bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinct nuclear localization patterns of DNA methyltransferases in developing and mature mammalian retina
Authors: Nasonkin Igor O. , Lazo Kevin , Hambright Dustin , Brooks Matthew , Fariss Robert , Swaroop Anand
Published: February 2011

DNA methyltransferases—DNMT1, DNMT3a, and DNMT3b—produce methylation patterns that dynamically regulate chromatin remodeling and gene expression. The vertebrate retina provides an ideal model to elucidate molecular control of neurogenesis as all neuronal cell types and Müller glia are generated in a conserved order from common pools of progenitor cells. As a prelude to exploring epigenetic regulation of mammalian retinal development, we investigated the expression of Dnmt1, Dnmt3a, and Dnmt3b in the mouse retina from embryonic day (E) 10.5 to 10 months of age. High levels of transcripts for all three Dnmt genes were observed in early stages of retinal differentiation, with significantly reduced expression after birth. Although DNMT1 protein is abundant in retinal progenitors at E10.5, it becomes restricted to postmitotic cells by E15.5. Most cells in the postnatal retina show nuclear immunostaining of DNMT1; however, the photoreceptors exhibit distinctive patterns. In rods, weak expression of DNMT1 is detected in perinuclear region and in the nucleus, whereas a strong nuclear labeling is evident in cones. DNMT3a and DNMT3b show a discrete pattern in developing retina with high expression at E11.5, little or no immunostaining by E15.5, and then postnatal expression overlapping with DNMT1 in early born neurons (ganglion, amacrine and horizontal cells, and cones). Robust nuclear localization of DNMTs in cones compared to rods suggests a potential role of DNA methylation in differential remodeling of chromatin in these two specialized neurons. Our studies indicate that DNA methyltransferases contribute to the establishment and maturation of cell fates during retinal development. J. Comp. Neurol. 519:1914–1930, 2011. †Published 2011 Wiley‐Liss, Inc.
Surface‐associated astrocytes, not endfeet, form the glia limitans in posterior piriform cortex and have a spatially distributed, not a domain, organization
Authors: Feig S.L. , Haberly L.B.
Published: February 2011

“Surface‐associated astrocytes” (SAAs) in posterior piriform cortex (PPC) are unique by virtue of a direct apposition to the cortical surface and large‐caliber processes that descend into layer I. In this study additional unique and functionally relevant features of SAAs in PPC of the rat were identified by light and electron microscopy. Examination of sections cut parallel to the surface of PPC and stained for glial fibrillar acidic protein revealed that, in addition to descending processes, SAAs give rise to an extensive matrix of “superficial processes.” Electron microscopy revealed that these superficial processes, together with cell bodies, form a continuous sheet at the surface of PPC with features in common with the glia limitans that is formed by endfeet in other cortical areas. These include a glia limiting membrane with basal lamina and similar associated organelles, including a striking array of mitochondria. Of particular interest, SAAs lack the domain organization observed in neocortex and hippocampus. Rather, superficial processes overlap extensively with gap junctions between their proximal regions as well as between cell bodies. Study of the descending processes revealed thin extensions, many of which appose synaptic profiles. We conclude that SAAs provide a potential substrate for bidirectional signaling and transport between brain and the pial arteries and cerebrospinal fluid in the subarachnoid space. We postulate that the spatially distributed character of SAAs in PPC reflects and supports the spatially distributed circuitry and sensory representation that are also unique features of this area. J. Comp. Neurol. 519:1952–1969, 2011. © 2011 Wiley‐Liss, Inc.
Dlx6 regulates molecular properties of the striatum and central nucleus of the amygdala
Authors: Wang Bei , Lufkin Thomas , Rubenstein John L. R.
Published: February 2011

We describe here the prenatal telencephalic expression of Dlx6 RNA and β‐galactosidase driven from a mutant Dlx6 locus. The mutant Dlx6 allele, which we believe is either a null or severe hypomorph, has an IRES‐lacZ‐neomycin resistance cassette inserted into the Dlx6 homeobox coding sequence (Dlx6LacZ). We compared expression from the Dlx6‐lacZ (Dlx6LacZ) allele in heterozygotes (Dlx6LacZ/+), with the expression of Dlx1, Dlx2, Dlx5 and Dlx6 RNA. Like these wild‐type alleles, Dlx6LacZ is expressed in the developing ganglionic eminences, and their derivatives. Unlike the other Dlx genes, Dlx6 and Dlx6LacZ expression is not readily observed in tangentially migrating interneurons. In addition to Dlx6's expression at later stages of differentiation of many basal ganglia nuclei, it shows particularly robust expression in the central nucleus of the amygdala. Histological analysis of Dlx6 mutants (Dlx6LacZ/LacZ) shows that this homeobox transcription factor is required for molecular properties of the striatum, nucleus accumbens, olfactory tubercle, and central nucleus of the amygdala. For instance, we observed reduced of Golf, RXRγ, and Tiam2 expression in the striatum, and reduced Dlx5 expression in the central nucleus of the amygdala. RNA expression array analysis of the E18.5 striatum was useful in identifying the transcription factors that are expressed in this tissue, but did not identify major changes in gene expression in the Dlx6LacZ/LacZ mutant. J. Comp. Neurol. 519:2320–2334, 2011. © 2011 Wiley‐Liss, Inc.
Identification of urocortin 3 afferent projection to the ventromedial nucleus of the hypothalamus in rat brain
Authors: Chen Peilin , Lin David , Giesler Jessica , Li Chien
Published: February 2011

