bluuebunny/crossref_metadata_2025 huggingface dataset:
CW measurements of resonance Raman profiles, line‐widths, and cross‐sections of fluorescent dyes: application to Nile Blue A in water and ethanol
Authors: Reigue Antoine , Auguié Baptiste , Etchegoin Pablo G. , Le Ru Eric C.
Published: January 2013

The aim of this work is to illustrate the power of recently developed methods for measuring resonance Raman scattering (RRS) spectra of efficient fluorophores (using a standard continuous wave excitation and a charge‐coupled device (CCD)‐based Raman spectrometer), by applying them to a detailed study of a specific fluorophore: Nile Blue A. A combination of methods are used to measure the RRS properties of Nile Blue A in water (quantum yield (QY) of 4%) and ethanol (QY of 22%) at excitation wavelengths between 514 and 647 nm, thus covering both pre‐resonance and RRS conditions. Standard Raman measurements are used in situations where the fluorescence background is small enough to clearly observe the Raman peaks, while the recently introduced polarization‐difference RRS and continuously shifted Raman scattering are used closer to (or at) resonance. We show that these relatively straightforward methods allow us to determine the Raman cross‐sections of the most intense Raman peaks and provide an accurate measurement of their line‐width; even for broadenings as low as ∼ 4 cm − 1. Moreover, the obtained Raman excitation profiles agree well with those derived from the optical absorption by a simple optical transform model. This study demonstrates the possibility of routine RRS measurements using standard Raman spectrometers, as opposed to more complicated time‐resolved techniques. Copyright © 2013 John Wiley & Sons, Ltd.
Effects of extracts of Humulus lupulus (hops) and Yucca schidigera applied alone or in combination with monensin on rumen fermentation and microbial populations in vitro
Authors: Narvaez Nelmy , Wang Yuxi , McAllister Tim
Published: January 2013

Background

β‐Acids in hops (Humulus lupulus) and saponins in yucca (Yucca schidigera) have been found to possess antimicrobial properties similar to that of monensin and could be an alternative to in‐feed antibiotics. The effects of monensin (MON) and ethanol extracts of hops (HE) and Y. schidigera (YE) alone and in combination with MON were assessed on ruminal microbial composition and fermentation in vitro of a barley‐based diet.

Results

All treatments decreased (P < 0.05) CH4 production (per unit of dry matter), microbial protein (mg), and NH3‐N accumulation. All treatments reduced (P < 0.01) the acetate:propionate (A:P) ratio and molar proportions of butyrate, but increased (P < 0.01) those of propionate, whereas those of acetate decreased (P < 0.001) with addition of MON (10 µg mL−1) and combined with HE or YE. Methane produced per unit of true digested dry matter decreased (P < 0.001) with all treatments except YE. Monensin reduced (P < 0.001) proportions of 16S rRNA copies of Ruminococcus flavefaciens, but increased (P < 0.01) those of Selenomonas ruminantium. Hops extract alone or combined with MON reduced (P < 0.01) proportions of R. flavefaciens but combined with MON tended (P < 0.1) to increase those of S. ruminantium. Yucca extract combined with MON increased (P < 0.01) the proportions of R. flavefaciens and S. ruminantium. All treatments except MON (2.5 µg mL−1) reduced (P < 0.01) the relative abundance of methanogens.

Conclusion

Hops extract and YE altered rumen microbes and fermentation in a manner similar to MON with many responses being additive when applied in combination. © 2013 Society of Chemical Industry
Sensory and instrumental texture measurements for assessing grape seed parameters during fruit development
Authors: Letaief Hend , Maury Chantal , Symoneaux Ronan , Siret René
Published: January 2013

Background

The evolution of the sensory and instrumental properties of grape seeds was investigated during berry development, with a focus on the effects of the harvest season and growing location.

Results

The sensory and instrumental texture analyses gave a consistent description of the ripening process. Moreover, the effect of maturation on the seed sensory descriptors was clearly influenced by the harvest season, and astringency was the most appropriate sensory attribute for the assessment of grape seed ripening. Except for seed cracking, which was positively correlated with fracturability (R = 0.69) and toughness (R = 0.68) in 2006, the compression parameters were generally not correlated with the sensory textural attributes but were more likely correlated with other sensory attributes such as astringency and vegetal aroma. The compression indices showed a logarithmic behaviour pattern during grape development, and seed stiffness was shown to be the most valuable textural index for parcel discrimination and identification of the optimal grape harvesting date.

Conclusion

This research showed that both seed sensory attributes and instrumental texture properties are indicators of grape ripening. However, these properties could be affected by the harvest season and growing location. As no clear correlation was found between the seed sensory attributes and instrumental texture parameters, a revision of the sensory method available in the literature could be suggested. © 2013 Society of Chemical Industry
Effects of krill oil intake on plasma cholesterol and glucose levels in rats fed a high‐cholesterol diet
Authors: Li Dong-Mei , Zhou Da‐Yong , Zhu Bei‐Wei , Chi Ya‐Li , Sun Li‐Ming , Dong Xiu‐Ping , Qin Lei , Qiao Wei‐Zhou , Murata Yoshiyuki
Published: January 2013

Background

In this study, whole krill oil (WKO) and phospholipid‐type krill oil (PKO) with different lipid composition were prepared. The effects of KO intake on plasma cholesterol and glucose levels in Wistar rats fed a high‐cholesterol diet (HCD) were investigated.

