bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring cell proliferation in silk fibroin scaffolds using spectroscopic optical coherence tomography
Authors: Tay Benjamin Chia‐Meng , Fu Chit‐Yaw , Ng Beng‐Koon , Liu Jolene Mei‐Jun , Chou Siaw‐Meng , Chua Chee‐Kai
Published: August 2013

Spectroscopic optical coherence tomography is used to monitor fibroblast cell proliferation in silk fibroin (SF) scaffolds. Time points of 1, 3, and 5‐weeks are chosen to give sufficient time for the fibroblasts to proliferate before harvesting. Fibroblasts and their distribution in the SF scaffolds are clearly differentiated in the spectroscopic images. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2587–2594, 2013
Reflector with designed EBG cells for ultrawideband antenna performance improvement
Authors: Huang Hui‐Fen , Zhang Shao‐Fang
Published: August 2013

In this article, a frequency selective surface (FSS) cell is proposed. The band stop frequency performance is compared between the two and four layer FSS structure with the proposed cells. The four‐layer structure has the same low frequency as the two‐layer structure, but the four‐layer structure has 3.6 GHz wider stop band in high frequency. Then, a reflector with the proposed EBG cells for ultrawideband antenna is developed. The performance for the reference antenna with and without the proposed reflector was compared, the average improvement of the front‐to‐back ratio of the UWB antenna with designed FSS reflector is 15 dB from 3.1 to 10.6 GHz and the peak even can get to 30 dB at 5 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2541–2544, 2013
RF characterization of 100‐nm separate gate InAlAs/InGaAs DG‐HEMT
Authors: Parveen  , Gupta Mridula , Gupta R. S. , Jogi Jyotika
Published: August 2013

This article presents a three port analysis for separate gate In0.52Al0.48As/In0.53Ga0.47As DG‐HEMT and a small signal equivalent circuit is developed using charge control model. The various intrinsic short circuit admittance parameters (Y‐parameters) are evaluated to extract scattering parameters, to determine the maximum transducer power gain of the device. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2796–2803, 2013
Development of slot array antenna using a multiresonant SIW cavity
Authors: Ali Razavi Seyed , Neshati Mohammad H.
Published: August 2013

A novel type of slot array antennas is presented in this article. The antenna 3‐dB beam could be steered in a wide angular region, including broadside, by discrete changing of the frequency. The idea is based on radiation by different cavity modes. The proposed antenna is designed and implemented using substrate integrated waveguide technology. Grounded coplanar waveguide is used as the feed to excite different cavity modes. A single layer of low‐cost printed circuit board is used for the designed antenna providing low cost, light weight, and easy integration with planar circuits. The designed antenna is fabricated and its radiation characteristics are measured. Measured results are in good agreement with those obtained by numerical investigation. The antenna provides high‐gain narrow beam in addition to the advantages of compactness and simplicity of design which make it suitable in radar and satellite communications. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2763–2767, 2013
An UWB diversity antenna array with a novel H‐type decoupling structure
Authors: Gogosh Nayab , Shafique M. Farhan , Saleem Rashid , Usman Imran , Faiz A. M.
Published: August 2013

This research work addresses the problem of mutual coupling between the antenna elements for ultra wideband diversity applications. A novel H‐type decoupling structure has been proposed which successfully suppresses the mutual coupling by 7 to 10 dB as compared to the nondecoupled radiating elements. The decoupling structure has been tested for shared and isolated ground planes. The isolation between the antennas was measured to be more than 25 dB in most of the band. The feasibility of the proposed structure in diversity applications has been analyzed by measuring the envelope correlation coefficient which was found out to be less than −30 dB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2715–2720, 2013
TWEAK transactivation of the epidermal growth factor receptor mediates renal inflammation
Authors: Rayego‐Mateos Sandra , Morgado‐Pascual Jose Luis , Sanz Ana Belen , Ramos Adrian Mario , Eguchi Satoru , Batlle Daniel , Pato Janos , Keri Gyorgy , Egido Jesus , Ortiz Alberto , Ruiz‐Ortega Marta
Published: August 2013

TWEAK, a member of the TNF superfamily, binds to the Fn14 receptor, eliciting biological responses. EGFR signalling is involved in experimental renal injury. Our aim was to investigate the relationship between TWEAK and EGFR in the kidney. Systemic TWEAK administration into C57BL/6 mice increased renal EGFR phosphorylation, mainly in tubular epithelial cells. In vitro, in these cells TWEAK phosphorylated EGFR via Fn14 binding, ADAM17 activation and subsequent release of the EGFR ligands HB‐EGF and TGFα. In vivo the EGFR kinase inhibitor Erlotinib inhibited TWEAK‐induced renal EGFR activation and downstream signalling, including ERK activation, up‐regulation of proinflammatory factors and inflammatory cell infiltration. Moreover, the ADAM17 inhibitor WTACE‐2 also prevented those TWEAK‐induced renal effects. In vitro TWEAK induction of proinflammatory factors was prevented by EGFR, ERK or ADAM17 inhibition. In contrast, EGFR transactivation did not modify TWEAK‐mediated NF‐κB activation. Our data suggest that TWEAK transactivates EGFR in the kidney, leading to modulation of downstream effects, including ERK activation and inflammation, and suggest that inhibition of EGFR signalling could be a novel therapeutic tool for renal inflammation. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
An approach to the measurement of shunt resistance of individual subcells in thin‐film tandem devices
Authors: Daliento Santolo , d'Alessandro Vincenzo , Guerriero Pierluigi , Tari Orlando
Published: August 2013

