bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrostatic Assemblies for Bioelectrocatalytic and Bioelectronic Applications
Authors: Domínguez Elena , Suárez Guillaume , Narváez Arántzazu 
Published: October 2006

AbstractThis work extensively covers the use of layer‐by‐layer (LbL) assembly of polyelectrolytes for the transduction of catalytic and affinity events. It is demonstrated that by controlling the charge of polyelectrolytes, electrostatic interactions drive then the LbL construction of supramolecular architectures with improved performance. Particularly, by adequately charging an osmium based redox polymer, a multicofactor protein (fructose dehydrogenase) may be deposited in a favored orientation resulting in a more efficient electrochemical communication. A H2O2 transducing interface is created by the enhancement of electrostatic interactions between the electrochemical and catalytic layer. Further assemblies include the coupling of an oxidase (alcohol oxidase) with the H2O2 transducing interface resulting in a linear increase of current with the number of AOX layers. Finally, affinity assemblies are demonstrated by deposition of anti Dexamethasone antibodies. Faraday currents are then obtained by the electrochemical communication between the HRP labeled immunoconjugate and the electrochemical interface in a heterogeneous competitive assay format.
Suppression of cell proliferation, induction of apoptosis and cell cycle arrest: Chemopreventive activity of vanadium in vivo and in vitro
Authors: Ray Rajarshi Sankar , Ghosh Balaram , Rana Ajay , Chatterjee Malay 
Published: October 2006

AbstractIn the present study, the authors evaluated the anticancer mechanism of vanadium, a dietary micronutrient and an important pharmacological agent, on a defined model of chemically induced rat mammary carcinogenesis in vivo and on human breast cancer cell line MCF7 in vitro. Female Sprague‐Dawley rats were treated with 7,12‐dimethylbenz(α)anthracene (0.5 mg/100 g body weight) by a single tail vein injection in an oil emulsion to induce mammary preneoplasia. Vanadium (ammonium monovanadate) at a concentration of 0.5 ppm (4.27 μmol/l) was supplemented in drinking water and given ad libitum to the experimental groups for 24 weeks. Histological finding showed substantial repair of hyperplastic lesions. There was a significant reduction in incidence, multiplicity (34%, p < 0.01), size of palpable mammary tumors and delay in mean latency period of tumor appearance. Immunohistochemical analysis in vivo indicated a decrease in cell proliferation (24.68% p < 0.05) and an increase among the TUNEL‐positive apoptotic cells along with strong expressions of p53 and Bax, and downregulation of Bcl2 proteins in the mammary tissue of vanadium‐treated animals. Further, MCF7 cells were cultured in minimal essential medium and were treated with 100, 175 and 250 μM of vanadium (ammonium monovanadate) for 36 hr. Exposure of MCF7 cells to vanadium led to induction of apoptosis in a dose‐dependent manner. It was found further that vanadium treatment brought about a prominent cell cycle arrest and chromosomal condensation, leading to apoptosis (42.62%, p < 0.05). Results of both the in vivo and in vitro study demonstrate that vanadium has the potential to be developed into an anti‐breast cancer drug in the near future. © 2006 Wiley‐Liss, Inc.
Polydimethylsiloxane as a substrate for retinal pigment epithelial cell growth
Authors: Krishna Yamini , Sheridan Carl M. , Kent David L. , Grierson Ian , Williams Rachel L. 
Published: October 2006

AbstractRetinal pigment epithelial (RPE) cell transplantation represents potential treatment for age‐related macular degeneration (AMD). Because delivery of isolated cells can cause serious complications, it is necessary to develop a suitable transplant membrane that could support an intact functioning RPE monolayer. Polydimethylsiloxane (PDMS) possesses the physical properties required for a transplanting device and is widely used clinically. We have investigated the use of PDMS as a potential surface for the growth of healthy RPE monolayers. PDMS discs were surface modified by air and ammonia gas plasma treatments. Dynamic contact angles were measured to determine the changes in wettability. Human ARPE‐19 cells were seeded onto untreated and treated samples. Cell number, morphology and monolayer formation, cytotoxicity, and phagocytosis of photoreceptor outer segments (POS) were assessed at set time‐points. Air plasma treatment increased the wettability of PDMS. This significantly enhanced cell growth, reaching confluence by day 7. Immunofluorescence revealed well‐defined actin staining, monolayer formation, and high cell viability on air plasma treated and untreated surfaces, and to a lesser extent, on ammonia plasma treated. Furthermore, RPE monolayers were able to demonstrate phagocytosis of POS in a time‐dependent manner similar to control. PDMS can support an intact functional monolayer of healthy differentiated RPE cells. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Zeta‐potentials of alginate‐PLL capsules: A predictive measure for biocompatibility?
Authors: de Vos Paul , de Haan Bart J. , Kamps Jan A.A.M. , Faas Marijke M. , Kitano Toshio 
Published: October 2006

