bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical properties of TiO2 thin films prepared by chemical spray pyrolysis from aqueous solutions
Authors: Ayouchi R. , Casteleiro C. , Schwarz R. , Barrado J. R. , Martín F. 
Published: March 2010

AbstractTitanium dioxide (TiO2) is known to have three different kinds of polymorphous crystalline forms: rutile, anatase, and brookite. The rutile phase is always formed at higher temperatures, while the anatase phase is formed at lower temperatures and transformed into rutile phase above 800 ºC. Various deposition techniques have been developed for depositing TiO2 thin films, including evaporation, sputtering, chemical vapour deposition and thermal oxidation of titanium. Among them, the Chemical Spray Pyrolysis (CSP) technique has many advantages, such as good conformal coverage, the possibility of epitaxial growth and the application to large area deposition. Also, this method is low cost and it is easy to control the deposition growth parameters. In the present work, TiO2 thin films have been deposited on p‐Si (001) and fused silica substrates by Chemical Spray Pyrolysis (CSP) method from aqueous solution containing titanium (IV) isopropoxide (Ti[OCH(CH3)2]4. As‐deposited thin films show anatase polycrystalline structure, and rutile phase formed for films annealed at 750ºC. SEM images have confirmed a smooth and crack‐free surface with low surface roughness. X‐ray photoelectron spectroscopy (XPS) combined with 4 keV Ar+ depth profiling has shown that crystallized films correspond to TiO2. Residual carbon coming from the organic precursor solution is only detected at the surface of the film. Thin films deposited on fused silica were highly transparent (more than 85%), with an indirect optical band gap of 3,43 and 3,33 eV for as‐deposited and annealed films, respectively, and refractive indexes in the range between 2.01–2.29. Spectroscopic Ellipsometry (SE) also has been used to extract optical parameters. SE data fitted to triple‐layer physical model revealed the same tendency to increase refractive index in annealed films. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Educative mentoring: Promoting reform‐based science teaching through mentoring relationships
Authors: Bradbury Leslie Upson 
Published: March 2010

AbstractEducative mentoring is an idea developed by Feiman‐Nemser [Feiman‐Nemser, S. (1998). Teachers as teacher educators.European Journal of Teacher Education, 21(1), 63–74; (2001). Helping novices learn to teach: Lessons from an exemplary support teacher.Journal of Teacher Education, 52(1), 17–30] to reflect current conceptions of mentoring that emphasize novices learning from their practice with the assistance of a mentor teacher. Educative mentoring seeks to meet the immediate needs of novice teachers while also focusing on long‐term goals for professional development. This paper discusses the meaning of educative mentoring, describes key behaviors of educative mentors, outlines important components for the professional development of mentors, and proposes areas for further research with a specific emphasis on the needs of beginning science teachers. © 2010 Wiley Periodicals, Inc.Sci Ed94:1049–1071, 2010
The Exploratory Behavior Scale: Assessing young visitors' hands‐on behavior in science museums
Authors: Van Schijndel Tessa J. P. , Franse Rooske K. , Raijmakers Maartje E. J. 
Published: March 2010

AbstractIn this paper, we introduce the Exploratory Behavior Scale (EBS), a quantitative measure of young children's interactivity. More specifically, the EBS is developed from the psychological literature on exploration and play and measures the extent to which preschoolers explore their physical environment. A practical application of the EBS in a science museum is given. The described study was directed at optimizing parent guidance to improve preschoolers' exploration of exhibits in science center NEMO. In Experiment 1, we investigated which adult coaching style resulted in the highest level of exploratory behavior at two exhibits. In Experiment 2, we investigated whether informing parents about an effective way of coaching influenced preschoolers' exploratory behavior at two exhibits. The results of the study demonstrate the added value of the EBS in visitor behavior research: compared to existing global measures of visitor interactivity; the EBS adds information about the quality of the hands‐on behavior. Compared to existing detailed measures of visitor interactivity, the EBS has the advantage of being applicable in different museum settings and enabling comparisons between exhibits or exhibitions. In addition, the EBS allows for quantification of unanticipated behavior. © 2010 Wiley Periodicals, Inc. Sci Ed 94:794–809, 2010
Tunable Water Channels with Carbon Nanoscrolls
Authors: Shi Xinghua , Cheng Yuan , Pugno Nicola M. , Gao Huajian 
Published: March 2010