In this paper, the selective illumination approach is adopted to separately extract the shunt resistance of the individual subcells belonging to a tandem cell. The method relies on simple theoretical considerations and is based on the measurement of the current–voltage characteristic of the tandem cell by alternately keeping one of the subcells under dark conditions. Numerical simulations are employed to support the reliability of the technique, which is experimentally tested on micromorph devices deposited onto glass covered by a V‐shaped transparent conducting oxide and subject to different thermal treatments. Copyright © 2013 John Wiley & Sons, Ltd.
Encapsulation of Photosensitizers and Upconversion Nanocrystals in Lipid Micelles for Photodynamic Therapy
Authors: Wang Han Jie , Shrestha Rishav , Zhang Yong
Published: August 2013

Photodynamic therapy (PDT) is a promising method for cancer therapy. However, it is constrained by limited penetration depth of visible light, hydrophobicity of photosensitizers, and lack of tumor targeting. In this work, the photosensitizer zinc phthalocyanine (ZnPc) and upconversion nanocrystals (UCNs) are encapsulated into OQPGA‐PEG/RGD/TAT lipid micelles. The UCNs acting as a nanotransducer convert deep‐penetrating near‐infrared (NIR) light to visible light for activating the photosensitizer. OQPGA‐PEG/RGD/TAT lipid micelles are used as a carrier for the photosensitizer, with improved biocompatibility and cancer‐targeting ability. The results show that the photosensitizer ZnPc‐ and UCNs‐loaded OQPGA‐PEG/RGD/TAT lipid micelles are nanoparticles with an average size of 25 nm. The lipid micelle nanoparticles are stable in water with low leakage of photosensitizer. The absorption peak of the photosensitizer overlaps with the emission peak of UCNs, so the visible fluorescence emitted from the UCNs upon excitation by the NIR laser at 980 nm can activate the photosensitizer to produce singlet oxygen for PDT. The targeting RGD peptide and cell‐penetrating TAT peptide on the surface help the nanoparticles getting into cancer cells. The OQPGA‐PEG/RGD/TAT lipid micelles encapsulated with both the photosensitizer ZnPc and UCNs could be used for targeted PDT by using deep‐penetrating NIR light as the light source.
Obstructive sleep apnea in infancy: A 7‐year experience at a pediatric sleep center
Authors: Ramgopal Sriram , Kothare Sanjeev V. , Rana Mandeep , Singh Kanwaljit , Khatwa Umakanth
Published: August 2013

Purpose

To investigate the common indications for polysomnogram (PSG) associated co‐morbid conditions, evaluation strategies, treatment options, and outcomes in a series of infants diagnosed with obstructive sleep apnea (OSA) by a PSG.

Methods

Retrospective chart review of infants who underwent PSG over a 7‐year period was done. Infants with PSG diagnosed OSA were included in this study.

Results

A total of 97 infants (59 males, mean age 4.6 months, standard deviation 3.3 months) were diagnosed with OSA (AHI ≥ 1/hr) based on PSG. The most common indication for PSG in infants were excessive snoring (53%) followed by nocturnal desaturations (24%). Associated co‐morbid conditions included gastro‐esophageal reflux (30%), laryngomalacia (24%), and craniofacial abnormalities (16%). Genetic abnormalities were found in 53%, of which trisomy 21 was the most common. Surgical treatments were employed in 36% and oxygen therapy in 15%. Thirty‐eight patients were followed up with a repeat sleep study after a median interval of 8 months (range 1–24 months), of whom 26/38 had resolution of symptoms. Twenty‐seven patients (28%) were followed clinically after a mean interval of 5 months of intervention (range, 1–34.5 months), in whom the symptoms resolved in 23/27 patients. Seven patients were deceased at review. Causes of death included status epilepticus, respiratory failure, hepatic failure, kidney failure, or unknown causes.

Conclusion

The etiologies of OSA in infants are different when compared to older children. PSG is feasible and a valuable tool in the diagnosis of OSA in infants and may help determine timely and appropriate evaluation and interventions. Clinical improvement in symptoms and resolution of PSG parameters were noted following medical and/or surgical interventions. Prospective studies need to be done to ascertain the long‐term outcome of infants diagnosed with OSA to assess the benefits of early intervention on their neurocognitive development. Pediatr Pulmonol. 2014; 49:554–560. © 2013 Wiley Periodicals, Inc.
To fuse or not to fuse: What is your purpose?
Authors: Bell Mark R. , Engleka Mark J. , Malik Asim , Strickler James E.
Published: August 2013

