bluuebunny/crossref_metadata_2025_split huggingface dataset:
International stock market indices comovements: a new look
Authors: Madaleno Mara , Pinho Carlos 
Published: April 2011

ABSTRACTThis study accounts for the time‐varying pattern of price shock transmission, exploring stock market linkages using continuous time wavelet methodology. In order to sustain and improve previous results regarding correlation analysis between stock market indices, namely FTSE100, DJIA30, Nikkei225 and Bovespa, we extend here such analysis using the Coherence Morlet Wavelet, considering financial crisis episodes.Results indicate that the relation among indices was strong but not homogeneous across scales, that local phenomenon's are more felt than others in these markets and that there seems to be no quick transmission through markets around the world, but yes a significant time delay. The relation among these indices has changed and evolved through time, mostly due to financial crisis that occurred at different time periods. Results also favor the view that geographically and economically closer markets exhibit higher correlation and more short run comovements among them. Strong comovement is mostly confined to long‐run fluctuations favoring contagion analysis. Copyright © 2011 John Wiley & Sons, Ltd.
Toward the development of an artificial cornea: Improved stability of interpenetrating polymer networks
Authors: Hartmann Laura , Watanabe Kenji , Zheng Luo Luo , Kim Chang‐Yeon , Beck Stayce E. , Huie Philip , Noolandi Jaan , Cochran Jennifer R. , Ta Christopher N. , Frank Curtis W. 
Published: April 2011

AbstractA novel interpenetrating network (IPN) based on poly(ethylene glycol) (PEG) and poly(acrylic acid) was developed and its use as an artificial cornea was evaluated in vivo. The in vivo results of a first set of corneal inlays based on PEG‐diacrylate precursor showed inflammation of the treated eyes and haze in the corneas. The insufficient biocompatibility could be correlated to poor long‐term stability of the implant caused by hydrolytic degradation over time. Adapting the hydrogel chemistry by replacing hydrolysable acrylate functionalities with stable acrylamide functionalities was shown to increase the long‐term stability of the resulting IPNs under hydrolytic conditions. This new set of hydrogel implants now shows increased biocompatibility in vivo. Rabbits with corneal inlay implants are healthy and have clear cornea and non‐inflamed eyes for up to 6 months after implantation. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
P2Y11 impairs cell proliferation by induction of cell cycle arrest and sensitizes endothelial cells to cisplatin‐induced cell death
Authors: Xiao Zhilin , Yang Mei , Lv Qingshan , Wang Wenmeng , Deng Minjie , Liu Xueting , He Qing , Chen Xiaobin , Chen Meifang , Fang Li , Xie Xiumei , Hu Jinyue 
Published: April 2011

AbstractExtracellular ATP mediates a wide range of physiological effects, including cell proliferation, differentiation, maturation, and migration. However, the effect of ATP on cell proliferation has been contradictory, and the mechanism is not fully understood. In the current study, we found that extracellular ATP significantly inhibited the proliferation of human umbilical vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs). Treatment with ATP did not induce cell apoptosis but instead induced cell cycle arrest in S phase. ATP induced the phosphorylation of ERK1/2, but the ERK inhibitors, U0126 and PD9809, did not regulate the inhibition of cell proliferation induced by ATP. However, ATP‐induced inhibition of cell proliferation was blocked by suramin, a nonspecific antagonist of the P2Y receptors, and endothelial cells expressed P2Y11, a P2Y receptor that specifically binds ATP. Moreover, the down‐regulation of P2Y11 by RNA interference not only reversed the inhibition of cell proliferation but also ameliorated cell cycle arrest in S phase. In addition, P2Y11 sensitized endothelial cells to cisplatin‐induced cell death by down‐regulation of the expression of Bcl‐2. Taken together, these results suggest that extracellular ATP impairs cell proliferation by triggering signaling to induce cell cycle arrest and sensitizes cell to death via P2Y11 in endothelial cells. J. Cell. Biochem. 112: 2257–2265, 2011. © 2011 Wiley‐Liss, Inc.
Isolation and characterization of squamous carcinoma cells resistant to photodynamic therapy
Authors: Milla Laura N. , Cogno Ingrid S. , Rodríguez Matías E. , Sanz‐Rodríguez Francisco , Zamarrón Alicia , Gilaberte Yolanda , Carrasco Elisa , Rivarola Viviana A. , Juarranz Ángeles 
Published: April 2011

AbstractPhotodynamic therapy (PDT) employing methyl δ‐aminolevulinic acid (Me‐ALA), as a precursor of the photosensitizer protoporphyrin IX (PpIX), is used for the treatment of non melanoma cutaneous cancer (NMCC). However, one of the problems of PDT is the apparition of resistant cell populations. The aim of this study was to isolate and characterize squamous carcinoma cells SCC‐13 resistant to PDT with Me‐ALA. The SCC‐13 parental population was submitted to successive cycles of Me‐ALA‐PDT and 10 resistant populations were finally obtained. In parental and resistant cells there were analyzed the cell morphology (toluidine blue), the intracellular PpIX content (flow cytometry) and its localization (fluorescence microscopy), the capacity of closing wounds (scratch wound assay), the expression of cell‐cell adhesion proteins (E‐cadherin and β‐catenin), cell‐substrate adhesion proteins (β1‐integrin, vinculin and phospho‐FAK), cytoskeleton proteins (α‐tubulin and F‐actin) and the inhibitor of apoptosis protein survivin, in the activated form as phospho‐survivin (indirect immunofluorescence and Western blot). The results obtained indicate that resistant cells showed a more fibroblastic morphology, few differences in intracellular content of the photosensitizer, higher capacity of closing wounds, higher number of stress fibers, more expression of cell‐substrate adhesion proteins and higher expression of phospho‐survivin than parental cells. These distinctive features of the resistant cells can provide decisive information to enhance the efficacy of Me‐ALA applications in clinic dermatology. J. Cell. Biochem. 112: 2266–2278, 2011. © 2011 Wiley‐Liss, Inc.
The role of TWIST as a regulator in giant cell tumor of bone
Authors: Singh Shalini , Mak Isabella W.Y. , Cowan Robert W. , Turcotte Robert , Singh Gurmit , Ghert Michelle 
Published: April 2011

AbstractGiant cell tumor of bone (GCT) is an aggressive tumor consisting of multinucleated osteoclast‐like giant cells and proliferating osteoblast‐like stromal cells. Our group has reported that the stromal cells express high levels of the bone resorbing matrix metalloproteinase (MMP)‐13, and that this expression is regulated by the osteoblast transcription factor Runx2. The purpose of this study was to determine the upstream regulation of Runx2 in GCT cells. Using GCT stromal cells obtained from patient specimens, we demonstrated that TWIST, a master osteogenic regulator, was highly expressed in all GCT specimens. TWIST overexpression downregulated Runx2 expression whereas TWIST siRNA knockdown resulted in Runx2 and MMP‐13 upregulation. Interestingly, cells obtained from a GCT lung metastasis showed a reverse regulatory pattern between TWIST and Runx2. In mutational analysis, we revealed a point mutation (R154S) at the Helix2 domain of TWIST. This TWIST mutation may be an essential underlying factor in the development and pathophysiology of these tumors in that they lead to inappropriate TWIST downregulation of Runx2, arrested osteoblastic differentiation, and the maintenance of an immature and neoplastic phenotype. J. Cell. Biochem. 112: 2287–2295, 2011. © 2011 Wiley‐Liss, Inc.
In‐source fragmentation and accurate mass analysis of multiclass flavonoid conjugates by electrospray ionization time‐of‐flight mass spectrometry
Authors: Abrankó László , García‐Reyes Juan F. , Molina‐Díaz Antonio 
Published: April 2011

AbstractIn‐source collision‐induced dissociation (CID) fragmentation features of multiclass flavonoid glycoconjugates were examined using liquid chromatography electrospray time‐of‐flight mass spectrometry. Systematic experiments were performed to search for optimal conditions for in‐source fragmentation in both positive and negative ion modes. The objective of the study was to attain uniformly appropriate conditions for a wide range of analytes independently of the aglycone, the attached sugar part and the type of bond between the aglycone and the glycan moieties (O‐ or C‐glycosides). Studied substances included representatives of flavonols, flavones, flavanones and anthocyanins and, regarding their glycan parts, mono‐, di‐ and triglycosides with varying distribution of carbohydrate moieties (di‐O‐glycosides, O‐diglycosides, O,C‐diglycosides). The breakdown properties of the analytes along with the abundances of the characteristic diagnostic ions required for structural elucidation of complex flavonoid derivatives were evaluated. An optimized value was found for the instrument parameter (fragmentor voltage) affecting the in‐source CID fragmentation of the analytes [230 V (ESI+) and 330 V (ESI−)]. Thus, appropriate performance in terms of both highly sensitive full‐scan acquisition and fragmentation information was obtained for all the investigated flavonoids. In addition, singularities in the abundance of selected diagnostic ions (e.g. Y0, Y1 and Y*) due to variations in the interglycosidic linkage (rutinoside–neohesperidoside) in the glycan part were found and are also evaluated and discussed in detail. The combination of in‐source CID fragmentation with high mass accuracy MS detection establishes a working basis for the development of versatile and useful LC‐MS methods for wide‐scope screening, non‐targeted detection and tentative identification of flavonoid derivatives. Copyright © 2011 John Wiley & Sons, Ltd.
Torque teno virus in fecal samples of patients with gastroenteritis: Prevalence, genogroups distribution, and viral load
Authors: Pinho‐Nascimento Carlos Augusto , Leite José Paulo Gagliardi , Niel Christian , Diniz‐Mendes Leonardo 
Published: April 2011

AbstractTorque teno virus (TTV, genus Alphatorquevirus, family Anelloviridae) is a DNA virus, highly prevalent in populations from around the world. TTV isolates have been classified into five main phylogenetic groups (1–5) showing a large genetic distance between them. The presence of TTV has been detected in feces. However, whether all five TTV genogroups are excreted in feces and the frequency of these events are presently unknown. The presence of TTV DNA was assessed in feces from 135 Brazilian (0–90 years old) patients with gastroenteritis by using three PCR methods, including real‐time PCR. One hundred twenty one (91.1%) samples were positive with at least one method. Using a genogroup‐specific assay, it was shown that all genogroups were present. Thirty‐seven (27.4%), 27 (20.0%), 57 (42.2%), 29 (21.5%), and 33 (24.4%) fecal samples contained TTV isolates belonging to genogroups 1–5, respectively. Coinfections with two, three, four, and five TTV genogroups were found in 23 (17.0%), 15 (11.1%), 7 (5.2%), and 7 (5.2%) fecal samples, respectively. Thus, 52 (38.5%) samples contained more than one TTV genogroup. Viral loads ranged from 2.6 to 6.5 log genome equivalents per gram of feces. However, only moderate variations of viral load were noted depending on genogroup and number of coinfecting TTV genogroups. These results show a high prevalence and a diversity of TTV isolates in feces. J. Med. Virol. 83:1107–1111, 2011. © 2011 Wiley‐Liss, Inc.
Presence of occult HBV, but near absence of active HBV and HCV infections in people infected with HIV in rural South Africa
Authors: Barth Roos E. , Huijgen Quirine , Tempelman Hugo A. , Mudrikova Tania , Wensing Annemarie M.J. , Hoepelman Andy I.M. 
Published: April 2011