AbstractMolecular dynamics simulations and theoretical analyses are performed to show that the flow rate of water through the core of carbon nanoscrolls (CNSs) can be adjusted over a broad range through the effective surface energy, which in turn can be tuned by an applied DC or AC electric field. The results suggest that the CNSs hold great promise for applications such as tunable water and ion channels, nanofluidic devices, and nanofilters, as well as tunable gene‐ and drug‐delivery systems.
Mineralocorticoid receptor activation restores medial perforant path LTP in diabetic rats
Authors: Stranahan Alexis M. , Arumugam Thiruma V. , Lee Kim , Mattson Mark P. 
Published: March 2010

AbstractIn the hippocampus, glucocorticoids bind to two types of receptors: the mineralocorticoid receptor, which binds corticosterone with high affinity and is tonically occupied; and the glucocorticoid receptor, which is occupied during stress and at certain phases in the circadian cycle. Diabetes mellitus increases levels of glucocorticoids in both humans and animal models. To explore the contributions of hippocampal corticosteroid receptors to the diabetes‐induced suppression of neuroplasticity, we manipulated these receptors in hippocampal slices from streptozocin‐diabetic rats, a model of Type 1 diabetes mellitus. STZ‐diabetes reduced long‐term potentiation (LTP) at medial perforant path synapses in the dentate gyrus, and induced a bias in favor of long‐term depression following intermediate stimulation frequencies. Bath application of the mineralocorticoid receptor agonist aldosterone restored LTP in slices from diabetic animals. These results suggest additional mechanisms for diabetes‐induced functional alterations and support a restorative role for dentate gyrus mineralocorticoid receptors. Synapse 64:528–532, 2010. © 2010 Wiley‐Liss, Inc.
Continuous dopaminergic stimulation by pramipexole is effective to treat early morning akinesia in animal models of Parkinson's disease: A pharmacokinetic‐pharmacodynamic study using in vivo microdialysis in rats
Authors: Ferger Boris , Buck Kerstin , Shimasaki Makoto , Koros Eliza , Voehringer Patrizia , Buerger Erich 
Published: March 2010

AbstractShort‐acting dopamine (DA) agonists are usually administered several times a day resulting in fluctuating plasma and brain levels. DA agonists providing continuous dopaminergic stimulation may achieve higher therapeutic benefit for example by alleviating nocturnal disturbances as well as early morning akinesia. In the present study continuous release (CR) of pramipexole (PPX) was maintained by subcutaneous implantation of Alzet® minipumps, whereas subcutaneous PPX injections were used to mimic PPX immediate release (IR) in male Wistar rats. In the catalepsy bar test, PPX‐CR (1 mg/kg/day) reversed the haloperidol‐induced motor impairment in the morning and over the whole observation period of 12h. In contrast, PPX‐IR (tid 1 mg/kg, pre‐treatment the day before) was not effective in the morning but catalepsy was reduced for 6 h after PPX‐IR (1 mg/kg) injection. In the reserpine model, early morning akinesia indicated by the first motor activity measurement in the morning was significantly reversed by PPX‐CR (2 mg/kg/day). Again, PPX‐IR (tid 0.3 mg/kg, pre‐treatment the day before) was not able to antagonise early morning akinesia. These results are in agreement with in vivo microdialysis measurements showing a continuous decrease of extracellular DA levels and a continuous PPX exposure in the PPX‐CR (1 mg/kg/day) group. In contrast, PPX‐IR (0.3 mg/kg) produced a transient decrease of extracellular DA levels over 6 h and showed maximum PPX levels 2 h after dosing which decreased over the following 6–8 h. The present study demonstrates that PPX‐CR may offer a higher therapeutic benefit than PPX‐IR on early morning akinesia and confirms earlier reports that PPX‐IR reverses motor impairment for several hours. Synapse 64:533–541, 2010. © 2010 Wiley‐Liss, Inc.
Identification and evaluation of [11C]GSK931145 as a novel ligand for imaging the type 1 glycine transporter with positron emission tomography
Authors: Passchier J. , Gentile G. , Porter R. , Herdon H. , Salinas C. , Jakobsen S. , Audrain H. , Laruelle M. , Gunn R.N. 
Published: March 2010