Since the dawn of time, or at least the dawn of recombinant DNA technology (which for many of today's scientists is the same thing), investigators have been cloning and expressing heterologous proteins in a variety of different cells for a variety of different reasons. These range from cell biological studies looking at protein‐protein interactions, post‐translational modifications, and regulation, to laboratory‐scale production in support of biochemical, biophysical, and structural studies, to large scale production of potential biotherapeutics. In parallel, fusion‐tag technology has grown‐up to facilitate microscale purification (pull‐downs), protein visualization (epitope tags), enhanced expression and solubility (protein partners, e.g., GST, MBP, TRX, and SUMO), and generic purification (e.g., His‐tags, streptag, and FLAG™‐tag). Frequently, these latter two goals are combined in a single fusion partner. In this review, we examine the most commonly used fusion methodologies from the perspective of the ultimate use of the tagged protein. That is, what are the most commonly used fusion partners for pull‐downs, for structural studies, for production of active proteins, or for large‐scale purification? What are the advantages and limitations of each? This review is not meant to be exhaustive and the approach undoubtedly reflects the experiences and interests of the authors. For the sake of brevity, we have largely ignored epitope tags although they receive wide use in cell biology for immunopreciptation.
Mechanistic investigation of domain specific unfolding of human serum albumin and the effect of sucrose
Authors: Yadav Rajeev , Sen Pratik
Published: August 2013

This study is devoted to understand the unfolding mechanism of a multidomain protein, human serum albumin (HSA), in absence and presence of the sucrose by steady‐state and time‐resolved fluorescence spectroscopy with domain specific marker molecules and is further being substantiated by molecular dynamics (MD) simulation. In water, the domain III of HSA found to unfold first followed by domains I and II as the concentration of GnHCl is increased in the medium. The sequential unfolding behavior of different domains of HSA remains same in presence of sucrose; however, a higher GnHCl concentration is required for unfolding, suggesting stabilizing effect of sucrose on HSA. Domain I is found to be most stabilized by sucrose. The stabilization of domain II is somewhat similar to domain I, but the effect of sucrose on domain III is found to be very small. MD simulation also predicted a similar behavior of sucrose on HSA. The stabilizing effect of sucrose is explained in terms of the entrapment of water molecules in between HSA surface and sucrose layer as well as direct interaction between HSA and sucrose.
Plateau effect of prostate cancer risk‐associated SNPs in discriminating prostate biopsy outcomes
Authors: Ren Shancheng , Xu Jianfeng , Zhou Tie , Jiang Haowen , Chen Haitao , Liu Fang , Na Rong , Zhang Limin , Wu Yishuo , Sun Jielin , Yang Bo , Gao Xu , Zheng S. Lilly , Xu Chuanliang , Ding Qiang , Sun Yinghao
Published: August 2013

BACKGROUND

Additional prostate cancer (PCa) risk‐associated single nucleotide polymorphisms (SNPs) continue to be identified. It is unclear whether addition of newly identified SNPs improves the discriminative performance of biopsy outcomes over previously established SNPs.

METHODS

A total of 667 consecutive patients that underwent prostate biopsy for detection of PCa at Huashan Hospital and Changhai Hospital, Shanghai, China were recruited. Genetic scores were calculated for each patient using various combinations of 29 PCa risk‐associated SNPs. Performance of these genetic scores for discriminating prostate biopsy outcomes were compared using the area under a receiver operating characteristic curve (AUC).

RESULTS

The discriminative performance of genetic score derived from a panel of all 29 SNPs (24 previous and 5 new) was similar to that derived from the 24 previously established SNPs, the AUC of which were 0.60 and 0.61, respectively (P = 0.72). When SNPs with the strongest effect on PCa risk (ranked based on contribution to the total genetic variance from an external study) were sequentially added to the models for calculating genetic score, the AUC gradually increased and peaked at 0.62 with the top 13 strongest SNPs. Under the 13‐SNP model, the PCa detection rate was 21.52%, 36.74%, and 51.98%, respectively for men with low (<0.5), intermediate (0.5–1.5), and high (>1.5) genetic score, P‐trend = 9.91 × 10−6.

CONCLUSION

Genetic score based on PCa risk‐associated SNPs implicated to date is a significant predictor of biopsy outcome. Additional small‐effect PCa risk‐associated SNPs to be discovered in the future are unlikely to further improve predictive performance. Prostate 73:1824–1835, 2013. © 2013 Wiley Periodicals, Inc.
A 2‐D continuum model of a mixture of bone tissue and bio‐resorbable material for simulating mass density redistribution under load slowly variable in time
Authors: Andreaus U. , Giorgio I. , Lekszycki T.
Published: August 2013