Results

WKO contained 37.63% triglycerides, 48.37% phospholipids, 13.54% free fatty acids and 0.66% cholesterol, whereas the corresponding values for PKO were 0.59, 69.80, 28.53 and 1.09% respectively. Meanwhile, PKO contained much more polyunsaturated fatty acids (PUFA, 37.76%) than WKO (28.36%). After 4 weeks of HCD consumption, plasma levels of total cholesterol (TC), low‐density lipoprotein cholesterol (LDL‐C) and glucose increased significantly, but that of high‐density lipoprotein cholesterol (HDL‐C) decreased significantly. The intake of PKO and WKO for 4 weeks caused a significant reduction in body weight gain and plasma levels of TC and LDL‐C in HCD‐fed rats. Compared with WKO, PKO was more effective in decreasing plasma TC and LDL‐C levels.

Conclusion

PKO showed better overall cholesterol‐lowering effects than WKO, which may be due to its higher n‐3 PUFA levels. © 2013 Society of Chemical Industry
Accumulation of soil‐borne aluminium, iron, manganese and zinc in plants cultivated in the region of Moanda (Gabon) and nutritional characteristics of the edible parts harvested
Authors: Ondo Jean Aubin , Menye Biyogo Richard , Eba François , Prudent Pascale , Fotio Daniel , Ollui‐Mboulou Magloire , Omva‐Zue Joseph
Published: January 2013

Background

In central Africa, studies on the transfer of metals from soil to food crops, the composition of foods and the dietary intake of cultivated vegetables are scarce. In this study, aluminium (Al), iron (Fe), manganese (Mn) and zinc (Zn) transfer from naturally (pedogeochemically) contaminated soils into ten edible plants and human exposure to these metals via edible parts of the plants were investigated.

Results

The fertility of the soils studied was still satisfactory. Soil Al (33 029–40 031 mg kg−1), Fe (20 869 ± 1124 mg kg−1) and Zn (248.3 ± 37.9 mg kg−1) concentrations were consistent with those found in agricultural soils, but Mn concentrations were above those normally encountered in arable fields (10 000 mg kg−1). The results indicated a substantial accumulation of Fe in red roselle leaves and of Al, Mn and Zn in some leafy plants and okra (fruits). The present study highlights that adults consuming vegetables grown on naturally Mn‐rich soils ingest significant amounts of Al, Mn and Zn. However, Zn amounts were below the recommended maximum tolerable levels for hazard risk.

Conclusion

The study indicated that Al and Mn accumulation in food crops cultivated in the Moanda area of Gabon may represent a health hazard. However, the high levels of Zn in vegetables could be a pathway for Zn supplementation in human nutrition to reduce Zn deficiency in developing countries. © 2013 Society of Chemical Industry
Octreotide labeled aggregates containing platinum complexes as nanovectors for drug delivery
Authors: Accardo Antonella , Mangiapia Gaetano , Paduano Luigi , Morelli Giancarlo , Tesauro Diego
Published: January 2013

The synthesis, formulation and a complete physico‐chemical characterization, by dynamic light scattering and small angle neutron scattering techniques, of new liposomal aggregates obtained by co‐assembling an amphiphilic molecule containing a platinum complex, Peg1500‐Lys(Pt‐aminoEtGly)‐Lys(C18)2, (abbreviated as (C18)2‐PKAG‐Pt), with a second amphiphilic monomer, (C18H37)2NCO(CH2)2CO(AdOO)5‐Oct ((C18)2L5‐Oct), containing the octreotide bioactive peptide, is reported. Liposomes of (C18)2‐PKAG‐Pt present a radius of 48 nm, whereas the mixed aggregates (C18)2‐PKAG‐Pt/(C18)2L5‐Oct at 90/10 M ratio give larger liposomes with a radius of 84 nm. In both cases, the bilayer thickness is ~5.3 nm. Encapsulation of doxorubicin in mixed liposomes is also obtained by using the pH gradient method. The obtained liposomes could represent a new target selective cargo system for delivery of cisplatin based drugs and/or doxorubicin on cells overexpressing the sstr2 and sstr5 somatostatin receptors. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.
Inherited agglomeration effects in hedge fund spawns
Authors: De Figueiredo Rui J. P. , Meyer‐Doyle Philipp , Rawley Evan
Published: January 2013

This paper studies inherited agglomeration effects, which we define as human capital that managers acquire while working in an industry hub that may be transferred to a spinoff. We test for inherited agglomeration effects in the hedge fund industry and find that hedge fund managers who previously worked in New York and London outperform their peers by about one percent per year. The results are driven by managers who worked in investment management positions previously, and are at least as large as traditional agglomeration effects that arise from being located in an industry hub contemporaneously. The evidence suggests that inherited agglomeration effects are an important, but as yet overlooked, factor influencing the performance of new firms. Copyright © 2013 John Wiley & Sons, Ltd.
How constraints and knowledge impact open innovation
Authors: Garriga Helena , von Krogh Georg , Spaeth Sebastian
Published: January 2013

