bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Impedimetric Glucose Biosensor Based on Overoxidized Polypyrrole Thin Film
Authors: Zane D. , Appetecchi G. B. , Bianchini C. , Passerini S. , Curulli A. 
Published: March 2011

AbstractPolypyrrole (pPy) thin films were synthesized electrochemically by a pulse method on platinum electrodes in N‐butyl‐N‐methyl‐pyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid (PYR14TFSI). An important aspect of this procedure is the use of an ionic liquid, as synthetic medium. Further, it can be used for several procedures and it can then be renewed and recycled by a simple extraction just with warm water. It is therefore possible to remove it from all the residual oxidized pyrrolic compounds and purify the solvent in a very simplicistic way. After the synthesis pPy was overoxidized (opPy ) and the process was followed by EIS (Electrochemical Impedance Spectroscopy). opPy is attractive for the realization of sensors and biosensors because of its good selectivity towards hydrogen peroxide (H2O2) with respect to the most common interferents. In particular it can find an application in food process control. The EIS response to hydrogen peroxide and biological interferents indicated opPy as a highly sensitive electrochemical platform for impedimetric sensing. The glucose oxidase enzyme (GOD) was immobilized onto the polymer and the modified electrode was assembled and tested as an impedimetric biosensor. This technique seems very promising for application in food process control.
Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase Immobilized on Water Soluble Sulfonated Graphene Film via Self‐assembly
Authors: Zhang Qian , Qiao Yun , Zhang Ling , Wu Shuyao , Zhou Hua , Xu Jingwei , Song Xi‐Ming 
Published: March 2011

AbstractA novel water soluble sulfonated graphene (denoted as sulfonated‐G), was synthesized for the immobilization and biosensing of horseradish peroxidase (HRP). Compared with unmodified graphene, sulfonated‐G could not only well disperse in aqueous solution as individual nanosheet, but also exhibit apparent negative charge. Using a simple self‐assembly method, HRP was immobilized on sulfonated‐G at the surface of GC electrode to form HRP/sulfonated‐G/GC electrode under mild condition. The immobilized HRP showed enhanced direct electron transfer for the HRP‐Fe(III)/Fe(II) redox centre. Based on the direct electron transfer of the immobilized HRP, HRP/sulfonated‐G/GC electrode exhibited excellent catalytic performance for H2O2 and NaNO2 reduction. Accordingly, the proposed method not only simplifies the methodology of enzyme immobilization, but also provides an efficient platform for fabricating novel biosensors and bioelectronic devices.
Experimental and PM6/SPARKLE Semiempirical Study of Interaction between 4‐Methoxyphenylcyanamide and Gadolinium(III) as a Fast Polymeric Membrane Sensor
Authors: Rezaei Behzad , Askarpour Neda , Hadadzadeh Hassan 
Published: March 2011

AbstractIn this study, a highly sensitive PVC–membrane sensor based on 4‐methoxyphenylcyanamide (4‐MeOpcyd) as a neutral carrier was prepared and the specific interaction between Gd3+ ions and ionophore at the surface of selective polymeric membrane was calculated using the PM6/SPARKLE semiempirical method. The results of the Mopac2009 calculations show selective complexation of Gd3+ by 4‐MeOpcyd ligand that correlate quite well with experimental data. This membrane sensor has a linear response in the range of 1.0×10−6–1.0×10−2 M Gd3+ with detection limit of 6.2×10−7 M. This electrode was applied in potentiometric titration for determination of gadolinium and also for fluoride ions in the mouthwash samples with satisfactory results.
Development of a Sputtered Nanocarbon Film Based Microdisk Array Electrode for the Highly Stable Detection of Serotonin
Authors: Inokuchi Hiroaki , Kato Dai , Ueda Akio , Niwa Osamu 
Published: March 2011