AbstractAlginate‐poly‐L‐lysine (PLL) microencapsulation of cells is a promising approach to prevent rejection in the absence of immunosuppression. Clinical application, however, is hampered by insufficient insight in factors influencing biocompatibility of the capsules. By now, it has been accepted that not only the chemical composition of the materials applied but also other factors contribute to bioincompatibility. The zeta‐potential serves as a measure for the electrical charge of the surface and has been shown to be a predictive value for the interfacial reactions between the biomaterial and the surrounding tissue in other applications. In the present study, we have assessed the streaming potential of alginate‐PLL capsules composed of either low‐, intermediate‐, or high‐guluronic (G) alginate to calculate the zeta‐potential. The zeta‐potentials of the capsules were compared to the biological response against the capsules at 4 weeks after implantation in the rat. We show that high‐G and low‐G alginates provoke a more severe response in the rat than capsules prepared of intermediate‐G alginate. This correlates with a higher zeta‐potential of the high‐G and low‐G alginates and by a change in zeta‐potential at lower pH. These lower pH‐levels are common directly after implantation as the consequence of a host‐response associated with mandatory surgery. Our results suggest that we should not only consider the capsule properties under physiological circumstances to explain bioincompatibility but also the capsule features during common pathophysiological situations. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Endoglin increases eNOS expression by modulating Smad2 protein levels and Smad2‐dependent TGF‐β signaling
Authors: Santibanez Juan F. , Letamendia Ainhoa , Perez‐Barriocanal Fernando , Silvestri Cristoforo , Saura Marta , Vary Calvin P.H. , Lopez‐Novoa Jose M. , Attisano Liliana , Bernabeu Carmelo 
Published: October 2006

AbstractThe endothelial nitric oxide synthase (eNOS) is a critical regulator of cardiovascular homeostasis, whose dysregulation leads to different vascular pathologies. Endoglin is a component of the transforming growth factor beta (TGF‐β) receptor complex present in endothelial cells that is involved in angiogenesis, cardiovascular development, and vascular homeostasis. Haploinsufficient expression of endoglin has been shown to downregulate endothelium‐derived nitric oxide in endoglin+/− (Eng+/−) mice and cultured endothelial cells. Here, we find that TGF‐β1 leads to an increased vasodilatation in Eng+/+ mice that is severely impaired in Eng+/− mice, suggesting the involvement of endoglin in the TGF‐β regulated vascular homeostasis. The endoglin‐dependent induction of eNOS occurs at the transcriptional level and is mediated by the type I TGF‐β receptor ALK5 and its downstream substrate Smad2. In addition, Smad2‐specific signaling is upregulated in endoglin‐induced endothelial cells, whereas it is downregulated upon endoglin gene suppression with small interference RNA (siRNA). The endoglin‐dependent upregulation of Smad2 was confirmed using eNOS and pARE promoters, whose activities are known to be Smad2 dependent, as well as with the interference of Smad2 with siRNA, Smurf2, or a dominant negative form of Smad2. Furthermore, increased expression of endoglin in endoglin‐inducible endothelial cells or in transfectants resulted in increased levels of Smad2 protein without affecting the levels of Smad2 mRNA. The increased levels of Smad2 appear to be due to a decreased ubiquitination and proteasome‐dependent degradation leading to stabilization of Smad2. These results suggest that endoglin enhances Smad2 protein levels potentiating TGF‐β signaling, and leading to an increased eNOS expression in endothelial cells. J. Cell. Physiol. 210: 456–468, 2007. © 2006 Wiley‐Liss, Inc.
Noninvasive three‐dimensional assessment of femoroacetabular impingement
Authors: Tannast Moritz , Kubiak‐Langer Monika , Langlotz Frank , Puls Marc , Murphy Stephen B. , Siebenrock Klaus A. 
Published: October 2006