Laursen andSalter (2006) examined the impact of a firm's search strategy for external knowledge on innovative performance. Based on organizational learning and open innovation literature, we extend the model hypothesizing that the search strategy itself is impacted by firm context. That is, both ‘constraints on the application of firm resources’ and the ‘abundance of external knowledge’ have a direct impact on innovative performance and a firm's search strategy in terms of breadth and depth. Based on a survey of Swiss‐based firms, we find that constraints decrease and external knowledge increases innovative performance. Although constraints lead to a broader but shallower search, external knowledge is associated with the breadth and the depth of the search in aU‐shaped relationship. Copyright © 2013 John Wiley & Sons, Ltd.
Do regions matter? An integrated institutional and semiglobalization perspective on the internationalization of MNEs
Authors: Arregle Jean‐Luc , Miller Toyah L. , Hitt Michael A. , Beamish Paul W.
Published: January 2013

Traditional research suggests a relationship between country‐level institutions and the location choices of MNEs. However, more recent theory suggests MNEs also focus on regions (semiglobalization). Therefore, this study examines institutional effects in the context of semiglobalization by considering the influences of three formal institutions (i.e., regulatory control, political democracy, capital investments) of countries and geographic regions on MNEs' location choices of internationalization. We use a sample of Japanese MNEs operating in 45 countries within eight regions. The results show that their degree of internationalization into a country is influenced by both country and regional institutional environments. Additionally, a semiglobalization perspective provides better explanatory power than does the country‐level perspective. These results present a new perspective on how MNEs consider institutional environments in their international strategy. Copyright © 2013 John Wiley & Sons, Ltd.
Market frictions as building blocks of an organizational economics approach to strategic management
Authors: Mahoney Joseph T. , Qian Lihong
Published: January 2013

This paper shows that market frictions are fundamental building blocks for an organizational economics approach to strategic management. Various organizational economic approaches (transaction costs, property rights, real options, and resource‐based) have distinctive focal problems and emphasize different combinations of market frictions. A wider recognition of the role of market frictions is useful for three main objectives. First, it helps identify an evolving market‐frictions paradigm in strategic management. Second, it shows how two primary questions in strategy of why firms exist and why some firms outperform others and the three primary strategic goals of cost minimization, value creation, and value capture can be better joined and evaluated. Third, different combinations of market frictions can generate new research questions and advance theory development in the strategic management field. Copyright © 2013 John Wiley & Sons, Ltd.
Intra‐industry diversification and firm performance
Authors: Zahavi Talli , Lavie Dovev
Published: January 2013

We study how intra‐industry product diversity affects firm performance by analyzing the implications of expanding a firm's product line within its core business. We conjecture that increases in product diversity initially undermine performance because of negative transfer effects but then improve it due to economies of scope. We further theorize that this U‐shaped effect of product diversity becomes more pronounced as the firm increases the intensity of its technology investment, yet is likely to be attenuated by the firm's accumulated experience with intra‐industry diversification. Data on 156 U.S.‐based software firms operating from 1990 to 2001 furnish support for these conjectures. Our study advances emerging research on intra‐industry diversification by underscoring some of its contingent performance effects. Copyright © 2013 John Wiley & Sons, Ltd.
A competition‐based explanation of collaborative invention within the firm
Authors: Toh Puay Khoon , Polidoro Francisco
Published: January 2013

Existing literature shows that collaborative invention within the firm enhances innovativeness by facilitating knowledge recombination. Despite such benefit, firms vary in their use of collaborative invention when drawing on their individual inventors' knowledge. In addressing this puzzle, we argue that competition from rival products building on similar knowledge compels firms to favor search depth over exploratory search and respond expeditiously, thus reducing a firm's inclination toward collaborative invention. In contrast with prior research's focus on how upstream resources influence a firm's position in downstream markets, this study shows that downstream competition drives heterogeneity across firms in their utilization of upstream resources. Copyright © 2013 John Wiley & Sons, Ltd.
Why pure strategies may be wrong for transition economy firms
Authors: Shinkle George A. , Kriauciunas Aldas P. , Hundley Greg
Published: January 2013

The strategy purity hypothesis argues firms will have better results pursuing a single, business‐level strategy of either cost leadership or differentiation rather than a mix of both. Since this claim implicitly assumes a developed‐economy context, we examine the efficacy of business strategies in transition economies. We find the benefits of a pure strategy are diminished when the institutional environment has a low degree of market orientation but are increased when the institutional environment is more market oriented. Our results indicate a boundary condition for the strategy purity hypothesis and support arguments for an institution‐based view of business strategy. Copyright © 2013 John Wiley & Sons, Ltd.
Nursing Ethics in Everyday Practice
Authors: Rockhill Wayne
Published: January 2013

Connie M. Ulrich, Nursing Ethics in Everyday Practice, 2012, Sigma Theta Tau International, 227 pages, softcover
Clinical Issues—February 2013
Authors: Burlingame Byron L.
Published: January 2013

This Month

Obtaining RN first assistant privileges to practice

Key words: RN first assistant (RNFA), privileging process, practice issues.

Creating policies and procedures for the RN first assistant credentialing process

Key words: RN first assistant (RNFA), credentialing process, privileging process.

Infection prevention guidelines for break rooms or lounges used by perioperative personnel

Key words: infection prevention, disease vectors, OR lounges, OR break rooms.

Sterilizing instruments when the sterilizer is malfunctioning

Key words: off‐site sterilization, sterilizing instruments, malfunctioning equipment.