AbstractWe report a nanocarbon film based microdisk array electrode with an extremely stable electrochemical response for measuring serotonin. The nanocarbon film was formed on a silicon substrate with an electron cyclotron resonance sputtering method, and the nanocarbon film based microdisk array electrode was fabricated using photolithography. The array electrode consists of 335 microdisks with a diameter of 10 µm. The center‐to‐center distance of each microdisk is 100 µm. The electrochemical properties of the nanocarbon film based microdisk array electrode are compared with those of a gold film based array electrode. Before microfabrication, both nanocarbon and gold film electrodes (both 2 mm in diameter) showed steady responses for the continuous voltammetric measurement of 1 µM of serotonin. Moreover, each microdisk array electrode exhibited a sigmoidal response. The obtained current densities were higher than those of conventional sized electrodes owing to the microelectrode effect. However, the current value at 0.45 V vs. Ag/AgCl at the gold film based microdisk array electrode decreased rapidly and fell to 30 % of its initial value after ten potential scans. In contrast, the nanocarbon film based microdisk array electrode decreased only 2 % under the same measurement condition. Despite the fact that there was more than 10 times the current density at the microelectrode, our nanocarbon film showed excellent performance in suppressing serotonin adsorption.
Trafficking and secretion of matrix metalloproteinase‐2 in olfactory ensheathing glial cells: A role in cell migration?
Authors: Gueye Yatma , Ferhat Lotfi , Sbai Oualid , Bianco John , Ould‐Yahoui Adlane , Bernard Anne , Charrat Eliane , Chauvin Jean‐Paul , Risso Jean‐Jacques , Féron François , Rivera Santiago , Khrestchatisky Michel 
Published: March 2011

AbstractOlfactory ensheathing cells (OECs) are unique glia found only in the olfactory system. They retain exceptional plasticity and support olfactory neurogenesis and retargeting across the PNS:CNS boundary in the olfactory system. OECs have been shown to improve functional outcome when transplanted into rodents with spinal cord injury. The growth‐promoting properties of implanted OECs encompass their ability to migrate through the scar tissue and render it more permissive for axonal outgrowth, but the underlying molecular mechanisms remain poorly understood. OECs appear to regulate molecules of the extracellular matrix (ECM) that inhibit axonal growth. Among the proteins that have the potential to promote cell migration, axonal regeneration and remodeling of the ECM are matrix metalloproteinases (MMPs), a family of endopeptidases that cleave matrix, soluble, and membrane‐bound proteins and that are regulated by their endogenous inhibitors, the tissue inhibitors of MMPs (TIMPs). Little is known about MMP/TIMP trafficking, secretion, and role in OECs. Using a combination of cell biology, biochemistry, pharmacology, and imaging techniques, we show that MMP‐2 and MMP‐9 are expressed and proteolytically active in the olfactory epithelium and in particular in the OECs of the lamina propria. These proteinases and regulatory proteins such as MT1‐MMP and TIMP‐2 are expressed in cultured OECs. MMPs exhibit nuclear localization and vesicular trafficking and secretion, with distribution along microtubules and microfilaments and co‐localization with the molecular motor protein kinesin. Finally, we show that MMPs are involved in migration of OECs in vitro on different ECM substrates. © 2011 Wiley‐Liss, Inc.
GDNF‐induced osteopontin from Müller glial cells promotes photoreceptor survival in the Pde6brd1 mouse model of retinal degeneration
Authors: Del Río Patricia , Irmler Martin , Arango‐González Blanca , Favor Jack , Bobe Caroline , Bartsch Udo , Vecino Elena , Beckers Johannes , Hauck Stefanie M. , Ueffing Marius 
Published: March 2011

AbstractGlial cell line‐derived neurotrophic factor (GDNF) enhances the survival of a variety of neurons, including photoreceptors (PR) in the retina. In contrast to most other GDNF receptive neurons, GDNF does, however, not exert its neuroprotective activity directly on PR neurons but transmits it indirectly by inducing expression of yet unknown neurotrophic factors in retinal Müller glial (RMG) cells. Genome‐wide differential transcriptome analyses of GDNF‐treated mouse retinas revealed 30 GDNF‐induced transcripts containing a total of six genes coding for secreted molecules. Among them was (OPN), a secreted glycoprotein which was expressed in mouse RMG and secreted from primary mouse RMG in culture. Furthermore, OPN secretion was significantly upregulated on GDNF treatment of primary RMG. To validate, whether OPN could qualify as a neuroprotective factor for PR, we evaluated its potential neurotrophic activity on isolated PR in vitro as well as on retinal explants from the retinal degeneration 1 (Pde6brd1) mouse mutant. OPN exerted a significant, positive survival effect on primary porcine PR cells in a concentration‐dependent manner and induced activation of PI3K/Akt pro‐survival pathway. Moreover, in retinal explant cultures from Pde6brd1 mice, OPN significantly reduced the percentage of apoptotic cells to levels comparable with that observed in explants from wild‐type mice and led to survival of significantly more PR in long‐term retinal explant cultures. Our findings suggest that RMG‐derived OPN is a novel candidate protein that transmits part of the GDNF‐induced neuroprotective activity of RMG to PR cells. © 2011 Wiley‐Liss, Inc.
Depression symptom ratings in geriatric patients with bipolar mania
Authors: Sajatovic Martha , Jurdi Rayan Al , Gildengers Ariel , Greenberg Rebecca L. , Tenhave Thomas , Bruce Martha L. , Mulsant Benoit , Young Robert C. 
Published: March 2011

