bluuebunny/crossref_metadata_2025 huggingface dataset:
Interventional endoscopy for the treatment of pancreatic pseudocyst and walled‐off necrosis (with videos)
Authors: Mukai Shuntaro , Itoi Takao , Moriyasu Fuminori
Published: August 2014

Pancreatic pseudocysts and walled‐off necrosis are typical late complications of acute pancreatitis, and they require drainage in symptomatic cases presenting with infection. Transgastrointestinal endoscopic treatment with endoscopic ultrasound‐guided drainage has become common and yields a good treatment outcome for pancreatic pseudocyst. Walled‐off necrosis, however, contains necrotic tissue, and thus many cases additionally require an invasive treatment that includes endoscopic necrosectomy. Methods that involve a procedure‐specific large‐diameter metal stent, additional endoscopic drainage techniques, and the hybrid approach method of adding percutaneous drainage have been described, and considerable advances in these methods have now made it possible to cure almost all cases of walled‐off necrosis with endoscopic treatment alone. However, without being restricted to endoscopic treatments, a wide range of options including surgery should be considered as treatments for walled‐off necrosis.
Artifactual microhemorrhage generated by susceptibility weighted image processing
Authors: Li Ningzhi , Wang Wen‐Tung , Pham Dzung L. , Butman John A.
Published: August 2014

Background

To report that artifactual microhemorrhages are introduced by the two‐dimensional (2D) homodyne filtering method of generating susceptibility weighted images (SWI) when open‐ended fringelines (OEF) are present in phase data.

Methods

SWI data from 28 traumatic brain injury (TBI) patients was obtained on a 3 tesla clinical Siemens scanner using both the product 3D gradient echo sequence (GRE) with generalized autocalibrating partially parallel acquisition acceleration and an in‐house developed segmented echo planar imaging (sEPI) sequence without GRAPPA acceleration. SWI processing included (i) 2D homodyne method implemented on the scanner console and (ii) a 3D Fourier‐based phase unwrapping followed by 3D high pass filtering. Original and enhanced magnitude and phase images were carefully reviewed for sites of type III OEFs and microhemorrhages by a neuroradiologist on a PACS workstation.

Results

Nineteen of 28 (68%) phase datasets acquired using GRAPPA‐accelerated GRE acquisition demonstrated type III OEFs. In SWI images, artifactual microhemorrhages were found on 17 of 19 (89%) cases generated using 2D homodyne processing. Application of a 3D Fourier‐based unwrapping method prior HP filtering minimized the appearance of the phase singularities in the enhanced phase, and did not generate microhemorrhage‐like artifacts in magnitude images.

Conclusion

The 2D homodyne filtering method may introduce artifacts mimicking intracranial microhemorrhages in SWI images when type III OEFs are present in phase images. Such artifacts could lead to overestimation of pathology, e.g., TBI. This work demonstrates that 3D phase unwrapping methods minimize this artifact. However, methods to properly combine phase across coils are needed to eliminate this artifact. J. Magn. Reson. Imaging 2015;41:1695–1700. © 2014 Wiley Periodicals, Inc.
Onset of Huntington's disease: Can it be purely cognitive?
Authors: Paulsen Jane S. , Long Jeffrey D.
Published: August 2014

Knowledge of the cognitive manifestation of Huntington's disease has burgeoned over the past two decades. Many studies from independent datasets have shown that cognitive impairment is evident before motor diagnosis, and annual cognitive decline is a robust marker of disease progression. Additionally, cognition is a critical concern to patients and families and is associated with meaningful outcomes, including functional capacity, driving, loss of accustomed work, and quality of life. In the past few years, Huntington's disease animal models of cognition have increased, preparing for preclinical experimental therapeutics with cognitive endpoints. A longitudinal analysis of cognitive variables was conducted with 559 gene‐positive cases and 233 controls showing no signs of motor abnormalities over approximately a 3‐year period. Results show statistically significant differences in rate of annual change for some cognitive variables, such that the cases group had worsening performance over time. These findings show that cognitive deterioration can be seen in persons with the Huntington's disease gene expansion with no overt motor signs or symptoms, suggesting that cognitive onset of Huntington's disease may precede motor. © 2014 International Parkinson and Movement Disorder Society
Vastus lateralis vascularized nerve graft in facial nerve reconstruction: An anatomical cadaveric study and clinical implications
Authors: Agrogiannis Nikolaos , Rozen Shai , Reddy Gangadasu , Audolfsson Thorir , Rodriguez‐Lorenzo Andres
Published: August 2014

Background

The present study investigates the vascular anatomy of the vastus lateralis motor nerve (VLMN) to be used as a vascularized nerve graft in facial nerve reconstruction. We evaluated the maximum length of the nerve that can be included in the flap and its vascular pedicle. In addition, we discuss its adequacy for use in early reconstruction of the facial nerve both as ipsilateral facial nerve reconstruction and as cross‐facial nerve graft.