AbstractA CT‐based method (“HipMotion”) for the noninvasive three‐dimensional assessment of femoroacetabular impingement (FAI) was developed, validated, and applied in a clinical pilot study. The method allows for the anatomically based calculation of hip range of motion (ROM), the exact location of the impingement zone, and the simulation of quantified surgical maneuvers for FAI. The accuracy of HipMotion was 0.7 ± 3.1° in a plastic bone setup and −5.0 ± 5.6° in a cadaver setup. Reliability and reproducibility were excellent [intraclass correlation coefficient (ICC) > 0.87] for all measures except external rotation (ICC = 0.48). The normal ROM was determined from a cohort of 150 patients and was compared to 31 consecutive hips with FAI. Patients with FAI had a significantly decreased flexion, internal rotation, and abduction in comparison to normal hips (p < 0.001). Normal hip flexion and internal rotation are generally overestimated in a number of orthopedic textbooks. HipMotion is a useful tool for further assessment of impinging hips and for appropriate planning of the necessary amount of surgical intervention, which represents the basis for future computer‐assisted treatment of FAI with less invasive surgical approaches, such as hip arthroscopy. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:122–131, 2007
L1, β1 integrin, and cadherins mediate axonal regeneration in the embryonic spinal cord
Authors: Blackmore Murray , Letourneau Paul C. 
Published: October 2006

AbstractEmbryonic birds and mammals are capable of axon regeneration after spinal cord injury, but this ability is lost during a discrete developmental transition. We recently showed that changes within maturing neurons, as opposed to changes solely in the spinal cord environment, significantly restrict axon regeneration during development. The developmental changes within neurons that limit axon regeneration remain unclear. One gap in knowledge is the identity of the adhesive receptors that embryonic neurons use to extend axons in the spinal cord. Here we test the roles of L1/NgCAM, β1 integrin, and cadherins, using a coculture system in which embryonic chick brainstem neurons regenerate axons into an explant of embryonic spinal cord. By in vivo and in vitro methods, we found that brainstem neurons reduce axonal expression of L1 as they mature. Disrupting either L1 or β1 integrin function individually in our coculture system partially inhibited growth of brainstem axons in spinal cords, while disrupting cadherin function alone had no effect. However, when all three adhesive receptors were blocked simultaneously, axon growth in the spinal cord was reduced by 90%. Using immunohistochemistry and in situ hybridization we show that during the period when neurons lose their regenerative capacity they reduce expression of mRNA for N‐cadherin, and reduce axonal L1/NgCAM protein through a post‐transcriptional mechanism. These data show that embryonic neurons use L1/NgCAM, β1 integrin, and cadherin receptors for axon regeneration in the embryonic spinal cord, and raise the possibility that a reduced expression of these essential receptors may contribute to the low‐regenerative capacity of older neurons. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Singing, but not seizure, inducessynaptotagmin IVin zebra finch song circuit nuclei
Authors: Poopatanapong A. , Teramitsu I. , Byun J.S. , Vician L.J. , Herschman H.R. , White S.A. 
Published: October 2006

AbstractSynaptotagmins are a family of proteins that function in membrane fusion events, including synaptic vesicle exocytosis. Within this family,synaptotagmin IV(Syt IV) is unique in being a depolarization‐induced immediate early gene (IEG). Experimental perturbation ofSyt IVmodulates neurotransmitter release in mice, flies, and PC12 cells, and modulates learning in mice. Despite these features, induction ofSyt IVexpression by a natural behavior has not been previously reported. We used the zebra finch, a songbird species, to investigateSyt IVbecause song is a naturally learned behavior whose neuroanatomical basis is largely identified. We observed that, similar to rodents,Syt IVis inducible in songbirds. This induction was selective and depended on the nature of neuronal depolarization. Generalized seizures caused by the GABAAreceptor antagonist, metrazole, induced the IEG,ZENK,in zebra finch brain. However, these same seizures failed to induceSyt IVin song control areas. In contrast, when nontreated birds sang, three song control areas showed strikingSyt IVinduction. Further, this induction appeared sensitive to the social context in which song was sung. Together, these data suggest that neural activity during singing can driveSyt IVexpression within song circuitry whereas generalized seizure activity fails to do so even though song control areas are depolarized. Our findings indicate that, within this neural circuit for a procedurally learned sensorimotor behavior,Syt IVis selective and requires precisely patterned neural activity and/or neuromodulation associated with singing. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
A coagulation factor VII deficiency protects against acute inflammatory responses in mice
Authors: Xu H , Ploplis VA , Castellino FJ 
Published: October 2006

