bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of the surface potential of GaN:Si
Authors: Köhler Klaus , Maier Markus , Kirste Lutz , Wiegert Joachim , Menner Hanspeter 
Published: January 2009

AbstractThe surface potential of GaN:Si is determined for Si doping from 2.4 × 1017 cm–3 to 2.3 × 1019 cm–3 in layers grown by low pressure metal‐organic vapor‐phase epitaxy. We used the sheet resistance of the samples with different thicknesses measured by eddy current, a nondestructive, contactless method, to determine the depleted region. From the width of the depletion layer, which is dependent on the doping concentration, measured by secondary ion mass spectrometry, we obtained the GaN:Si surface potential on the basis of the depletion approximation. The surface potential decreases with increasing carrier concentration from about 1.6 eV down to 0.2 eV. Based on the behavior of the surface potential with doping we determined the surface state density. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐reflectivity Ag‐based p‐type ohmic contacts for blue light‐emitting diodes
Authors: Kawai Ryosuke , Mori Toshiaki , Ochiai Wataru , Suzuki Atushi , Iwaya Motoaki , Amano Hiroshi , Kamiyama Satoshi , Akasaki Isamu 
Published: January 2009

AbstractIn this paper, we propose a novel p‐contact material, which is an Ag‐Pd‐Cu alloy (APC) with high reflectivity, low specific contact resistance, and high thermal stability. APC is an alloy with 98% Ag, 1% Pd and 1% Cu. The APC contact showed a higher reflectance of 88% at 450 nm, a contact resistance as low as 1.4×10–4 Ω cm2, and better thermal stability than an Ag contact that was annealed at 475 °C for 5 min in N2 ambient. We applied the APC contact to a large blue light‐emitting diode (LED) (1 mm × 1 mm) with an emission peak wavelength of 450 nm. At 200 mA, the output power of the LED with the APC contact is 1.6 times higher than that of the LED with the Ni/Au contact. In addition, a significant reduction of the operating voltage at a given current was realized. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
33 μm free standing thick film vertical structure LED made by laser lift‐off
Authors: Sun Yongjian , Qi Shengli , Chen Zhizhong , Kang Xingning , Zhu Guangmin , Chen Cheng , Li Shitao , Pan Yaobo , Yan Jianfeng , Deng Junjing , Long Hao , Hao Maosheng , Yu Tongjun , Zhang Guoyi 
Published: January 2009

AbstractThe 33 μm thick film vertical structure LEDs without any substrate were fabricated and their free standings were successfully realized by laser lift‐off and HVPE technology. Through the AFM analyses we know that the laser irradiation can causes big damage to the wafer. However, since the 33 μm thick film vertical structure LEDs without any substrate have longer distance between the laser irradiating plane and the quantum well than the the thin film (3‐4 μm) vertical structure LED on Cu or Si substrate, the 33 μm free standing thick film vertical structure LEDs exhibited good electrical and optical characteristics for the less damage on the quantum well caused by the laser lift off process. It has also been proved that the 33 μm thick film vertical structure LEDs without any substrate has lower thermal series resistance than the vertical structure LEDs on 300‐400 μm free standing GaN substrate. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN nano‐pendeo‐epitaxy on Si(111) substrates
Authors: Liu Chaowang , Wang Wang Nang , Denchitcharoen Somyod , Gott Alan , Shields Philip A. , Allsopp Duncan W. E. 
Published: January 2009

AbstractNano‐pendeo‐epitaxial GaN films have been grown by metalorganic vapour phase epitaxy on nanocolumns fabricated on thin GaN‐on‐Si(111) templates. Optical and structural performances of the films are improved, crack densities are reduced, and self‐separation of GaN films from the substrates at the nanocolumns has been realized. The success of the nano‐pendeo‐epitaxy of GaN films is attributed to the following three techniques developed in this study: (1) the growth of high quality ultrathin GaN/AlN templates on on Si(111) substrates, (2) the fabrication of uniform nanocolumns across the 2‐inch wafer surface, and (3) the in situ conversion of the exposed silicon surfaces of the fabricated nanocolumns to silicon nitride. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antidiarrhoeal activity ofHypoxis hemerocallideaFisch. & C. A. Mey. (Hypoxidaceae) Corm (‘African potato’) aqueous extract in rodents
Authors: Ojewole John A. O. , Awe Emmanuel O. , Nyinawumuntu Agatha 
Published: January 2009

