bluuebunny/crossref_metadata_2025_split huggingface dataset:
Twinkling fractal theory of the glass transition: Rate dependence and time–temperature superposition
Authors: Wool Richard P. , Campanella Alejandrina 
Published: November 2009

AbstractThe twinkling fractal theory (TFT) of the glass transition temperature Tg provides a new method of analyzing rate effects and time–temperature superposition in amorphous materials. The rate dependence of Tg was examined in the light of new experimental and theoretical evidence for the nature of the dynamic heterogeneity near Tg. As Tg is approached from above, dynamic solid fractal clusters begin to form and eventually percolate rigidity at Tg. The percolation cluster is a solid fractal and to the observer, appears to “twinkle” as solid and liquid clusters interchange in dynamic equilibrium with a vibrational density of states g(ω) ∼ ω. The solid‐to‐liquid twinkling frequencies ωTF are controlled by the Boltzmann population of intermolecular oscillators in excited energy levels of their anharmonic potential energy functions U(x) such that ωTF = ω exp −B(T*2 − T2)/kT in which T* ≈ 1.2Tg. An oscillator changes from a solid to a liquid when a thermal fluctuation causes it to expand beyond its inflection point in the anharmonic potential. This leads to a continuous solid fraction Ps near Tg given by PS ≈ 1−[(1 − pc) T/Tg] where pc ≈ 1/2 is the rigidity percolation threshold. Since g(ω) is continuous from very low to very high frequencies, the complex twinkling dynamics existing near Tg produces a continuous relaxation spectrum with many different length scales and times associated with the fractal clusters. The twinkling frequencies control the kinetics of Tg such that for a given observation time t when the rate γ > 1/t, only those parts of the twinkling spectrum with ω > γ can contribute to relaxation or percolation upto time t. The most important results in this article are as follows: The TFT describes the rate dependence of Tg, both for DSC thermal heating/cooling rates and DMA frequencies as the classic Tg − lnγ law as Tg(γ) = Tgo + (k/2B) ln γ/γo in which the constant B = 0.3 cal/mol K2. The constant B appears quite universal for the 17 thermoset polymers investigated in this study and 18 linear polymers investigated by others. Many other amorphous metal and ceramic glass materials exhibited the same rate law but required a new B value approximately half that for polymers. The same B = 0.3 value was also used to successfully describe the TTS shift factors using the twinkling fractal frequencies ωTF = ωexp −B(T*2 − T2)/kT, as ln aT(TFT) = exp B(TR2 − T2)/kT, which gave comparable results with the classical WLF equation, log aT = [−C1(T − TR)]/[C2 + (T − TR)]. The advantage of the TFT over the WLF is that C1 and C2 are not universal constants and must be determined for every material, whereas the TFT uses one known constant B which appears to be the same for all polymers. The TFT has also been found to describe the strong and fragile nature of the viscosity behavior of liquids and the rate and temperature dependence of the yield stress in polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2578–2590, 2009
Structural Investigations of Composites Produced from Copper and Polypyrrole with a Dual PVD/PE‐CVD Process
Authors: Walter Christian , Brüser Volker , Quade Antje , Weltmann Klaus‐Dieter 
Published: November 2009

AbstractCopper–polypyrrole composites were successfully produced with a dual plasma process. X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT‐IR) were used to characterise the structural properties. Topological and electrochemical investigations were also performed using atomic force and scanning electron microscopy (AFM, SEM) as well as cyclic voltammetry (CV) respectively. The results show that different composites were produced. When a low power was used, copper atoms bound to aromatic polymer structures were formed. Indications for the formation of electroactive copper–polypyrrole complexes are presented. Using higher power values, copper(I)oxide (ca. 3 nm) and copper nanoparticles (5–40 nm) embedded in a polymeric matrix were produced. Pulsing of the magnetron resulted in a modification of the chemical bonds within the samples.magnified image
Intrinsic subtype‐associated changes in the plasma proteome in breast cancer
Authors: Nakshatri Harikrishna , Qi Guihong , You Jinsam , Kerry Bemis , Schneider Bryan , Zon Robin , Buck Charles , Regnier Fred , Wang Mu 
Published: November 2009