AbstractObjectiveGiven the paucity of information available regarding standardized ratings of depression symptoms in bipolar manic states, and in particular those in older adults, we explored depression ratings in symptomatic participants in a multicenter study of treatment of bipolar I disorder in late life.MethodsBaseline data was obtained from the first 100 patients enrolled in an NIMH‐funded, 9‐week, randomized, double‐blind RCT comparing treatment with lithium or valproate in patients of age 60 years and older with Type I Bipolar mania or hypomania. This multi‐site study was conducted at six academic medical centers in the United States and enrolled inpatients and outpatients with a total Young Mania Rating Scale (YMRS) score of 18 or greater. Depressive symptoms were evaluated with the Hamilton Depression Rating Scale (HAM‐D) and the Montgomery‐Asberg Depression Rating Scale (MADRS). The criterion for at least moderate bipolar depressive symptoms was the European College of Neuropsychopharmacology (ECNP) Consensus Meeting definition of HAM‐D 17 total score >20.ResultsEleven percent of patients had mixed symptoms defined by depression scale severity according to ECNP criterion. In the overall sample, total scores on the two depression scales were highly correlated. Total YMRS scores of this mixed symptom group were similar to the remainder of the sample.ConclusionsThese preliminary findings suggest that moderate to severe depressive symptoms occur in about one in ten bipolar manic elders. Future studies are needed to further evaluate symptom profiles, clinical correlates, and treatments for bipolar older adults with combined manic and depressive symptoms. Copyright © 2011 John Wiley & Sons, Ltd.
Performance variation of an R22 window air conditioner retrofitted with a HFC/HC refrigerant mixture under different ambient conditions over a range of charge quantities
Authors: Herbert Raj M. , Mohan Lal D. 
Published: March 2011

AbstractR22 has been generally accepted as the most suitable refrigerant for air conditioners, due to its favorable thermodynamic properties. However, R22 is a controlled substance under the Montreal protocol. M20 is a HFC/HC refrigerant mixture that can be used as a substitute for R22. This paper presents experimental investigation on the performance comparison of a window air conditioner operated with the M20 tested under different refrigerant charge levels and outdoor conditions against that with R22. Experiments were conducted in accordance with BIS procedure in a psychrometric test facility. Refrigerant charge in the air conditioner was systematically varied from 900 to 1600 g in steps of 50 g for R22 and 697 to 1279 g in steps of 39 g [equivalent to 50 g of R22] for the M20. At each charge levels, the outdoor room conditions were changed in accordance with BIS standards. It is observed that R22 is more sensitive to deviations in charge levels as compared to the M20. A decrease in charge level of about 7% reduced the system refrigerating capacity by 11.3% with R22 while with the M20 refrigerant mixture it reduces by 6.9% only. Similarly an overcharge by 7% reduces the refrigerating capacity of the system by 13.8% with R22 while with M20 it reduces by 6.5% only. Thus M20 is less sensitive to charge deviations. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20339
Analytical and numerical investigation of fin efficiency and temperature distribution of conductive, convective, and radiative straight fins
Authors: Ganji D.D. , Rahimi M. , Rahgoshay M. , Jafari M. 
Published: March 2011

AbstractIn this study, fin efficiency, temperature distribution, and effectiveness of conductive, convective, and radiative straight fins with temperature dependent thermal conductivity are solved using the differential transformation method (DTM).The concept of differential transformation is briefly introduced, and then it is employed to derive the solutions of nonlinear governing equations of fins with highly nonlinear terms because of existing radiation in this study. The obtained results of DTM are compared with those of the Galerkin method (GM) and numerical boundary value problem method (BVP) to verify the accuracy of the proposed method. Furthermore, the effects of some physical appropriate parameters such as thermo‐geometric fin parameters and thermal parameters are analyzed. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20341
The effect of estrogen vs. combined estrogen‐progestogen therapy on the risk of colorectal cancer
Authors: Lin Kueiyu Joshua , Cheung Winson Y. , Lai Jennifer Yi‐Chun , Giovannucci Edward L. 
Published: March 2011

AbstractStudies suggest that estrogen therapy (ET) and combined estrogen‐progestogen therapy (EPT) may have different associations with colorectal cancer (CRC) risk, but data are conflicting. Prior meta‐analyses did not distinguish between ET and EPT. We conducted a meta‐analysis to summarize the relative risks (RR) of CRC due to ET versus EPT among peri‐ or postmenopausal women. From a total of 2,661 articles, four randomized controlled trials, eight cohort and eight case‐control studies were included. Variables assessed included study characteristics, duration and recency of menopausal hormone therapy (HT) use, method of assessment of HT use, outcome definition and its ascertainment method. RRs were synthesized by random‐effects models. We found that EPT ever use was associated with a decreased risk of CRC (RR 0.74, 95% CI 0.68‐0.81), and so was ET ever use (RR 0.79, 95% CI 0.69‐0.91). While current use of ET was associated with a significantly reduced risk of CRC (RR 0.70, 95% CI 0.57‐0.85), former use was not (RR 0.86, 95%CI 0.67‐1.11). Recency did not significantly modify the association between EPT and CRC risk. EPT former use was associated with a lower RR of CRC compared to ET former use (p = 0.008) but no such difference was observed between EPT and ET current use (p = 0.12). Overall, we found consistent evidence supporting the association between EPT and CRC risk reduction, regardless of recency. While literature for the association between ET and CRC risk is heterogeneous, our analyses suggest only current use of ET is associated with a decreased CRC risk.
The impact of amyloid precursor protein signalling and histone deacetylase inhibition on neprilysin expression in human prostate cells
Authors: Hong Yue , Beckett Caroline , Belyaev Nikolai D. , Turner Anthony J. 
Published: March 2011

AbstractThe zinc metallopeptidase, neprilysin (NEP), is an endothelin‐1 degrading enzyme whose expression is extensively downregulated in prostate cancer. The expression of NEP in neuronal cells is regulated by intramembrane proteolysis of the amyloid precursor protein (APP) through its intracellular domain (AICD) facilitating histone acetylation of the NEP promoter and gene transcription. The present study has examined whether similar mechanisms operate in prostate cell lines. The expression of APP and its processing enzymes (β‐ and γ‐secretases) was examined in a number of prostate cell lines, and the effect of γ‐secretase inhibition was explored on NEP expression and activity. The potential interaction of AICD with the NEP promoter was examined by chromatin immunoprecipitation. Our results indicated that all key components involved in APP processing were expressed in prostate cancer cell lines but suppression of AICD production using a γ‐secretase inhibitor did not decrease NEP expression and activity, and no direct AICD‐NEP promoter interaction could be detected. However, histone deacetylase inhibitors (valproate and trichostatin A) caused a 2‐ to 3‐fold increase in NEP expression in PC‐3 cells, and combinatorial treatment with the DNA demethylating agent, AzaC, further increased NEP expression levels. Although AICD is detectable in prostate cell lines, it does not appear to regulate NEP by AICD‐mediated signalling. Apart from promoter de‐methylation, the data suggest that histone acetylation may facilitate partial re‐activation of NEP expression in advanced prostate cancer cells. Upregulation of this tumour‐suppressing protein may provide a novel therapeutic strategy in prostate cancer.
The seed and soil hypothesis revisited—The role of tumor‐stroma interactions in metastasis to different organs
Authors: Langley Robert R. , Fidler Isaiah J. 
Published: March 2011