AbstractThis study investigated the antidiarrhoeal activity ofHypoxis hemerocallideacorm aqueous extract (APE) on experimentally‐induced diarrhoea, gastrointestinal motility, intestinal transit and enteropooling in rodents.H.hemerocallideacorm aqueous extract (APE, 50–400 mg/kg, p.o.) produced dose‐dependent and significant (p< 0.05–0.01) protection of rats and mice against castor oil‐induced diarrhoea, inhibited intestinal transit and delayed gastric emptying. Like atropine (1 mg/kg, p.o.), APE (50–400 mg/kg, p.o.) produced dose‐dependent and significant (p< 0.05–0.01) antimotility effect, and caused dose‐related inhibition of castor oil‐induced enteropooling in the animals. Like loperamide (10 mg/kg, p.o.), APE (50–400 mg/kg, p.o.) dose‐dependently and significantly (p< 0.05–0.01) delayed the onset of castor oil‐induced diarrhoea, decreased the frequency of defaecation and reduced the severity of diarrhoea in the rodents. Compared with control animals, APE (50–400 mg/kg, p.o.) dose‐dependently and significantly (p< 0.05–0.01) decreased the volume of castor oil‐induced intestinal fluid secretion, and reduced the number, weight and wetness of faecal droppings. APE (50–400 mg/mL) also produced concentration‐related and significant (p< 0.05–0.01) inhibitions of the spontaneous, pendular contractions of the rabbit isolated duodenum, and attenuated acetylcholine (ACh, 0.1–5.0 µg/mL)‐induced contractions of the guinea‐pig isolated ileum. Although the precise mechanism of the antidiarrhoeal activity of APE could not be established, the results of this study indicate that APE possesses antidiarrhoeal activity. This finding supports the use of ‘African potato’ as a natural supplementary remedy for the treatment, management and/or control of diarrhoea in some rural communities of southern Africa. Copyright © 2009 John Wiley & Sons, Ltd.
Germinated Buckwheat extract decreases blood pressure and nitrotyrosine immunoreactivity in aortic endothelial cells in spontaneously hypertensive rats
Authors: Kim Dae Won , Hwang In Koo , Lim Soon Sung , Yoo Ki‐Yeon , Li Hua , Kim Young Sup , Kwon Dae Young , Moon Won Kuk , Kim Dong‐Woo , Won Moo‐Ho 
Published: January 2009

AbstractThee present study analysed the quantification of rutin in raw buckwheat extract (RBE) and germinated buckwheat extract (GBE) by high performance liquid chromatography (HPLC), and examined changes in body weight, systolic blood pressure (SBP) and nitrotyrosine (a marker for peroxynitrite formation) immunoreactivity in aortic endothelial cells in spontaneously hypertensive rats (SHRs) and normotensive Wistar‐Kyoto (WKY) rats after treatment with RBE and GBE for 5 weeks. In the HPLC study, RBE and GBE contained a mean content of rutin of 1.52 ± 0.21 and 2.92 ± 0.88 mg/g, respectively. In the 600 mg/kg GBE‐treated group, SBP was lower than that in the 600 mg/kg RBE‐treated group. The treatment with RBE and/or GBE significantly reduced oxidative damage in aortic endothelial cells by lowering nitrotyrosine immunoreactivity. These results suggest that GBE has an antihypertensive effect and may protect arterial endothelial cells from oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.
Phenolic alkaloids as a new class of antioxidants in Portulaca oleracea
Authors: Yang Zijuan , Liu Cejia , Xiang Lan , Zheng Yinan 
Published: January 2009

AbstractAntioxidant activities of three phenolic alkaloids, i.e., oleracein A (OA), oleracein B (OB) and oleracein E (OE), isolated from Portulaca oleracea were determined, based on scavenging activity against 1,1‐diphenyl‐ 2‐picryl‐hydrazyl (DPPH) radical and inhibitory effect on hydrogen peroxide‐induced lipid peroxidation in rat brain homogenates. The DPPH radical scavenging activities of these phenolic alkaloids were lower than caffeic acid but higher than ascorbic acid and α‐tocopherol, being in the following order: OB > OA > OE. OE was most potent in preventing formation of malondialdehyde (MDA) with an EC50 value of 73.13 µM, close to that of caffeic acid (72.09 µM). It was demonstrated that phenolic alkaloids served as a new class of antioxidant agents in this plant. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of boldo (Peumus boldus Molina) infusion on lipoperoxidation induced by cisplatin in mice liver
Authors: Fernández J. , Lagos P. , Rivera P. , Zamorano‐Ponce E. 
Published: January 2009