AbstractBreast cancers are classified into five intrinsic subtypes: Luminal subtype A, Luminal subtype B, HER2+, Basal, and Normal‐like. In this study, we compared the plasma proteome of patients with Luminal A, Luminal B, HER2+, and Basal subtype with plasma from healthy individuals. Protein changes were considered significant if q‐value (false discovery rate) was less than 5%. The highest number of changes in the plasma proteome was observed in patients with Luminal type B followed by Basal type breast cancers. The plasma proteome of Luminal A and HER2+ breast cancer patients did not differ significantly from healthy individuals. In Basal breast cancer, a significant number of plasma proteins were downregulated compared with healthy individuals. Acute phase‐response proteins α‐glycoprotein orosomucoid 1 and serum amyloid protein P were specifically upregulated in the plasma of Luminal B breast cancer patients, suggesting prevalence of low‐grade inflammation. Proteins involved in immune response and free radical scavenging were downregulated in the plasma of Luminal B patients, which is in agreement with defective immune system observed in cancer patients. These results reveal intrinsic subtype specific changes in the plasma proteome that may influence tumor progression as well as the systemic effects of cancer.
A glimpse into the clinical proteome of human malaria parasites Plasmodium falciparum and Plasmodium vivax
Authors: Acharya Pragyan , Pallavi Rani , Chandran Syama , Chakravarti Harshini , Middha Sheetal , Acharya Jyoti , Kochar Sanjay , Kochar Dhanpat , Subudhi Amit , Boopathi Arun P. , Garg Shilpi , Das Ashis , Tatu Utpal 
Published: November 2009

AbstractMalaria causes a worldwide annual mortality of about a million people. Rapidly evolving drug‐resistant species of the parasite have created a pressing need for the identification of new drug targets and vaccine candidates. By developing fractionation protocols to enrich parasites from low‐parasitemia patient samples, we have carried out the first ever proteomics analysis of clinical isolates of early stages of Plasmodium falciparum (Pf) and P. vivax. Patient‐derived malarial parasites were directly processed and analyzed using shotgun proteomics approach using high‐sensitivity MS for protein identification. Our study revealed about 100 parasite‐coded gene products that included many known drug targets such as Pf hypoxanthine guanine phosphoribosyl transferase, Pf L‐lactate dehydrogenase, and Plasmepsins. In addition, our study reports the expression of several parasite proteins in clinical ring stages that have never been reported in the ring stages of the laboratory‐cultivated parasite strain. This proof‐of‐principle study represents a noteworthy step forward in our understanding of pathways elaborated by the parasite within the malaria patient and will pave the way towards identification of new drug and vaccine targets that can aid malaria therapy.
Heterogeneous expressions of hepcidin isoforms in hepatoma‐derived cells detected using simultaneous LC‐MS/MS
Authors: Hosoki Takaaki , Ikuta Katsuya , Shimonaka Yasushi , Sasaki Yusuke , Yasuno Hideyuki , Sato Kazuya , Ohtake Takaaki , Sasaki Katsunori , Torimoto Yoshihiro , Saito Keiji , Kohgo Yutaka 
Published: November 2009

AbstractHepcidin, a key regulator of iron homeostasis, is known to have three isoforms: hepcidin‐20, ‐22, and ‐25. Hepcidin‐25 is thought to be the major isoform and the only one known to be involved in iron metabolism; the physiological roles of other isoforms are poorly understood. Because of its involvement in the pathophysiology of hereditary hemochromatosis and the anemia of chronic disease, the regulatory mechanisms of hepcidin expression have been extensively investigated, but most studies have been performed only at the transcriptional level. Difficulty in detecting hepcidin has impeded in vitro research. In the present study, we developed a novel method for simultaneous quantification of hepcidin‐20, ‐22, and ‐25 in the media from hepatoma‐derived cell lines. Using this method, we determined the expression patterns of hepcidin isoforms and the patterns of responses to various stimuli in human hepatoma‐derived cultured cells. We found substantial differences among cell lines. In conclusion, a novel method for simultaneous quantification of hepcidin isoforms is presented. Heterogeneous expressions of hepcidin isoforms in human hepatoma‐derived cells were revealed by this method. We believe our method will facilitate quantitative investigation of the role hepcidin plays in iron homeostasis.
Establishment and characterization of an androgen receptor‐dependent, androgen‐independent human prostate cancer cell line, LNCaP‐CS10
Authors: Ishikura Nobuyuki , Kawata Hiromitsu , Nishimoto Ayako , Nakamura Ryo , Ishii Nobuya , Aoki Yuko 
Published: November 2009

