bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation, characterization, and antimicrobial activity of quaternized chitosan/organic montmorillonite nanocomposites
Authors: Wang Xiaoying , Du Yumin , Yang Jianhong , Tang Yufeng , Luo Jiwen 
Published: July 2007

AbstractQuaternized chitosan/layered silicate nanocomposite was prepared by simple solution‐mixing in aqueous media. Montmorillonite (MMT) modified with cetyltrimethyl ammonium bromide was used as an organically modified layered silicate. XRD and TEM analyses respectively confirmed that silicate layers of MMT were intercalated and nicely distributed in quaternized chitosan matrix in despite of the high content of MMT (25–50 wt %). The interactions between the quaternized chitosan macromolecules and MMT in aqueous media were analyzed using FTIR, XRD, and ζ‐potential measurements. Antimicrobial studies showed that the nanocomposites could strongly inhibit the growth of a wide variety of microorganisms, including Gram‐positive bacteria, Gram‐negative bacteria, and fungi; more importantly, they exhibited good antimicrobial capacity in whichever medium, in weak acid, water, or weak base. As the amount of MMT increased, the nanocomposites had better inhibitory effect on microorganisms, especially Gram‐positive bacteria. The lowest minimum inhibition concentration (MIC) value of the nanocomposites against Staphylococcus aureus and Bacillus subtilis were less than 0.00313% (w/v) under all the conditions. The adsorption action of MMT on bacteria was simply discussed via SEM images. The results revealed that the strong antimicrobial of the nanocomposites may be attributed to the fine dispersion and the interaction between quaternized chitosan and MMT. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Influence of energy and pulse repetition rate of Er:YAG laser on enamel ablation ability and morphological analysis of the laser‐irradiated surface
Authors: Corona Silmara Aparecida Milori , Souza‐Gabriel Aline Evangelista , Chinelatti Michelle Alexandra , Pécora Jesus Djalma , Borsatto Maria Cristina , Palma‐Dibb Regina Guenka 
Published: July 2007

AbstractObjective: To assess the influence of energy and pulse repetition rate of Er:YAG laser on the enamel ablation ability and substrate morphology. Methods: Fifteen crowns of molars were sectioned in four fragments, providing 60 samples, which were ground to flatten the enamel surface. The initial mass was obtained by weighing the fragments. The specimens were hydrated for 1 h, fixed, and a 3‐mm‐diameter area was delimited. Twelve groups were randomly formed according to the combination of laser energies (200, 250, 300, or 350 mJ) and pulse repetition rates (2, 3, or 4 Hz). The final mass was obtained and mass loss was calculated by the difference between the initial and final mass. The specimens were prepared for SEM. Data were submitted to ANOVA and Scheffé test. Results: The 4 Hz frequency resulted in higher mass loss and was statistically different from 2 and 3 Hz (p < 0.05). The increase of frequency produced more melted areas, cracks, and unselective and deeper ablation. The 350 mJ energy promoted greater mass loss, similar to 300 mJ. Conclusions: The pulse repetition rate influenced more intensively the mass loss and morphological alteration. Among the tested parameters, 350 mJ/3 Hz improved the ability of enamel ablation with less surface morphological alterations. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Cell‐surface interactions of rat tooth germ cells on various biomaterials
Authors: Chen Rung‐Shu , Chen Yi‐Jane , Chen Min‐Huey , Young Tai‐Horng 
Published: July 2007