The bio‐mechanical phenomena occurring in bones grafted with the inclusion of artificial materials demand the formulation of mathematical models which are refined enough to describe their not trivial behavior. A 3D theoretical model, previously developed and used in 1D space, is employed to investigate and explain possible effects resulting from 2D interactions, which may not be present in 1D case so more realistic situations are approached and discussed. The enhanced model was used to numerically analyze the physiological balance between the processes of bone apposition and resorption and material resorption in a bone sample under plain stress state. The specimen was constituted by a portion of bone living tissue and one of bio‐resorbable material and was acted by an in‐plane loading condition. The signal intensity between sensor cells and actor cells was assumed to decrease exponentially with their distance; the effects of adopting two different laws, namely an absolute and a quadratic functions, were compared. Ranges of load magnitudes were identified within which physiological states are established. A parametric analysis was carried out to evaluate the sensitivity of the model to changes of some critical quantities within physiological ranges, namely resorption rate of bio‐material, load level and homeostatic strain. In particular the spatial distribution of mass densities of bone tissue and of resorbable bio‐material and their time evolution were considered in order to analyze the biological effects due to the parameter's changes. Synthetically, these biological effects can be associated to different ratios between bone and bio‐material densities at the end of the process and to different delays in the bone growth and material resorption. These numerical analyses allowed for finding the most desirable situations in which a gradual resorption of the artificial graft occurs together with the simultaneous formation of new bone, finally leading to an almost complete substitution of the bio‐resorbable material with living tissue.
Discussing the Study of High Tc Properties of Superconductors with Electron Paramagnetic Resonance (EPR) Spectrometers
Authors: Shaltiel D.
Published: August 2013

This work discusses investigations of properties of superconductors with the electron spin resonance (ESR) spectrometers. A significant number of articles were published on this subject. Many authors have tried to explain results derived when applying the (ESR) spectrometers to investigate the properties of superconductors. We show that, except for a single publication, most have missed a very important issue, namely, that it is not possible to study superconducting properties with the electron spin resonance spectrometers unless the mechanism that induces the ESR signals is understood. None of the authors were aware that the mechanisms that induce ESR signals in superconductors must be different than the ESR mechanism that induces signals in compounds that holds spins. Explanations that describe this issue are presented.
Recovery of Saponins from Jua (Ziziphus joazeiro) by Micellar Extraction and Cloud Point Preconcentration
Authors: Ribeiro Bernardo Dias , Barreto Daniel Weingart , Coelho Maria Alice Zarur
Published: August 2013

Juá (Ziziphus joazeiro) is a Brazilian plant and its bark has been used as a detergent and phytotherapic due to its high saponin content (2–10 %). Saponins are triterpenic glycosides with some properties that aid their use in food, cosmetic and pharmaceutical industries. The object of the present work was to develop an extraction and concentration process of saponins from jua bark, using green solvents such as water and ethanol. Firstly, the extraction conditions optimization was carried out using a central composite design, and compared with other methods such as Soxhlet, ultrasound‐assisted extraction and micellar extraction. Then, cloud point preconcentration was tested to select the salt type and its concentration which promotes a higher concentration factor and partition coefficient at room temperature. Finally, the removal of a t‐octyl phenol ethoxylate (9–10 EO) nonionic surfactant by adsorption was evaluated by optimizing the adsorbent type and its concentration, temperature and time of adsorption, in addition to the adsorbent recycling. Orbital shaker extraction leads to a recovery of 45.6 % saponins under the following conditions: temperature, 38.8 °C; jua/solvent ratio, 0.272; stirring speed, 300 rpm; extraction time, 2 h. Under these conditions, saponins recovery reached 90.8 % when using 15 % v/v of the nonionic surfactant, and a preconcentration factor of 14.2 was obtained by adding sodium carbonate 20 % w/v. The preconcentration factor decreased to a value of 10.1, after nonionic surfactant removal by a hydrophobic crosslinked polystyrene copolymer resin.
The Personal and Professional Impact of the Future of Nursing Report
Authors: Chard Robin
Published: August 2013

Perioperative nurses can apply the four key messages outlined in the Institute of Medicine report The Future of Nursing: Leading Change, Advancing Health from personal and professional perspectives. Advocating to remove barriers to practice and educating the public about the perioperative nurse's role can help nurses practice to the full extent of their education and training. Nurses can achieve higher levels of education and training by taking advantage of new educational opportunities that offer a more seamless progression to an advanced degree. To act as full partners with other health professionals, nurses can participate in interdisciplinary teams and implement evidence‐based practice, and they can contribute to effective workforce planning and policy making by helping to collect and analyze data that will improve practice environments. The key messages of the report address all nurses, whether they are direct care providers, advanced practice RNs, educators, or administrators.
Partnering to Lead Change: Nurses' Role in the Redesign of Health Care
Authors: Strech Scott , Wyatt David A.
Published: August 2013

Health care has a long‐held perception of perioperative nurses as providers who advocate for patients and who carry out physician orders. According to the Institute of Medicine's 2010 report on the future of nursing, not only must that view evolve, but nurses also must play a leading role, in partnership with physicians and other health care colleagues, if health care reform is to succeed. Several factors will prepare nurses for this new role of partnering to advance health, including advancing their formal education, developing leadership as a core competency, acquiring leadership skills, and being active in new models of leadership (ie, mentorship, volunteering, advocacy).
Native iron in the sediments of Lake Baikal (borehole BDP-98): results of thermomagnetic analysis
Authors: Pechersky D.M. , Gil’manova D.M. , Ivanov E.V. , Kuz’min M.I. , Markov G.P. , Nurgaliev D.K. , Tsel’movich V.A.
Published: August 2013