AbstractBACKGROUNDHormone refractoriness is a lethal event for advanced prostate cancer patients, but the mechanisms of the disease are not well elucidated, especially for the so‐called “outlaw” pathways of androgen receptor (AR)‐dependent, androgen‐independent hormone‐refractory prostate cancer.METHODSAndrogen‐dependent prostate cancer LNCaP cells were treated with bicalutamide under an androgen‐depleted condition to obtain refractory cells. In the obtained cell line, LNCaP‐CS10, we analyzed the effects of androgen and bicalutamide on cell growth and prostate‐specific antigen (PSA) production. In addition, AR gene mutation, AR expression levels, and AR subcellular localizations were analyzed.RESULTSIn LNCaP‐CS10, cell growth and PSA production were found under an androgen‐depleted condition and were induced by both R1881 and bicalutamide. Knocking down AR by siRNAs did suppress the growth and PSA production of LNCaP‐CS10 cells in the androgen‐depleted condition. In comparison to LNCaP, amplification or additional new mutations were not found in the AR genes, but AR nuclear translocation induced by bicalutamide was identified in the LNCaP‐CS10 cells. The growth and PSA production of xenografted LNCaP‐CS10 tumors, which secrete PSA not only in non‐castrated SCID mice but also in castrated SCID mice, were not inhibited by bicalutamide.CONCLUSIONSWe have generated a bicalutamide‐resistant and androgen‐independent prostate cancer cell line, LNCaP‐CS10, with outlaw activation both in vitro and in vivo. The LNCaP‐CS10 cell line is beneficial for elucidating outlaw pathway mechanisms and evaluating the efficacy of new therapeutics for hormone‐refractory prostate cancer. Prostate 70: 457–466, 2010. © 2009 Wiley‐Liss, Inc.
A functional polymorphism in Pre‐miR‐146a gene is associated with prostate cancer risk and mature miR‐146a expression in vivo
Authors: Xu Bin , Feng Ning‐Han , Li Peng‐Chao , Tao Jun , Wu Deyao , Zhang Zheng‐Dong , Tong Na , Wang Jin‐Feng , Song Ning‐Hong , Zhang Wei , Hua Li‐Xin , Wu Hong‐Fei 
Published: November 2009

AbstractBACKGROUNDA G > C polymorphism (rs2910164) which is located in the sequence of miR‐146a precursor, results in a change from a G:U pair to a C:U mismatch in its stem region. To explore whether rs2910164 plays any role in prostate cancer (CaP), we analyzed the association between miR‐146a polymorphism and risk of CaP and the expression of miR‐146a with different genotypes in CaP tissues in southern Chinese Han population.MATERIALS AND METHODSTwo hundred fifty‐one CaP and 280 control subjects were included in the cancer association study, and 15 CaP tissue samples were used to test the expression of the miRNA precursors by real‐time quantitative reverse transcription PCR.RESULTSWe found that subjects carrying CC homozygotes had a 0.65‐fold reduced risk (95% CI = 0.43–0.99) than those carrying GG/GC genotypes (P = 0.03), and the C allele displayed a lower prevalence of CaP compared with the G allele (OR = 0.73, 95% CI = 0.57–0.94, P = 0.01). Moreover, hsa‐miR‐146a quantification showed that homozygous carriers of the C‐variant had significantly decreased miRNA levels compared to the carriers of the GG/GC genotype.CONCLUSIONSThe natural genetic variation in pre‐miR‐146a affects the amount of mature miR‐146a, contributes to the genetic predisposition to CaP. Prostate 70: 467–472, 2010. © 2009 Wiley‐Liss, Inc.
Colostrum and bioactive, colostral peptides differentially modulate the innate immune response of intestinal epithelial cells
Authors: Jørgensen Ann Louise Worsøe , Juul‐Madsen Helle Risdahl , Stagsted Jan 
Published: November 2009

AbstractCharacterization and identification of peptides with bioactivity from food have received considerable interest recently since such bioactive components must be adequately documented if they are part of functional food claims. We have characterized peptides from colostrum or those generated by a simulated gastrointestinal digest (GI) and tested them for bioactivity using murine intestinal (mICc12) cells and compared with bioactivity of intact colostrum. The peptides were recovered in the permeate after dialysis. The presence of peptides in the permeate was confirmed by C18 RP‐HPLC, determination of free amino termini and MALDI MS. The bioactivity of the intact colostrum and colostral peptides in the permeate was tested using mICc12 cells stimulated in the absence or presence of different bacterial ligands that mediate cellular activation through stimulation of Toll‐like receptors (TLR). Whereas intact colostrum generally reduced TLR‐mediated signaling, the isolated peptides seemed to either stimulate or reduce the immune response depending on the bacterial ligand used for stimulation. Interestingly, the most potent bioactive peptides originated from nondigested colostrum, which had only been subject to endogenous protease activity. Identified peptides in the nondigested colostrum originated exclusively from the casein fraction of colostrum as shown by MALDI MS/MS identification. Thus, multiple components with different bioactivities towards the innate immune response appear in bovine colostrum. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Microwave‐assisted TFA cleavage of peptides from Merrifield resin
Authors: Kluczyk Alicja , Rudowska Magdalena , Stefanowicz Piotr , Szewczuk Zbigniew 
Published: November 2009