AbstractThis is the first study to explore the effect of biomaterial on tooth germ cell adhesion and proliferation in vitro. The purpose of this study is to evaluate the effects of cell–surface interactions of tooth germ cells on biomaterials with various surface hydrophilicities. The biomaterials used in this study included polyvinyl alcohol (PVA), poly(lactic‐co‐glycolic acid) (PLGA), poly(ethylene‐co‐vinyl alcohol; EVAL), and polyvinylidene fluoride (PVDF). Cell morphology was observed by photomicroscopy. Cell growth was assayed with 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) reduction activity and the characteristic expression of amelogenin and collagen type I in tooth germ cells was investigated using immunocytochemistry. The results indicated that adhesion and proliferation of tooth germ cells to biomaterials with moderate hydrophilicity/hydrophobicity was superior compared to most hydrophobic material PVDF or mosthydrophilic material PVA in this study. Cellular adhesion and proliferation was evident on all tested biomaterials except PVA. The cell spheroids on PVA appeared not to be proliferated and remained as well as reattachable to tissue culture plates. In conclusion, biomaterials with moderate hydrophilicity are suitable for adhesion and proliferation of tooth germ cells. The material PVA may be a good biomaterial for maintaining tooth germ cells in three‐dimensional biological restoration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Calcium sulfate acts on the miRNA of MG63E osteoblast‐like cells
Authors: Palmieri Annalisa , Pezzetti Furio , Brunelli Giorgio , Scapoli Luca , Muzio Lorenzo Lo , Scarano Antonio , Martinelli Marcella , Carinci Francesco 
Published: July 2007

AbstractCalcium sulfate (CaS) is a highly biocompatible material and enhances bone formation in vivo. However, how CaS alters osteoblast activity to promote bone formation is incompletely understood. We therefore investigated the translation regulation in osteoblasts exposed to CaS by using microRNA microarray techniques. Transduction, transcription, and translation are the three levels of regulation of cell activity. Recently, a new type of translation regulation has been identified: RNA interference (RNAi). RNAi is a process in which microRNA, (miRNA), that is, noncoding RNAs of 19–23 nucleotides can induce sequence‐specific mRNA degradation and/or translational repression. The human genome encodes a few hundred miRNAs that can post‐transcriptionally repress thousands of genes. The miRNA oligonucleotide microarray provides a novel method of carrying out genome‐wide miRNA profiling in human samples. By using miRNA microarrays containing 329 probes designed from Human miRNA sequences, we identified in osteoblast‐like cells line (MG‐63) cultured with CaS (Surgiplaster, Classimplant, Roma, Italy) several miRNA whose expression is significantly modified. The data reported are, to our knowledge, the first study on translation regulation in osteoblasts exposed to CaS. They could be relevant to a better understanding of the molecular mechanism of bone regeneration and as a model for comparing other materials with similar clinical effects. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Essential role of PSM/SH2‐B variants in insulin receptor catalytic activation and the resulting cellular responses
Authors: Zhang Manchao , Deng Youping , Tandon Ruchi , Bai Cheng , Riedel Heimo 
Published: July 2007

AbstractThe positive regulatory role of PSM/SH2‐B downstream of various mitogenic receptor tyrosine kinases or gene disruption experiments in mice support a role of PSM in the regulation of insulin action. Here, four alternative PSM splice variants and individual functional domains were compared for their role in the regulation of specific metabolic insulin responses. We found that individual PSM variants in 3T3‐L1 adipocytes potentiated insulin‐mediated glucose and amino acid transport, glycogenesis, lipogenesis, and key components in the metabolic insulin response including p70 S6 kinase, glycogen synthase, glycogen synthase kinase 3 (GSK3), Akt, Cbl, and IRS‐1. Highest activity was consistently observed for PSM alpha, followed by beta, delta, and gamma with decreasing activity. In contrast, dominant‐negative peptide mimetics of the PSM Pro‐rich, pleckstrin homology (PH), or src homology 2 (SH2) domains inhibited any tested insulin response. Potentiation of the insulin response originated at the insulin receptor (IR) kinase level by PSM variant‐specific regulation of the Km (ATP) whereas the Vmax remained unaffected. IR catalytic activation was inhibited by peptide mimetics of the PSM SH2 or dimerization domain (DD). Either peptide should disrupt the complex of a PSM dimer linked to IR via SH2 domains as proposed for PSM activation of tyrosine kinase JAK2. Either peptide abolished downstream insulin responses indistinguishable from PSM siRNA knockdown. Our results implicate an essential role of the PSM variants in the activation of the IR kinase and the resulting metabolic insulin response. PSM variants act as internal IR ligands that in addition to potentiating the insulin response stimulate IR catalytic activation even in the absence of insulin. J. Cell. Biochem. 103: 162–181, 2008. © 2007 Wiley‐Liss, Inc.
Inhibition of lipopolysaccharide‐induced inducible nitric oxide synthase and cyclooxygenase‐2 gene expression by 5‐aminoimidazole‐4‐carboxamide riboside is independent of AMP‐activated protein kinase
Authors: Kuo Chih‐Lin , Ho Feng‐Ming , Chang Mei Ying , Prakash Ekambaranellore , Lin Wan‐Wan 
Published: July 2007