AbstractPeumus boldus Molina (Monimiaceae), commonly referred to as ‘boldo’, is used in traditional Chilean medicine to treat hepatic and gastrointestinal diseases. Its leaves are rich in antioxidant compounds, principally alkaloids and flavonoids. This study evaluates the protective effect of a complete boldo leaf infusion on lipoperoxidation (MDA determination at 532 nm) induced by cisplatin in mice liver. To determine if the observed effect can be explained by the action of boldine or catechin, each compound was studied separately. The mice were divided into 8 groups (n = 6): (I) not treated; (II) treated with cisplatin 6 mg/Kg b.w.; (III) treated with boldo leaf infusion 5%; (IV) pretreated with boldo leaf infusion 5% and treated with cisplatin 6 mg/Kg b.w.; (V) treated with boldine 50 mg/Kg b.w.; (VI) pretreated with boldine 50 mg/Kg b.w. and treated with cisplatin 6 mg/kg.b.w.; (VII) treated with catechin; and (VIII) pretreated with catechin 50 mg/Kg b.w. and treated with cisplatin 6 mg/Kg b.w. As expected, the treatment with cisplatin significantly increased (p < 0.01) lipoperoxidation in comparison with the non‐treated group. Pretreatment with boldo leaf infusion significantly diminished (p < 0.05) the lipoperoxidation induced by cisplatin with respect to the animals not pretreated with the infusion. The pretreatments with boldine and catechin significantly diminished (p < 0.05) the lipoperoxidation induced by cisplatin with respect to the group treated only with cisplatin. The results suggest that the boldo infusion is acting as a protector with respect to the oxidative hepatic damage caused by cisplatin, and that this protective ability would be due to the presence in the infusion of the natural antioxidants boldine and principally catechin. These findings suggest the potential use of the infusion as a chemoprotector. Copyright © 2009 John Wiley & Sons, Ltd.
Quantitative Structure‐Toxicity Models for Heterogeneous Aliphatic Compounds
Authors: Duchowicz Pablo R. , Ocsachoque Marco A. 
Published: January 2009

AbstractThe presented work deals with the Quantitative Structure–Activity Relationships (QSAR) analysis for the growth inhibition of the ciliated protozoan Tetrahymena pyriformis by a mechanistically diverse set of aliphatic organic compounds. A pool of 1509 theoretical descriptors coding for lipophilic, constitutional, steric, and electronic properties of these molecules is calculated with the Dragon software. The simultaneous linear regression analyses on 370 compounds led to a five‐parameter model characterized by R=0.909 and leave more out Rl‐30%‐o=0.843. An external test set of 100 structurally related derivatives that is not employed during the model development demonstrates that the relationship found shows good predictive power, with Rval=0.881. Finally, the application of this subset of descriptors on the complete set of 470 aliphatic structures outperforms previous reported results. Our study corroborates that hydrophobicity, calculated among more than a thousand of structural variables, represents an important factor for predicting the toxicity of aliphatic compounds.
Enhanced Replacement Method‐based Quantitative Structure–Activity Relationship Modeling and Support Vector Machine Classification of 4‐Anilino‐3‐quinolinecarbonitriles as Src Kinase Inhibitors
Authors: Sun Min , Zheng Youguang , Wei Hongtao , Chen Junqing , Cai Jin , Ji Min 
Published: January 2009

AbstractQuantitative Structure–Activity Relationship (QSAR) analyses have been carried out for a set of 4‐anilino‐3‐quinolinecarbonitriles. Considering simplicity and interpretability, Src kinase‐inhibiting activity of these compounds expressed in log units have been modeled by Multiple Linear Regression (MLR) analysis combined with various variable selection approaches, including Forward Selection (FS), Genetic Algorithm (GA), Simulated Annealing (SA), and Enhanced Replacement Method (ERM), based on descriptors generated by E‐Dragon software. Performances of these models are rigorously validated by Leave‐One‐Out Cross‐Validation (LOOCV), five‐fold Cross‐Validation (5‐CV), and external validation. The ERM–MLR model is much better than other models, with R2=0.854 and $\rm{ R_{{\rm{pred}}}^{\rm{2}} }$=0.840. Robustness and predictive ability of this model are prudently evaluated. Moreover, another classification analysis using Fisher Linear Discriminant Analysis (FLDA) and Support Vector Machine (SVM) is also developed with the aim of dissecting the most significant factors that lead to the activity difference between highly active compounds and those not so active. The 5‐CV and external validation prediction accuracy reached 95.00 and 93.75% for the SVM‐based model, respectively. The resulting models could act as an efficient strategy for estimating the Src‐inhibiting activity of novel 4‐anilino‐3‐quinolinecarbonitriles and provide some insight into the structural features related to the biological activity of these compounds.
Fragment‐Based QSAR and Molecular Modeling Studies on a Series of Discodermolide Analogs as Microtubule‐Stabilizing Anticancer Agents
Authors: Salum Lívia B. , Dias Luiz C. , Andricopulo Adriano D. 
Published: January 2009