AbstractMicrowave‐assisted (MW) reactions are of special interest to the chemical community due to faster reaction times, cleaner reactions and higher product yields. The adaptation of MW to solid phase peptide synthesis resulted in spectacular syntheses of difficult peptides. In the case of Merrifield support, used frequently in synthesis of special peptides, the conditions used in product cleavage are not compatible with off‐resin monitoring of the reaction progress. The application of MW irradiation in product removal from Merrifield resin using trifluoroacetic acid (TFA) was investigated using model tetrapeptides and the effects were compared with standard trifluoromethanesulphonic acid (TFMSA) cleavage using elemental analysis as well as chromatographic (HPLC) and spectroscopic (IR) methods. The deprotection of benzyloxycarbonyl and benzyl groups in synthetic bioactive peptides was analyzed using LC‐MS and MS/MS experiments. In a 5 min microwave‐assisted TFA reaction at low temperature, the majority of product is released from the resin, making the analytical scale MW‐assisted procedure a method of choice in monitoring the reactions carried out on Merrifield resin due to the short reaction time and compatibility with HPLC and ESI‐MS conditions. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Student switchers and the regulation of residency: the interface of the individual and Australia's immigration regime
Authors: Robertson Shanthi 
Published: November 2009

AbstractSince 1998, policy changes to Australia's skilled migration program have favoured international students as potential skilled migrants. This has included legislation allowing holders of an Australian tertiary qualification to apply for permanent residency (PR) onshore within 6 months of completing their study. This process, dubbed ‘student switching’ (McLaughlan and Salt, 2002) has created a distinct migration process through which increasing numbers of international students use their study in Australia as a pathway to residency. In this paper, I will address how individuals experience the bureaucratic processes of application for PR, in that the granting or denying of visas involves the interface between government and individual. I will explore how individuals' interactions with the power of the state as gatekeeper impact on their experiences as transnational subjects, and their social positioning within the new society. Copyright © 2009 John Wiley & Sons, Ltd.
Ab‐initio investigation of thermoactivated directional transport of hydrogen molecules inside narrow carbon nanotubes
Authors: Fedorov A. S. , Sadreev A.F. 
Published: November 2009

AbstractUsing the pseudopotential DFT and the empirical potential methods we calculate the potential acting to the hydrogen molecules in narrow single‐wall carbon nanotubes (SWCNT) (6,0),(7,0) and (3,3). The potential forms a goffered potential surface and can be approximated as $V(z,r,\phi ) \approx V_0 \sin (2\pi z/a) + V(r)$. We show that in these SWCNTs transport of molecules is given mainly by thermoactivated hoppings between minima of the periodic potential along the tube axis. Taking into account that hydrogen density distribution inside nanotube is stationary and assuming the temperature is changed linearly along the SWCNT length we show that the H2 density is sufficiently variated, especially for the case of (6,0)SWCNT where the density on both SWCNT ends are different at ∼ 30 times when the temperature is changed along the SWCNTf rom 300K to 1200K. Suppose that H2 molecules can penetrate in the both open SWCNT ends, the molecules would move in the direction of the temperature decreasing. This effect may be used potentially to build up a molecular pump driven by the temperature gradient along narrow nanotube.
Junctions of left‐ and right‐handed chiral carbon nanotubes – nanobamboo
Authors: Koltai János , Rusznyák Ádám , Zólyomi Viktor , Kürti Jenő , László István 
Published: November 2009