AbstractRecent studies suggest AMP‐activated protein kinase (AMPK), an enzyme involved in energy homeostasis, might be a novel signaling pathway in regulating inflammatory response, but the precise intracellular mechanisms are not fully understood. In this study, we have demonstrated that 5‐aminoimidazole‐4‐carboxamide riboside (AICAR), an activator of AMPK, inhibited lipopolysaccharide (LPS)‐induced protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2) in macrophages and microglial cells at the gene transcription level. Data obtained from electrophoretic mobility shift assay (EMSA) and promoter activity assay have further confirmed the ability of AICAR to block LPS‐mediated NF‐κB, AP‐1, CREB, and C/EBPβ activation. However, AICAR did not affect LPS‐mediated IKK, ERK, and p38 activation. Regardless of the ability of AICAR to activate AMPK, the inhibitory effects of AICAR on iNOS and COX‐2 expression were not associated with AMPK. An adenosine kinase inhibitor 5′‐iodotubercidin, which effectively abolished AMPK activation caused by AICAR, did not reverse the anti‐inflammatory effect of AICAR. Moreover, another AMPK activator metformin was not able to mimic the effects of AICAR. Direct addition of AICAR in EMSA assay interrupted binding of NF‐κB, CREB, and C/EBPβ to specific DNA elements. Taken together, this study demonstrates that the anti‐inflammatory effects of AICAR against LPS‐induced iNOS and COX‐2 gene transcription are not associated with AMPK activation, but might be resulting from the direct interference with DNA binding to transcription factors. J. Cell. Biochem. 103: 931–940, 2008. © 2007 Wiley‐Liss, Inc.
Adsorption of fulvic acids from aqueous solutions by carbon nanotubes
Authors: Wang Shu‐Guang , Liu Xian‐Wei , Gong Wen‐Xin , Nie Wei , Gao Bao‐Yu , Yue Qin‐Yan 
Published: July 2007

AbstractCarbon nanotubes (CNTs) were used as adsorbent to remove fulvic acids (FA) from aqueous solutions. The adsorption capacity of CNTs for FA can reach 24 mg g−1 at 5 °C and equilibrium concentration of 18 mg dm−3. The kinetic and thermodynamic parameters, such as rate of adsorption, standard free energy changes (ΔG0), standard enthalpy change (ΔH0) and standard entropy change (ΔS0), have been obtained. Acidic conditions (pH = 2–5) favor FA removal. An increase in the ionic strength or the addition of divalent cations increase the adsorption of FA dramatically (FA = 60 mg dm−3). An increase in the maximum adsorbed amount of FA was observed when treating FA in synthetic seawater. Desorption studies reveal that FA can be easily and quickly removed from CNTs by altering the pH values of the solution. Good adsorption capacity and quick desorption indicate that CNTs are a promising adsorbent to remove FA from aqueous solutions. Copyright © 2007 Society of Chemical Industry
Effects of culture temperature on the production of bioactive polysaccharides by Agaricus blazei in batch cultures
Authors: Shu Chin‐Hang , Lin Ko‐Jung , Wen Bor‐Jiun 
Published: July 2007