Urocortin 3 (Ucn 3) is a corticotrophin‐releasing factor related neuropeptide highly expressed in the brain. Ucn 3 nerve fibers heavily innervate the hypothalamic ventromedial nucleus (VMH), and Ucn 3 injection into the VMH suppresses feeding. Currently, the origin of the Ucn 3 afferent input into the VMH is unknown. In the present study, anatomical tracing shows that the major Ucn 3 afferent input to the VMH resides in the anterior parvicellular part of the paraventricular nucleus of the hypothalamus (PVHap) and the adjacent posterior part of the bed nucleus of stria terminalis (pBNST). VMH also receives moderate Ucn 3 input from the medial amygdala. Ucn 3 neurons located immediately caudal to the PVHap/pBNST in the rostral perifornical hypothalamic area (rPFH) provide only minimal input. The paucity of rPFH‐VMH Ucn 3 projection is consistent with the finding that only Ucn 3 neurons in the rPFH co‐expressed enkephalin (Enk), and Ucn 3/Enk double‐labeled nerve fibers and terminals were observed predominately in the lateral septum (LS), whereas only a few double‐labeled fibers were found in other brain areas including the VMH. Furthermore, retrograde tracing demonstrates that Ucn 3 neurons in the rPFH project to the LS. In conclusion, the present study determines that the major Ucn 3 afferent into the VMH originates from the PVHap/pBNST. Moreover, anatomical heterogeneity is observed in the hypothalamic Ucn 3 neuron population as the rostral part (PVHap/pBNST) of the population projects to the VMH and the caudal part (rPFH) co‐localizes with Enk and provides major afferent input to the LS. J. Comp. Neurol. 519:2023–2042, 2011. © 2011 Wiley‐Liss, Inc.
Molecular analysis of two FMRFamide‐encoding transcripts expressed during the development of the tropical abalone haliotis asinina
Authors: Cummins Scott F. , Tollenaere Alina , Degnan Bernard M. , Croll Roger P.
Published: February 2011

FMRFamide‐related peptides (FaRPs) are involved in numerous neural functions across the animal kingdom and serve as important models for understanding the evolution of neuropeptides. Gastropod molluscs have proved to be particularly useful foci for such studies, but the developmental expression of FaRPs and the evolution of specific transcripts for different peptides are unclear within the molluscs. Here we show that FaRPs are encoded by two transcripts that appear to be splice variants of a single gene in the abalone, Haliotis asinina, which represents the basal vetigastropods. Has‐FMRF1 comprises 1,438 nucleotides and encodes a precursor protein of 329 amino acids that can potentially produce two copies of FLRFamide, one copy each of TLAGDSFLRFamide, QFYRIamide, SDPDLDDVIRASLLAYSLDDSPNN, and SVATAPVEAKAVEAGNKDIE, and 13 copies of FMRFamide. The second 1,241‐nucleotide transcript, Has‐FMRF2, encodes a 206‐amino acid precursor protein with single copies of FLRFamide and FMRFamide along with such extended forms as NFGEPFLRFamide, FDSYEDKALRFamide, and NGWLHFamide, in addition to SDPGEDMLKSILLRGAPSNNGLQY and DTUDETTUNDNAHSRQ. Both transcripts are present early in life and are expressed in different but overlapping patterns within the developing larval nervous system. Mass spectrometry and immunocytochemistry demonstrate that FaRPs are cleaved from larger precursors and localize to the developing nervous system. Our results confirm previous evidence that FaRPs are expressed early and potentially play many roles during molluscan development and suggest that the last common ancestor to living gastropods used alternative splicing of an FMRFamide gene to generate a diversity of FaRPs in spatially restricted patterns in the nervous system. J. Comp. Neurol. 519:2043–2059, 2011. © 2011 Wiley‐Liss, Inc.
Space–time fluid–structure interaction modeling of patient‐specific cerebral aneurysms
Authors: Tezduyar Tayfun E. , Takizawa Kenji , Brummer Tyler , Chen Peng R.
Published: February 2011

We provide an extensive overview of the core and special techniques developed earlier by the Team for Advanced Flow Simulation and Modeling (T★AFSM) for space–time fluid–structure interaction (FSI) modeling of patient‐specific cerebral aneurysms. The core FSI techniques are the Deforming‐Spatial‐Domain/Stabilized Space–Time (DSD/SST) formulation and the stabilized space–time FSI (SSTFSI) technique. The special techniques include techniques for calculating an estimated zero‐pressure (EZP) arterial geometry, a special mapping technique for specifying the velocity profile at an inflow boundary with non‐circular shape, techniques for using variable arterial wall thickness, mesh generation techniques for building layers of refined fluid mechanics mesh near the arterial walls, a recipe for pre‐FSI computations that improve the convergence of the FSI computations, the Sequentially‐Coupled Arterial FSI (SCAFSI) technique and its multiscale versions, techniques for the projection of fluid–structure interface stresses, calculation of the wall shear stress (WSS) and calculation of the oscillatory shear index (OSI) and arterial‐surface extraction and boundary condition techniques. We show how these techniques work with results from earlier computations. We also describe the arterial FSI techniques developed and implemented recently by the T★AFSM and present a sample from a wide set of patient‐specific cerebral‐aneurysm models we computed recently. Copyright © 2011 John Wiley & Sons, Ltd.
Iterative operator splitting method for capillary formation model in tumor angiogenesis problem: Analysis and application
Authors: Gücüyenen Nurcan , Tanoğlu Gamze
Published: February 2011