AbstractUpregulation of the activated Factor VII (FVIIa)/Tissue Factor complex, downregulation of natural anticoagulation pathways, and inhibition of fibrinolysis, are major contributors to coagulopathies associated with acute inflammation. Provision of FVIIa, and consequent downstream coagulation‐related proteases, also stimulates further inflammatory changes, which can result in disseminated intravascular coagulation. Thus, the potential protective effects in vivo of a genetic‐based reduction in FVII levels have been investigated in a murine model of acute inflammation, namely lipopolysaccharide (LPS)‐induced lethal endotoxaemia. Mice with a total FVII deficiency do not survive the neonatal period. Therefore mice expressing low levels of FVII (FVIItTA/tTA), producing sufficient amounts of FVII for survival (approximately 5% of wild‐type (WT) FVII), were employed to investigate in vivo pathways involved in the crosstalk between coagulation, inflammation, and survival, consequent to administration of a lethal dose of LPS. The FVIItTA/tTA mice presented with reduced mortality, coagulation, and inflammatory responses in comparison with similarly treated WT mice after administration of LPS. The attenuated inflammatory responses in FVIItTA/tTA mice were associated with downregulation of Egr‐1 signalling. Administration, in vivo, of specific inhibitors of FXa and thrombin demonstrated that the inflammatory responses were unaltered in WT mice, but further reduced in FVIItTA/tTA mice. Therefore, a FVII deficiency enhances survival from lethal endotoxaemia both through attenuation of inflammatory responses that result directly from reduced FVIIa levels, and, indirectly, from downregulation of coagulation proteases downstream of the FVII‐dependent cascade. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Synthesis, characterization and properties of photoresponsive polymers comprising photocrosslinkable pendant chalcone moieties
Authors: Tamilvanan Muthusamy , Pandurangan Arumugam , Reddy Boreddy SR , Subramanian Kathavarayan 
Published: October 2006

AbstractNew methacrylate monomers, namely 4‐methacryloyloxyphenyl‐4′‐fluorostyryl ketone and 4‐methacryloyloxyphenyl‐4′‐ethylstyryl ketone comprising a free radical polymerizable group and a photocrosslinkable group, were synthesized by reacting the respective hydroxychalcones with methacryloyl chloride in the presence of triethylamine. The monomers were polymerized in the presence of ethyl methyl ketone (EMK) at 70 °C using benzoyl peroxide as the initiator. The chemical structures were characterized using various spectroscopic techniques: ultraviolet, Fourier transform infrared, 1H NMR and 13C NMR. The thermal stability of the polymers was studied using thermogravimetric analysis in nitrogen atmosphere. Differential scanning calorimetry was used to determine the glass transition temperature of the homopolymers. Photocrosslinking of the synthesized homopolymers was investigated in solution. The two homopolymers were crosslinked within 10–15 min. After crosslinking, the homopolymers were insoluble in the same solvent. Copyright © 2006 Society of Chemical Industry
Synthesis and characterization of ABS resin using in situ transferring from emulsion to suspension polymerization
Authors: Zhang Dalei , Luan Mingyue , Lin Quan , Gu Qiang , Cui Zhanchen , Yang Bai 
Published: October 2006