AbstractEffects of culture temperature ranging from 20 to 34 °C on cell growth, polysaccharide biosynthesis and the bioactivity of polysaccharides of Agaricus blazei were evaluated via eight batch cultures in steps of 2 °C in a stirred tank bioreactor. Results indicated that the optimal temperature for the biomass was 28 °C with a cell yield of 780 mg g−1, while that for polysaccharide formation was 30 °C with a product yield of 230 mg g−1. Both the β‐glucan content and average molecular weight of the polysaccharides from different temperature‐controlled cultures were closely correlated with their tumour necrosis factor‐α (TNF‐α) release capability on macrophage cells. The polysaccharides from the low temperature range (20–24 °C) not only had higher relative content of β‐glucan and average molecular weight but also exhibited higher bioactivity compared with those from the high temperature range (30–34 °C). The optimal temperature for the production of bioactive polysaccharides of A. blazei was 24 °C, at which their relatively high molecular weight, β‐glucan content and TNF‐α release capability on macrophage cells were 1650 kDa, 188 mg g−1 and 1560 pg per 5 × 104 cells respectively. Copyright © 2007 Society of Chemical Industry
Effect of an emulsifying surfactant on diesel degradation by cultures exhibiting inducible cell surface hydrophobicity
Authors: Mohanty Gita , Mukherji Suparna 
Published: July 2007

AbstractBACKGROUND: Accumulation of petroleum hydrocarbons in the environment is often attributed to inherently slow degradation rates. This study was conducted to determine if diesel biodegradation by cultures exhibiting inducible cell surface hydrophobicity could be enhanced by addition of a chemical surfactant promoting emulsification. Experiments were designed to determine quantitatively the enhancement in diesel degradation caused by Triton X‐100 for two bacterial cultures, Exiguobacterium aurantiacum and Burkholderia cepacia.RESULTS: In the presence of Triton X‐100 at twice the critical micelle concentration (CMC) the extent of degradation in whole diesel in 5 days was 1.6–1.8 times that observed over 15 days with no surfactant. The enhancement in overall degradation of diesel range resolved peaks (DRRP, representing n‐alkanes and branched alkanes) was 1.76 and 1.26 times for E. aurantiacum and B. cepacia cultures respectively. Although an enhancement in decay rate was observed for all n‐alkane components, it was most significant for C19, C25 and pristane.CONCLUSION: For cultures exhibiting direct interfacial uptake, the beneficial effect of an emulsifying surfactant found here is in contrast to earlier studies reporting a detrimental effect due to detachment of cells from the oil/water interface. Surfactant addition may have significant potential in enhancing degradation of the more recalcitrant components. Copyright © 2007 Society of Chemical Industry
A new procedure for the preparative separation and isolation of Z‐ligustilide from the roots of Angelica sinensis
Authors: Yi Tao , Zhang Hao , Xie Jing , Xue Dan 
Published: July 2007

AbstractA new procedure for the separation and isolation of Z‐ligustilide from the roots of Angelica sinensis (AS) was developed, and the storage conditions for Z‐ligustilide were optimized. Using the present procedure, Z‐ligustilide was enriched by decomposing the Z‐ligustilide dimers yielding Z‐ligustilide and dissolving the polar impurities in hot water. Then, the crude Z‐ligustilide was further purified by a semipreparative HPLC system. The spiked and nonspiked samples were used for the evaluation of the proposed procedure. Recoveries obtained varied from 86.2 to 90.7% and RSDs from 4.0 to 6.6%. The yield and purity of the isolated Z‐ligustilide were found to be 4.57 mg/g and 99.6%, respectively. The results of stability tests have shown that the presence of oxidant contributes to Z‐ligustilide degradation, therefore argon was chosen as a shielding gas for storage. The overall procedure is efficient and convenient which is considered suitable for the preparative separation of Z‐ligustilide from AS.
Separation of pyridine derivatives from synthetic mixtures by pH‐zone‐refining counter‐current chromatography
Authors: Tong Shengqiang , Yan Jizhong , Li Jian , Lou Jianzhong 
Published: July 2007