Methods

Five fresh cadavers were used in this study. In all specimens, the VLMN and its vascular pedicle were dissected, photodocumented and measured using calipers. In addition, two vascularized VLMN were injected with a radiopaque contrast and underwent CT angiography and three dimensional reconstructions were scanned to illustrate the vascular supply of the nerve using OsiriX Software.

Results

The VLMN was divided into two divisions, an oblique proximal and a descending distal, in 70% of the dissections with a mean maximal length of 8.4 ± 4.5 cm for the oblique division and 15.03 ± 3.87 cm for the descending division. The length of the oblique division, when present, was shorter than the length of the descending branch in all specimens. The mean length of the pedicle was 2.93 ± 1.69 cm, and 3.27 ± 1.49 cm until crossing the oblique and the descending division of the nerve respectively. The mean caliber of the nerve was 2.4 ± 0.62 mm. Three‐dimensional computed tomography angiography demonstrated perfusion throughout the entire VLMN by branches from the descending branch of the lateral femoral circumflex artery which ran parallel to the descending division of the VLMN. Additionally, we observed that technically it was possible to preserve the oblique branch of the VLMN.

Conclusion

This study confirms that VLMN presents adequate anatomic features to be used as a vascularized nerve graft for facial nerve reconstruction in terms of length, pedicle, and caliber. © 2014 Wiley Periodicals, Inc. Microsurgery 35:135–139, 2015.
Dynamic NMR study of cyclic derivatives of pyridoxine
Authors: Rakhmatullin I.Z. , Galiullina L.F. , Garipov M.R. , Strel'nik A.D. , Shtyrlin Y.G. , Klochkov V.V.
Published: August 2014

A series of pyridoxine derivatives was investigated by 1H and 2D nuclear overhauser enhancement spectroscopy (NOESY) NMR. The free energies of activation for the pyridyl‐oxygen rotation of the 2,4‐dinitrophenyl ether of the seven‐membered acetals of pyridoxine were measured by dynamic NMR. A conformational exchange between the chair and twist forms of the seven‐membered acetal ring was confirmed by dynamic NMR and STO3G computations. Copyright © 2014 John Wiley & Sons, Ltd.
A Call to Wellness – Whitiwhitia i te ora: Exploring Māori and Occupational Therapy Perspectives on Health
Authors: Hopkirk Jane , Wilson Linda H
Published: August 2014

The World Health Organization records that indigenous peoples throughout the world experience poor health. The concept of health was explored from a Māori world view and compared with occupational therapy perspectives. The aim was to understand and value indigenous knowledge and promote culturally safe responsive practice.

Māori methodologies were employed to protect the Māori knowledge shared in the study. This involved applying seven principles, including respect for people, be cautious, and look, listen, and speak. Perspectives on health and wellbeing were collected in 2008–2009 from indigenous occupational therapists, other occupational therapists and indigenous health practitioners using interviews and a questionnaire.

The findings are presented as a conceptual framework, depicting a whare, a Māori meeting house to show relationships between culture and health. Key concepts held by occupational therapists and Māori were spirituality, holistic views, client responsive practice, and environmental contexts. Areas of difference were the focus on occupations, the interdependence of indigenous relationships, and the place of the extended family in supporting wellness.

A strength was the respect for Māori methodologies and limitations were the number of participants (N = 23) and the small proportion of Māori therapists in Aotearoa/New Zealand.

Recommendations: Attention to culture is vital for appropriate, safe, and responsive practice. The conceptual framework provides a tool to inform, guide, and evaluate practice understandings. It acknowledges the importance of the individual within their extended family, their natural environment, and the historical, social, and political realities of living as Māori. Further research should explore the use of the framework and interaction between occupational therapy practice and specific indigenous cultures. Copyright © 2014 John Wiley & Sons, Ltd.
A longitudinal study on the impact of active surveillance for prostate cancer on anxiety and distress levels
Authors: Venderbos Lionne D. F. , van den Bergh Roderick C. N. , Roobol Monique J. , Schröder Fritz H. , Essink‐Bot Marie‐Louise , Bangma Chris H. , Steyerberg Ewout W. , Korfage Ida J.
Published: August 2014

Objective

Patients with potentially indolent prostate cancer (PC) can be managed with active surveillance (AS). Our objective was to analyse how anxiety and distress develop in men with untreated PC and whether highly anxious men quit AS.