Iterative operator splitting method is used to solve numerically the mathematical model for capillary formation in tumor angiogenesis problem. The method is based on first splitting the complex problem into simpler sub‐problems. Then each sub‐equation is combined with iterative schemes. The algorithms are obtained by applying the proposed method to the given model problem. The explicit local error bounds are derived to show consistency. We also explained the stability by constructing the stability functions. The obtained numerical results show that iterative splitting method provides high accuracy and efficiency with respect to other classical methods in the literature. Copyright © 2011 John Wiley & Sons, Ltd.
An approach to enhance the efficiency of opportunistic grids
Authors: de Aquino Gomes Raphael , Costa Fábio M.
Published: February 2011

Opportunistic grid computing middleware has as a main concern the need to preserve the performance of the local applications running on machines that donate resources to the grid. This concern, together with the fact that it happens in an extremely dynamic environment, causes the adoption of a treatment based on thetextitbest‐effort principle for grid applications. This means that efficient application management schemes are usually not employed, which results in less than optimal performance as grid applications often need to be restarted due to (often temporary) resource claims by local user applications. This paper presents a method to improve the performance of grid applications, taking into account resource usage profiles for local applications, trying to identify when such resource claims are temporary and avoiding costly actions such as the migration of grid tasks. The approach is proposed as an extension to the InteGrade middleware and its evaluation shows promising results for the efficient management of grid applications. Copyright © 2011 John Wiley & Sons, Ltd.
A sub‐1V supply CMOS voltage reference generator
Authors: Tsitouras A. , Plessas F. , Birbas M. , Kikidis J. , Kalivas G.
Published: February 2011

An integrated sub‐1V voltage reference generator, designed in standard 90‐nm CMOS technology, is presented in this paper. The proposed voltage reference circuit consists of a conventional bandgap core based on the use of p‐n‐p substrate vertical bipolar devices and a voltage‐to‐current converter. The former produces a current with a positive temperature coefficient (TC), whereas the latter translates the emitter‐base voltage of the core p‐n‐p bipolar device to a current with a negative TC. The circuit includes two operational amplifiers with a rail‐to‐rail output stage for enabling stable and robust operation overall process and supply voltage variations while it employs a total resistance of less than 600 K Ω. Detailed analysis is presented to demonstrate that the proposed circuit technique enables die area reduction. The presented voltage reference generator exhibits a PSRR of 52.78 dB and a TC of 23.66ppm/∘C in the range of − 40 and 125∘C at the typical corner case at 1 V. The output reference voltage of 510 mV achieves a total absolute variation of ± 3.3% overall process and supply voltage variations and a total standard deviation, σ, of 4.5 mV, respectively, in the temperature range of − 36 and 125∘C. Copyright © 2011 John Wiley & Sons, Ltd.
MOCVD of Vanadium Oxide Films with a Novel Vanadium(III) Precursor
Authors: Crociani Laura , Carta Giovanni , Natali Marco , Rigato Valentino , Rossetto Gilberto
Published: February 2011

In this communication we report the synthesis and characterization of the vanadium (III) alkoxide [V(OCMe2CH2OMe)3], which presents an appreciable volatility (55°C/1.5Torr), its successful use as MOCVD precursor for the deposition of pure VO2 and V2O5 films and the characterization of the films by means of Rutherford Backscattering Spectroscopy (RBS), X‐Ray Diffraction (XRD) and Cyclic Voltammetry.
Growth of the Initial Atomic Layers of Ta‐N Films During Atomic Layer Deposition on Silicon‐Based Substrates
Authors: Strehle Steffen , Schmidt Daniela , Albert Matthias , Bartha Johann W.
Published: February 2011

The growth of ultra‐thin Ta‐N films using atomic layer deposition (ALD) is investigated by in‐situ X‐ray photoelectron spectroscopy (XPS) starting from the first precursor pulse, as precursor substances tert‐butylimido‐tris(diethylamido)tantalum (TBTDET) and tert‐butylimido‐bis(diethylamido)cyclopentadienyl)tantalum (TBDETCp) are applied mainly on SiOH and SiH surfaces. The chemical composition, the growth mode, and the film thickness are derived as functions of the cycle number and the substrate chemistry. The growth rates are significantly higher on SiOH than on SiH substrates, which is related to the oxygen surface concentration. The film composition changes with the cycle number but stabilizes at an approximate stoichiometry of Ta2N2O for both precursors.
Observation of Structure‐Sensitive Decomposition of Cp(allyl)Pd on Pd Nanodots Formed by MOCVD
Authors: Binder Axel , Seipenbusch Martin , Kasper Gerhard
Published: February 2011

The decomposition kinetics of the organometallic precursor cyclopentadienyl‐allyl‐Pd [Cp(allyl)Pd] on silica and titania substrates (as well as previously deposited Pd) are investigated by continuous metal‐organic (MO)CVD under atmospheric pressure. The substrate particles are freshly generated in an aerosol process with well‐defined and known densities of surface OH groups, and then coated immediately in a second reactor. Time‐resolved data on size and number density of deposited Pd nanodots on the carrier particles are obtained by electron microscopy and used as a means to infer the decomposition kinetics. It is found that decomposition proceeds very rapidly for a few seconds, both by proton‐initiated decomposition on surface OH groups and by autocatalysis, until the Pd nanodots have grown to a size of about 2 nm, where autocatalysis comes to a standstill, regardless of precursor concentration, residence time in the CVD reactor, or decomposition temperature. Proton‐initiated decomposition on OH groups continues to depend measurably on these process parameters in terms of the number density of Pd dots, even after autocatalysis has stopped. Our observations indicate that autocatalysis is structure‐sensitive.
MC‐CDMA MIMO systems with quasi‐orthogonal space–time block codes: Channel estimation and multiuser detection
Authors: Yu Jung‐Lang , Wu Chun‐Hsien , Lee Ming‐Feng
Published: February 2011