AbstractThe type‐1 glycine transporter (GlyT1) is an important target for the development of new medications for schizophrenia. A specific and selective positron emission tomography (PET) GlyT1 ligand would facilitate drug development studies to determine whether a drug reaches this target and help establish suitable doses for clinical trials. This article describes the evaluation of three candidate GlyT1 PET radioligands (GSK931145, GSK565710, and GSK991022) selected from a library of compounds based on favorable physicochemical and pharmacological properties. Each candidate was successfully labeled using [11C]methyl iodide or [11C]methyl triflate and administered to a pig pre‐ and postadministration with a pharmacological dose of a GlyT1 inhibitor to determine their suitability as PET ligands in the porcine brain in vivo. All three candidate ligands were analyzed quantitatively with compartment analyses employing a plasma input function. [11C]GSK931145 showed good brain penetration and a heterogeneous distribution in agreement with reported GlyT1 localization. Following pretreatment with GSK565710, uptake of [11C]GSK931145 was reduced to homogeneous levels. Although [11C]GSK565710 also showed good brain penetration and a heterogeneous distribution, the apparent level of specific binding was reduced compared to [11C]GSK931145. In contrast, [11C]GSK991022 showed a much lower brain penetration and resultant signal following pretreatment with GSK565710. Based on these findings [11C]GSK931145 was identified as the most promising ligand for imaging GlyT1 in the porcine brain, possessing good brain penetration, specific signal, and reversible kinetics. [11C]GSK931145 is now being progressed into higher species. Synapse 64:542–549, 2010. © 2010 Wiley‐Liss, Inc.
Genotoxicity of tetracycline as an emerging pollutant on root meristem cells of wheat (Triticum aestivum L.)
Authors: Xie Xiujie , Zhou Qixing , Bao Qiuhua , He Zhangchun , Bao Yanyu 
Published: March 2010

AbstractIncreasing attention has been paid to antibiotic contamination as an increasingly serious environmental issue. Tetracycline has been widely used for decades in human and veterinary medicines, with incremental residues in the environment and adverse influences on living organisms. In the present study, the genetic toxicity of tetracycline was investigated using a bioassay method with wheat (Triticum aestivum L.) root‐meristem cells at a concentration range of 0.25–300 mg L−1 and exposure times of 24, 48, and 72 h. The results indicated that tetracycline at lower concentrations (0.25–1 mg L−1) stimulated cell mitotic division, whereas at 50–300 mg L−1 concentration caused a concentration‐related decrease in mitotic index (MI). The lower tetracycline concentrations induced a slight increase in the frequency of micronucleus (MN), chromosomal aberration (CA), and sister chromatid exchange (SCE) in wheat root tips. However, there were significant increases in these indices at higher concentrations in concentration‐ and time‐dependent manners, including the frequencies of MN (25–200 mg L−1), CA (10–200 mg L−1), and SCE (5–200 mg L−1), respectively. The inducement of MN, CA, and SCE decreased at 250 and 300 mg L−1 due to acute cell toxicity for all tested times. Comparatively, SCE was the most sensitive, followed by CA, with MN the least sensitive to the genotoxicity of tetracycline in wheat. These results imply that tetracycline may be genotoxic to plant cells, and exposure to tetracycline may pose a genotoxic risk to living organisms. The results also suggest that the wheat bioassay was efficient, simple, and reproducible in monitoring the genotoxicity of tetracycline in the environment. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2011.
The apoptotic effect of oral administration of microcystin‐RR on mice liver
Authors: Huang Pu , Zheng Qun , Xu Li‐Hong 
Published: March 2010