Methods

One hundred and fifty Dutch patients who opted for AS in the Prostate cancer Research International: Active Surveillance Study were invited to participate in an additional prospective, longitudinal quality of life (QoL) study within 6 months after diagnosis. Participants completed questionnaires with validated measures on anxiety and distress at inclusion (t = 0), 9 (t = 9) and 18 (t = 18) months after diagnosis. We assessed changes in scores on depression (Center for Epidemiologic Studies Depression (CES‐D) scale), generic anxiety (State–Trait Anxiety Inventory (STAI‐6)), PC‐specific anxiety (Memorial Anxiety Scale for Prostate Cancer (MAX‐PC)) and decisional conflict (Decisional Conflict Scale (DCS)) about patients' treatment choice between t = 0, t = 9 and t = 18 using repeated measures analysis.

Results

Response rates for patients still on AS at t = 0, t = 9 and t = 18 assessments were 86%, 90% and 96%, respectively. Nine patients (7%, 9/129) between t = 0 and t = 9 and 33 of 108 patients (31%) between t = 9 and t = 18 stopped AS, mostly (86%) because of protocol‐based reasons. CES‐D, total MAX‐PC and DCS scores did not change significantly (p > 0.05) when comparing t = 18 with t = 9 and t = 0 scores, but generic anxiety (STAI‐6; p = 0.033) and fear of disease progression (sub‐score of the MAX‐PC; p = 0.007) decreased significantly. These differences, however, were clinically modest (0.089 SD and 0.281 SD). Overall, six of 129 men (5%) discontinued AS because of anxiety and distress.

Conclusions

When men with low‐risk PC are managed with AS, fear of disease progression and general anxiety decreased, and only few may discontinue AS because of anxiety and distress. This suggests that negative QoL effects are limited in men with favourable clinical characteristics who opted for AS. (Registered trial number, NTR1718) Copyright © 2014 John Wiley & Sons, Ltd.
Science‐policy interfacing on the issue of groundwater and groundwater‐dependent ecosystems in Europe: implications for research and policy
Authors: Batubara Bosman , Batelaan Okke , Quevauviller Philippe
Published: August 2014

A policy‐oriented research initiative should be directed to support the development of environmental policy, tackling specific questions and identifying policy gaps. However, that is not always the case. Recent research designed to assist in the revision of the European Union's (EU's) Groundwater Directive (GWD) illustrates different interpretations of research needs by scientists. The EU's GWD made a specific call for research to provide better criteria for ensuring groundwater ecosystem quality and protection (recital 20 of the directive). To date, scientific responses actually focused on a better understanding of groundwater‐dependent (aquatic and terrestrial) ecosystems which contributed to a better approach of environmental quality standards (threshold values) but did not fulfil the specific request of the Directive. In term of policy, on‐going research is aiming at contributing to the revision of the GWD regarding chemical aspects (and better knowledge of groundwater interactions with associated ecosystems) but is not addressing specific groundwater ecological aspects as required in the Directive's recital. Looking ahead, a stronger interface between policy makers and scientists in the EU is necessary to ensure that research better addresses specific requests of the GWD. WIREs Water 2014, 1:561–571. doi: 10.1002/wat2.1041

This article is categorized under:

Water and Life > Nature of Freshwater Ecosystems

Human Water > Water Governance

Science of Water > Water Quality
Cross‐market spillovers with ‘volatility surprise’
Authors: Aboura Sofiane , Chevallier Julien
Published: August 2014

This article adopts the asymmetric DCC with one exogenous variable (ADCCX) model developed by Vargas (2008), by updating the concept of ‘volatility surprise’ to capture cross‐market relationships. Current methods for measuring spillovers do not focus on volatility interactions, and neglect cross‐effects between the conditional variances. This paper aims to fill this gap. The dataset includes four aggregate indices representing equities, bonds, foreign exchange rates and commodities from 1983 to 2013. The results provide strong evidence of spillover effects coming from the ‘volatility surprise’ component across markets. Against the background of the recent financial crisis, the aim is to contribute to the literature on the interdependencies of financial markets, both in conditional means and (co)variances. In addition, asset management implications are derived.
Taylor bubble rising in a vertical pipe against laminar or turbulent downward flow: symmetric to asymmetric shape transition
Authors: Fabre Jean , Figueroa-Espinoza Bernardo
Published: August 2014