AbstractSingle walled carbon nanotubes can be used as nanoscale reaction chambers for producing smaller nanotubes within the host tube from encapsulated fullerenes by annealing. The diameter of the host outer tube restricts the diameter of the inner tube due to van der Waals interactions, but not chirality; however, only a few chiralities are allowed for any given outer tube diameter. It is possible that inner tubes with different chiralities – or the same chirality but left‐ and right‐handedness– can start to grow in different places at the same time. A straight junction occurs at the connection of these two tubes. The geometry of different kinds of junctions containing pentagon and heptagon defects was optimized by density functional theory. The effect of the localized states on the electronic band structure was investigated. Geometry of our (6,4) nanobamboo from two points of view. The pentagon and heptagon defects are highlighted.
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Sensing mechanism of metal‐decorated single‐walled carbon nanotube field effect transistor sensors
Authors: Loh Young‐Seob , Lee Keum‐Ju , So Hye‐Mi , Chang Hyunju , Kim Ju‐Jin , Lee Jeong‐O 
Published: November 2009

AbstractWe investigate the sensing mechanism underlying metal‐decorated single‐walled carbon nanotube field effect transistor (SWNT‐FET) sensors. Upon lowering the temperature, two types of periodic oscillations appeared in the I–Vg characteristics of Ni‐decorated SWNT‐FETs, specifically, oscillations with a smaller period superimposed (beating) on larger oscillations. These oscillations may have originated from charging of the Ni nanoparticles. This behavior is consistent with a system of multiple quantum dots that are resistively coupled via the SWNT, in which charges generated through biomolecular interactions can be transferred from the metal nanoparticles to the SWNTs without delay.
magnified imageAFM image of a Ni‐decorated SWNT‐FET.
Raman investigation of strain effects in CdSe nanorods
Authors: Lange Holger , Artemyev Mikhail , Woggon Ulrike , Thomsen Christian 
Published: November 2009

AbstractWe use Raman spectroscopy to investigate strain in thin CdSe–ZnS core‐shell nanorods. Bare CdSe nanorods are compressed due to surface reconstruction mechanisms. The addition of an epitaxial ZnS shell around the nanorod leads to a compressive strain of the nanorod due to the lattice mismatch between ZnS and CdSe. The amount of strain in the CdSe lattice increases with an increasing shell size.Longitudinal optical phonon Raman bands of CdSe nanorods. The nanorod covered with a ZnS shell is strained and the related Raman band is shifted.
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Validation of pentaacetylaldononitrile derivative for dual 2H gas chromatography/mass spectrometry and 13C gas chromatography/combustion/isotope ratio mass spectrometry analysis of glucose
Authors: Sauvinet Valérie , Gabert Laure , Qin Du , Louche‐Pélissier Corinne , Laville Martine , Désage Michel 
Published: November 2009

AbstractA reference method to accurately define kinetics in response to the ingestion of glucose in terms of total, exogenous and endogenous glucose is to use stable‐isotope‐labelled compounds such as 2H and 13C glucose followed by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis. The use of the usual pentaacetyl (5Ac) derivative generates difficulties in obtaining accurate and reproducible results due to the two chromatographic peaks for the syn and anti isomers, and to the isotopic effect occurring during acetylation. Therefore, the pentaacetylaldononitrile derivative (Aldo) was validated for both isotopes, and compared with the 5Ac derivative. A correction factor including carbon atom dilution (stoichiometric equation) and the kinetic isotopic effect (KIE) was determined.Analytical validation results for the 2H GC/MS and 13C GC/C/IRMS measurements produced acceptable results with both derivatives. When 2H enrichments of plasma samples were ≤1 mol % excess (MPE), the repeatability (RSDAldo Intra assay and Intra day <0.94%, RSD5Ac Intra assay and Intra day <3.29%), accuracy (Aldo <3.4%, 5Ac <29.0%), and stability of the derivatized samples were significantly better when the Aldo derivatives of the plasma samples were used (p < 0.05).When the glucose kinetics were assessed in nine human subjects, after glucose ingestion, the plasma glucose 2H enrichments were identical with both derivatives, whereas the 13C enrichments needed a correction factor to fit together. Due to KIE variation, this correction factor was not constant and had to be calculated for each batch of analyses, to obtain satisfactory results. Mean quantities of exogenous glucose exhibit marked difference (20.9 ± 1.3g (5Ac) vs. 26.7 ± 2.5g (Aldo)) when calculated with stoichiometric correction, but fit perfectly when calculated after application of the correction factor (22.1 ± 1.3g (5Ac) vs. 22.9 ± 1.9g (Aldo)).Finally, the pentaacetylaldononitrile derivative, used here in GC/C/IRMS for the first time, enables measurement of 2H and 13C enrichments in plasma glucose with a single sample preparation. Copyright © 2009 John Wiley & Sons, Ltd.