AbstractA novel approach based on an emulsion in situ suspension polymerization process for synthesizing poly(acrylonitrile–butadiene–styrene) (ABS) resin is reported. Experimental results show that the reaction system can be transformed from an emulsion state to a suspension polymerization state steadily with the content of polybutadiene (PB) in the range 0–15 wt% in ABS resin. When PB is replaced by poly(styrene‐co‐butadiene) with the content of rubber particles being kept below 20 wt%, the emulsion system can be easily transferred to the suspension polymerization state through a process of latex coagulation in the forward direction, which means that the emulsion solution was dripped slowly into the suspension reaction system in the presence of coagulating agent. The dispersion status of the rubber particles in the ABS resin was studied using transmission electron microscopy, which indicated that the rubber particles were in a dispersed state in a continuous matrix of poly(styrene‐co‐acrylonitrile) when the content of rubber particles was below 20 wt%. The mechanical properties of the ABS resins obtained are as follows: elongation at break, 9.4–45.7%; yield tensile strength, 35.1–42.2 MPa; impact strength, 98.2–116.3 J m−1. Copyright © 2006 Society of Chemical Industry
Fine‐grained erbium‐doped strontium hexaferrite
Authors: Rezlescu N. , Doroftei C. , Rezlescu E. , Popa P. D. 
Published: October 2006

AbstractIn the present work the Er‐substituted Sr hexaferrite, SrFe12–x Erx O19, prepared by sol–gel self combustion and subsequent heat treatments, is investigated. The combusted powders were annealed at 800, 900 and 1000 °C for 5, 10, 20, 40, 80, 160 and 320 min. The influence of annealing temperature and time on the structure and magnetic properties (specific saturation magnetization M s, specific remanent magnetization M r and coercivity H c) is studied. The structural characterization was made using X‐ray diffraction and scanning electron microscopy. The magnetic measurements were carried out with a vibrating sample magnetometer. During the heat treatments the soft magnetic powder obtained by sol–gel self combustion is changed to a hard magnetic powder. The coercivity increases to a value much greater than its value before annealing. The remarkable increase of H c is explained by crystallization of the hard magnetic hexaferrite phase and corresponds to a transition from superparamagnetic to stable single‐domain particles, as a result of the grain growth during the heat treatment. The H c values of the samples heat treated for longer times (over 80 min) are fairly satisfactory. This means that the particle sizes were well under control to prevent abnormal growth of the particles. M s and M r depend on both annealing time and temperature. M s and M r begin to increase when H c sharply increases and tend to a constant value with increasing annealing time. Also, M s and M r decrease with increasing Er content. This dependence may be ascribed to the lowering of the total magnetic moment when Er3+ ions substitute magnetic Fe3+ ions in the M‐hexagonal structure or to the formation of more non‐magnetic phase like hematite, α‐Fe2O3. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Natural terrain classification using three‐dimensional ladar data for ground robot mobility
Authors: Lalonde Jean‐François , Vandapel Nicolas , Huber Daniel F. , Hebert Martial 
Published: October 2006

AbstractIn recent years, much progress has been made in outdoor autonomous navigation. However, safe navigation is still a daunting challenge in terrain containing vegetation. In this paper, we focus on the segmentation of ladar data into three classes using local threedimensional point cloud statistics. The classes are: “scatter” to represent porous volumes such as grass and tree canopy; “linear” to capture thin objects like wires or tree branches, and finally “surface” to capture solid objects like ground surface, rocks, or large trunks. We present the details of the proposed method, and the modifications we made to implement it on‐board an autonomous ground vehicle for real‐time data processing. Finally,we present results produced from different stationary laser sensors and from field tests using an unmanned ground vehicle. © 2006 Wiley Periodicals, Inc.
Neuroprotective effects of tetramethylpyrazine on hydrogen peroxide‐induced apoptosis in PC12 cells
Authors: Cheng Xin‐Rui , Zhang Li , Hu Juan‐Juan , Sun Lan , Du Guan‐Hua 
Published: October 2006

AbstractIn the present study, we investigated the effects of tetramethylpyrazine (TMP) on hydrogen peroxide (H2O2)‐induced apoptosis in PC12 cells. The apoptosis in H2O2‐induced PC12 cells was accompanied by a decrease in Bcl‐2/Bax protein ratio, release of cytochrome c to cytosol and the activation of caspase‐3. TMP not only suppressed the down‐regulation of Bcl‐2, up‐regulation of Bax and the release of mitochondrial cytochrome c to cytosol, but also attenuated caspase‐3 activation and eventually protected against H2O2‐induced apoptosis. These results indicated that TMP blocked H2O2‐induced apoptosis by the regulation of Bcl‐2 family members, suppression of cytochrome c release, and caspase cascade activation in PC12 cells.