The symmetry of Taylor bubbles moving in a vertical pipe is likely to break when the liquid flows downward at a velocity greater than some critical value. The present experiments performed in the inertial regime for Reynolds numbers in the range $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}100<\mathit{Re} < 10\, 000$ show that bifurcation to an eccentric motion occurs, with a noticeable increase of the bubble velocity. The influence of the surface tension parameter (an inverse Eötvös number), $\varSigma $, has been investigated for $0.0045<\varSigma <0.067$. It appears that the motion of an asymmetric bubble is much more sensitive to surface tension than that of a symmetric bubble. For any given $\varSigma $, the symmetry-breaking bifurcation occurs in both laminar and turbulent flow at the same vorticity-to-radius ratio ${(\omega /r)}_0$ on the axis of the carrier fluid. This conclusion also applies to results obtained previously from numerical experiments in plane flows.
A depth-averaged -rheology for shallow granular free-surface flows
Authors: Gray J. M. N. T. , Edwards A. N.
Published: August 2014

The $\mu (I)$-rheology is a nonlinear viscous law, with a strain-rate invariant and pressure-dependent viscosity, that has proved to be effective at modelling dry granular flows in the intermediate range of the inertial number, $I$. This paper shows how to incorporate the rheology into depth-averaged granular avalanche models. To leading order, the rheology generates an effective basal friction, which is equivalent to a rough bed friction law. A depth-averaged viscous-like term can be derived by integrating the in-plane deviatoric stress through the avalanche depth, using pressure and velocity profiles from a steady-uniform solution to the full $\mu (I)$-rheology. The resulting viscosity is proportional to the thickness to the three halves power, with a coefficient of proportionality that is angle dependent. When substituted into the depth-averaged momentum balance this term generates second-order derivatives of the depth-averaged velocity, which are multiplied by a small parameter. Its inclusion therefore represents a singular perturbation to the equations. It is shown that a granular front propagating down a rough inclined plane is completely unaffected by the rheology, but, discontinuities, which naturally develop in inviscid roll-wave solutions, are smoothed out. By comparison with existing experimental data, it is shown that the depth-averaged $\mu (I)$-rheology accurately predicts the growth rate of spatial instabilities to steady-uniform flow, as well as the dependence of the cutoff frequency on the Froude number and inclination angle. This provides strong evidence that, in the steady-uniform flow regime, the predicted decrease in the viscosity with increasing slope is correct. Outside the range of angles where steady-uniform flows develop, the viscosity becomes negative, which implies that the equations are ill-posed. This is a signature of the ill-posedness of the full $\mu (I)$-rheology at both high and low inertial numbers. The depth-averaged $\mu (I)$-rheology therefore cannot be used outside the valid range of angles without additional regularization.
Identity and the evolving relationship between Inuit women and the land in the eastern Canadian Arctic
Authors: Dowsley Martha
Published: August 2014

Academic discussions around Inuit identity once focused on acculturation. These have mainly been replaced by concepts of adaptation to new living conditions. Yet, Inuit in the eastern Canadian Arctic still frame identity concerns around their land activities and are wary of becoming too much like ‘Qallunaat’ or southerners. This paper examines what material and non-material goods (for example psychological goods) Inuit seek from the land today in order to understand what traditional aspects of their relationships with the land persist and what new ones might have emerged recently. It then discusses the implications these have for Inuit identity. The study found a decrease in the procurement and use of material goods from the land compared with previous generations. Concomitantly, the acquisition of non-material goods has become more formalised and distinctly identified in discussions of land excursions. The non-material goods are clearly linked to Inuit ideology and traditions, rather than to southern ideas. The desire for, and acquisition of, non-material goods is developing both from a top-down or group consensus and bottom-up or individual decision, illustrating an interplay between the construction of group and individual identities in relation to the land. Inuit in the eastern Canadian Arctic are transforming their relationship with the land in a way that demonstrates an emerging identity as community Inuit who are rooted in their own local history and geography and also consciously subscribe to a larger Inuit culture that is premised on values such as sharing and building harmonious relationships.
Effects of patch size on liana diversity and distributions in the tropical montane evergreen forests of the Nilgiri Mountains, southern India
Authors: Mohandass Dharmalingam , Hughes Alice C. , Campbell Mason , Davidar Priya
Published: August 2014