AbstractThree novel pyridine derivatives were successfully separated from their partially purified synthetic mixtures by pH‐zone‐refining counter‐current chromatography using a multilayer coil planet centrifuge designed in our laboratory. After equilibration of a two‐phase solvent system consisting of methyl tert‐butyl ether–tetrahydrofuran–water at an optimized volume ratio of 4:6:7, triethylamine (10 mM) was added to the organic phase as a retainer and hydrochloric acid (10 mM) to the aqueous phase as an eluter. Separation runs of 1.20, 1.16, and 1.15 g of three samples yielded three pyridine derivatives in weights of 306, 255, and 314 mg at a high purity of over 98.5, 99.0, and 98.2% (determined by HPLC), respectively. The structures were identified by electron impact mass spectrometry and 1H NMR.
Analysis of 4‐methyl‐piperazine‐1‐carbodithioic acid 3‐cyano‐3,3‐diphenyl‐propyl ester hydrochloride and its major metabolites in rat plasma and tissues by LC‐MS/MS
Authors: Jiang Xiaomei , Ling Xiaomei , Han Fangbin , Li Runtao , Cui Jingrong 
Published: July 2007

Abstract4‐Methyl‐piperazine‐1‐carbodithioic acid 3‐cyano‐3,3‐diphenylpropyl ester hydrochloride (TM‐208) is a newly synthesized compound, which has shown excellent in vivo and in vitro anticancer activity and low toxicity. To investigate the metabolism of TM‐208 in rats, in the present study, we administered TM‐208 orally to rats and analyzed its metabolites existing in rat plasma and central tissues by LC‐MS/MS. Rat plasma and tissue samples were collected before or after a single oral dose (250 mg/kg) of TM‐208, then the analytes were extracted from samples by liquid–liquid extraction and analyzed using LC‐MS/MS. The structures of proposed metabolites were elucidated according to the rules of drug metabolism and disposition in vivo and the characteristic fragmentation behaviors of TM‐208 in ESI‐ITMSn. Five metabolites (M1–M5) were tentatively or assuredly identified: (2‐amino‐ethyl)‐dithiocarbamic acid 3‐cyano‐3,3‐diphenyl‐propyl ester (M1), (2‐methylamino‐ethyl)‐dithiocarbamic acid 3‐cyano‐3,3‐diphenyl‐propyl ester (M2), 4‐methyl‐piperazine‐1‐carbothioic acid S‐(3‐cyano‐3,3‐diphenyl‐propyl) ester (M3), piperazine‐1‐carbodithioic acid 3‐cyano‐3,3‐diphenylpropyl ester (M4), and sulfine of (4‐methyl‐piperazine‐1‐carbodithioic acid 3‐cyano‐3,3‐diphenylpropyl ester) (M5).
Entwicklung hochverschleißbeständiger wolframschmelzkarbidbasierter Schichten auf Aluminiumbauteilen durch Plasma‐Pulver‐Auftragschweißen
Authors: Kondapalli S. , Balashov B. , Geffers C. , Riedel F. 
Published: July 2007

AbstractDurch den Einsatz von Wolframschmelzkarbid können Funktionsflächen von Bauteilen mit stark abrasiven Beanspruchungen wirkungsvoll geschützt werden. Bereits seit vielen Jahren wird Wolframschmelzkarbid eingesetzt, um die Verschleißeigenschaften von Stahl zu verbessern. In diesem Artikel werden Ergebnisse von Untersuchungen zum Verschleißschutz von Aluminiumoberflächen mithilfe des Plasma‐Pulver‐Auftragschweißens von wolframschmelzkarbidbasierten Schichten vorgestellt. Die Wolframschmelzkarbid‐Schichten werden mit zwei Methoden entwickelt, zum einen durch Dispergieren von Wolframschmelzkarbidpartikeln, zum anderen durch eine Kombination aus Dispergieren und Legieren von Verbundpulvern auf Wolframschmelzkarbidbasis. Die Schweißbarkeit der Pulversysteme wird für variierende Auftragschweißparameter und Karbidpartikelanteile untersucht. Im Anschluss erfolgt die Analyse der spezifischen Eigenschaften und der Verschleißbeständigkeit der entwickelten Schichten. Abschließend wird das Anwendungspotenzial am Beispiel von Führungsrollen dargestellt.
Beanspruchungsgerechte Formgebung von Umformwerkzeugen durch formgebendes Plasma‐Pulver‐Auftragschweißen
Authors: Alaluss K. , Matthes K.‐J. 
Published: July 2007