AbstractHuman immunodeficiency (HIV), hepatitis B (HBV), and hepatitis C (HCV) viruses are endemic in Sub‐Saharan Africa, but data regarding the prevalence of hepatitis co‐infections in HIV‐positive individuals residing there are limited. The aim of the study was to determine the prevalence of HBV, HCV, and occult HBV (presence of HBV‐DNA in the absence of HBsAg) in a rural, South African cohort. The results were compared to various ethnic groups in a Dutch cohort of people infected with HIV. Antiretroviral‐naïve individuals with HIV from both a rural South African clinic (n = 258), and a Dutch University hospital (n = 782), were included. Both serological (HBV and HCV) and molecular (occult HBV) assays were performed. Logistic regression analysis was used to define independent predictors of a hepatitis co‐infection. HBV and HCV prevalence rates in the South African cohort were exceptionally low (0.4%, 1/242 and 0.8%, 2/242, respectively), compared to those observed in Caucasians (HBV 4.4% and HCV 10.9%) and African immigrants (HBV 8.9% and HCV 4.8%). Conversely, occult HBV was observed in a considerable proportion (10%, 6/60) of South African patients who were anti‐HBc‐positive but HBsAg‐negative. Occult infections were less frequent in Caucasians and Africans in the Dutch cohort (3.2% and 1.4%, respectively). Independent predictors for occult HBV were not identified, but a trend towards more occult HBV at lower CD4 counts was observed. Local HBV/HCV prevalence data are needed to optimize vaccination and antiretroviral treatment strategies. Occult HBV in patients with HIV may be missed regularly when molecular analyses are not available. J. Med. Virol. 83:929–934, 2011. © 2011 Wiley‐Liss, Inc.
High prevalence of significant liver fibrosis and cirrhosis in chronic hepatitis B patients with normal ALT in central Europe
Authors: Göbel Thomas , Erhardt Andreas , Herwig Mathias , Poremba Christopher , Baldus Stephan Ernst , Sagir Abdurrahman , Heinzel‐Pleines Ulrike , Häussinger Dieter 
Published: April 2011

AbstractThe indication for antiviral treatment of patients with chronic hepatitis B is based on serum HBV DNA levels, transaminases, and histological grade and stage. The relation of liver fibrosis and inflammation to ALT activity in chronic hepatitis B infection was investigated in a non‐endemic, European setting. A total of 253 patients with chronic hepatitis B who had undergone liver biopsy at the Clinic of Gastroenterology, Hepatology, and Infectious Diseases, Düsseldorf, Germany over the past 19 years (1990–2009) were evaluated. Thirty‐nine patients had persistently normal transaminases, 86 patients had ALT with 1–2 × ULN (upper limit of normal) and 128 patients had ALT >2 × ULN. Liver fibrosis or inflammation was defined as significant for stages or grades ≥ 2 according to the Desmet/Scheuer score. Significant liver fibrosis (F ≥ 2) was found in 36%, cirrhosis in 18%, and significant inflammation (G ≥ 2) in 27% of patients with normal transaminases. There was no difference in the stage of liver fibrosis and the frequency of cirrhosis between patients with normal and elevated transaminases. The most important factor associated with the presence of cirrhosis in multivariate analysis was age ≥40 years (P < 0.003). If concomitant factors like elevated GGT or male sex were furthermore present high prevalences of significant liver disease were found. The data indicate that, in a European setting, patients with chronic hepatitis B infection, and normal transaminases frequently have significant liver fibrosis or cirrhosis. Therefore, liver biopsy or liver stiffness measurement (LSM) should be performed in these patients to determine the stage of liver fibrosis. J. Med. Virol. 83:968–973, 2011. © 2011 Wiley‐Liss, Inc.
Comparative evaluation of different DNA extraction methods for HPV genotyping by linear array and INNO‐LiPA
Authors: Donà Maria Gabriella , Benevolo Maria , Pimpinelli Fulvia , Battista Mara , Rollo Francesca , Stivali Francesca , Moscarelli Antonella , Giuliani Massimo , Di Carlo Aldo , Vocaturo Amina 
Published: April 2011