We investigate the effect of patch size on liana diversity and distribution in 19 patches of montane evergreen forest in the Nilgiri hills, Western Ghats, southern India. Additionally, we examined how liana species richness and community assemblage in both edge (within 10 m of the forest edge) and interior regions of forest patches respond to patch size, in order to infer the impact of forest expansion or reduction on the liana communities. A total of 1276 woody liana individuals of 15 species were identified, belonging to 10 genera and nine families. Total species richness of lianas was significantly positively related to forest-patch area, both when analysed for the entire patch, in addition to both core and edge regions when examined separately. Species richness of larger lianas also showed a significant positive relationship with increasing forest patch area. Community assemblage varied with respect to forest edge, with shade-dependent species only occurring in interior patch regions, shade-averse species in edge regions, and shade-tolerant species occurring throughout. Disturbance also played a role in determining the response of liana diversity to patch size, with heavily disturbed patches showing no relationship between patch size and diversity, whereas positive relationships exist in low to moderately disturbed patches. The most significant result is the change in liana community composition between small and larger fragments. Many species present in smaller patches are also present in edge zones of larger fragments. This suggests that lianas are important structural components of montane forest ecosystems, and their compositional patterns are possibly driven by succession. Moreover, this study reveals the importance of edge effect and patch size in influencing liana species richness and compositional patterns.
Large-scale oil spills and flag-use within the global tanker fleet
Authors: MILLER DANA D. , TOOLEY KATHRYN , SUMAILA U. RASHID
Published: August 2014

Within the global oil shipping sector, flag states that inadequately fulfil obligations to effectively exert jurisdiction over vessels flying their flags have been criticized for facilitating the existence of substandard ships. This paper examines the topic of flag-use and its potential association with oil spill risk. Flags most associated with accidental oil spills were identified through comparing the flag composition of the global oil tanker fleet with that of vessels that have been involved in the 100 largest tanker spills on record. Vessels flying flags of states that have exhibited consistent patterns of failure in compliance with international obligations, defined here as ‘flags of non-compliance’ (FoNCs), were found to be significantly more common amongst the vessels that have been involved in spill incidents. However, this was dependent on how the Liberian flag was qualified throughout the time period considered. If measures are being sought to reduce the risk of tanker involvement in large-scale oil spills further, vessel owners should be deterred from registering with FoNCs that are highly accessible to foreign owners, and political measures should be taken to put pressure on flag states that operate all other FoNCs to improve effective jurisdiction over ships flying these flags.
Allelic variants at codon 146 in thePRNPgene show significant differences in the risk for natural scrapie in Cypriot goats
Authors: ORTIZ-PELAEZ A. , GEORGIADOU S. , SIMMONS M. M. , WINDL O. , DAWSON M. , ARNOLD M. E. , NEOCLEOUS P. , PAPASAVVA-STYLIANOU P.
Published: August 2014

Previous studies have shown the association between the polymorphisms serine (S) or aspartic acid (D) at codon 146 of thePRNPgene and resistance to scrapie. All goats aged >12 months (a total of 1075 animals) from four herds with the highest prevalence of scrapie in the country were culled and tested, of which 234 (21·7%) were positive by either the rapid test or immunohistochemistry (IHC) for any of the tissues tested. The odds of scrapie infection occurring in NN146goats was 101 [95% credible interval (CrI) 19–2938] times higher than for non-NN146or unknown genotypes. IHC applied to lymphoreticular tissue produced the highest sensitivity (94%, 95% CrI 90–97). The presence of putatively resistant non-NN146alleles in the Cypriot goat population, severely affected by scrapie, provides a potential tool to reduce/eradicate scrapie provided that coordinated nationwide breeding programmes are implemented and maintained over time.
Molecular epidemiology and antimicrobial susceptibility profiles of methicillin-resistantStaphylococcus aureusblood culture isolates: results of the Quebec Provincial Surveillance Programme
Authors: LÉVESQUE S. , BOURGAULT A. M. , GALARNEAU L. A. , MOISAN D. , DOUALLA-BELL F. , TREMBLAY C.
Published: August 2014

The objectives of this study were to characterize methicillin-resistantStaphylococcus aureus(MRSA) blood culture isolates and to determine their relative importance in both nosocomial and community-acquired infections. A total of 535 MRSA blood culture isolates were analysed.In vitrosusceptibility to 14 agents was determined. The genesnuc, mecAand coding for PVL toxin were identified by PCR. All isolates were characterized by PFGE orspatyping to assess their genomic relationships. Most MRSA isolates were retrieved from nosocomial bloodstream infections (474, 89%) and were of the CMRSA2 genotype. Healthcare-associated (HA)-MRSA bloodstream infections were associated with older age (70–89 years,P = 0·002) and most often secondary to central line infections (P = 0·005). Among MRSA strains associated with community-acquired (CA)-MRSA, 28·8% were isolated in intravenous drug users. CA-MRSA genotypes were more frequently found in young adults (20–39 years,P < 0·0001) with skin/soft tissue as the primary sources of infection (P = 0·006). CMRSA10 genotype was the predominant CA-MRSA strain. All MRSA isolates were susceptible to doxycycline, tigecycline, trimethoprim/sulfamethoxazole and vancomycin. Both the presence of the genes coding for PVL toxin (89·8%) and susceptibility to clindamycin (86·5%) were predictive of CA-MRSA genotypes. Whereas in the USA, HA-MRSA have been replaced by USA300 (CMRSA10) clone as the predominant MRSA strain type in positive blood cultures from hospitalized patients, this phenomenon has not been observed in the province of Quebec.
Definition and Classification of Disasters
Authors: Rutherford W. H.
Published: August 2014

An International Working Party on the Definition and Classification of Disasters, sponsored by the International Trauma Foundation, developed recommendations on the definition and classification of disasters. The party consisted of: WHRutherford(Chairman), Royal Victoria Hospital, Belfast UK; Dr. JacobAdler, Shaare Zedek Hospital, Jerusalem, Israel; Dr. PeterBaskett, Frenchay Hospital, Bristol UK; Dr.Jan De Boer, Het Nieve Spittal, Warnsveld, Netherlands; Professor BoBrismar, Department of Surgery, Huddinge, Sweden; Dr. Rudolf Frey, Department of Anesthesiology, University of Mainz, West Germany; Dr. OlafurJonson, Borgarspitalinn, Reykjavik, Iceland; Dr. StanelyMiles, International Trauma Foundation, Salsbury, UK; Dr. RonaldStewart, University of Pittsburgh, USA; Dr. HenrykZielinski, League of Red Cross Societies, Geneva, Switzerland.
Welcome to JEPS!
Authors: Morton Rebecca B. , Tucker Joshua A.
Published: August 2014

It is with great pleasure that we welcome readers to the inaugural issue of the Journal of Experimental Politics (JEPS). JEPS is the official journal of the Organized Section of the American Political Science Association (APSA) on Experimental Research. We are greatly honored to have been selected by the section as the first editors of the journal, and wanted to take this opportunity to briefly share with readers our vision for the journal, some interesting new—dare we say experimental?—policies that we have put in place for the journal, as well as the content in this first issue.
Stabilizing Gold Nanoparticles by Solid Supports
Authors: Ma Zhen , Dai Sheng
Published: August 2014

Catalysis by supported gold nanocatalysts has attracted much attention recently. However, gold nanoparticles tend to sinter under realistic conditions (e.g., under elevated temperatures or in reaction media), leading to degraded activity. Although there are many excellent reviews covering various aspects of gold catalysis, few have focused on the stabilization of gold nanoparticles on solid supports. Here we summarize several synthesis strategies for the stabilization of gold nanoparticles on solid supports, including: (1) pre-modification of supports before loading gold; (2) post-modification of supported gold catalysts; (3) dispersion of gold oxide dumbbell structures on supports; (4) in situ transformation of supported alloy catalysts into metal oxide modified supported gold catalysts; and (5) development of Au@oxide core-shell or yolk-shell structures. These synthesis strategies not only help develop new gold catalysts with tailored structures and better catalytic performance, but also furnish some ideas for the development of other supported metal catalysts. In addition, the observations on the enhanced thermal stability of these new gold catalysts provide new opportunities for future fundamental research.
Well-defined Gold Nanoclusters for Catalytic Applications
Authors: Li Gao , Jin Rongchao
Published: August 2014