We performed a thermomagnetic analysis of 91 samples and a probe microanalysis of five samples of sedimentary rocks from the lower zone of the borehole BDP-98 drilled at the bottom of Lake Baikal. The results show the scarcity of native iron: It was found only in five samples. Its concentration varies from ∼10–5 to 7 × 10–4%. The distribution of native iron by content is bimodal, with a distinct “zero” mode. This scarcity of native iron in the Baikal sediments distinguishes them from continental (Eurasia) and oceanic (Atlantic) sediments of different ages. It is due to the high rate of sedimentation in the studied interval of BDP-98.
Topography formation as an element of lithospheric self-organization
Authors: Goryainov P.M. , Ivanyuk G.Yu. , Kalashnikov A.O.
Published: August 2013

In geologic objects of different characters and extents, the fractal properties of topography are related to the intensity of endogenic energy flows and the composition of geologic complexes. A good correlation between the topographic differentiation of the Khibiny pluton and the variables of different levels of its structural and compositional organization (mineral and chemical compositions of the rocks and minerals, rock texture, etc.) suggests that topography formation is an element of the self-organization of the Khibiny pluton. Analysis of the fractal dimension of topography in the Khibiny pluton, Primorye, and detailed areas in Transbaikalia revealed a coincidence of its maxima with the position of ore clusters, fields, and deposits, i.e., areas with the contents of elements significantly higher than their clarkes. All the above data suggest that the fractal properties of topography can be used as a prospecting criterio.
Seismic inhomogeneities in the upper mantle beneath the Siberian craton (Meteorite profile)
Authors: Suvorov V.D. , Mel’nik E.A. , Mishen’kina Z.R. , Pavlov E.V. , Kochnev V.A.
Published: August 2013

The upper-mantle structure was studied from first-arrival data along the Meteorite profile, run using underground nuclear explosions. Unlike the layered, slightly inhomogeneous models in the previous works, emphasis was laid on lateral inhomogeneity at the minimum possible number of abrupt seismic boundaries. We used forward ray tracing of the traveltimes of refracted and overcritical reflected waves. The model obtained is characterized by considerable velocity variations, from 7.7 km/s in the Baikal Rift Zone to 8.0–8.45 km/s beneath the Tunguska syneclise. A layer of increased velocity (up to 8.5–8.6 km/s), 30–80 km thick, is distinguished at the base of seismic lithosphere. The depth of the layer top varies from 120 km in the northern Siberian craton to 210 km in its southeastern framing. It has been shown that, with crustal density anomalies excluded, the reduced gravity field is consistent with the upper-mantle velocity model.
Characteristic interactions and evaluation of the parameters of the transport equation and formation, including porosity, from data of measurements by some nuclear geophysical methods
Authors: Khisamutdinov A.I.
Published: August 2013

An important but problematic component of nuclear geophysical technologies is computer inversion of measurement data based on the equation of particle transport. In this paper, we propose an approach and iterative methods for this inversion that are applicable to many problems of evaluation formation characteristics, including elemental composition, from data of corresponding logging methods. This approach is based on defining characteristic elements, interactions, and trajectories and using the superposition principle for transport processes, and linear a priori constraints on unknowns are used. In comparison with the previous publications of the author, this paper deals with a broader type of measurement data, including the reading ratio of detectors and normalized measurements. The iterative methods are specified for problems of determining the porosity and density from data of neutron-neutron and gamma-gamma logs, respectively. For the first of them, the results of numerical experiments are presented.
Intra- and Interindividual Variability of Daily Affect in Adult Couples
Authors: Ferrer Emilio , Gonzales Joseph E. , Steele Joel
Published: August 2013

In this paper, we examine the intra- and interindividual variability of daily affect in adult couples. We use a variety of analytic techniques to inspect the daily fluctuations in emotions and to determine whether such fluctuations are influenced by the partner’s affect as well as the weather. The techniques include multiple regression analysis, longitudinal mixed models, and differential equations. To illustrate the different approaches, we use data consisting of self-reports of affect from ten adult couples that filled out a questionnaire daily for three months. All analytic approaches include parameters representing effects from the couple (i.e., oneself and partner) and from external sources (i.e., daily temperature).
School-Based Feeding Intervention to Increase Variety and Quantity of Foods Consumed by an Adolescent With Autism
Authors: Barahona Carolyn , DuBard Melanie , Luiselli James K. , Kesterson Janine
Published: August 2013

Although food selectivity is a common problem among children and youth who have autism, research has infrequently evaluated school-based feeding intervention. In this study an 18-year old girl with autism was taught to eat greater variety and quantity of previously rejected foods through a combination of antecedent intervention and positive reinforcement procedures that a teacher implemented during lunch meals. The study describes application of a changing criterion design to measure the effects of gradually increasing feeding expectations through food variation and portion control. We discuss the advantages of antecedent intervention for treating food selectivity in a school setting.
Mechanism of wavelength conversion in polystyrene doped with benzoxanthene: emergence of a complex
Authors: Nakamura Hidehito , Shirakawa Yoshiyuki , Kitamura Hisashi , Sato Nobuhiro , Shinji Osamu , Saito Katashi , Takahashi Sentaro
Published: August 2013

