2007. © 2007 Wiley‐Liss, Inc.
Molecular, cellular, and functional characterizations of pituitary adenylate cyclase‐activating polypeptide and its receptors in the cerebellum of New and Old World monkeys
Authors: Aubert Nicolas , Basille Magali , Falluel‐Morel Anthony , Vaudry David , Bucharles Christine , Jolivel Valerie , Fisch Cecile , De Jouffrey Stephane , Le Bigot Jean‐Francois , Fournier Alain , Vaudry Hubert , Gonzalez Bruno J. 
Published: July 2007

AbstractThe neuropeptide pituitary adenylate cyclase‐activating polypeptide (PACAP) exerts trophic activities during cerebellar development, and a neuroprotective effect of PACAP has been demonstrated in pathological conditions such as stroke. However, all these data have been obtained in rodents, and neuroprotective effects of PACAP in primates remain unknown. Because of their evolutionary relationships with humans, monkeys represent powerful models for validating the therapeutic interest in PACAP. The objective of the present study was to characterize PACAP and its receptors in the cerebellum of two nonhuman primates. RT‐PCR and in situ hybridization experiments revealed that PACAP is expressed in the cerebellum by Purkinje cells. Via immunohistochemistry, PACAP was detected in Purkinje cells and radial glial fibers. With regard to PACAP receptors, PAC1‐R and VPAC1‐R were detected by RT‐PCR. In situ hybridization revealed a strong expression of PAC1‐R and VPAC1‐R in the granule cell layer (GCL), and VPAC1‐R was also expressed in the Purkinje cell layer. A high density of PACAP binding sites was visualized in the GCL and the Purkinje cell layer. Competition studies indicated that, in the GCL, PACAP induced complete displacement of [125I]PACAP27 binding, whereas vasoactive intestinal polypeptide (VIP) was a weak competitor. In contrast, in the Purkinje cell layer, both PACAP and VIP displaced [125I]PACAP27 binding. Measurement of cAMP levels showed that PACAP is a powerful activator of adenylyl cyclase, whereas VIP is about 100‐fold less potent. Altogether, these observations constitute the first demonstration of a functional PACAPergic system in monkey cerebellum. They strongly suggest that neuroprotective effects of PACAP can be transposed to primates, including human. J. Comp. Neurol. 504:427–439, 2007. © 2007 Wiley‐Liss, Inc.
Sodium deprivation and salt intake activate separate neuronal subpopulations in the nucleus of the solitary tract and the parabrachial complex
Authors: Geerling Joel C. , Loewy Arthur D. 
Published: July 2007

AbstractSalt intake is an established response to sodium deficiency, but the brain circuits that regulate this behavior remain poorly understood. We studied the activation of neurons in the nucleus of the solitary tract (NTS) and their efferent target nuclei in the pontine parabrachial complex (PB) in rats during sodium deprivation and after salt intake. After 8‐day dietary sodium deprivation, immunoreactivity for c‐Fos (a neuronal activity marker) increased markedly within the aldosterone‐sensitive neurons of the NTS, which express the enzyme 11‐β‐hydroxysteroid dehydrogenase type 2 (HSD2). In the PB, c‐Fos labeling increased specifically within two sites that relay signals from the HSD2 neurons to the forebrain—the pre‐locus coeruleus and the innermost region of the external lateral parabrachial nucleus. Then, 1–2 hours after sodium‐deprived rats ingested salt (a hypertonic 3% solution of NaCl), c‐Fos immunoreactivity within the HSD2 neurons was virtually eliminated, despite a large increase in c‐Fos activation in the surrounding NTS (including the A2 noradrenergic neurons) and area postrema. Also after salt intake, c‐Fos activation increased within pontine nuclei that relay gustatory (caudal medial PB) and viscerosensory (rostral lateral PB) information from the NTS to the forebrain. Thus, sodium deficiency and salt intake stimulate separate subpopulations of neurons in the NTS, which then transmit this information to the forebrain via largely separate relay nuclei in the PB complex. These findings offer new perspectives on the roles of sensory information from the brainstem in the regulation of sodium appetite. J. Comp. Neurol. 504:379–403, 2007. © 2007 Wiley‐Liss, Inc.
Vestibular ganglion neurons survive hair cell defects in jerker, shaker, and varitint‐waddler mutants and downregulate calretinin expression
Authors: Čabraja Mario , Bäurle Jörg 
Published: July 2007

AbstractBipolar neurons (BNs) in the vestibular ganglion (VG) connect vestibular hair cells with the central nervous system (CNS). Disturbed function and cell loss in central vestibular target areas or in the vestibular periphery involve BNs either retro‐ or anterogradely. However, the impact of central vestibular disturbances or hair cell defects on the maintenance of BNs is poorly understood. In the present study the volume of the VG, the size and total number of BNs, and the number of BNs expressing the calcium‐binding protein calretinin (Calr) were quantified stereologically in the cerebellar mutants purkinje cell degeneration (pcd/pcd), weaver (wv/wv), and Lurcher (Lc/+), and in the vestibular mutants jerker (je/je), shaker‐1 (sh/sh), and Varitint‐waddler (Va/+). In all the different mutant mice investigated the total number of BNs did not differ from that of wildtypes. In contrast, the number of Calr‐positive BNs was significantly reduced in je/je (23%) and sh/sh (33%) mutants. Reduced cell size was apparent in sh/sh mutants and the volume of the VG significantly decreased in je/je mice. Calr was virtually absent from calyx endings in the vestibular periphery of je/je, sh/sh, and Va/+ mutants, whereas in wildtypes and cerebellar mutants many calyces displayed intense Calr labeling. These results imply that the survival of BNs is apparently unaffected by the peripheral and central target defects found in the mutants investigated. Whether the decrease in Calr expression may reflect biochemical adaptations in response to input disturbances or a specific loss of large BNs is discussed. J. Comp. Neurol. 504:418–426, 2007. © 2007 Wiley‐Liss, Inc.
Convergence of olfactory and vomeronasal projections in the rat basal telencephalon
Authors: Pro‐Sistiaga Palma , Mohedano‐Moriano Alicia , Ubeda‐Bañon Isabel , del mar Arroyo‐Jimenez Maria , Marcos Pilar , Artacho‐Pérula Emilio , Crespo Carlos , Insausti Ricardo , Martinez‐Marcos Alino 
Published: July 2007

AbstractOlfactory and vomeronasal projections have been traditionally viewed as terminating in contiguous non‐overlapping areas of the basal telencephalon. Original reports, however, described areas such as the anterior medial amygdala where both chemosensory afferents appeared to overlap. We addressed this issue by injecting dextran amines in the main or accessory olfactory bulbs of rats and the results were analyzed with light and electron microscopes. Simultaneous injections of different fluorescent dextran amines in the main and accessory olfactory bulbs were performed and the results were analyzed using confocal microscopy. Similar experiments with dextran amines in the olfactory bulbs plus FluoroGold in the bed nucleus of the stria terminalis indicate that neurons projecting through the stria terminalis could be integrating olfactory and vomeronasal inputs. Retrograde tracing experiments using FluoroGold or dextran amines confirm that areas of the rostral basal telencephalon receive inputs from both the main and accessory olfactory bulbs. While both inputs clearly converge in areas classically considered olfactory‐recipient (nucleus of the lateral olfactory tract, anterior cortical amygdaloid nucleus, and cortex–amygdala transition zone) or vomeronasal‐recipient (ventral anterior amygdala, bed nucleus of the accessory olfactory tract, and anteroventral medial amygdaloid nucleus), segregation is virtually complete at posterior levels such as the posteromedial and posterolateral cortical amygdalae. This provides evidence that areas so far considered receiving a single chemosensory modality are likely sites for convergent direct olfactory and vomeronasal inputs. Therefore, areas of the basal telencephalon should be reclassified as olfactory, vomeronasal, or mixed chemosensory structures, which could facilitate understanding of olfactory–vomeronasal interactions in functional studies. J. Comp. Neurol. 504:346–362, 2007. © 2007 Wiley‐Liss, Inc.
Projection of diffusions on submanifolds: Application to mean force computation
Authors: Ciccotti Giovanni , Lelièvre Tony , Vanden‐Eijnden Eric 
Published: July 2007

AbstractWe consider the problem of sampling a Boltzmann‐Gibbs probability distribution when this distribution is restricted (in some suitable sense) on a submanifold Σ of ℝn implicitly defined by N constraints q1(x) = ⃛ = qN(x) = 0 (N < n). This problem arises, for example, in systems subject to hard constraints or in the context of free energy calculations. We prove that the constrained stochastic differential equations (i.e., diffusions) proposed in [7, 13] are ergodic with respect to this restricted distribution. We also construct numerical schemes for the integration of the constrained diffusions. Finally, we show how these schemes can be used to compute the gradient of the free energy associated with the constraints. © 2007 Wiley Periodicals, Inc.