In recent years, atomically precise gold nanoclusters [Aun(SR)m, where SR=thiolate] have emerged as a new promising class of catalysts for a wide range of reactions, including selective oxidation, chemoselective hydrogenation and carbon–carbon coupling reactions. These well-defined gold nanoclusters possess a sizable bandgap and quantized electronic structure, as opposed to the continuous conduction band in metallic gold nanoparticles. Moreover, some of the Aun(SR)m nanoclusters have been characterized crystallographically. These Aun(SR)m nanocluster model catalysts provide a unique opportunity to correlate the catalytic performance of nanogold catalysts with the atomic structure of gold nanoclusters and eventually to understand the mechanism of the gold nanocluster-catalysed processes at the atomic level.
Nanocrystal Superlattices: Novel Model Materials for Study of Catalysis
Authors: Kang Yijin , Stamenkovic Vojislav R. , Murray Christopher B.
Published: August 2014

Well-defined extended surfaces under highly controlled conditions are employed as model materials to study catalysis, while the real catalysts used in industrial processes are mainly nanomaterials. Nanomaterials with well-defined structures are greatly helpful to connect information gained from the extended surfaces to real catalysts. Recent developments in self-assembly allowed large-scale fabrication of multi-component superlattices, offering a single periodic architecture that combines the chemical and physical properties from different building blocks to exploit possible synergies. In this chapter, the preparation, characterization and properties of nanocrystal superlattices are discussed. The applications of binary superlattices in searching activity sites and investigating thermal stability are introduced and discussed in depth. It is expected that nanocrystal superlattices will provide a powerful new platform for research in the field of catalysis that bridges traditional studies of single crystals and supported particulate catalysts.
Twenty Years of Golden Future in the Water Gas Shift Reaction
Authors: Ramírez Reina T. , González Castaño M. , Palma S. , Ivanova S. , Odriozola J. A.
Published: August 2014

This chapter attempts to summarize the major part of existing information from the past 20 years dedicated to the application of gold-based catalysts in the water gas shift reaction. It is organized in five-year periods in which the most relevant aspects concerning the gold-based materials are described. Within the groups, the achievements are organized around the nature of the support, in a wish to underline the evolution of the materials and at the same time to emphasize the extreme importance of the supports for the good performance of the catalytic systems.
Advances in Catalytic Reactions by Gold-based Catalysts Through the Radical Chain Mechanism
Authors: Yang Xue-Jing , Ouyang Like , Xu Jing , Han Yi-Fan
Published: August 2014

Unlike the published literature, the chapter focuses on recent developments in our understanding of the radicals involved catalytic reactions on heterogeneous gold-based catalysts. This chapter is composed of four parts: (1) selective oxidation of alkanes; (2) selective oxidation of alkenes; (3) selective oxidation of alcohols and aldehydes; and (4) Fenton-like reaction and photocatalytic oxidation. The role of gold in the decomposition of hydrogen peroxide is analysed and the mechanism for the production of hydroxyl radicals (•OH) is envisaged.
Heterogeneous Gold Catalysts for Selective Oxidation Reactions
Authors: Gunawan Poernomo , Xu Rong , Zhong Ziyi
Published: August 2014

This chapter presents applications of supported gold catalysts in a number of important selective oxidation reactions, presenting particularly the related results published in the literature in the past three years. These reactions include selective oxidation of hydrocarbons such as epoxidation of propylene to propylene oxide, and selective oxidation of sugars, alcohols, glycerol and other polyols in the liquid and/or gas phase. Besides the often mentioned catalytic activity issues, topics such as the optimization of selectivity and the use of cheap oxidants such as air and oxygen are addressed as they are important in selective oxidations. A number of fundamental aspects, including preparation methods of gold catalysts, reaction mechanisms and the activation of molecular oxygen (a crucial step in oxidation reactions) are also discussed. Some theoretical calculations and modelling results, some of which are not available under the current experimental conditions, are mentioned as they shed light on various aspects including the structure of the active sites, activation of molecular oxygen and the role of the support.
Metal–Support Interaction Effects on Gold Catalysts over Reducible Oxides
Authors: Wu Hongjing , Liotta Leonarda F.
Published: August 2014

This chapter describes and critically analyses the growing literature dealing with metal–support interaction effects on gold catalysts over reducible oxides. It begins by introducing the synthesis of reducible oxide-supported gold catalysts (Au-MOx) prepared by chemical routes. Subsequently the emphasis is on low-temperature carbon monoxide oxidation over gold catalysts and how catalytic activity is enhanced by the interaction between gold nanoparticles and reducible oxides, as a function of the nature of the support. Several kinds of synergetic/cooperation effects on gold catalysts and the corresponding structural properties are discussed. Attention is given in particular to Au-TiO2, Au-CeO2, Au-FexOy and Au-MnOx catalysts. Carbon monoxide oxidation was used as a sensitive probe reaction in all the cases examined. The reaction mechanism and influence of different factors such as the nature and properties of the support, preparation methods, gold particle size and shape, and the electronic state of gold are discussed in detail. The final section highlights the challenges in the design and control of synergetic/interaction effects in heterogeneous gold catalysts.
A novel green synthesis approach for polymer nanocomposites decorated with silver nanoparticles and their antibacterial activity
Authors: Chen Guofang , Lu Jingran , Lam Clarissa , Yu Yong
Published: August 2014