AbstractMicrocystin produced by cyanobacteria in diverse water systems is a potent hepatotoxin that has been documented to induce hepatocyte apoptosis and liver injury. There are more than eighty reported microcystins. The present work aimed at investigating the apoptotic effect of MC‐RR (a common member of microcystin family), and its related mechanism. MC‐RR was administered orally to ICR mice for 7 days with different dosages. Apoptotic cell death in liver was detected by TUNEL assay, and the expression levels of Bcl‐2, Bax and p53, GRP 78 and CHOP which have been reported to be related to apoptosis and ER stress were determined via western‐blot. The activity of PP2A was measured using the serine‐threonine phosphatase assay system and PP2A A subunit expression at both transcription and protein levels was measured by RT‐PCR and western blot, respectively. A significant difference was observed on the number of TUNEL positive liver cells between the control and MC‐RR‐treated groups. The expression levels of Bcl‐2, Bax, p53, and GRP 78 in MC‐RR‐treated groups were altered significantly compared to the control, but no obvious alteration was found in CHOP expression. The PP2A activity and A subunit expression did not manifest any obvious change at both transcription and protein levels. The results indicated that oral exposure to MC‐RR can cause apoptosis as well as moderate ER stress in mice liver. The mitochondrial pathway via Bcl‐2 family members may contribute to the apoptosis. However, PP2A may not be involved in the regulation of apoptotic process under the current conditions. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.
Effects of diazinon on antioxidant defense system and lipid peroxidation in the liver of Cyprinus carpio (L.)
Authors: Oruc Elif 
Published: March 2010

AbstractDiazinon is a widely used organophosphorus pesticide in agriculture and environmental health, hence its adverse effects on nontarget animals, especially on fish is to be determined. The present study therefore aimed at detecting the biochemical changes caused by diazinon. To accomplish this aim, we studied the effects of sublethal concentrations (0.0036, 0.018, and 0.036 ppb) of diazinon on acetylcholine esterase activity, antioxidant enzyme activities, and lipid peroxidation in the liver of Cyprinus carpio on days 5, 15, and 30 after the exposure. The results revealed that the antioxidant enzyme activities such as superoxide dismutase, glutathione peroxidase, and catalase were induced by diazinon exposure. In addition, the highest catalytic activity of glutathione S‐transferase (GST) was obtained with 1‐chloro‐2, 4‐dinitrobenzene (CDNB). GST activity toward 1,2‐dichloro‐4‐nitrobenzene (DCNB) was also observed in the liver, yet it was relatively low as opposed to the other substrates tested. On the other hand, hepatic malondialdehyde level did not show any significant alteration except after the exposure on day 15. The exposure of low concentrations of diazinon to C. carpio can induce oxidative stress in liver; yet restoring susceptibility and adapting to oxidative stress are likely to occur when low level of oxidative stress is administered. Furthermore, no significant change was observed in hepatic lipid peroxidation after diazinon treatment indicating that liver tissue resisted to oxidative stress by enhancing their antioxidant mechanisms. The level of lipid peroxidation was assumed to be associated with the concentrations of diazinon and experimentation periods. The induction of glutathione S‐transferase and antioxidant enzyme activities were also assumed to have resulted from the defense against the toxicity of diazinon. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2011.
Local replacement for route recovery on a collaborative mobilead hocnetwork
Authors: Lin Jenn‐Wei , Chen Yi‐Ting 
Published: March 2010