Guidelines for the location of automatic endoscope reprocessors

Key words: endoscope reprocessor, department layout.
The Lived Spiritual Experiences of Patients Transitioning Through Major Outpatient Surgery
Authors: Griffin Andrew
Published: January 2013

Dramatic changes in outpatient surgery have occurred in recent years, but the basic care needs of surgical patients remain constant. Most outpatients face the same spiritual and coping issues that inpatients do, but outpatient surgery requires that patients cope with the surgery at an accelerated pace. This phenomenological study describes the meanings of the lived spiritual experiences of patients transitioning through major outpatient surgery. Analysis of interviews with participants resulted in four distinct themes: a point in time, holy other, vulnerability in the OR, and appraisals of uncertainty. Ways that health care providers can provide holistic case include developing an understanding of the patient's overall experience, understanding the patient's goals, and supporting the patient's own coping mechanisms and resources. Additional research should be conducted to explore interventions related to patients’ spiritual well‐being in outpatient settings.
Evaluation of OR Staffing and Postoperative Patient Outcomes
Authors: Talsma AkkeNeel , Anderson Christine , Geun HyoGeun , Guo Ying , Campbell Darrell A.
Published: January 2013

The purpose of this cross‐sectional cohort study was to evaluate the relationship between the number of OR personnel involved in a surgery and subsequent postoperative outcomes. We collected data from a sample of general surgery patients (N = 911) by using the American College of Surgeons National Surgical Quality Improvement Project processes. Data obtained from electronic medical records about the number of different personnel involved in the surgeries were used to create total OR staffing and nurse staffing variables for each surgery. Two associations approached statistical significance after we controlled for significant risk factors, including OR duration. A higher number of total nursing personnel involved in a surgical procedure was associated with any postoperative complication at the P = .095 level. A higher number of total OR personnel was associated with surgical site infections at the P = .057 level. We recommend further evaluation of these measures in multiple hospital settings.
Vimentin is a component of a complex that binds to the 5′‐UTR of human heme‐regulated eIF2α kinase mRNA and regulates its translation
Authors: Chatterjee Sangeeta , Panda Amaresh C. , Berwal Sunil K. , Sreejith R.K. , Ritvika Charu , Seshadri Vasudevan , Pal Jayanta K.
Published: January 2013

The human heme‐regulated eIF2α kinase, also called the human heme‐regulated inhibitor (hHRI) is significantly up‐regulated particularly at the level of translation during stress. In this report we show that during lead‐stress, the regulation of hHRI mRNA translation is mediated through its 5′‐untranslated region (UTR) that interacts with specific trans‐acting factors. Further, vimentin has been identified as one of the trans‐acting factors that contribute to this regulation.
Indication of ICD in Brugada syndrome
Authors: Shimizu Akihiko
Published: January 2013

Without question, implantable cardioverter–defibrillators (ICDs) are required in symptomatic Brugada patients with an aborted sudden cardiac death and/or documented ventricular fibrillation (VF) for the so‐called secondary prevention of sudden cardiac death, even if there is a possibility of complications and inappropriate shocks.

On the other hand, it is difficult to identify high‐risk patients requiring ICD placement among the Brugada syndrome patients with syncope and those asymptomatic. The incidence of de novo VF in asymptomatic patients with Brugada syndrome is very low. However, the cardiac events caused by this syndrome are very serious and lethal.

Currently, a spontaneous type 1 ECG and the presence of at least two multiparametric risk factors, including syncope, a family history, and a positive electrophysiological (EP) study, are the only criteria used to correctly identify patients requiring ICD placement (Class IIa in the Japanese guidelines).

Further investigation and the observation of the long‐term prognosis in asymptomatic Brugada syndrome patients are necessary to define criteria for accurately identifying high‐risk patients.
Is head injury characteristic of arrhythmic syncope?
Authors: Furukawa Toshiyuki , Hachiya Hitoshi , Isobe Mitsuaki , Hirao Kenzo
Published: January 2013

Background

Of the syncope types, arrhythmic syncope is the most life threatening and therefore requires proper treatment. However, the clinical predictors of arrhythmic syncope remain unknown. Some patients with syncope suffer from head injury, a serious side effect whose importance in the differential diagnosis of syncope has not been fully studied. Here, we attempted to identify the clinical characteristics of arrhythmic syncope, including the role played by head injuries.

Methods

We studied inpatients referred to the cardiology section for the diagnosis and treatment of syncope. Clinical characteristics including age, sex, incidence of head injury during syncope, and cardiologic studies were evaluated in patients with arrhythmic and non‐arrhythmic syncope.

Results

Of 5590 inpatients, 273 (4.8%) (170 men; mean age, 61±17 years) suffered a syncopal episode before admission, 119 (43%) of whom were diagnosed with arrhythmic syncope and 30 (11%) of whom were undiagnosed. In multivariate analysis, age >65 years (65% vs. 42%, p<0.005), abnormal electrocardiogram (66% vs. 43%, p<0.01), and the presence of a head injury (31% vs. 16%, p<0.01) were more prevalent in patients with arrhythmic syncope than in patients with non‐arrhythmic syncope.