AbstractIn order to investigate the influence of DNA extraction on two PCR‐based HPV genotyping tests (Linear Array, Roche and INNO‐LiPA Extra, Innogenetics), three different procedures were used to purify DNA from 28 cervico‐vaginal samples tested previously by the Hybrid Capture 2: the AmpliLute Liquid Media Extraction kit (Roche), the QIAamp DNA Blood mini kit (QIAGEN), and the NucliSENS EasyMAG automated platform (bioMérieux). All HC2‐positive samples were found positive by both assays, independently of the extract used. Type‐specific concordance (i.e., identical HPV type‐specific profile in all the extracts of the same sample) was observed in 55% and 75% of the cases testing samples by the Linear Array and the INNO‐LiPA, respectively. Using the DNA extracted with the two manual methods the results were concordant in 75% of the cases both for the Linear Array and the INNO‐LiPA. When comparing the Linear Array results obtained on either of the two manual extracts with those obtained following automated extraction, 65% of the samples showed type‐specific concordance in both cases. The INNO‐LiPA results were concordant in 80% of the cases comparing the AmpliLute versus the automated extract, while concordant results were observed in 90% of the cases when comparing the QIAGEN versus the automated extract. In conclusion, the Linear Array and INNO‐LiPA results are affected by the method of DNA extraction. Consequently, different HPV type‐specific profiles may be observed using different extracts of the same sample. The use of consistent protocols for DNA purification is a priority to guarantee intra‐assay reproducibility over time. J. Med. Virol. 83:1042–1047, 2011. © 2011 Wiley‐Liss, Inc.
Mass diffusion‐based separation of sugars in a microfluidic contactor with nanofiltration membranes
Authors: Kolfschoten Ruben C. , Janssen Anja E. M. , Boom Remko M. 
Published: April 2011

AbstractProcesses such as chromatographic separation and nanofiltration can remove low molecular weight sugars from liquid mixtures of oligosaccharides. As an alternative for the separation of such liquid mixtures, we studied mass diffusion separation of such sugars in a microfluidic device with incorporated nanofiltration membranes. This separation method is based on differences between diffusivities of components and does not require high transmembrane pressures. The effects of channel depth and flow rate were studied in experiments. The key parameters selectivity and rejection increased with increasing channel depth due to increased external mass transfer limitations. Among the studied membranes, the obtained selectivities and rejections correlated to the specified retention values by the manufacturers. Compared to more conventional nanofiltration where high pressure forces solutes through membranes, we obtained corresponding selectivities and fluxes of only an order of magnitude smaller. Simulated results indicated that with optimized microchannel and membrane dimensions, the presented separation process can compete with currently available separation technologies.
Selective recognition of 4‐nitrophenol from aqueous solution by molecularly imprinted polymers with functionalized tetratitanate whisker composites as support
Authors: Guan Wei , Pan Jianming , Wang Xue , Hu Wei , Xu Longcheng , Zou Xiaohua , Li Chunxiang 
Published: April 2011

AbstractThree kinds of molecularly imprinted polymers (MIPs) were obtained with surface molecular imprinting technique on functionalized potassium tetratitanate whisker (F‐PTW). The results of adsorption experiments indicated that MIP prepared using PTW modified with N‐(2‐aminoethyl)‐3‐(trimethoxysilyl)propylamine (AAPTS) (F‐PTW A) as support [MIP(1)] was superior to the other two polymers, then MIP(1) was selected to analyze the 4‐nitrophenol (4‐NP) adsorption process from aqueous solution in this study. AAPTS offered hydrophilic exterior that allowed to self‐assemble with the template 4‐NP through intermolecular interaction rather than based on the interactions between the functional monomers and template. Equilibrium adsorption data were analyzed by the Langmuir and Freundlich isotherm models at various temperatures. Kinetic properties were successfully investigated by pseudo‐first‐order model, pseudo‐second‐order model, intraparticle diffusion equation, initial adsorption rate, half‐adsorption time. A diffusion‐controlled process as the essential adsorption rate‐controlling step was also proposed. The performance of such imprinted polymer was further demonstrated by high‐performance liquid chromatography, and the results showed that the selectivity of MIP(1) exhibited higher affinity for template 4‐NP over competitive phenolic compounds than that of non‐imprinted polymer NIP(1). MIP(1) could be reused four times without significant loss in the adsorption capacity.
CHARACTERIZING VARIATIONS IN SOIL PARTICLE‐SIZE DISTRIBUTION ALONG A GRASS–DESERT SHRUB TRANSITION IN THE ORDOS PLATEAU OF INNER MONGOLIA, CHINA
Authors: Jin Z. , Dong Y. S. , Qi Y. C. , Liu W. G. , An Z. S. 
Published: April 2011

ABSTRACTThe application of fractal geometry to describe soil degradation and dynamics is becoming a useful tool for better understanding of the performance of soil systems. In this study, four different land cover types, which represent a sequence of grass–desert shrub transition and a gradient of desertification, were selected, and soils at depths of 0–10, 10–20 and 20–40 cm were sampled in the Ordos Plateau of Inner Mongolia, PR China. The fractal theory was used to analyse the soil particle‐size distribution (PSD) and its variations. The results showed that (i) vegetation conversion and desertification significantly changed the soil PSD. During the desertification process, soil coarse fractions that ranged from 250 to 100 µm significantly increased, whereas fine fractions lower than 50 µm significantly decreased (p < 0·01); (ii) fractal model of the accumulative volume particle‐size distribution is appropriate, and fractal dimensions (Dm) of soil PSD significantly decreased along the sequence of grass–desert shrub transition; (iii) Dm is more sensitive to the desertification process, and therefore, we suggest Dm other than soil texture and soil organic carbon as a reliable parameter to reflect the soil environment change induced by desertification. Copyright © 2011 John Wiley & Sons, Ltd.
Evaluation of pH‐Sensitive Poly(β‐amino ester)‐graft‐poly(ethylene glycol) and its Usefulness as a pH‐Sensor and Protein Carrier
Authors: Kim Min Sang , Gao Guang Hui , Kang Seong Woo , Lee Doo Sung 
Published: April 2011

AbstractIn this study, some possible biomedical applications of a pH‐sensitive and amphiphilic copolymer as a pH sensor and protein delivery system are reported. PAE‐g‐PEG was used as a pH‐sensitive polymer that can exhibit a sharp pH‐dependent transition. Various fluorescent dyes including pyrene and RITC can be used to label the pH‐sensitive polymer PAE‐g‐PEG, which was evaluated for protein encapsulation. pH‐sensing was possible by observing excimer formation of the labeled pyrene via pH‐dependent expansion of the polymeric chain. Also, it was confirmed that FITC‐BSA could be entrapped in RITC‐labeled pH‐sensitive micelles of PAE‐g‐PEG by FRET. As a result, PAE‐g‐PEG can be a pH sensor and carrier for protein delivery. magnified image
Microphase Separation of Phenylene Oligomers with Polymeric Side Chains: A Dissipative Particle Dynamics Study
Authors: Yıldırım Erol , Yurtsever Mine , Kenarlı Burcu , Demirel A. Levent 
Published: April 2011

AbstractThe microphase‐separated morphologies of p‐phenylene oligomers with POx, PCL, PS, and PEO side chains are studied using DPD simulations. It is shown that the microphase‐separated morphologies depend significantly on the degree of chemical incompatibility between the components as indicated by the Flory‐Huggins interaction parameters. The good agreement of the microphase separated morphologies as simulated by DPD with the experimentally determined thin film morphologies suggests that DPD can produce convincing morphological information at the nanoscale. The results show that grafting of polymeric side chains can be an important tool to control the morphology of polymers with a rigid backbone. magnified image