AbstractInhibition of microtubule function is an attractive rational approach to anticancer therapy. Although taxanes are the most prominent among the microtubule‐stabilizers, their clinical toxicity, poor pharmacokinetic properties, and resistance have stimulated the search for new antitumor agents having the same mechanism of action. Discodermolide is an example of nontaxane natural product that has the same mechanism of action, demonstrating superior antitumor efficacy and therapeutic index. The extraordinary chemical and biological properties have qualified discodermolide as a lead structure for the design of novel anticancer agents with optimized therapeutic properties. In the present work, we have employed a specialized fragment‐based method to develop robust quantitative structure–activity relationship models for a series of synthetic discodermolide analogs. The generated molecular recognition patterns were combined with three‐dimensional molecular modeling studies as a fundamental step on the path to understanding the molecular basis of drug–receptor interactions within this important series of potent antitumoral agents.
Slope traversal controls for planetary exploration rover on sandy terrain
Authors: Ishigami Genya , Nagatani Keiji , Yoshida Kazuya 
Published: January 2009

AbstractIn this paper, two control approaches are presented for exploration rovers traversing sandy‐sloped terrain. One of the proposed controls is a model‐based feed‐forward control using a characteristic diagram, called athrust‐cornering characteristic diagram. It consists of various characteristic curves of wheel forces for varied wheel slip conditions. An appropriate steering maneuver for slope traversal can be found using the diagram with slope traversal criteria. The other control is a sensor‐based feedback control. A key approach to this feedback control is to compensate for three types of slip, namely, the vehicle sideslip and longitudinal/lateral slips of a wheel. The feedback control calculates both steering and driving maneuvers that can compensate for these slips and also allow the rover to successfully traverse a sandy slope. The performances of these two control approaches are confirmed in slope traversal experiments using a four‐wheeled rover test bed. The proposed controls are verified by quantitative evaluations of distance and orientation errors. Through the experiment, it was found that the two controls have advantages and disadvantages, and the possibility of merging the model‐based control and the sensor‐based control is discussed. © 2009 Wiley Periodicals, Inc.
Privacy‐preserving robust data aggregation in wireless sensor networks
Authors: Conti Mauro , Zhang Lei , Roy Sankardas , Di Pietro Roberto , Jajodia Sushil , Mancini Luigi Vincenzo 
Published: January 2009

AbstractIn‐network data aggregationin wireless sensor networks (WSNs) is a technique aimed at reducing the communication overhead—sensed data are combined into partial results at intermediate nodes during message routing. However, in the above technique, some sensor nodes need to send their individual sensed values to an aggregator node, empowered with the capability to decrypt the received data to perform a partial aggregation. This scenario raises privacy concerns in applications like personal health care and the military surveillance. A few other solutions exist where the data are not disclosed to the aggregator (e.g., using privacy homomorphism (PH)), but these solutions are not robust to node or communication failure.The contributions of this paper are two‐fold: first, we design a private data aggregation protocol that does not leak individual sensed values during the data aggregation process. In particular, neither the base station (BS) nor the other nodes are able to compromise the privacy of an individual node's sensed value. Second, the proposed protocol is robust to data‐loss; if there is a node‐failure or communication failure, the protocol is still able to compute the aggregate and to report to the base station the number of nodes that participated in the aggregation. To the best of our knowledge, our scheme is the first one that efficiently addresses the above issues all at once. Copyright © 2009 John Wiley & Sons, Ltd.
Mathematical model for constructing passwords from biometrical data
Authors: Balakirsky Vladimir B. , Ghazaryan Anahit R. , Han Vinck A. J. 
Published: January 2009