This paper investigates blind channel estimation and multiuser detection for quasi‐synchronous multi‐carrier code‐division multiple‐access (MC‐CDMA) multiple‐input multiple‐output (MIMO) systems with quasi‐orthogonal space–time block codes (QO‐STBC). Subspace‐based blind channel estimation is proposed by considering a QO‐STBC scheme that involves four transmit antennas and multiple receive antennas. Based on the first‐order perturbation theory, the mean square error of the channel estimation is derived. With the estimated channel coefficients, we employ minimum output energy and eigenspace receivers for symbol detection. Using the QO‐STBC coding property, the weight analyses are performed to reduce the computational complexity of the system. In addition, the forward–backward averaging technique is presented to enhance the performance of multiuser detection. Numerical simulations are given to demonstrate the superiority of the proposed channel estimation methods and symbol detection techniques. Copyright © 2011 John Wiley & Sons, Ltd.
Bandwidth efficient asymmetric fingerprinting scheme
Authors: Hu Defa , Li Qiaoliang
Published: February 2011

In asymmetric fingerprinting, the merchant can trace the traitors from a pirated multimedia content copy by means of the embedded unique fingerprint, while the customer is immune of being framed due to the asymmetric property. The existing schemes are inefficient in practice due to their high bandwidth usage. This paper proposes an asymmetric fingerprinting scheme that is efficient from the bandwidth usage point of view. First, multicast an efficient transport technology for one‐to‐many communication is exploited, which can reduce the bandwidth usage significantly. Second, symmetric encryption instead of public‐key encryption is performed on the multimedia content, which can also reduce the complexity and communication cost. Copyright © 2011 John Wiley & Sons, Ltd.
Generation of a conditional null allele of Lbx1
Authors: Watanabe Shuichi , Matsushita Shoko , Hayasaka Michiko , Hanaoka Kazunori
Published: February 2011

The homeobox gene Lbx1 not only plays critical roles in myogenesis and neurogenesis during embryonic development but is also expressed in activated satellite cells of adult mice. To address the potential postnatal functions of Lbx1, we generated conditional Lbx1‐null mice using the Cre‐loxP system. We generated a mouse in which Exon 2 of Lbx1 was floxed (Lbx1flox/flox), followed by cross‐breeding between the Lbx1flox/flox mouse and either a transgenic mouse where a tamoxifen‐inducible Cre‐recombinase (Cre) was ubiquitously expressed, or a Myf5Cre mouse where Cre was inserted into the Myf5 locus. In both Lbx1‐null mouse lines generated, Pax3‐expressing limb muscle precursor cells were seriously reduced during embryonic development and eventually the limb extensor muscles were lost after birth. Since the conditional Lbx1‐null mice generated were viable for a prolonged time, they will be useful in the investigation of Lbx1 function throughout the lifespan of the mouse. genesis 49:803–810, 2011. © 2011 Wiley‐Liss, Inc.
Sub‐optimal CD4+ T‐cell activation triggers autonomous TGF‐β‐dependent conversion to Foxp3+ regulatory T cells
Authors: Oliveira Vanessa G. , Caridade Marta , Paiva Ricardo S. , Demengeot Jocelyne , Graca Luis
Published: February 2011

Classical in vitro Treg conversion assays, which rely on optimal T‐cell activation in the presence of exogenous TGF‐β, induce Foxp3 expression at a frequency far above that which is observed in vivo in Treg‐dependent models of oral or transplantation tolerance. We have found that suboptimal murine T‐cell activation in vitro results in induction of Foxp3 expression, in the absence of exogenous TGF‐β, at a frequency similar to that which we found in vivo upon anti‐CD4‐induced transplantation tolerance. We show that TCR triggering with either low‐dose anti‐CD3 or low‐dose agonist peptide, as well as down‐modulation of the TCR signal with non‐depleting anti‐CD4, promotes TGF‐β production by T cells, an event that precedes Foxp3 expression and is Foxp3 independent. These findings support the view that sub‐immunogenic regimens lead to dominant tolerance as a result of T‐cell intrinsic properties.
Chemokine receptor CX3CR1 promotes dendritic cell development under steady‐state conditions
Authors: Łyszkiewicz Marcin , Witzlau Katrin , Pommerencke Jens , Krueger Andreas
Published: February 2011

Expression of CX3CR1 is an attribute of myeloid precursors committed to the monocyte/macrophage (Mφ)/DC lineages and is maintained during all stages of DC differentiation. Nevertheless, the exact role of this molecule during developmental progression of myeloid precursors towards the DC lineage remains elusive. To overcome potential compensatory mechanisms and issues of redundancy, we employed competitive adoptive transfer experiments to assess a possible function of CX3CR1 in DC and monocyte/Mφ differentiation in vivo. We show here that expression of CX3CR1 promotes the generation of DCs and monocytes/Mφ under steady‐state conditions and during compensatory expansion after selective depletion of DCs, but not under inflammatory conditions evoked by sub‐lethal irradiation. Direct administration of CX3CR1‐deficient and CX3CR1‐sufficient precursors into the spleen or the thymus resulted in a similar competitive advantage of WT over CX3CR1‐deficient precursors as i.v. transfer, suggesting that CX3CR1‐mediated survival rather than recruitment to lymphoid organs is critical for DC/Mφ differentiation. In conclusion, our data support the hypothesis that CX3CR1 promotes proper development of myeloid precursors into DCs and monocytes/Mφs under steady‐state conditions, possibly by providing survival signals or mediating accessibility to organ‐specific niches, rather than acting as a mediator of homing to the spleen or the thymus.
TCR‐like antibodies distinguish conformational and functional differences in two‐ versus four‐domain auto reactive MHC class II–peptide complexes
Authors: Dahan Rony , Tabul Moran , Chou Yuan K. , Meza‐Romero Roberto , Andrew Shayne , Ferro Adolph J. , Burrows Gregory G. , Offner Halina , Vandenbark Arthur A. , Reiter Yoram
Published: February 2011