Conclusions

Patients with arrhythmic syncope were older, suffered collateral head injuries more frequently, and were more likely to have abnormal electrocardiograms than patients with non‐arrhythmic syncope did.
Integrated care: a proposal for a European research agenda
Authors: Schrijvers Guus
Published: January 2013

Since 1999 concepts, theories and empirical research on integrated care came up in the research world. Their main applications were related to chronic patients and elderly. Emergency care and oncological care were less investigated from an integrated care perspective. Now at least four research questions are unanswered. They relate to payment systems, disease management versus care for the elderly, organizational structures versus networks and implementation on national level. These four questions are suggested as components for a European research agenda.
Entwicklung und Evaluation von Disease-Management- Programmen in Deutschland
Authors: Miksch Antje , Szecsenyi Joachim
Published: January 2013

Einleitung

Ausgehend von einer bestehenden Über-, Unter und Fehlversorgung wurden seit 2003 Disease-Management-Programme (DMP) als arztbasierte strukturierte Behandlungsprogramme für bestimmte Indikationen eingeführt. Ziele der Programme sind die Strukturierung und Qualitätssicherung der Versorgung, die Umsetzung evidenzbasierter Medizin, die Schulung von Patienten und Leistungserbringern sowie die standardisierte Dokumentation. In diesem Beitrag werden der Umsetzungsstand sowie ausgewählte Ergebnisse der gesetzlichen Evaluation und der Begleitforschung dargestellt.
A NEW PROOF OF THE REALISATION OF CUBIC TABLEAUX
Authors: YANG FEI , YIN YONGCHENG
Published: January 2013

By means of the dynamics on trees introduced by Emerson, DeMarco and McMullen, we give a new proof of the realisation of cubic tableaux.
Laser-driven torsional coherences
Authors: Ashwell Benjamin A. , Ramakrishna S. , Seideman Tamar
Published: January 2013

We discuss several interesting phenomena in the dynamics of strong field-triggered torsional wavepackets, which carry implications for the problem of torsional alignment in nonrigid molecules. Our results point to the origin and consequences of the fundamental differences between rotational and torsional coherences. In addition, we provide design guidelines for torsional control experiments by illustrating the role played by the laser intensity, pulse width, temperature, and molecular parameters. Specifically, as an example of several classes of molecules expected to make suitable candidates for laboratory experiments, we explore the torsional control of 9-[2-(anthracen-9-yl)ethynyl]anthracene and contrast it with that of biphenyl. Finally, we propose several potential applications for coherent torsional control in chemistry, physics, and material science.
Generalized Gauss maps and integrals for three-component links: Toward higher helicities for magnetic fields and fluid flows
Authors: DeTurck Dennis , Gluck Herman , Komendarczyk Rafal , Melvin Paul , Shonkwiler Clayton , Vela-Vick David Shea
Published: January 2013

To each three-component link in the 3-sphere we associate a generalized Gauss map from the 3-torus to the 2-sphere, and show that the pairwise linking numbers and Milnor triple linking number that classify the link up to link homotopy correspond to the Pontryagin invariants that classify its generalized Gauss map up to homotopy. We view this as a natural extension of the familiar situation for two-component links in 3-space, where the linking number is the degree of the classical Gauss map from the 2-torus to the 2-sphere. The generalized Gauss map, like its prototype, is geometrically natural in the sense that it is equivariant with respect to orientation-preserving isometries of the ambient space, thus positioning it for application to physical situations. When the pairwise linking numbers of a three-component link are all zero, we give an integral formula for the triple linking number analogous to the Gauss integral for the pairwise linking numbers. This new integral is also geometrically natural, like its prototype, in the sense that the integrand is invariant under orientation-preserving isometries of the ambient space. Versions of this integral have been applied by Komendarczyk in special cases to problems of higher order helicity and derivation of lower bounds for the energy of magnetic fields. We have set this entire paper in the 3-sphere because our generalized Gauss map is easiest to present here, but in a subsequent paper we will give the corresponding maps and integral formulas in Euclidean 3-space.
Asymmetric Rayleigh-Taylor and double-diffusive fingers in reactive systems
Authors: Lemaigre L. , Budroni M. A. , Riolfo L. A. , Grosfils P. , De Wit A.
Published: January 2013

Buoyancy-driven flows induced by the hydrodynamic Rayleigh-Taylor or double-diffusive instabilities develop symmetrically around the initial contact line when two solutions of given solutes with different densities are put in contact in the gravitational field. If the solutes affecting the densities of these solutions are involved in chemical reactions, changes in composition due to the underlying reaction-diffusion processes can modify the density profile in space and time, and affect the hydrodynamic patterns. In particular, if the density difference between the two reactant solutions is not too large, the resulting chemo-hydrodynamic patterns are asymmetric with regard to the initial contact line. We quantify both experimentally and numerically this asymmetry showing that fingers here preferentially develop above the reaction zone and not across the mixing zone as in the non reactive situation. In some cases, the reaction can even lead to the onset of a secondary double-diffusive instability between the product of the reaction, dynamically generated in situ, and one of the reactants.
Nanoscale domain switchings of Bi3.15Dy0.85Ti3O12 thin film under the simultaneous application of polarizing voltage and loading force
Authors: Zhu Z. , Zheng X. J. , Yang Z. C. , Qu S. S.
Published: January 2013

