bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Conjugated Hyperbranched Polytriazoles Containing Truxene Units by Click Polymerization
Authors: Li Dongzhi , Wang Xin , Jia Yutao , Wang Aiqing , Wu Yonggang 
Published: March 2012

AbstractIt has been a challenge to synthesize high molecular weight and soluble conjugated hyperbranched poly(1,2,3‐triazole)s (hb‐PTAs). In this paper a series of soluble hyperbranched polytriazoles, whose number‐average molecular weight (Mn) and polydispersity index ranged in (1.2–3.3)×104 and 1.7–3.0, respectively, were synthesized with A2+B3 approach. In the polymerization process, diazides A1–A4 and triyne B1 were used as A2 and B3 monomers; Cu(I)‐catalyst, THF and water were used as their reaction system. At room temperature the final molecular weight could be controlled through reaction time, so finally we obtained soluble conjugated hyperbranched poly(1,2,3‐triazole)s hb‐PTAs (1–4). The polymers were soluble in common organic solvents, and all emitted blue light; the films of polymers emitted yellow and blue light, due to the difference in the aggregation of their chromophoric units in the solid state. The thermal properties of the final copolymers were analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).
Design, Synthesis and Biological Activities of Novel Benzoyl Hydrazines Containing Pyrazole
Authors: Yan Tao , Yu Shujing , Liu Pengfei , Liu Zhuo , Wang Baolei , Xiong Lixia , Li Zhengming 
Published: March 2012

AbstractIn search of environmentally benign compounds with high biological activity, low toxicity and low resistance, 8 novel benzoyl hydrazines containing pyrazole were designed and synthesized. All compounds were characterized by 1H NMR spectra and HRMS. The preliminary results of biological activity assessment indicated that most of title compounds exhibited certain insecticidal activities against Mythimna separata Walker at 200 mg·L−1 but excellent fungicidal activities against six fungus at 50 mg·L−1, which were better than the control.
Frizzled receptors in neurons: From growth cones to the synapse
Authors: Varela‐Nallar Lorena , Ramirez Valerie T. , Gonzalez‐Billault Christian , Inestrosa Nibaldo C. 
Published: March 2012

AbstractThe Wnt signaling pathway has been implicated in several different aspects of neural development and function, including dendrite morphogenesis, axonal growth and guidance, synaptogenesis and synaptic plasticity. Here, we studied several Frizzled Wnt receptors and determined their differential expression during hippocampal development. In cultured hippocampal neurons, the cellular distributions of Frizzleds vary greatly, some of them being localized at neurites, growth cones or synaptic sites. These findings suggest that the Wnt signaling pathway might be temporally and spatially fine tuned during the development of neuronal circuits through specific Frizzled receptors. © 2012 Wiley Periodicals, Inc
ERBB2 overexpression triggers transient high mechanoactivity of breast tumor cells
Authors: Martin Mireille , Müller Karla , Cadenas Cristina , Hermes Matthias , Zink Mareike , Hengstler Jan G. , Käs Josef A. 
Published: March 2012

AbstractBiomechanical properties of tumor cells play an important role for the metastatic capacity of cancer. Cellular changes of viscoelastic features are prerequisite for cancer progression since they are essential for proliferation and metastasis. However, only little is known about the way how expression of oncogenes influences these biomechanical properties. To address this aspect we used a breast cancer cell line with inducible expression of an oncogenic version of ERBB2. ERBB2 is known to be correlated with bad prognosis in breast cancer. Cell elasticity was determined by the Optical Stretcher, where suspended cells are deformed by two slightly divergent laser beams. We found that induction of ERBB2 caused remarkable biomechanical alterations of the MCF‐7 cells after 24 h: the cells actively contracted in response to mechanical stimuli, a phenomenon known as mechanoactivation. After this period, as the cells became senescent, the mechanoactivity returned to control levels. Time‐resolved gene array analysis revealed that mechanoactivation was accompanied by temporal upregulation of 46 cytoskeletal genes. A possible role of these genes in tumor progression was investigated by expression analyses of 766 breast cancer patients. This showed an association of 12 out of these 46 genes with increased risk of metastasis. Our results demonstrate that overexpression of ERBB2 causes mechanoactivation of tumor cells, which may enhance tumor cell motility fostering distant metastasis. © 2012 Wiley Periodicals, Inc.
Interplay between H‐Bonding and Alkyl‐Chain Ordering in Self‐Assembly of Monodendritic L‐Alanine Derivatives
Authors: Anokhin Denis V. , Lejnieks Jānis , Mourran Ahmed , Zhu Xiaomin , Keul Helmut , Möller Martin , Konovalov Oleg , Erina Natalia , Ivanov Dimitri A. 
Published: March 2012