AbstractZur Verbesserung der mechanisch‐technologischen Eigenschaften der Umformwerkzeuge (insbesondere mittelgroßer Bauteilgeometrien) hat sich das formgebende Plasma‐Pulver‐Auftragschweißen als Fertigungsmethode etabliert. Es konnte nachgewiesen werden, dass durch den Einsatz von Kobalt‐ und Nickelbasislegierungen die thermomechanischen Eigenschaften dieser Werkzeuge verbessert werden. Mit der Einlagerung von Karbiden in den Kobaltbasis‐Matrixwerkstoff wurden die stark gefährdeten Flächenbereiche der Werkzeugstrukturen besser geschützt und damit die Standzeiten gegenüber den bisher hergestellten Bauteilen aus konventionellen Werkstoffen deutlich erhöht. Mit hergestellten und erprobten Segmenten eines Querwalzwerkzeuges konnten die gewonnenen Kenntnisse überprüft werden, inwieweit sie in die Praxis umsetzbar sind.
Pallidal deep brain stimulation in patients with cranial–cervical dystonia (Meige syndrome)
Authors: Ostrem Jill L. , Marks William J. , Volz Monica M. , Heath Susan L. , Starr Philip A. 
Published: July 2007

AbstractIdiopathic cranial–cervical dystonia (ICCD) is an adult‐onset dystonia syndrome affecting orbicularis oculi, facial, oromandibular, and cervical musculature. ICCD is frequently difficult to treat medically. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is a highly effective treatment for idiopathic generalized dystonia, however less is known about the effect of GPi DBS on ICCD. In this article, we present the results from a pilot study assessing the effect of GPi DBS in a series of patients with ICCD. Six patients underwent bilateral stereotactic implantation of DBS leads into the sensorimotor GPi. Patients were evaluated with the Burke–Fahn–Marsden dystonia rating scale (BFMDRS) and Toronto western spamodic torticollis rating scale (TWSTRS) before surgery and 6 months postoperatively. At 6 months, patients showed a 72% mean improvement in the BFMDRS total movement score (P < 0.028, Wilcoxin signed rank test). The mean BFMDRS disability score showed a trend toward improvement (P < 0.06). The total TWSTRS score improved 54% (P < 0.043). Despite improvement in dystonia, mild worsening of motor function was reported in previously nondystonic body regions with stimulation in 4 patients. Although GPi DBS was effective in these patients, the influence of GPi DBS on nondystonic body regions deserves further investigation. © 2007 Movement Disorder Society
Small scale socio‐cultural thematic maps for development and administrative planning
Authors: Kent Robert B. 
Published: July 2007

AbstractBecause of the domination of development and administrative planning by economists there has in the past been a concentration on variables that are mostly economic and measurable and a tendency to give insufficient attention to socio‐cultural and socio‐political variables. Now perspectives are changing and there is an awareness of the need to use more accurate and complete data on social and cultural phenomena. There is as a result a need to appreciate the contribution that geographers and cartographers can make. This article reviews the small scale socio‐cultural mapping of third world countries. It considers the available range of such maps and carto‐bibliographical guides, and proceeds to consider how socio‐cultural mapping could be extended in a way that would be useful for development planners and administrators.