The nanoscale domain switchings of Bi3.15Dy0.85Ti3O12 thin film annealed at 700 °C were observed by piezoresponse force microscopy under the different DC polarizing voltages, loading forces, and simultaneously both of them. Then, the formation mechanisms of domain switchings were analyzed from the perspective of dynamics of ferroelectric nanodomain and equilibrium state free energy of ferroelectric nanodomain. First, the 180° domain switchings were observed under the single polarizing voltages ±12 V. However, there are small amounts of anti-parallel domains. Second, the 90° domain switching was detected under the different single loading forces (150 and 300 nN). Finally, both 90° and 180° domain switchings were obtained under the simultaneously applied fields of polarizing voltage (+10 V) and loading forces (100 and 200 nN). The formation mechanisms of typical electric-generated nanoscale domain switchings were analyzed by forward domain-growth mechanism and grain deformation, and the abnormal electric-generated domain switching is interpreted by grain boundary effect and built-in electric field. Furthermore, we adopted the domain switching criterion from the perspective of equilibrium state free energy of ferroelectric nanodomain to uniformly explain the mechanisms of domain switchings induced by different external fields. It is necessary to understand the evolution mechanism of nanoscale domain switching for ferroelectric thin film devices.
A low-voltage spark-discharge method for generation of consistent oscillating bubbles
Authors: Goh B. H. T. , Oh Y. D. A. , Klaseboer E. , Ohl S. W. , Khoo B. C.
Published: January 2013

Underwater spark-discharge methods have been widely utilized for experimental studies in many fields such as material processing, water treatment, and cavitation bubble dynamics. However, the precise control of bubble size using this method has been difficult. This poses challenges to better understand the complex interactions of non-spherical cavitation bubble growth and collapse, which require fine and careful control of bubble size. A novel low-voltage (60.0 V) underwater spark-discharge method using a metal–oxide–semiconductor field effect transistor is presented here. We are able to repeatedly generate oscillating bubbles of consistent maximum radius, a. The dependency of the total circuit resistance to spark-generated bubble size in this method is discussed.
Uncertainty relation for non-Hamiltonian quantum systems
Authors: Tarasov Vasily E.
Published: January 2013

General forms of uncertainty relations for quantum observables of non-Hamiltonian quantum systems are considered. Special cases of uncertainty relations are discussed. The uncertainty relations for non-Hamiltonian quantum systems are considered in the Schrödinger-Robertson form since it allows us to take into account Lie-Jordan algebra of quantum observables. In uncertainty relations, the time dependence of quantum observables and the properties of this dependence are discussed. We take into account that a time evolution of observables of a non-Hamiltonian quantum system is not an endomorphism with respect to Lie, Jordan, and associative multiplications.
Application of the scaled-opposite-spin approximation to algebraic diagrammatic construction schemes of second order
Authors: Krauter Caroline M. , Pernpointner Markus , Dreuw Andreas
Published: January 2013

With the concept of scaled-opposite-spin (SOS), a pragmatic semi-empirical approximation has been introduced to the extended algebraic diagrammatic construction scheme of second order (ADC(2)-x) that leads to a significant saving in computational effort. The parameters included were fitted with respect to a benchmark set of electronically excited states in standard organic molecules that include some doubly-excited states, as well. Like the original, unscaled ADC(2)-x scheme it can be used to identify electronically excited states with high double excitation character, however at reduced computational cost. At the same time, it is possible to reduce the overestimation of doubly-excited configurations that is inherent to ADC(2)-x. Additionally, a scheme for the strict variant (ADC(2)-s) was derived directly from SOS-MP2 by application of the intermediate state formalism and compared to an existing version of SOS-ADC(2)-s.
Simulation of neoclassical transport with the continuum gyrokinetic code COGENT
Authors: Dorf M. A. , Cohen R. H. , Dorr M. , Rognlien T. , Hittinger J. , Compton J. , Colella P. , Martin D. , McCorquodale P.
Published: January 2013

The development of the continuum gyrokinetic code COGENT for edge plasma simulations is reported. The present version of the code models a nonlinear axisymmetric 4D (R, v∥, μ) gyrokinetic equation coupled to the long-wavelength limit of the gyro-Poisson equation. Here, R is the particle gyrocenter coordinate in the poloidal plane, and v∥ and μ are the guiding center velocity parallel to the magnetic field and the magnetic moment, respectively. The COGENT code utilizes a fourth-order finite-volume (conservative) discretization combined with arbitrary mapped multiblock grid technology (nearly field-aligned on blocks) to handle the complexity of tokamak divertor geometry with high accuracy. Topics presented are the implementation of increasingly detailed model collision operators, and the results of neoclassical transport simulations including the effects of a strong radial electric field characteristic of a tokamak pedestal under H-mode conditions.
Kinetic energy budgets near the turbulent/nonturbulent interface in jets
Authors: Taveira Rodrigo R. , da Silva Carlos B.
Published: January 2013