Antigen‐presenting cell‐associated four‐domain MHC class II (MHC‐II) molecules play a central role in activating autoreactive CD4+ T cells involved in multiple sclerosis (MS) and type 1 diabetes (T1D). In contrast, two‐domain MHC‐II structures with the same covalently attached self‐peptide (recombinant T‐cell receptor ligands (RTLs)) can regulate pathogenic CD4+ T cells and reverse clinical signs of experimental autoimmune diseases. RTL1000, which is composed of the β1α1 domains of human leukocyte antigen (HLA)‐DR2 linked to the encephalitogenic human myelin oligodendrocyte glycoprotein (MOG)‐35‐55 peptide, was recently shown to be safe and well tolerated in a phase I clinical trial in MS. To evaluate the opposing biological effects of four‐ versus two‐domain MHC‐II structures, we screened phage Fab antibodies (Abs) for the neutralizing activity of RTL1000. Five different TCR‐like Abs were identified that could distinguish between the two‐ versus four‐domain MHC–peptide complexes while the cognate TCR was unable to make such a distinction. Moreover, Fab detection of native two‐domain HLA‐DR structures in human plasma implies that there are naturally occurring regulatory MHC–peptide complexes. These results demonstrate for the first time distinct conformational determinants characteristic of activating versus tolerogenic MHC–peptide complexes involved in human autoimmunity.
Role of CLIC4 in the host innate responses to bacterial lipopolysaccharide
Authors: He Guoan , Ma Yao , Chou Szu‐Yi , Li Huihong , Yang Chingwen , Chuang Jen‐Zen , Sung Ching‐Hwa , Ding Aihao
Published: February 2011

Chloride intracellular channel (CLIC) 4 has diverse functions in membrane trafficking, apoptosis, angiogenesis and cell differentiation. CLIC4 is abundantly expressed in macrophages, but its role in innate immune functions is unclear. Here, we show that primary murine macrophages express increased amounts of CLIC4 after exposure to bacterial lipopolysaccharide (LPS). Endogenous CLIC4 level was significantly elevated in the brain, heart, lung, kidney, liver and spleen after LPS injection of mice. Stable macrophage lines overexpressing CLIC4 produced more TNF, IL‐6, IL‐12 and CCL5 than mock transfectants when exposed to LPS. To explore the role of CLIC4 in vivo, we generated CLIC4‐null mice. These mice were protected from LPS‐induced death, and had reduced serum levels of inflammatory cytokines. Upon infection with Listeria monocytogenes, CLIC4‐deficient mice were impaired in their ability to clear infection, and their macrophages responded to Listeria by producing less inflammatory cytokines and chemokines than the WT controls. When challenged with LPS in vitro, deletion of clic4 gene had little effect on MAPK and NF‐κB activation, but led to a reduced accumulation of phosphorylated interferon response factor 3 (IRF3) within macrophages. Conversely, overexpression of CLIC4 enhanced LPS‐mediated IRF3. Thus, these findings suggest that CLIC4 is an LPS‐induced product that can serve as a positive regulator of LPS signaling.
A Rare μ4‐O Centred Dy4 Tetrahedron with Coordination‐Induced Local Chirality and Single‐Molecule Magnet Behaviour
Authors: Lin Po‐Heng , Korobkov Ilia , Wernsdorfer Wolfgang , Ungur Liviu , Chibotaru Liviu F. , Murugesu Muralee
Published: February 2011

Coordination‐induced chirality was achieved in a uniquetetrahedral [Dy4(μ4‐O)(μ‐OMe)2(beh)2(esh)4]·3MeOH complex through a twisted diazine bridge from a Schiff base ligand. Magnetic measurements reveal weak intramolecular antiferromagnetic interactions (J = –0.3 cm–1) with single‐molecule magnet behaviour (Ueff = 23.42 K).
Argan oil and other argan products: Use in dermocosmetology
Authors: Guillaume Dominique , Charrouf Zoubida
Published: February 2011

Argan oil is of food or cosmetic (INCI name: Argania spinosa kernel oil) grade. During the past 15 years cosmetic argan oil, as beauty oil or cosmetic ingredient, has become one of the major actors in the dermocosmetic field. Beauty argan oil is produced by cold‐pressing argan‐fruit kernels. As a cosmetic ingredient, argan oil is produced by solvent‐assisted extraction of the finely crushed kernels. Enriched‐argan oil which is produced by distillation of cosmetic argan oil can be supplemented with antioxidants. Hence, it presents an even better cosmetic potential. Argan fruit pulp and argan leaves also contain proteins, peptides, saponins and other chemicals presenting highly interesting dermocosmetics. Therefore, the argan tree (A. spinosa) is sometimes nicknamed A. cosmetosa. We comprehensively review the current knowledge (literature and patent) related to argan oil and argan tree products in the dermocosmetic domain.
Enantioselective Conjugate Addition of Malononitrile to Chalcones Promoted by α,α‐L‐Diaryl Prolinols: Noncovalent versus Covalent Catalysis?
Authors: Russo Alessio , Capobianco Amedeo , Perfetto Alessandra , Lattanzi Alessandra , Peluso Andrea
Published: February 2011