AbstractThis paper reports on the synthesis and self‐organizing properties of monodendrons consisting of L‐alanine at the focal point and alkyl chains with different length at the periphery. The structures of thin films and monolayers are studied by temperature‐resolved grazing‐incidence X‐ray diffraction and scanning force microscopy. The interplay between H‐bonding and ordering of the alkyl chains results in a rich temperature‐dependent phase behavior. The monodendrons form H‐bonded stabilized clusters with the number of molecules depending on the length of the aliphatic chains and temperature. The clusters play the role of constitutive units in the subsequent self‐assembly. Short alkyl chains allow the material to form thermodynamically stable crystalline phases. The molecules with longer side groups exhibit additional transitions from the crystalline phase to thermotropic columnar hexagonal or columnar rectangular liquid‐crystalline phases. In monolayers deposited on highly ordered pyrolytic graphite, the materials show ordering similar to thin films. However, for the compound bearing hexadecyl chains the affinity of the alkyl groups to graphite dominates the self‐assembly and thereby allows epitaxial growth of a 2D lattice with flat‐on oriented molecules.
Single‐Walled Carbon Nanotubes as Scaffolds to Concentrate DNA for the Study of DNA–Protein Interactions
Authors: Liu Zunfeng , Galli Federica , Waterreus Willem‐Jan , Meulenbroek Elisabeth , Koning Roman I. , Lamers Gerda E. M. , Olsthoorn René C. L. , Pannu Navraj , Oosterkamp Tjerk. H. , Koster Abraham J. , Dame Remus T. , Abrahams Jan Pieter 
Published: March 2012

AbstractGenomic DNA in bacteria exists in a condensed state, which exhibits different biochemical and biophysical properties from a dilute solution. DNA was concentrated on streptavidin‐covered single‐walled carbon nanotubes (Strep⋅SWNTs) through biotin–streptavidin interactions. We reasoned that confining DNA within a defined space through mechanical constraints, rather than by manipulating buffer conditions, would more closely resemble physiological conditions. By ensuring a high streptavidin loading on SWNTs of about 1 streptavidin tetramer per 4 nm of SWNT, we were able to achieve dense DNA binding. DNA is bound to Strep⋅SWNTs at a tunable density and up to as high as 0.5 mg mL−1 in solution and 29 mg mL−1 on a 2D surface. This platform allows us to observe the aggregation behavior of DNA at high concentrations and the counteracting effects of HU protein (a histone‐like protein from Escherichia coli strain U93) on the DNA aggregates. This provides an in vitro model for studying DNA–DNA and DNA–protein interactions at a high DNA concentration.
DyeCycle violet used for side population detection is a substrate of P‐glycoprotein
Authors: Boesch Maximilian , Reimer Daniel , Rumpold Holger , Zeimet Alain G. , Sopper Sieghart , Wolf Dominik 
Published: March 2012

AbstractCancer stem cells (CSC) are increasingly recognized as key target cells for cancer therapy because they are both tumorigenic and chemoresistant and, therefore, can give rise to recurrent disease. Side population (SP) sorting using an ultraviolet (UV) laser is an established method to isolate CSC based on ABC drug transporter‐dependent (e.g., ABCG2) Hoechst 33342 efflux. We here show that Vybrant® DyeCycle™ Violet (DCV), a DNA‐binding fluorophor allowing SP sorting using a non‐UV laser (such as violet laser), is transported via P‐glycoprotein (PgP). Because PgP might be particularly abundant in multidrug‐resistant cancer cells rather than bona fide CSC, investigators using DCV should be aware that this strategy might also detect PgP‐expressing non‐CSC. © 2012 International Society for Advancement of Cytometry
Latent learning of spatial information is impaired in middle‐aged rats
Authors: Stouffer Eric M. , Heisey Jamie L. 
Published: March 2012

AbstractThe present study determined if the middle age related impairment that occurs with nonspatial latent learning also occurs in spatial latent learning. Thirty young (3‐months‐old) and 30 middle‐aged (12‐months‐old) male Sprague–Dawley rats were given either pre‐exposure to spatial cues surrounding a Barnes maze (SpatialPX), or pre‐exposure to just the maze (MazePX). They were then given 10 training trials in which they had to find a hidden escape box while experiencing an aversive environment produced by bright lights and wind. Results showed that young rats given the SpatialPX condition demonstrated faster escape latencies and fewer errors than young rats given the MazePX condition. However, middle‐aged rats given the SpatialPX condition did not show this improved performance. These findings indicate that the middle age learning deficit is not task specific, but rather is a general impairment in latent learning, possibly due to the early degeneration of the entorhinal cortex. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 309–315, 2013
Structural Study of the Lipopolysaccharide O‐Antigen Produced by the Emerging Cystic Fibrosis Pathogen Pandoraea pulmonicola
Authors: Di Lorenzo Flaviana , Silipo Alba , Costello Anne , Sturiale Luisa , Garozzo Domenico , Callaghan Máire , Lanzetta Rosa , Parrilli Michelangelo , McClean Siobhán , Molinaro Antonio 
Published: March 2012