The dynamics of the kinetic energy near the turbulent/nonturbulent (T/NT) interface separating the turbulent from the irrotational flow regions is analysed using three direct numerical simulations of turbulent planar jets, with Reynolds numbers based on the Taylor micro-scale across the jet shear layer in the range Reλ ≈ 120–160. Important levels of kinetic energy are already present in the irrotational region near the T/NT interface. The mean pressure and kinetic energy are well described by the Bernoulli equation in this region and agree with recent results obtained from rapid distortion theory in the turbulent region [M. A. C. Teixeira and C. B. da Silva, “Turbulence dynamics near a turbulent/non-turbulent interface,” J. Fluid Mech. 695, 257–287 (2012)]10.1017/jfm.2012.17 while the normal Reynolds stresses agree with the theoretical predictions from Phillips [“The irrotational motion outside a free turbulent boundary,” Proc. Cambridge Philos. Soc. 51, 220 (1955)]10.1017/S0305004100030073. The use of conditional statistics in relation to the distance from the T/NT interface allow a detailed study of the build up of kinetic energy across the T/NT interface, pointing to a very different picture than using classical statistics. Conditional kinetic energy budgets show that apart from the viscous dissipation of kinetic energy, the maximum of all the mechanisms governing the kinetic energy are concentrated in a very narrow region distancing about one to two Taylor micro-scales from the T/NT interface. The (total and fluctuating) kinetic energy starts increasing in the irrotational region by pressure-velocity interactions – a mechanism that can act at distance, and continue to grow by advection (for the total kinetic energy) and turbulent diffusion (for the turbulent kinetic energy) inside the turbulent region. These mechanisms tend to occur preferentially around the core of the large-scale vortices existing near T/NT interface. The production of turbulent kinetic energy then becomes the dominating mechanism and the so called “peak production” is located at about one Taylor micro-scale from the T/NT interface. Simple analytical estimates are given for the peaks of pressure strain, turbulent diffusion, and production near the T/NT interface. The growth of kinetic energy across the T/NT interface is an inertial process, since the viscous terms (diffusion and dissipation) are negligible during this process. The present results highlight the importance of the region near the T/NT interface in the entire jet development.
Similarity analysis of the momentum field of a subsonic, plane air jet with varying jet-exit and local Reynolds numbers
Authors: Deo Ravinesh C. , Nathan Graham J. , Mi Jianchun
Published: January 2013

A similarity analysis is presented of the momentum field of a subsonic, plane air jet over the range of the jet-exit Reynolds number Reh (≡ Ubh/υ where Ub is the area-averaged exit velocity, h the slot height, and υ the kinematic viscosity) = 1500 − 16 500. In accordance with similarity principles, the mass flow rates, shear-layer momentum thicknesses, and integral length scales corresponding to the size of large-scale coherent eddy structures are found to increase linearly with the downstream distance from the nozzle exit (x) for all Reh. The autocorrelation measurements performed in the near jet confirmed reduced scale of the larger coherent eddies for increased Reh. The mean local Reynolds number, measured on the centerline and turbulent local Reynolds number measured in the shear-layer increases non-linearly following x1/2, and so does the Taylor microscale local Reynolds number that scales as x1/4. Consequently, the comparatively larger local Reynolds number for jets produced at higher Reh causes self-preservation of the fluctuating velocity closer to the nozzle exit plane. The near-field region characterized by over-shoots in turbulent kinetic energy spectra confirms the presence of large-scale eddy structures in the energy production zone. However, the faster rate of increase of the local Reynolds number with increasing x for jets measured at larger Reh is found to be associated with a wider inertial sub-range of the compensated energy spectra, where the −5/3 power law is noted. The downstream region corresponding to the production zone persists for longer x/h for jets measured at lower Reh. As Reh is increased, the larger width of the sub-range confirms the narrower dissipative range within the energy spectra. The variations of the dissipation rate (ɛ) of turbulent kinetic energy and the Kolmogorov (η) and Taylor (λ) microscales all obey similarity relationships, $\varepsilon h/U_{\rm b}^3 \sim Re_h^3$ɛh/Ub3∼Reh3, η/h ∼ Reh−3/4, and λ/h ∼ Reh−1/2. Finally, the underlying physical mechanisms related to discernible self-similar states and flow structures due to disparities in Reh and local Reynolds number is discussed.
One-dimensional lateral growth of epitaxial islands on focused ion beam patterned substrates
Authors: Gray J. L. , Nichols P. L. , Hull R. , Floro J. A.
Published: January 2013

Lateral growth of highly elongated SiGe islands in one dimension has been achieved by ex-situ substrate patterning using a focused ion beam (FIB) to create an array of surface grooves in the Si substrate. Growth of Si0.7Ge0.3 on this template results in preferential formation of strain-relieving islands next to the edges of the grooves under kinetically limited growth conditions. The length of the nanowire-like islands is limited only by the length of the patterned trench. Occasional bridging across the groove is also observed due to non-uniformity of the underlying topography and the strong preference for the formation of four-fold island structures in this system. The success of this method is dependent upon the initial Si buffer layer thickness and on the orientation of the grooves, which must be parallel to the crystallographic 〈110〉 directions. These results demonstrate that important crystallographic as well as kinetic factors must be considered for controlling the lateral growth of nanostructures on patterned substrates.
Adaptive femtosecond laser-induced breakdown spectroscopy of uranium
Authors: Ko P. , Hartig K. C. , McNutt J. P. , Schur R. B. D. , Jacomb-Hood T. W. , Jovanovic I.
Published: January 2013