AbstractWe propose a probabilistic model for constructing passwords on the basis of outcomes of biometrical measurements. An algorithm for the transformation of biometrical data to passwords is given. Performance of the authentication scheme is evaluated by the compression factor, the false acceptance/rejection rates, the probability distribution over the set of passwords, and the probability of a correct guess of the input biometrical data mapped to the known password. An application of the results to the DNA measurements is presented. Copyright © 2009 John Wiley & Sons, Ltd.
Correction
Authors: Giraudeau B. , Ravaud P. , Donner A. 
Published: January 2009

Abstract‘Sample size calculation for cluster randomized cross‐over trials’ by Giraudeau B, Ravaud P, Donner A (Statist. Med. 2008; 27(27):5578–5585 [Epub ahead of print])Equation (5) reads

which should read as

Therefore, the inflation factor discussed two lines after should read as $${\{({1+({p_{0}} -1})\rho)-p_{0}\eta \}}$$.
Participant experiences of a written emotional disclosure intervention in asthma
Authors: Theadom Alice , Smith Helen , Horne Rob , Bowskill Richard , Apfelbacher Christian J. , Frew Anthony J 
Published: January 2009

AbstractStress has been associated with the exacerbation of asthma symptoms. Written emotional disclosure (WED) is a potentially cheap, low‐risk intervention that may reduce stress and improve lung function in patients with asthma. The aims of this study were to explore asthma patients' subjective experiences of completing a WED exercise and the feasibility of conducting the intervention unsupervised in participants' homes. The data were collected during the pilot for a randomized controlled trial of the effectiveness of WED in adults with asthma. Thirty‐six participants completed the writing exercises, and 28 participants (13 experimental subjects and 15 controls) provided free‐text feedback on their experiences of completing the writing exercises. Framework analysis identified four themes in the participants' experiences: writing encouraged reflection; the challenge of the writing exercise; emotional reactions; and perceived impact. The feedback highlighted the need to control for previous experience of WED and time of day in any future studies exploring the effect of WED. The WED intervention was feasible to implement within the participants' homes without researcher supervision. Copyright © 2009 John Wiley & Sons, Ltd.
Cell‐targeting and cell‐penetrating peptides for delivery of therapeutic and imaging agents
Authors: Juliano Rudolph L , Alam Rowshon , Dixit Vidula , Kang Hyun Min 
Published: January 2009

AbstractThis review will discuss the basic concepts concerning the use of cell‐targeting peptides (CTPs) and cell‐penetrating peptides (CPPs) in the context of nanocarrier technology. It deals with the discovery and subsequent evolution of CTPs and CPPs, issues concerning their interactions with cells and their biodistribution in vivo, and their potential advantages and disadvantages as delivery agents. The article also briefly discusses several specific examples of the use of CTPs or CPPs to assist in the delivery of nanoparticles, liposomes, and other nanocarriers. © 2009 John Wiley & Sons, Inc.This article is categorized under:

Therapeutic Approaches and Drug Discovery > Emerging Technologies
Polyalkylcyanoacrylate nanoparticles for delivery of drugs across the blood–brain barrier
Authors: Andrieux Karine , Couvreur Patrick 
Published: January 2009

AbstractThe major problem in drug delivery to the brain is the presence of the blood–brain barrier (BBB) which limits drug penetration even if in certain pathological situations the BBB is partly disrupted. Among noninvasive techniques to overcome this barrier, the use of nanoparticles has been proposed. This review focuses on poly(alkylcyanoacrylates) (PACA)‐based nanoparticles which have been developed for brain targeting. Both types of ‘stealth’ PACA nanoparticles with modified surface, those coated with surfactant and those with chains of polyethylene glycol (PEG) linked to the hydrophobic core of PACA are presented. The synthesis of polymers, the preparation of nanoparticles with modified surface and their physicochemical characterization are described. The review of their in vivo results evidenced their ability to enter into the brain using healthy animals or models of central nervous system (CNS) diseases. The nature of the surface modification (surfactant nature, PEG linkage, drug loading interference) seems to have a great influence on the efficacy of brain targeting which can be related to the adsorption of some apolipoproteins (Apo E, B, A‐I). The mechanism of their passage through the BBB has been studied by in vitro and in vivo experiments, which suggested the implication of receptor‐mediated endocytosis processes. According to these data, some antibodies (OX26) and ligands (transferrin, Apo E/B/A‐I) seem to be good candidates to be coupled with ‘stealth’ PACA nanoparticles in order to increase their passage through the BBB and to promote active targeting to the brain Copyright © 2009 John Wiley & Sons, Inc.This article is categorized under:

Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease