bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypercrosslinked polystyrene microspheres with bimodal pore size distribution and controllable macroporosity
Authors: Liu Qingquan , Wang Li , Yu Weiting , Xiao Anguo , Yu Haojie , Huo Jia 
Published: November 2009

AbstractA combination of suspension polymerization and postcrosslinking was used to prepare hypercrosslinked polystyrene (H‐PS) microspheres with controllably bimodal pore size distribution in the presence of toluene and polypropylene (PP) as a coporogen. The proportion of PP in the coporogen was changed to investigate the influence of the coporogen composition on the pore structure of the H‐PS microspheres. The addition of a small amount of PP achieved the aim of a clearly bimodal pore size distribution and the control of the macroporosity of the H‐PS microspheres, which have potential application in the preparation of catalyst supports. The specific surface area of the H‐PS microspheres could be adjusted in the range 380–790 m2/g by changes in the concentration of PP in the coporogen. Moreover, the H‐PS microspheres displayed all the characteristics of Davankov‐type resins by their ability to be swollen in both thermodynamically poor solvents such as water and good solvents such as toluene. Finally, the possible mechanism of porosity formation during polymerization and postcrosslinking was also examined by a combination of pore structure data and the appearance of the microspheres before and after postcrosslinking. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of Glycocinnasperimicin D
Authors: Nishiyama Taihei , Kusumoto Yoshifumi , Okumura Ken , Hara Kanako , Kusaba Shohei , Hirata Keiko , Kamiya Yukihiro , Isobe Minoru , Nakano Keiji , Kotsuki Hiyoshizo , Ichikawa Yoshiyasu 
Published: November 2009

AbstractThe first total synthesis of amino sugar antibiotic glycocinnasperimicin D (1) has been achieved by a convergent, three‐component coupling strategy. The key steps involve the Heck–Mizoroki reaction by using the iodophenyl glycoside 50 and acryl amide 32 to furnish the right core structure of 1, and the construction of the urea glycoside employing the reaction of glycosyl isocyanate 8 with amino sugar 9. Glycosyl isocyanate 8 was prepared by the oxidation of isonitrile 10, which displayed excellent reactivity in the coupling event. Synthetic roadblocks, encountered during this synthetic effort, have led to the development of the α‐selective, Lewis acid catalyzed phenyl glycosylation process with 2‐amino‐hexopyranose and a procedure for acetonide deprotection without affecting the silyl ethers.
Bisnaphthalimidopropyl Derivatives as Inhibitors ofLeishmaniaSIR2 Related Protein 1
Authors: Tavares Joana , Ouaissi Ali , Kong Thoo Lin Paul , Loureiro Inês , Kaur Simranjeet , Roy Nilanjan , Cordeiro‐da‐Silva Anabela 
Published: November 2009

AbstractThe NAD+‐dependent deacetylases, namely sirtuins, are involved in the regulation of a variety of biological processes such as gene silencing, DNA repair, longevity, metabolism, apoptosis, and development. An enzyme from the parasiteLeishmania infantumthat belongs to this family, LiSIR2RP1, is a NAD+‐dependent tubulin deacetylase and an ADP‐ribosyltransferase. This enzyme's involvement inL. infantumvirulence and survival underscores its potential as a drug target. Our search for selective inhibitors of LiSIR2RP1 has led, for the first time, to the identification of the antiparasitic and anticancer bisnaphthalimidopropyl (BNIP) alkyl di‐ and triamines (IC50values in the single‐digit micromolar range for the most potent compounds). Structure–activity studies were conducted with 12 BNIP derivatives that differ in the length of the central alkyl chain, which links the two naphthalimidopropyl moieties. The most active and selective compound is the BNIP diaminononane (BNIPDanon), with IC50values of 5.7 and 97.4 μMagainst the parasite and human forms (SIRT1) of the enzyme, respectively. Furthermore, this compound is an NAD+‐competitive inhibitor that interacts differently with the parasite and human enzymes, as determined by docking analysis, which might explain its selectivity toward the parasitic enzyme.
Targeted three‐dimensional immunohistochemistry reveals localization of presynaptic proteins Bassoon and Piccolo in the rat calyx of Held before and after the onset of hearing
Authors: Dondzillo Anna , Sätzler Kurt , Horstmann Heinz , Altrock Wilko D. , Gundelfinger Eckart D. , Kuner Thomas 
Published: November 2009

AbstractBassoon and Piccolo contribute to the cytomatrix of active zones (AZ), the sites of neurotransmitter release in nerve terminals. Here, we examined the 3D localization of Bassoon and Piccolo in the rat calyx of Held between postnatal days 9 and 21, the period of hearing onset characterized by pronounced structural and functional changes. Bassoon and Piccolo were identified by immunohistochemistry (IHC) on slices of the brainstem harboring calyces labeled with membrane‐anchored green fluorescent protein (mGFP). By using confocal microscopy and 3D reconstructions, we examined the distribution of Bassoon and Piccolo in calyces delineated by mGFP. This allowed us to discriminate calyceal IHC signals from noncalyceal signals located in the spaces between the calyceal stalks, which could mimic a calyx‐like distribution. We found that both proteins were arranged in clusters resembling the size of AZs. These clusters were located along the presynaptic membrane facing the principal cell, close to or overlapping with synaptic vesicle (SV) clusters. Only about 60% of Bassoon and Piccolo clusters overlapped, whereas the remaining clusters contained predominantly Bassoon or Piccolo, suggesting differential targeting of these proteins within a single nerve terminal and potentially heterogeneous AZs functional properties. The total number of Bassoon and Piccolo clusters, which may approximate the number of AZs, was 405 ± 35 at P9 and 601 ± 45 at P21 (mean ± SEM, n = 12). Normalized to calyx volume at P9 and P21, the density of clusters was similar, suggesting that the absolute number of clusters, not density, may contribute to the functional maturation associated with hearing onset. J. Comp. Neurol. 518:1008–1029, 2010. © 2009 Wiley‐Liss, Inc.
Comparative analyses of the neuron numbers and volumes of the amygdaloid complex in old and new world primates
Authors: Carlo C.N. , Stefanacci L. , Semendeferi K. , Stevens C.F. 
Published: November 2009

AbstractThe amygdaloid complex (AC), a key component of the limbic system, is a brain region critical for the detection and interpretation of emotionally salient information. Therefore, changes in its structure and function are likely to provide correlates of mood and emotion disorders, diseases that afflict a large portion of the human population. Previous gross comparisons of the AC in control and diseased individuals have, however, mainly failed to discover these expected correlations with diseases. We have characterized AC nuclei in different nonhuman primate species to establish a baseline for more refined comparisons between the normal and the diseased amygdala. AC nuclei volume and neuron number in 19 subdivisions are reported from 13 Old and New World primate brains, spanning five primate species, and compared with corresponding data from humans. Analysis of the four largest AC nuclei revealed that volume and neuron number of one component, the central nucleus, has a negative allometric relationship with total amygdala volume and neuron number, which is in contrast with the isometric relationship found in the other AC nuclei (for both neuron number and volume). Neuron density decreases across all four nuclei according to a single power law with an exponent of about minus one‐half. Because we have included quantitative comparisons with great apes and humans, our conclusions apply to human brains, and our scaling laws can potentially be used to study the anatomical correlates of the amygdala in disorders involving pathological emotion processing. J. Comp. Neurol. 518:1176–1198, 2010. © 2009 Wiley‐Liss, Inc.
Postnatal changes in tryptophan hydroxylase and serotonin transporter immunoreactivity in multiple brainstem nuclei of the rat: Implications for a sensitive period
Authors: Liu Qiuli , Wong‐Riley Margaret T.T. 
Published: November 2009

AbstractPreviously, we found that the brainstem neuronal network in normal rats undergoes abrupt neurochemical, metabolic, and physiological changes around postnatal days (P) 12–13, a critical period when the animal's response to hypoxia is also the weakest. This has special implications for sudden infant death syndrome (SIDS), insofar as seemingly normal infants succumb to SIDS when exposed to respiratory stressors (e.g., hypoxia) during a narrow postnatal window. Because an abnormal serotonergic system has recently been implicated in SIDS, we conducted a large‐scale investigation of the 5‐HT‐synthesizing enzyme tryptophan hydroxylase (TPH) and serotonin transporter (SERT) with semiquantitative immunohistochemistry in multiple brainstem nuclei of normal rats aged P2–21. We found that 1) TPH and SERT immunoreactivity in neurons of raphé magnus, obscurus, and pallidus and SERT in the neuropil of the pre‐Bötzinger complex, nucleus ambiguus, and retrotrapezoid nucleus were high at P2–11 but decreased markedly at P12 and plateaued thereafter until P21; 2) SERT labeling in neurons of the lateral paragigantocellular nucleus (LPGi) and parapyramidal region (pPy) was high at P2–9 but fell significantly at P10, followed by a gradual decline until P21; 3) TPH labeling in neurons of the ventrolateral medullary surface was stable except for a significant fall at P12; and 4) TPH and SERT immunoreactivity in a number of other nuclei was relatively stable from P2 to P21. Thus, multiple brainstem nuclei exhibited a significant decline in TPH and SERT immunoreactivity during the critical period, suggesting that such normal development can contribute to a narrow window of vulnerability in postnatal animals. J. Comp. Neurol. 518:1082–1097, 2010. © 2009 Wiley‐Liss, Inc.
Differential distribution of tight junction proteins suggests a role for tanycytes in blood‐hypothalamus barrier regulation in the adult mouse brain
Authors: Mullier Amandine , Bouret Sebastien G. , Prevot Vincent , Dehouck Bénédicte 
Published: November 2009

AbstractThe median eminence is one of the seven so‐called circumventricular organs. It is located in the basal hypothalamus, ventral to the third ventricle and adjacent to the arcuate nucleus. This structure characteristically contains a rich capillary plexus and features a fenestrated endothelium, making it a direct target of blood‐borne molecules. The median eminence also contains highly specialized ependymal cells called tanycytes, which line the floor of the third ventricle. It has been hypothesized that one of the functions of these cells is to create a barrier that prevents substances in the portal capillary spaces from entering the brain. In this paper, we utilize immunohistochemistry to study the expression of tight junction proteins in the cells that compose the median eminence in adult mice. Our results indicate that tanycytes of the median eminence express occludin, ZO‐1, and claudin 1 and 5, but not claudin 3. Remarkably, these molecules are organized as a continuous belt around the cell bodies of the tanycytes that line the ventral part of the third ventricle. In contrast, the tanycytes at the periphery of the arcuate nucleus do not express claudin 1 and instead exhibit a disorganized expression pattern of occludin, ZO‐1, and claudin 5. Consistent with these observations, permeability studies using peripheral or central injections of Evans blue dye show that only the tanycytes of the median eminence are joined at their apices by functional tight junctions, whereas tanycytes located at the level of the arcuate nucleus form a permeable layer. In conclusion, this study reveals a unique expression pattern of tight junction proteins in hypothalamic tanycytes, which yields new insights into their barrier properties. J. Comp. Neurol. 518:943–962, 2010. © 2009 Wiley‐Liss, Inc.
Building the central complex in Drosophila: The generation and development of distinct neural subsets
Authors: Young J.M. , Armstrong J.D. 
Published: November 2009

AbstractThe distinctive midline neuropil, the central complex (CX), is one of the most prominent features of the insect brain. We investigated the development of the four CX structures and several sets of CX neurons in the Drosophila brain using immunostaining for two cell adhesion molecules, DN‐cadherin and Echinoid, and a set of seven enhancer trap lines. Our results showed that the CX is first identifiable in the third instar larva and that it elaborates over the first 48 hours of metamorphosis. The first identifiable structures to appear in their immature form are the protocerebral bridge and fan‐shaped body, which are present in the brain of the third instar larva, followed by the noduli (from P12h), and finally the ellipsoid body (from P24h). We observed that neurons are added incrementally to the developing CX structure, with sets of small‐field neurons projecting to the CX prior to the large‐field neurons. The small‐field neurons first project to the developing fan‐shaped body, before arborizing or extending to the other structures. We found evidence to suggest that small‐field neurons exist in sets of 16 and that they originate from eight common clusters of perikarya in the cortex, suggesting a common origin. We also identified a novel set of pontine neurons that connect contralateral segments in the fan‐shaped body. J. Comp. Neurol. 518:1525–1541, 2010. © 2009 Wiley‐Liss, Inc.
Raman and Neutron Scattering Study of Partially Deuterated L‐Alanine: Evidence of a Solid‐Solid Phase Transition
Authors: de Souza Joelma M. , Freire Paulo T. C. , Argyriou Dimitri N. , Stride John A. , Barthès Mariette , Kalceff Walter , Bordallo Heloisa N. 
Published: November 2009

AbstractRaman and neutron experiments using specific isotope labeling were combined in order to study the dynamics and structure of L‐alanine. Inelastic neutron and Raman scattering data of C2H4(ND2)CO2D are discussed in relation to the doubling of the lattice parameter a observed by means of neutron powder diffraction in C2D4 (NH2)CO2H. The major changes accompanying the phase transition are found in the vibrational frequencies involving the torsional vibration τ(CO2−), which is clearly affected by the hydrogen bonds between the protons of the ammonium group and the oxygen atoms of the carboxylate group. At lower temperatures the rearrangement of identifiable hydrogen bonds induces changes in the bending vibration δ(ND3), confirming some orientational disorder.
Encoding and Processing of Alphanumeric Information by Chemical Mixtures
Authors: Ratner Tamar , Reany Ofer , Keinan Ehud 
Published: November 2009

AbstractA novel infochemical device that is based on 1H NMR readout of chemical information is presented. This chemical encoding system utilizes two measurable parameters of homogeneous mixtures, chemical shift and peak integration, for three different applications: 1) a text‐encoding device that is based on spectral representation of a sequence of symbols, 2) encoding of 21‐digit binary numbers, each represented by an NMR spectrum, and their algebraic manipulations, such as addition and subtraction, and 3) encoding of 21‐digit decimal numbers. The first application enables molecular information storage and encryption. The relative concentration of each component, as measured by the relevant peak integration, can represent a symbol. The second application of this system, in addition to its obvious memory capability, enables mathematical operations. The NMR spectrum of a given mixture represents a 21‐digit binary number where each of the peaks encodes for a specific digit. In any of the input mixtures (numbers) each compound is either present or absent, representing either 1 or 0, respectively. We used the various binary numbers to carry out addition operations by combining two or more solutions (numbers). Subtraction operations were also preformed by digital processing of the information. The third application is the representation of decimal numbers. As before, each of the peaks encodes for a specific digit. In any of the input mixtures each compound is present in one of 10 different relative concentrations, representing the 10 digits of a decimal number.
Electronic Structure and Interface Properties of a Model Molecule for Organic Solar Cells
Authors: Hintz Holger , Peisert Heiko , Aygül Umut , Latteyer Florian , Biswas Indro , Nagel Peter , Merz Michael , Schuppler Stefan , Breusov Dietrich , Allard Sybille , Scherf Ullrich , Chassé Thomas 
Published: November 2009

AbstractWe study the electronic structure of 4,7‐bis(5‐methylthiophen‐2‐yl)benzo[c][1,2,5]thiadiazole (MTBT) and its interface properties with gold using X‐ray photoemission spectroscopy (XPS), valence‐band ultraviolet photoemission spectroscopy (UPS), X‐ray absorption spectroscopy (XAS), as well as resonant photoemission (ResPES). MTBT can be regarded as a model molecule for PCPDTBT, a promising candidate for efficient bulk heterojunction solar cells. Almost no contribution of sulfur and only a weak contribution of nitrogen to the HOMO level is found. At the interface with gold, a strong chemical interaction between the sulfur of the benzothiadiazole and gold occurs, which may have consequences for interface properties in devices.
Comprehensive Analysis of DNA Strand Breaks at the Guanosine Site Induced by Low‐Energy Electron Attachment
Authors: Gu Jiande , Wang Jing , Leszczynski Jerzy 
Published: November 2009

AbstractTo elucidate the role of guanosine in DNA strand breaks caused by low‐energy electrons (LEEs), theoretical investigations of the LEE attachment‐induced CO σ‐bonds and N‐glycosidic bond breaking of 2′‐deoxyguanosine‐3′,5′‐diphosphate (3′,5′‐dGMP) were performed using the B3LYP/DZP++ approach. The results reveal possible reaction pathways in the gas phase and in aqueous solutions. In the gas phase LEEs could attach to the phosphate group adjacent to the guanosine to form a radical anion. However, the small vertical detachment energy (VDE) of the radical anion of guanosine 3′,5′‐diphosphate in the gas phase excludes either CO bond cleavage or N‐glycosidic bond breaking. In the presence of the polarizable surroundings, the solvent effects dramatically increase the electron affinities of the 3′,5′‐dGDP and the VDE of 3′,5′‐dGDP−. Furthermore, the solvent–solute interactions greatly reduce the activation barriers of the CO bond cleavage to 1.06–3.56 kcal mol−1. These low‐energy barriers ensure that either C5′O5′ or C3′O3′ bond rupture takes place at the guanosine site in DNA single strands. On the other hand, the comparatively high energy barrier of the N‐glycosidic bond rupture implies that this reaction pathway is inferior to CO bond cleavage. Qualitative agreement was found between the theoretical sequence of the bond breaking reaction pathways in the PCM model and the ratio for the corresponding bond breaks observed in the experiment of LEE‐induced damage in oligonucleotide tetramer CGTA. This concord suggests that the influence of the surroundings in the thin solid film on the LEE‐induced DNA damage resembles that of the solvent.
Syntheses of the First Coordination Compounds of the New Strong Molecular Electron Donor and Double Proton Sponge 1,4,5,8‐Tetrakis(tetramethylguanidino)naphthalene
Authors: Vitske Viktoriia , König Carolin , Hübner Olaf , Kaifer Elisabeth , Himmel Hans‐Jörg 
Published: November 2009

AbstractHerein we report on the synthesis and properties of a new electron donor featuring an aromatic system to which four guanidino groups are attached, namely, 1,4,5,8‐tetrakis(tetramethylguanidino)naphthalene (ttmgn). The molecule is a double proton sponge with an asymmetric N–H···N bridge being formed in the protonated form. Oxidation is followed electrochemically, and two oxidation waves at E1/2(CH3CN) = –0.25 and +0.50 V vs. SCE are observed. Chemical oxidation with I2 yields ttmgn(I3)2, in which the I3– units interact with the ttmgn2+ cations through I···C contacts. Reaction with an excess amount of Br2 leads to removal of four electrons from the aromatic system and formation of the salt (ttmgn)Br4 with a chair‐type conformation of the C10 core. The binuclear Al alkyl complex [(ttmgn)(AlMe2)2][BPh4]2 can be prepared by reaction between the diprotonated ttmgn molecule and AlMe3 and serves as a benchmark system for the understanding of dynamic effects. Magnetic superexchange through the ligand unit is studied for the binuclear CoII complex [(ttmgn)(CoCl2)2]. SQUID measurements show an extremely weak antiferromagnetic coupling. The coupling might be affected by the unusual geometry of the coordination compounds of ttmgn, in which the metal ions are significantly displaced from the plane defined by the aromatic ring of the ttmgn ligand. We also report the analogous Co complex of ttmgb [ttmgb = 1,2,4,5‐tetrakis(tetramethylguanidino)benzene], namely, [(ttmgb)(CoCl2)2], in which the bonding situation is quite different.
Exfoliated Titanosilicate Material UZAR‐S1 Obtained from JDF‐L1
Authors: Rubio César , Casado Clara , Gorgojo Patricia , Etayo Fernando , Uriel Santiago , Téllez Carlos , Coronas Joaquín 
Published: November 2009

AbstractA new material, UZAR‐S1, has been obtained by exfoliation of the layered precursor microporous titanosilicate JDF‐L1. The exfoliation consists of a first stage of proton exchange with histidine followed by intercalation with nonylamine and final extraction in HCl/water/ethanol solution. UZAR‐S1 is an exfoliated material composed of sheets of a few nanometers of thickness with a high aspect ratio, a BET specific surface area of 160 m2/g (JDF‐L1 scarcely adsorbs N2), and a Si/Ti atomic ratio below 6. The dispersion of this material in commercial polysulfone results in an improved H2‐selective mixed matrix membrane.
One‐Pot Synthesis of Fluorinated 1‐Benzoyl‐3,4‐dihydroisoquinolines from [2‐(o‐Alkynylphenyl)ethyl]amines by a Hydroamination/Oxidation Sequence
Authors: Severin René , Reimer Jessica , Doye Sven 
Published: November 2009

AbstractFluorinated 1‐benzoyl‐3,4‐dihydroisoquinolines can easily be synthesized by a new one‐pot procedure from corresponding fluorinated [2‐(o‐alkynylphenyl)ethyl]amines in high yields. The one‐pot process consists of an initial [Ind2TiMe2]‐catalyzed intramolecular alkyne hydroamination and a subsequent Pd‐catalyzed oxidation of the benzyl side chain of the resulting hydroamination product. The process tolerates electron‐donating and ‐withdrawing substituents on the benzene ring that is converted into the benzoyl side chain of the products as well as ortho‐substitution.