Laser-induced breakdown spectroscopy (LIBS) is an established technique for material characterization applicable to a variety of problems in research, industry, environmental studies, and security. LIBS conducted with femtosecond laser pulses exhibits unique properties, arising from the characteristics of laser-matter interactions in this pulse width regime. The time evolution of the electric field of the pulse determines its interaction with sample materials. We present the design and performance of a femtosecond LIBS system developed to systematically optimize the technique for detection of uranium. Sample analysis can be performed in vacuum environment, and the spectral and temporal diagnostics are coupled through an adaptive feedback loop, which facilitates optimization of the signal-to-noise ratio by pulse shaping. Initial experimental results of LIBS on natural uranium are presented.
Thermodynamic properties of liquid water from a polarizable intermolecular potential
Authors: Yigzawe Tesfaye M. , Sadus Richard J.
Published: January 2013

Molecular dynamics simulation results are reported for the pressure, isothermal pressure coefficient, thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, Joule-Thomson coefficient and speed of sound of liquid water using a polarizable potential [Li et al., J. Chem. Phys. 127, 154509 (2007)]. These properties were obtained for a wide range of temperatures and pressures at a common liquid density using the treatment of Lustig [J. Chem. Phys. 100, 3048 (1994)] and Meier and Kabelac [J. Chem. Phys. 124, 064104 (2006)], whereby thermodynamic state variables are expressible in terms of phase-space functions determined directly from molecular dynamics simulations. Comparison with experimental data indicates that the polarizable potential can be used to predict most thermodynamic properties with a very good degree of accuracy.
Discussion on integrable properties for higher-dimensional variable-coefficient nonlinear partial differential equations
Authors: Zhang Yufeng , Tam Honwah
Published: January 2013

In this paper we introduce two new higher-dimensional variable-coefficient partial differential equations. One is a (2+1)-dimensional equation which can be reduced to the well-known KP equation which first occurs to the paper B. B. Kadomtsev and V. I. Petviashvili, “On the stability of solitary waves in weakly dispersive media,” Sov. Phys. Dokl. 15, 539 (1970), whose bilinear representation, Lax pairs, Bäcklund transformations, and infinite conservation laws are obtained respectively by using the Bell polynomials. Another one is a (3+1)-dimensional equation whose integrability is also investigated by us and whose Lax pairs, Bäcklund transformations, and infinite conservation laws are obtained, respectively.
Near-room-temperature refrigeration through voltage-controlled entropy change in multiferroics
Authors: Binek Ch. , Burobina V.
Published: January 2013

Composite materials with large magnetoelectric effect are proposed for application in advanced near-room-temperature refrigeration. The key innovation rests on utilizing the magnetocaloric effect in zero applied magnetic fields. This approach promises sizable isothermal entropy change and virtually temperature-independent refrigerant capacity through pure voltage-control. It is in sharp contrast with the conventional method of exploiting the magnetocaloric effect through applied magnetic fields. We outline the thermodynamics and estimate an isothermal entropy change specifically for the La0.7Sr0.3MnO3/Pb(Mg1/3Nb2/3)O3-PbTiO3(001) two-phase composite material. Finally, we propose structural variations of two-phase composites, which help in overcoming the challenging task of producing nanostructured material in macroscopic quantities.
Finite temperature performance of hard-soft composite nanomagnets and its dependence on geometry structure of composites
Authors: Belemuk A. M. , Chui S. T.
Published: January 2013

We study with finite temperature Monte Carlo simulation under periodic boundary conditions remanence, coercivity, and energy product behavior of exchanged-coupled hard and soft alternating layers. We compare multilayer properties with that of a composite composed of cube inclusions of hard phase embedded into a soft matrix. The easy axis of the hard (SmCo5) and soft (FeCo) phases is parallel to the layers and the applied magnetic field. We find a significant increase of the energy product for the multilayer structure as compared with that of the cube structure. In the former case, the switching occurs as a result of a two-step demagnetization process, realizing the concept of exchange-spring behavior, when first the soft layers gradually rotate to the direction of applied field, and then the hard phase layers rotate. In the latter case, we find a significant lowering of the remanent magnetization with increasing soft magnet content than anticipated. This is due to the boundary mismatch of magnetization on the hard/soft interface. We investigate this mismatch as a function of the soft phase content and temperature. The boundary mismatch significantly affects the finite temperature energy product of composites.
Compensational scintillation detector with a flat energy response for flash X-ray measurements
Authors: Chen Liang , Ouyang Xiaoping , Liu Bin , Liu Jinliang , Quan Lin , Zhang Zhongbing
Published: January 2013

To measure the intensity of flash X-ray sources directly, a novel scintillation detector with a fast time response and flat energy response is developed by combining film scintillators of doped ZnO crystal and fast organic scintillator together. Through compensation design, the dual-scintillator detector (DSD) achieved a flat energy response to X-rays from tens of keV to several MeV, and sub-nanosecond time response by coupling to ultrafast photo-electronic devices. A prototype detector was fabricated according to the theoretical design; it employed ZnO:In and EJ228 with thicknesses of 0.3 mm and 0.1 mm, respectively. The energy response of this detector was tested on monoenergetic X-ray and γ-ray sources. The detector performs very well with a sensitivity fluctuation below 5% for 8 discrete energy points within the 40–250 keV energy region and for other energies of 662 keV and 1.25 MeV as well, showing good accordance with the theoretical design. Additionally, the detector works properly for the application to the flash X-ray radiation field absolute intensity measurement. This DSD may be very useful for the diagnosis of time-resolved dynamic physical processes of flash X-ray sources without knowing the exact energy spectrum.