AbstractThis is the first report on the molecular structure of the O‐chain of the lipopolysaccharide produced by the emerging and highly virulent clinical isolate Pandoraea pulmonicola strain LMG 18108, an opportunistic human pathogen in cystic fibrosis patients. Monosaccharide analysis and 2D NMR spectroscopy revealed a novel polysaccharide, the structure of which consists of the trisaccharide repeating unit [→2‐β‐D‐Quip3NAcyl‐(1→4)‐α‐D‐GalpNAc‐(1→3)‐α‐D‐GlcpNAc‐1→]n. The quinovosamine residue was found to be linked by a very unusual acyl substituent, a five‐membered‐ring acyl residue, the 3‐hydroxy‐2,3‐dimethyl‐5‐oxoprolyl group.
Simultaneous Determination of Trace Uranium(VI) and Cadmium(II) by Adsorptive Stripping Voltammetry in the Presence of Cupferron as a Complexing Agent
Authors: Grabarczyk Malgorzata , Koper Anna 
Published: March 2012

AbstractThe application of cupferron as a complexing agent for a simultaneous voltammetric determination of U(VI) and Cd(II) in a single scan in environmental water samples has been developed. Optimal conditions were found to be: 0.05 mol L−1 acetate buffer (pH 5.3) as a supporting electrolyte, 1×10−3 mol L−1 cupferron, the accumulation potential −0.25 V, the accumulation time 30 s. The linear range of uranium(VI) and cadmium(II) were observed over the concentration range from 1×10−8 mol L−1 to 5×10−7 mol L−1 and from 2.5×10−9 mol L−1 to 2×10−7 mol L−1, respectively. The procedure was applied to the determination in natural water samples.
Lysine and Arginine Oligopeptides Tagged with Anthraquinone: Electrochemical Properties
Authors: Czupryniak Justyna , Niedziałkowski Paweł , Karbarz Marcin , Ossowski Tadeusz , Stojek Zbigniew 
Published: March 2012

AbstractNew, electroactive, positively charged peptides consisting of either L‐lysine or L‐arginine and containing one or two anthraquinone units in the structure were synthesized. Electrochemical properties of the synthesized compounds were examined by cyclic‐, normal pulse‐ and microelectrode voltammetries. Spectroscopic and potentiometric methods were used to characterize such properties of the new peptides as: pKa, diffusion coefficients and formal potentials in water and DMSO. The obtained results show that the number of noninteracting, anthraquinone units incorporated into one peptide chain leads to proportional increase of height of voltammetric and spectroscopic signals.
The tumour suppressor and chromatin‐remodelling factor BRG1 antagonizes Myc activity and promotes cell differentiation in human cancer
Authors: Romero Octavio A. , Setien Fernando , John Sam , Gimenez‐Xavier Pol , Gómez‐López Gonzalo , Pisano David , Condom Enric , Villanueva Alberto , Hager Gordon L. , Sanchez‐Cespedes Montse 
Published: March 2012

AbstractBRG1, a member of the SWI/SNF complex, is mutated in cancer, but it is unclear how it promotes tumourigenesis. We report that re‐expression of BRG1 in lung cancer cells up‐regulates lung‐specific transcripts, restoring the gene expression signature of normal lung. Using cell lines from several cancer types we found that those lacking BRG1 do not respond to retinoic acid (RA) or glucocorticoids (GC), while restoration of BRG1 restores sensitivity. Conversely, in SH‐SY5Y cells, a paradigm of RA‐dependent differentiation, abrogation of BRG1 prevented the response to RA. Further, our data suggest an antagonistic functional connection between BRG1 and MYC, whereby, refractoriness to RA and GC by BRG1 inactivation involves deregulation of MYC activity. Mechanistically, some of these effects are mediated by BRG1 binding to MYC and MYC‐target promoters. The BRG1‐MYC antagonism was also evident in primary tumours. Finally, BRG1 restoration significantly dampened invasion and progression and decreased MYC in lung cancer cells orthotopically implanted in nude mice. Thus, BRG1 inactivation enables cancer cells to sustain undifferentiated gene expression programs and prevent its response to environmental stimuli.
Tabu search for dynamic spectrum allocation in cellular networks
Authors: Kamal Hany , Coupechoux Marceau , Godlewski Philippe 
Published: March 2012

ABSTRACTIn this paper, we present and analyse a Tabu Search algorithm for Dynamic Spectrum Allocation in cellular networks. We study a case where an operator is providing packet services to the end users. The objective of the cellular operator is to maximise its reward while taking into account the trade‐off between the spectrum cost and the revenues obtained from end users. These revenues are modelled here as an increasing function of the achieved throughput. The cost is proportional to the bandwidth of the spectrum leased to the regulator or some spectrum broker. Results show that the algorithm allows the operator to increase its reward by taking advantage of the spatial and temporal heterogeneities of the traffic in the network, rather than assuming homogeneous traffic for its radio resource allocation. Our Tabu Search‐based Dynamic Spectrum Allocation algorithm is efficient in terms of the required memory space and convergence speed. Results show that the algorithm is fast enough to suit a dynamic context. Copyright © 2012 John Wiley & Sons, Ltd.
Caloplaca lacinulata rediscovered for the lichen flora of South Korea
Authors: Joshi Yogesh , Andreev Mikhail , Hur Jae‐Seoun 
Published: March 2012

AbstractThe existence of the lichen species Caloplaca lacinulata (Hue) Zahlbr. (1930) [1931] is confirmed after a gap of about 100 years. The taxon was first described by Hue (1913), growing over granite rocks nearly Seoul. Its rediscovery is documented by a specimen recently collected in Mt. Sorak, extending its distribution within South Korea. A brief description and illustrations are provided for the species. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Association of cerebral small vessel disease with delusions in patients with Alzheimer's disease
Authors: Ogawa Yusuke , Hashimoto Mamoru , Yatabe Yusuke , Kaneda Keiichiro , Honda Kazuki , Yuuki Seiji , Hirai Toshinori , Ikeda Manabu 
Published: March 2012

BackgroundCerebral small vessel disease (SVD) is frequently observed in patients with Alzheimer's disease (AD). However, the association between SVD and clinical symptoms exhibited by patients with AD remains unclear. This study examined the association of SVD as observed on magnetic resonance imaging (MRI) with behavioural and psychological symptoms of dementia and cognitive function of patients with probable AD.MethodsA total of 163 consecutive patients (55 men, 108 women) with probable AD were included in this cross‐sectional study of a prospective cohort. Patients were divided into two groups based on the presence or absence of cerebral SVD [white matter hyperintensities (WMH) grade 0/1 (Fazekas scale) and no lacunes: SVD absent, WMH grade 2/3 (Fazekas scale) or the number of lacunes ≥1: SVD present]. Cognitive functions were assessed using the Mini mental state examination, word recall and recognition subtests in the Alzheimer's Disease Assessment Scale—Cognitive Subscale, as well as the letter fluency task and the category fluency task. Psychiatric symptoms were rated according to Neuropsychiatric Inventory.ResultsPatients with probable AD with cerebral SVD had significantly more delusions and depression than those without SVD. No significant differences were observed in other neuropsychiatric symptoms, MMSE or word recall and recognition tests between both groups.ConclusionsOur results suggest that cerebral SVD observed on MRI of patients with AD is associated with delusions and depression. Copyright © 2012 John Wiley & Sons, Ltd.
Improvement of the cytocompatibility of electrospun poly[(R)‐3‐hydroxybutyrate‐co‐(R)‐3‐hydroxyvalerate] mats by Ecoflex
Authors: Wang Anhui , Gan Yunna , Yu Hao , Liu Yuan , Zhang Min , Cheng Baixiang , Wang Fang , Wang Huixia , Yan Juanjuan 
Published: March 2012

AbstractPoly[(R)‐3‐hydroxybutyrate‐co‐(R)‐3‐hydroxyvalerate] (PHBV) is a nature‐derived polyester with potential application in tissue engineering scaffolds. However, PHBV is associated with disadvantages including high brittleness, slow degradation, high hydrophobicity, and unsatisfactory biocompatibility. In this study, we sought to improve the properties of PHBV by blending it with Ecoflex, a synthetic biopolyester with a high flexibility, fast degradation, and comparatively higher hydrophilicity. PHBV was codissolved with Ecoflex in dichloromethane at different mass ratios (PHBV/Ecoflex: 100/0, 70/30, 50/50, and 30/70) and electrospun into mats. Compared with the pure PHBV mat, the Ecoflex‐containing mats showed decreased contact angles with phosphate‐buffered saline (PBS), accelerated weight loss in PBS, and increased strain at break with increasing Ecoflex mass ratios. In vitro cell culture also showed significantly improved adhesion and proliferation of human bone marrow stroma cells with the introduction of Ecoflex. Blending PHBV with Ecoflex is a simple and effective method to improve the chemical, mechanical, and biological properties of PHBV simultaneously and thereby to expedite its application in tissue engineering. To our knowledge, this is the first report showing the biocompatibility of Ecoflex‐containing materials with human cells. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Effect of biological/physical stimulation on guided bone regeneration through asymmetrically porous membrane
Authors: Kim Tae Ho , Oh Se Heang , Na Seung Yeon , Chun So Young , Lee Jin Ho 
Published: March 2012

AbstractAsymmetrically porous polycaprolactone (PCL)/Pluronic F127 guided bone regeneration (GBR) membranes were fabricated. The top surface of the membrane had nanosize pores (∼10 nm) which can effectively prevent invasion by fibrous connective tissue but permeate nutrients, whereas the bottom surface had microsize pores (∼200 μm) which can enhance the adhesiveness with bone tissue. Ultrasound was applied to a bone morphogenetic protein (BMP‐2)‐immobilized PCL/F127 GBR membrane to investigate the feasibility of using dual biological (BMP‐2) and physical (ultrasound) stimulation for enhancing bone regeneration through the membrane. In an animal study using SD rats (cranial defect model), the bone regeneration behavior that occurred when using BMP‐2‐loaded GBR membranes with ultrasound treatment (GBR/BMP‐2/US) was much faster than when the same GBR membrane was used without the ultrasound treatment (GBR/BMP‐2), as well as when GBR membranes were used without stimulations (GBR). The enhanced bone regeneration of the GBR/BMP‐2/US group can be interpreted as resulting from the synergistic or additive effect of the asymmetrically porous PCL/F127 membrane with unique properties (selective permeability, hydrophilicity, and osteoconductivity) and the stimulatory effects of BMP‐2 and ultrasound (osteoinductivity). The asymmetrically porous GBR membrane with dual BMP‐2 and ultrasound stimulation may be promising for the clinical treatment of delayed and insufficient bone healing. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Student award winner in the undergraduate category for the society of biomaterials 9th World Biomaterials Congress, Chengdu, China, June 1–5, 2012
Authors: Blakney Anna K. , Swartzlander Mark D. , Bryant Stephanie J. 
Published: March 2012

AbstractPoly(ethylene glycol) (PEG) hydrogels, modified with RGD, are promising platforms for cell encapsulation and tissue engineering. While these hydrogels offer tunable mechanical properties, the extent of the host response may limit their in vivo applicability. The overall objective was to characterize the effects of hydrogel stiffness on the in vitro macrophage response and in vivo host response. We hypothesized that stiffer substrates induce better attachment, adhesion, and increased cell spreading, which elevates the macrophage classically activated phenotype and leads to a more severe foreign body reaction (FBR). PEG‐RGD hydrogels were fabricated with compressive moduli of 130, 240, and 840 kPa, and the same RGD concentration. Hydrogel stiffness did not impact macrophage attachment, but elicited differences in cell morphology. Cells retained a round morphology on 130 kPa substrates, with localized and dense F‐actin and localized αV integrin stainings. Contrarily, cells on stiffer substrates were more spread, with filopodia protruding from the cell, a more defined F‐actin, and greater αV integrin staining. When stimulated with lipopolysaccharide, macrophages had a classical activation phenotype, with increased expression of TNF‐α, IL‐1β, and IL‐6, however the degree of activation was significantly reduced with the softest hydrogels. A FBR ensued in response to all hydrogels when implanted subcutaneously in mice, but 28 days postimplantation the layer of macrophages at the implant surface was significantly lower in the softest hydrogels. In conclusion, hydrogels with lower stiffness led to reduced macrophage activation and a less severe and more typical FBR, and therefore are more suited for in vivo tissue engineering applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
The First Synthesis of Natural Occurring Juncaceae Coumarin, 9‐Hydroxy‐8‐methyl‐3H‐benzo[f]chromen‐3‐one, Featuring a One‐pot Rearrangement and Aromatization Cascade
Authors: Hon Yung‐Son , Hong Ya‐Chun , Hong Bor‐Cherng , Liao Ju‐Hsiou 
Published: March 2012

AbstractThe synthesis of benzocoumarins from β‐tetralones has been achieved via two pathways in the first total synthesis of the Juncaceae natural product, 9‐hydroxy‐8‐methyl‐3H‐benzo[f]chromen‐3‐one, featuring a one‐pot rearrangement and aromatization cascade.