Fluorescent guest molecules doped in polymers have been used to convert ultraviolet light into visible light for applications ranging from optical fibres to filters for the cultivation of plants. The wavelength conversion process involves the absorption of light at short wavelengths followed by fluorescence emission at a longer wavelength. However, a precise understanding of the light conversion remains unclear. Here we show light responses for a purified polystyrene base substrates doped with fluorescent benzoxanthene in concentrations varied over four orders of magnitude. The shape of the excitation spectrum for fluorescence emission changes significantly with the concentration of the benzoxanthene, indicating formation of a base substrate/fluorescent molecule complex. Furthermore, the wavelength conversion light yield increases in three stages depending on the nature of the complex. These findings identify a mechanism that will have many applications in wavelength conversion materials.
High Performance Graphene Oxide Based Rubber Composites
Authors: Mao Yingyan , Wen Shipeng , Chen Yulong , Zhang Fazhong , Panine Pierre , Chan Tung W. , Zhang Liqun , Liang Yongri , Liu Li
Published: August 2013

In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications.
Unfolded protein ensembles, folding trajectories, and refolding rate prediction
Authors: Das A. , Sin B. K. , Mohazab A. R. , Plotkin S. S.
Published: August 2013

Computer simulations can provide critical information on the unfolded ensemble of proteins under physiological conditions, by explicitly characterizing the geometrical properties of the diverse conformations that are sampled in the unfolded state. A general computational analysis across many proteins has not been implemented however. Here, we develop a method for generating a diverse conformational ensemble, to characterize properties of the unfolded states of intrinsically disordered or intrinsically folded proteins. The method allows unfolded proteins to retain disulfide bonds. We examined physical properties of the unfolded ensembles of several proteins, including chemical shifts, clustering properties, and scaling exponents for the radius of gyration with polymer length. A problem relating simulated and experimental residual dipolar couplings is discussed. We apply our generated ensembles to the problem of folding kinetics, by examining whether the ensembles of some proteins are closer geometrically to their folded structures than others. We find that for a randomly selected dataset of 15 non-homologous 2- and 3-state proteins, quantities such as the average root mean squared deviation between the folded structure and unfolded ensemble correlate with folding rates as strongly as absolute contact order. We introduce a new order parameter that measures the distance travelled per residue, which naturally partitions into a smooth “laminar” and subsequent “turbulent” part of the trajectory. This latter conceptually simple measure with no fitting parameters predicts folding rates in 0 M denaturant with remarkable accuracy (r = −0.95, p = 1 × 10−7). The high correlation between folding times and sterically modulated, reconfigurational motion supports the rapid collapse of proteins prior to the transition state as a generic feature in the folding of both two-state and multi-state proteins. This method for generating unfolded ensembles provides a powerful approach to address various questions in protein evolution, misfolding and aggregation, transient structures, and molten globule and disordered protein phases.
Environmental taxation in the European Union—Analysis, challenges, and the future
Authors: Golušin Mirjana , Munitlak Ivanović Olja , Filipović Sanja , Andrejević Andrea , Djuran Jelena
Published: August 2013

In this paper, the authors intend to show that environmental taxes are an economic instrument that entirely supports the principles of sustainable development and has impact on balanced improvement of all its four pillars (economic, ecological, social, and institutional). Environmental taxes provide a flexible and cost-effective means for reinforcing the polluter-pays principle and for reaching environmental policy objectives. Enforcement of environmental taxes (and penalties) simultaneously generates multiple values—it stimulates ecologically acceptable production, generates budget revenue, and stimulates socially responsible behavior. The subject of the analysis is determination of environmental taxes in the European Union (EU) member states in total amount and as a percentage of Gross Domestic Product (GDP), as well as monitoring of their trend in the period 2005–2010. To obtain a broad picture, results collected for EU-27 region have been compared with data for sample countries worldwide, including Brazil, Russia, India, China, and South Africa (BRICS) countries. The revenue from environmental taxes in the EU-27 is not negligible, amounting to about 3% of total revenues. The highest tax revenue as a percent of GDP was noted in Denmark—9% on average. Environmentally related revenues and their percent of GDP in sample countries reported diverse results. In the USA, China, and India, environmentally related revenue as a percent of GDP stood at around 1%, with a downward trend in time. The highest tax revenue as a percent of GDP was recorded in Turkey, Russia, South Africa, and Brazil, 4% on average, with an upward trend in time. However, increasing revenues from environmental taxes should be interpreted with caution. The increases may be caused by the introduction of new taxes or an increase in tax rates, or alternatively may be linked to an increase in the tax base.
Inclined crack problem in a rectangular slab of superconductor under an electromagnetic force
Authors: Wang Xin , Yong Huadong , Xue Cun , Zhou Youhe
Published: August 2013