AbstractThe fact that certain tumors exhibit a predilection for metastasis to specific organs has been recognized for well over a century now. An extensive body of clinical data and experimental research has confirmed Stephen Paget's original “seed and soil” hypothesis that proposed the organ‐preference patterns of tumor metastasis are the product of favorable interactions between metastatic tumor cells (the “seed”) and their organ microenvironment (the “soil”). Indeed, many of the first‐line therapeutic regimens, currently in use for the treatment of human cancer are designed to target cancer cells (such as chemotherapy) and also to modulate the tumor microenvironment (such as antiangiogenic therapy). While some types of tumors are capable of forming metastases in virtually every organ in the body, the most frequent target organs of metastasis are bone, brain, liver and the lung. In this review, we discuss how tumor‐stromal interactions influence metastasis in each of these organs.
The ring current model of the pentaprismane molecule
Authors: Pelloni Stefano , Carion Raphaël , Liégeois Vincent , Lazzeretti Paolo 
Published: March 2011

AbstractThree‐dimensional models of the quantum‐mechanical current density
JB, induced in the electron cloud of the C10H10 pentaprismane molecule by a magnetic field B
applied along the C5 (a C2) symmetry axis, orthogonal to the pentagonal (a rectangular) face, and denoted by B‖ (B⟂), have been constructed. Predictions of near Hartree‐Fock quality are reported for the diagonal components of magnetic tensors, magnetizability (ξ), nuclear shielding of carbon (σC)
and hydrogen (σH), and virtual shielding at the center of mass (σCM). The complicated spatial features of the induced electronic current‐density field have been rationalized and compactly described via stagnation graphs that elucidate the details of its topological structure. A representation of JB
is obtained by three‐dimensional perspective plots and by planar maps visualizing phase portraits of electron flow in a series of molecular domains. Both streamline JB/|JB|
and modulus |JB|
are analyzed. These graphic tools illustrate the competition between diatropic and paratropic regimes which determine the magnitude of various components of magnetizability and magnetic shielding of hydrogen and carbon nuclei. Shielding density maps show that the differential Biot‐Savart law explains magnetic shielding at hydrogen and carbon nuclei, and virtual shielding at ring and cage centers. Similarities and/or contrasting ring current effects on magnetotropicity are discussed by a comparison with triprismane C6H6 and cubane C8H8. © 2011 Wiley Periodicals, Inc. J Comput Chem , 2011.
Can the transition from tunneling to hopping in molecular junctions be predicted by theoretical calculation?
Authors: Liu Hongmei , Zhao Zhenzhen , Wang Nan , Yu Cui , Zhao Jianwei 
Published: March 2011

AbstractThe electron transport mechanism changes from tunneling to hopping as molecular length increases. To validate the theoretical simulation after the transition point and clarify influence of electronic structures on the transition, we calculated the conductance of a series of conjugated molecules by density functional theory together with the nonequilibrium Green's function. We found that the highest occupied molecular orbital energy level, transmission spectrum, and the reorganization energy are good indicators for the transition of the electron transport mechanism. The calculated resistances of short junctions (<50 Å, before the transition point) are consistent with the experimental result, following the tunneling mechanism. However, the theoretical predication failed for long molecules, indicating the limitation of the theoretical framework of elastic scattering when the electron transport mechanism changes to hopping. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
New ab initio potential energy surfaces for both the ground (X̃1A′) and excited (Ã1A″) electronic states of HSiCl and the absorption and emission spectra of HSiCl/DSiCl
Authors: Lin Sen , Xie Daiqian 
Published: March 2011

AbstractNew ab initio potential energy surfaces for the ground (
$ \tilde X^1 A' $) and excited ($ \tilde A^1 A'' $) electronic states of HSiCl were obtained by using the single and double excitation coupled‐cluster theory with a noniterative perturbation treatment of triple excitations and the multi‐reference configuration interaction with Davidson correction, respectively, employing an augmented correlation‐consistent polarized valence quadruple zeta basis set. For the excited state $ \tilde A^1 A'' $, an extended active space (18 electrons in 12 orbitals) was used. The calculated vibrational energy levels of HSiCl and DSiCl of the ground and excited electronic states are in better agreement with the available experimental values than the previous theoretical results. In addition, with the calculated transition dipole moment, the absorption and emission spectra of HSiCl and DSiCl were calculated using an efficient single Lanczos propagation method and are in reasonable agreement with the available observed spectra. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011