AbstractThis paper presents an efficient route recovery approach for a collaborative mobilead hocnetwork (MANET). In the collaborative MANET, the movement of a node can be controlled by other nodes. Based on the property of the controllable movement, each active node (each node on a route) can be protected by its neighboring nodes. When the movement of an active node causes a link breakage on a route, its neighboring nodes compete with each other to move to the original location of the moving active node. Using the movements of neighboring nodes, the proposed approach can achieve route recovery without pre‐establishing or dynamically finding backup routes. The proposed approach also has much less recovery overhead than previous approaches because of the local recovery. Finally, we perform extensive simulations to compare the proposed approach with previous approaches. The simulation results show that the proposed approach has better recovery performance under dense and sparse MANET architectures. Copyright © 2010 John Wiley & Sons, Ltd.
A study on the influence of transmission errors on WLAN IEEE 802.11 MAC performance
Authors: Lopez‐Aguilera Elena , Casademont Jordi , Villegas Eduard Garcia 
Published: March 2010

AbstractSince the advent of the first IEEE 802.11 standard for WLANs, several papers have been presented that evaluate the IEEE 802.11 DCF access method. In realistic WLAN environments frame errors usually occur due to non‐ideal channel conditions; in this way, papers including adverse transmission conditions in the evaluation have been published later in the literature. In this paper, we review existent analytical models that include the influence of transmission errors in IEEE 802.11 DCF performance. We modify current models and provide a more accurate analysis, thus allowing the evaluation in single rate and multi‐rate scenarios with stations subject to different link error conditions. Moreover, this paper exposes the unfairness problem that arises in IEEE 802.11 DCF networks with stations subject to different transmission conditions through analytical and simulation results. Stations are not able to distinguish collisions from failed transmissions due to link errors; both result in a missing ACK and, consequently, the transmitting stations apply the exponential backoff algorithm. This fact leads to a lower performance for stations in worse transmission conditions. Copyright © 2010 John Wiley & Sons, Ltd.
An infrastructure for detecting and punishing malicious hosts using mobile agent watermarking
Authors: Esparza Oscar , Muñoz Jose L. , Tomàs‐Buliart Joan , Soriano Miguel 
Published: March 2010

AbstractMobile agents are software entities consisting of code, data, and state that can migrate autonomously from host to host executing their code. In such scenario there are some security issues that must be considered. In particular, this paper deals with the protection of mobile agents against manipulation attacks performed by the host, which is one of the main security issues to solve in mobile agent systems. This paper introduces an infrastructure for mobile agent watermarking (MAW). MAW is a lightweight approach that can efficiently detect manipulation attacks performed by potentially malicious hosts that might seek to subvert the normal agent operation. MAW is the first proposal in the literature that adapts software watermarks to verify the execution integrity of an agent. The second contribution of this paper is a technique to punish a malicious host that performed a manipulation attack by using a trusted third party (TTP) called host revocation authority (HoRA). A proof‐of‐concept has also been developed and we present some performance evaluation results that demonstrate the usability of the proposed mechanisms. Copyright © 2010 John Wiley & Sons, Ltd.
Effective capacity of a correlated Rayleigh fading channel
Authors: Wang Qing , Wu Dapeng , Fan Pingyi 
Published: March 2010

AbstractThe next generation wireless networks call for quality of service (QoS) support. The effective capacity (EC) proposed by Wu and Negi provides a powerful tool for the design of QoS provisioning mechanisms. In their previous work, Wu and Negi derived a formula for effective capacity of a Rayleigh fading channel with arbitrary Doppler spectrum. However, their paper did not provide simulation results to verify the accuracy of the EC formula derived in their paper. This is due to difficulty in simulating a Rayleigh fading channel with a Doppler spectrum of continuous frequency, required by the EC formula. To address this difficulty, we develop a verification methodology based on a new discrete‐frequency EC formula; different from the EC formula developed by Wu and Negi, our new discrete‐frequency EC formula can be used in practice. Through simulation, we verify that the EC formula developed by Wu and Negi is accurate. Furthermore, to facilitate the application of the EC theory to the design of practical QoS provisioning mechanisms in wireless networks, we propose a spectral‐estimation‐based algorithm to estimate the EC function, given channel measurements; we also analyze the effect of spectral estimation error on the accuracy of EC estimation. Simulation results show that our proposed spectral‐estimation‐based EC estimation algorithm is accurate, indicating the excellent practicality of our algorithm. Copyright © 2010 John Wiley & Sons, Ltd.