In this paper, the critical state Bean model is employed to estimate the effect of the electromagnetic force on the fracture behavior of the superconductor slab. The superconductor slab with an inclined crack is subjected to an applied field. Based on the finite element method, the stress intensity factors are computed for two activation processes, zero field cooling and field cooling. Numerical results obtained show that the crack length and the inclined angle have significant effects on the fracture behavior. Generally, maximum of mode-I stress intensity factor is larger than that of mode-II stress intensity factor. The stress intensity factors analyzed in the paper are useful to learn fracture behavior and mechanical failure of superconductors.
A numerical study of high-pressure non-equilibrium streamers for combustion ignition application
Authors: Breden Douglas , Raja Laxminarayan L. , Idicheria Cherian A. , Najt Paul M. , Mahadevan Shankar
Published: August 2013

We present a computational simulation study of non-equilibrium streamer discharges in a coaxial electrode and a corona geometry for automotive combustion ignition applications. The streamers propagate in combustible fuel-air mixtures at high pressures representative of internal combustion engine conditions. The study was performed using a self-consistent, two-temperature plasma model with finite-rate plasma chemical kinetics. Positive high voltage pulses of order tens of kV and duration of tens of nanoseconds were applied to the powered inner cylindrical electrode which resulted in the formation and propagation of a cathode-directed streamer. The resulting spatial and temporal production of active radical species such as O, H, and singlet delta oxygen is quantified and compared for lean and stoichiometric fuel-air mixtures. For the coaxial electrode geometry, the discharge is characterized by a primary streamer that bridges the inter-electrode gap and a secondary streamer that develops in the wake of the primary streamer. Most of the radicals are produced in the secondary streamer. For the corona geometry, only the primary streamer is observed and the radicals are produced throughout the length of the primary streamer column. The stoichiometry of the mixture was observed to have a relatively small effect on both the plasma discharge structure and the resulting yield of radical species.
Thermodynamic scaling of dynamic properties of liquid crystals: Verifying the scaling parameters using a molecular model
Authors: Satoh Katsuhiko
Published: August 2013

The thermodynamic scaling of molecular dynamic properties of rotation and thermodynamic parameters in a nematic phase was investigated by a molecular dynamic simulation using the Gay–Berne potential. A master curve for the relaxation time of flip–flop motion was obtained using thermodynamic scaling, and the dynamic property could be solely expressed as a function of $TV^{\gamma _\tau }$TVγτ, where T and V are the temperature and volume, respectively. The scaling parameter γτ was in excellent agreement with the thermodynamic parameter Γ, which is the logarithm of the slope of a line plotted for the temperature and volume at constant P2. This line was fairly linear, and as good as the line for p-azoxyanisole or using the highly ordered small cluster model. The equivalence relation between Γ and γτ was compared with results obtained from the highly ordered small cluster model. The possibility of adapting the molecular model for the thermodynamic scaling of other dynamic rotational properties was also explored. The rotational diffusion constant and rotational viscosity coefficients, which were calculated using established theoretical and experimental expressions, were rescaled onto master curves with the same scaling parameters. The simulation illustrates the universal nature of the equivalence relation for liquid crystals.
A consistent approach to estimate the breakdown voltage of high voltage electrodes under positive switching impulses
Authors: Arevalo L. , Wu D. , Jacobson B.
Published: August 2013

The main propose of this paper is to present a physical model of long air gap electrical discharges under positive switching impulses. The development and progression of discharges in long air gaps are attributable to two intertwined physical phenomena, namely, the leader channel and the streamer zone. Experimental studies have been used to develop empirical and physical models capable to represent the streamer zone and the leader channel. The empirical ones have led to improvements in the electrical design of high voltage apparatus and insulation distances, but they cannot take into account factors associated with fundamental physics and/or the behavior of materials. The physical models have been used to describe and understand the discharge phenomena of laboratory and lightning discharges. However, because of the complex simulations necessary to reproduce real cases, they are not in widespread use in the engineering of practical applications. Hence, the aim of the work presented here is to develop a model based on physics of the discharge capable to validate and complement the existing engineering models. The model presented here proposes a new geometrical approximation for the representation of the streamer and the calculation of the accumulated electrical charge. The model considers a variable streamer region that changes with the temporal and spatial variations of the electric field. The leader channel is modeled using the non local thermo-equilibrium equations. Furthermore, statistical delays before the inception of the first corona, and random distributions to represent the tortuous nature of the path taken by the leader channel were included based on the behavior observed in experimental tests, with the intention of ensuring the discharge behaved in a realistic manner. For comparison purposes, two different gap configurations were simulated. A reasonable agreement was found between the physical model and the experimental test results.
Proposal for all-graphene monolithic logic circuits
Authors: Kang Jiahao , Sarkar Deblina , Khatami Yasin , Banerjee Kaustav
Published: August 2013