The enantioselective conjugate addition of malononitrile to trans‐chalcones has been investigated as a case study using easily available α,α‐L‐diaryl prolinols as promoters. Both experimental and computational results are consistent with a bifunctional noncovalent mode of activation of the reactive partners, provided by the secondary amine and hydroxyl groups of the promoter as general base and acid catalysis. This most energetically affordable pathway predicts predominant formation of the R‐configured adducts, which is in agreement with the experimental findings. The present study addresses, for the first time, the ability of proline derivatives to assist product formation through noncovalent catalysis, in analogy to the mode of action typically recognized for Cinchona alkaloids.
Magnetically Separable and Reusable Copper Ferrite Nanoparticles for Cross‐Coupling of Aryl Halides with Diphenyl Diselenide
Authors: Swapna Kokkirala , Murthy Sabbavarapu Narayana , Nageswar Yadavalli Venkata Durga
Published: February 2011

A simple and efficient procedure for the synthesis of diaryl selenides has been developed by a copper ferrite nanoparticle catalyzed reaction of aryl iodides/aryl bromides with diphenyl diselenide in the presence of base and solvent at 120 °C. Using this protocol, a variety of diselenides were obtained in good to excellent yields. The copper ferrite nanoparticles were magnetically separated, recycled, and reused up to three cycles.
Macrocycle or Cage? The Presence or Absence of Ca2+ Template Ions Controls the Equilibrium in an Oligoimine Dynamic Combinatorial Library
Authors: Schleef Frank , Lüning Ulrich
Published: February 2011

A dynamic combinatorial library (DCL) was formed by mixing the triamine 1 and the diamine 3 with the pyridine‐2,6‐dicarbaldehyde 2 (R = OMe). In the absence of any template ion, the bimacrocyclic cage 4 (R = OMe) derived from the triamine 1 formed nicely whereas the monomacrocycle 5 (R = OMe) originating from the diamine 3 was only formed in small amounts (product ratio, after reduction: [6]/[7] = 4.3:1). Addition of calcium ions reversed the product ratio ([6]/[7] = 1:17).
Easy‐to‐Execute Carbonylative Arylation of Aryl Halides using Molybdenum Hexacarbonyl: Efficient Synthesis of Unsymmetrical Diaryl Ketones
Authors: Jafarpour Farnaz , Rashidi‐Ranjbar Parviz. , Kashani Asieh Otaredi
Published: February 2011

A versatile procedure for the synthesis of unsymmetrical diaryl ketones through a palladium‐catalyzed carbonylative arylation of iodoarenes through easy‐to‐handle molybdenum hexacarbonyl as a condensed source of carbon monoxide is described. This method provides an efficient route to a wide variety of substituted diaryl ketones without direct use of high‐pressure carbon monoxide.
The extended N2 method taking into account higher mode effects in elevation
Authors: Kreslin Maja , Fajfar Peter
Published: February 2011

The N2 method has been extended in order to take into account higher mode effects in elevation. The extension is based on the assumption that the structure remains in the elastic range when vibrating in higher modes. The seismic demand in terms of displacements and storey drifts can be obtained by enveloping the results of basic pushover analysis and the results of standard elastic modal analysis. The approach is consistent with the extended N2 method used for plan‐asymmetric buildings. The proposed procedure was applied to three variants of three steel frame buildings used in the SAC project. The structural response was investigated for two sets of ground motions. Different ground motion intensities were used in order to investigate the influence of the magnitude of plastic deformations. The N2 results were compared with the results of nonlinear response‐history analysis, two other pushover‐based methods (modal pushover analysis (MPA) and modified MPA (MMPA)), and pushover analysis without consideration of higher modes. It was found that a considerable influence of higher modes on storey drifts is present at the upper part of medium‐and high‐rise structures. This effect is the largest in the case of elastic behaviour and decreases with ground motion intensity. The higher mode effects also depend on the spectral shape. The approximate methods (extended N2, MPA and MMPA) are able to provide fair estimates of response in the case of the test examples. Accuracy decreases with the height of the building, and with the intensity of ground motion. The N2 results are generally conservative. Copyright © 2011 John Wiley & Sons, Ltd.
Theory and experimental study for sliding isolators with variable curvature
Authors: Lu Lyan‐Ywan , Lee Tzu‐Ying , Yeh Shih‐Wei
Published: February 2011

Because a conventional isolation system with constant isolation frequency is usually a long‐period dynamic system, its seismic response is likely to be amplified in earthquakes with strong long‐period wave components, such as near‐fault ground motions. Seismic isolators with variable mechanical properties may provide a promising solution to alleviate this problem. To this end, in this work sliding isolators with variable curvature (SIVC) were studied experimentally. An SIVC isolator is similar to a friction pendulum system (FPS) isolator, except that its sliding surface has variable curvature rather being spherical. As a result, the SIVC's isolation stiffness that is proportional to the curvature becomes a function of the isolator displacement. By appropriately designing the geometry of the sliding surface, the SIVC is able to possess favorable hysteretic behavior. In order to prove the applicability of the SIVC concept, several prototype SIVC isolators, whose sliding surfaces are defined by a sixth‐order polynomial function, were fabricated and tested in this study. A cyclic element test on the prototype SIVC isolators and a shaking table test on an SIVC isolated steel frame were all conducted. The results of both tests have verified that the prototype SIVC isolators do indeed have the hysteretic property of variable stiffness as prescribed by the derived formulas in this study. Moreover, it is also demonstrated that the proposed SIVC is able to effectively reduce the isolator drift in a near‐fault earthquake with strong long‐period components, as compared with that of an FPS system with the same friction coefficient. Copyright © 2011 John Wiley & Sons, Ltd.
Comparing landscape evolution models with quantitative field data at the millennial time scale in the Belgian loess belt
Authors: Temme A. J. A. M. , Peeters I. , Buis E. , Veldkamp A. , Govers G.
Published: February 2011

This study compares three landscape evolution models and their ability to correctly simulate measured 2500 year landscape evolution in two small catchments in the Belgian loess belt. WATEM LT and LAPSUS both model tillage and water erosion and deposition and have detachment‐limited descriptions for water erosion and deposition. Equations in LAPSUS are more mechanistic than those in WATEM LT. WATEM LTT resembles WATEM LT, but is a transport‐limited model. All three models are DEM‐based. Calibration and validation simulations were performed forward in time on (1D) transects for four spatial resolutions, and backward in time for (2D) catchments at 20 m resolution. For transects, model outputs were compared with discretized observations of transect shape. For catchments, outputs were compared with point observations of palaeo‐altitude, averaged over landscape element classes. For transects, the three models performed well, resulting in model efficiency factors of 0.92 to 0.99 for calibration and 0.62 to 0.96 for validation. However, for catchments, simulations showed that the transport‐limited WATEM LTT model could not realistically simulate long‐term landscape evolution. Performance of WATEM LT and LAPSUS at catchment scale was similar to that on transects, although LAPSUS has problems with backward calculation. Tests demonstrate that a transport‐limited approach cannot be used to model long‐term landscape evolution in the Belgian loess belt, which is in agreement with theoretical and empirical understanding of soil erosion processes in this environment. The difference in performance between transport‐limited and detachment‐limited models is clear only when the models are evaluated in a 2D catchment. The lack of such distinction when models were applied in a 1D transect highlights the importance of evaluating landscape evolution models in a 2D setting so that effects of flow convergence/divergence can be accounted for. Copyright © 2011 John Wiley & Sons, Ltd.
Endocrine-disrupting effects of spironolactone in female western mosquitofish, Gambusia affinis
Authors: Raut Samiksha A , Howell W. Mike , Angus Robert A
Published: February 2011

The discovery of pharmaceuticals in effluent from wastewater treatment plants and drug manufacturing facilities and in receiving waters has raised environmental concern. Because these compounds are ending up in the environment, it is important to investigate the effects of these compounds on wildlife as well as humans. The present study used a fish model to investigate the endocrine-disrupting effects of spironolactone (SPL), an aldosterone antagonist used as a diuretic, but which also exhibits antiandrogenic effects in humans. A dose–response study measured the effects of SPL on anal fin ray elongation, an androgen-dependent secondary sex trait, and expression of the vitellogenin gene, an estrogen-dependent trait, in female western mosquitofish, Gambusia affinis. Fish were exposed to SPL in the water for 35 d at four nominal concentrations: 10, 100, 250, and 500 nM (4.2, 41.7, 104.1, and 208.3 µg/L, respectively) via the static renewal method. Masculinization of females, as evidenced by development of an elongated and modified anal fin, was observed in the fish exposed to the three highest concentrations. Anal fin elongation was observed in the group exposed to the lowest SPL concentration, but without the development of a tip apparatus. These results confirm the results of a preliminary study that, in contrast to antiandrogenic effects seen in humans, SPL has androgenic and/or antiestrogenic activity in a fish. Environ. Toxicol. Chem. 2011; 30:1376–1382. © 2011 SETAC
EROD activity in peripheral blood lymphocytes and 1-hydroxypyrene in urine and milk as biomarkers of PAH exposure in dairy ruminants
Authors: Guiavarc'h Yann P , Chahin Abir , Dziurla Marie-Antoinette , Yen Frances T , Jondreville Catherine , Rychen Guido
Published: February 2011

Presently, few biomarker-based approaches are available for the evaluation of environmental exposure to persistent organic pollutants in dairy ruminants. In this study, goats (Capra hircus) were orally administered a mixture of pyrene, phenanthrene, and benzo[a]pyrene daily over a 40-d period (1 or 50 mg/d). Milk and urine 1-hydroxypyrene levels, ethoxyresorufin-O-deethylase (EROD) activity in peripheral blood lymphocytes (PBL) as well as urinary levels of 2- and 3-hydroxyphenanthrene were determined at 10-d intervals. 1-Hydroxypyrene excretion in milk and urine significantly increased and then achieved a plateau at 10 d. Transfer rates of 1-hydroxypyrene were calculated to be approximately 0.5 and 25% in milk and urine, respectively. Concentrations in milk and urine were proportional to the ingested doses. These results demonstrate that 1-hydroxypyrene in milk or urine may be used as a biomarker for evaluating the exposure of dairy ruminants to polycyclic aromatic hydrocarbons (PAHs) over an extended exposure period. Constitutive EROD activity in lymphocytes was 0.5 ± 0.3 pmol resorufin/min/mg protein, and was significantly induced over the entire exposure time, before stabilizing after 40 d at 6.30 ± 1.3 and 18.89 ± 1.12 pmol resorufin/min/mg protein for 1 mg/d and 50 mg/d doses, respectively. Induction kinetics were calculated using a logistic-like model and approximate dose–response curves were designed. We therefore propose EROD activity in PBL as a relevant, convenient, and noninvasive biomarker of subchronic exposure of dairy ruminants to CYP450 inducing PAH. Environ. Toxicol. Chem. 2011; 30:1346–1353. © 2011 SETAC
Occurrence and source apportionment of sulfonamides and their metabolites in Liaodong Bay and the adjacent Liao River basin, North China
Authors: Jia Ai , Hu Jianying , Wu Xiaoqin , Peng Hui , Wu Shimin , Dong Zhaomin
Published: February 2011

The presence of antibiotics in the environment is of great concern because of their potential for resistance selection among pathogens. In the present study we investigated the occurrence of 19 sulfonamides, five N-acetylated sulfonamide metabolites, and trimethoprim in the Liao River basin and adjacent Liaodong Bay, China, as well as 10 human/agricultural source samples. Within the 35 river samples, 12 sulfonamides, four acetylated sulfonamides, and trimethoprim were detected, with the dominant being sulfamethoxazole (66.6 ng/L), N-acetylsulfamethoxazole (63.1 ng/L), trimethoprim (29.0 ng/L), sulfadiazine (14.0 ng/L), and sulfamonomethoxine (8.4 ng/L); within the 36 marine samples, 10 chemicals were detected, with the main contributions from sulfamethoxazole (25.2 ng/L) and N-acetylsulfamethoxazole (28.6 ng/L). Sulfamethoxazole (25.9%), N-acetylsulfamethoxazole (46.6%), trimethoprim (22.9%), and sulfapyridine (1.4%) were the main chemicals from human sources, while sulfamonomethoxine, sulfamethazine, sulfaquinoxaline, sulfaguanidine, sulfadiazine, sulfanilamide, and sulfamethoxypyridazine were dominant in the animal husbandry sources, specifically, swine and poultry farms, and sulfamethoxazole (91%) was dominant in the mariculture source. A principal component analysis with multiple linear regression was performed to evaluate the source apportionment of total sulfonamides in Liaodong Bay. It was found that animal husbandry contributed 15.2% of total sulfonamides, while human sources contributed 28.5%, and combined human and mariculture sources contributed 56.3%. In addition, the mariculture contribution was 24.1% of total sulfonamides into the sea based on mass flux estimation. The present study is the first report that the environmental levels of sulfonamide metabolites were comparable to the corresponding parents; therefore, we should pay attention to their environmental occurrence. Source apportionment showed human discharge (60.7%) significantly contributed to these antibiotics in Liaodong Bay, which provides important information for environmental management. Environ. Toxicol. Chem. 2011; 30:1252–1260. © 2011 SETAC
Effects of time-variable exposure regimes of the insecticide chlorpyrifos on freshwater invertebrate communities in microcosms
Authors: Zafar Mazhar Iqbal , Van Wijngaarden Rene P.A , Roessink Ivo , Van den Brink Paul J
Published: February 2011

The present study compared the effects of different time-variable exposure regimes having the same time-weighted average (TWA) concentration of the organophosphate insecticide chlorpyrifos on freshwater invertebrate communities to enable extrapolation of effects across exposure regimes. The experiment was performed in outdoor microcosms by introducing three different regimes: a single application of 0.9 µg active ingredients (a.i.)/L; three applications of 0.3 µg a.i./L, with a time interval of 7 d; and continuous exposure to 0.1 µg a.i./L for 21 d. Measurements showed that the TWA21d concentration in the continuous-exposure treatment (0.098 µg/L) was slightly lower than in the three-application (0.116 µg/L) and single-application (0.126 µg/L) treatments. The application of chlorpyrifos resulted in decreased abundances in the arthropod community, with the largest adverse effects reported for the mayfly Cloeon dipterum and cladocerans Daphnia gr. longispina and Alona sp., while smaller effects were observed for other insects, copepods, and amphipods. At the population level, however, the mayfly C. dipterum only responded to the single-application treatment, which could be explained by the toxicokinetics of chlorpyrifos in this species. At the end of the experimental period the invertebrate community showed approximately the same effect magnitude for all treatment regimes. These results suggest that for this combination of concentrations and duration of the TWA, the TWA concentration is more important for most species than the peak concentration for the assessment of long-term risks of chlorpyrifos. Environ. Toxicol. Chem. 2011; 30:1383–1394. © 2011 SETAC
Comparison of polymeric samplers for accurately assessing PCBs in pore waters
Authors: Gschwend Philip M , MacFarlane John K , Reible Danny D , Lu X , Hawthorne Steven B , Nakles David V , Thompson Timothy
Published: February 2011

Assessing the hazard posed by sediments contaminated with hydrophobic organic compounds is difficult, because measuring the freely dissolved porewater concentrations of such low-solubility chemicals can be challenging, and estimating their sediment–water partition coefficients remains quite uncertain. We suggest that more accurate site assessments can be achieved by employing sampling devices in which polymers, with known polymer–water partition coefficients, are used to absorb the contaminants from the sediment. To demonstrate the current accuracy and limitations of this approach, we compared use of three polymers, polydimethylsiloxane, polyoxymethylene, and polyethylene, exposed to a single sediment in two modes, one in which they were exhaustively mixed (tumbled) with the sediment and the other in which they were simply inserted into a static bed (passive). Comparing porewater concentrations of specific polychlorinated biphenyl (PCB) congeners with results obtained using air bridges, we found the results for tumbled polymers agreed within 20%, and the passive sampling agreed within a factor of 2. In contrast, porewater estimates based on sediment concentrations normalized to fOCKOC, the weight fraction of organic carbon times the organic–carbon normalized partition coefficient, averaged a factor of 7 too high. We also found good correlations of each polymer's uptake of the PCBs with bioaccumulation by the polychaete, Neanthes arenaceodentata. Future improvements of the passive sampling mode will require devices that equilibrate faster and/or have some means such as performance reference compounds to estimate mass transfer limitations for individual deployments. Environ. Toxicol. Chem. 2011; 30:1288–1296. © 2011 SETAC