Since the very inception of integrated circuits, dissimilar materials have been used for fabricating devices and interconnects. Typically, semiconductors are used for devices and metals are used for interconnecting them. This, however, leads to a “contact resistance” between them that degrades device and circuit performance, especially for nanoscale technologies. This letter introduces and explores an “all-graphene” device-interconnect co-design scheme, where a single 2-dimensional sheet of monolayer graphene is proposed to be monolithically patterned to form both active devices (graphene nanoribbon tunnel-field-effect-transistors) as well as interconnects in a seamless manner. Thereby, the use of external contacts is alleviated, resulting in substantial reduction in contact parasitics. Calculations based on tight-binding theory and Non-Equilibrium Green's Function (NEGF) formalism solved self-consistently with the Poisson's equation are used to analyze the intricate properties of the proposed structure. This constitutes the first NEGF simulation based demonstration that devices and interconnects can be built using the “same starting material” – graphene. Moreover, it is also shown that all-graphene circuits can surpass the static performances of the 22 nm complementary metal-oxide-semiconductor devices, including minimum operable supply voltage, static noise margin, and power consumption.
First-principles calculations of the electronic structure and defects of Al2O3
Authors: Liu D. , Guo Y. , Lin L. , Robertson J.
Published: August 2013

We present first-principles calculations of the electronic structure of the oxygen vacancies in θ-Al2O3 and amorphous Al2O3 (am-Al2O3) using the screened exchange (sX) hybrid functional. The sX hybrid functional can give correct band gap for both phases. The defect energy levels depend strongly on the charge state, with negative defects lying deep in conduction band. Transition levels between different charge states were determined. The 3-fold coordinated O vacancy dominates in θ-Al2O3 due to the higher formation energy of the 4-fold coordinated O vacancy. In am-Al2O3, only the +1/0 charge state of the 3-fold coordinated O vacancy and the +1/0, 0/−1 charge states of the 4-fold coordinated O vacancy have transition levels in the gap and these are near the conduction band edge. The large negative formation energy at O poor condition suggests that the oxygen defects widely exist in both phases.
Extreme ultraviolet ionization of pure He nanodroplets: Mass-correlated photoelectron imaging, Penning ionization, and electron energy-loss spectra
Authors: Buchta D. , Krishnan S. R. , Brauer N. B. , Drabbels M. , O’Keeffe P. , Devetta M. , Di Fraia M. , Callegari C. , Richter R. , Coreno M. , Prince K. C. , Stienkemeier F. , Ullrich J. , Moshammer R. , Mudrich M.
Published: August 2013

The ionization dynamics of pure He nanodroplets irradiated by Extreme ultraviolet radiation is studied using Velocity-Map Imaging PhotoElectron-PhotoIon COincidence spectroscopy. We present photoelectron energy spectra and angular distributions measured in coincidence with the most abundant ions He+, \documentclass[12pt]{minimal}\begin{document}${\rm He}^+_2$\end{document} He 2+, and \documentclass[12pt]{minimal}\begin{document}${\rm He}^+_3$\end{document} He 3+. Surprisingly, below the autoionization threshold of He droplets, we find indications for multiple excitation and subsequent ionization of the droplets by a Penning-like process. At high photon energies we observe inelastic collisions of photoelectrons with the surrounding He atoms in the droplets.
A computational infrared spectroscopic study of graphene oxide
Authors: Yin Di , Lu Ning , Li Zhenyu , Yang Jinlong
Published: August 2013

Infrared (IR) spectroscopy is an important means to study the atomic structure of graphene oxide (GO). In this study, computational simulations of GO IR spectra are carried out. The widely accepted Lerf model gives most experimental IR characteristics correctly except the strong C=O stretching peak. This is a result of the absence of carbonyl groups in the interior part of GO. Defects or small oxidative debris should thus be introduced into GO models to accommodate more carbonyl groups. Unfortunately, even for those with defects or oxidative debris included, most previous models in the literature still fail to give a correct IR response. Actually, the C=O stretching frequency is found to be very sensitive to local chemical environment. Therefore, to introduce defects or oxidative debris into GO models, certain constrains apply.
Structural phase diagrams of supported oxide nanowires from extended Frenkel-Kontorova models of diatomic chains
Authors: Noguera C. , Goniakowski J.
Published: August 2013

Relying on Frenkel Kontorova (FK) models of diatomic chains of increasing levels of complexity, this study presents an overall view of the diversity of structural effects that a compound (oxide) chain supported on a metal may display and helps assigning them to precise microscopic mechanisms. At each stage, the models are solved numerically, in order to provide phase diagrams as a function of chain-substrate interaction and misfit. Analytic derivations of transition lines are also provided within the continuum approximation. Their predictions are shown to quantitatively account for the numerical results, thus showing the validity of the continuum approximation in the misfit range under consideration. The present study thus extends our knowledge of the FK model by specifically focusing on diatomic chains and brings new information on a potentially interesting system which experimentalists just start being able to synthesize—oxide chains on metal substrates.
Theory and simulation of field emission diode oscillators
Authors: Benedik A. I. , Ryskin N. M. , Han S. T.
Published: August 2013

The results of a theoretical analysis of a diode oscillator with a field-emission cathode are presented. A small-signal analysis of self-excitation conditions is performed. The time-domain particle-in-cell code is developed, and the performance of an X-band oscillator is numerically demonstrated using the simulation code. The simulation shows a rather high output power and efficiency for reasonable values of cathode current density.