A novel green synthesis strategy was developed for polymer composite spheres decorated with silver nanoparticles, mediated by a polymer colloid support itself, which are very stable and of high purity with excellent antibacterial activity.
Genomodifier capacity assay: a non-cell test using dsDNA molecules to evaluate the genotoxic/genoprotective properties of chemical compounds
Authors: Cadoná Francine C. , Manica-Cattani Maria F. , Machado Alencar K. , Oliveira Raul M. , Ribas da Silveira Flôres Eliza , Assmann Charles , Algarve Thais D. , da Cruz Ivana B. M.
Published: August 2014

We describe here an ultrasensitive and fast protocol called a GEMO assay (genomodifier capacity assay).
Modulating H2 sorption in metal–organic frameworks via ordered functional groups
Authors: Dau Phuong V. , Cohen Seth M.
Published: August 2014

Herein, we present the use of presynthetic and postsynthetic modification (PSM) approaches to regulate the structural organization of functional groups in the pores of isoreticular metal–organic frameworks (IRMOFs).
Cross-diffusion-induced convective patterns in microemulsion systems
Authors: Budroni M. A. , Lemaigre L. , De Wit A. , Rossi F.
Published: August 2014

Cross-diffusion phenomena are experimentally and theoretically shown to be able to induce convective fingering around an initially stable stratification of two microemulsions with different compositions.
The control of Pt and Ru nanoparticle size on high surface area supports
Authors: Liu Qiuli , Joshi Upendra A. , Über Kevin , Regalbuto John R.
Published: August 2014

Supported Ru and Pt nanoparticles were synthesized by the method of strong electrostatic adsorption and subsequently treated to achieve a series of catalysts with particle sizes ranging from 1 to 8 nm. This methodology allows the control of particle size applicable to high surface area supports with common metal precursors.
Hydrogen photochromism in Nb2O5 powders
Authors: Pan Lei , Wang Yi , Wang XianJie , Qu HuiYing , Zhao JiuPeng , Li Yao , Gavrilyuk Alexander
Published: August 2014

A more pronounced photochromic effect was observed in the M and H phases of Nb2O5 than in the other phases.
X-Ray absorption spectroscopy of LiBF4 in propylene carbonate: a model lithium ion battery electrolyte
Authors: Smith Jacob W. , Lam Royce K. , Sheardy Alex T. , Shih Orion , Rizzuto Anthony M. , Borodin Oleg , Harris Stephen J. , Prendergast David , Saykally Richard J.
Published: August 2014

X-ray absorption spectra, interpreted using first-principles electronic structure calculations, provide insight into the solvation of the lithium ion in propylene carbonate.
On the role of H2 to modify surface NOx species over Ag–Al2O3 as lean NOx reduction catalyst: TPD and DRIFTS studies
Authors: Azis Muhammad Mufti , Härelind Hanna , Creaser Derek
Published: August 2014

TPD and DRIFTS study to investigate dual role of H2 to promote and eliminate surface NOx species over Ag/Al2O3 catalyst.
Layered V–B–O polyoxometalate nets linked by diethylenetriamine complexes with dangling amine groups
Authors: Chen Hong , Zhang Yunfeng , Yu Zheng-Bao , Sun Junliang
Published: August 2014

Dangling amine groups were found in the diethylenetriamine (DETA) metal complexes, which worked as linkers in the construction of two-dimensional V–B–O polyoxometalate.
Avoiding problem reactions at the ferrocenyl-alkyne motif: a convenient synthesis of model, redox-active complexes for molecular electronics
Authors: Inkpen Michael S. , White Andrew J. P. , Albrecht Tim , Long Nicholas J.
Published: August 2014

A much improved route to 1,1′-bis(arylethynyl)ferrocenes comprising accessible thiolates on the aryl ring is reported. Unanticipated reactions between AcCl, TBAF–BBr3 and ferrocenyl-alkynes are also discussed, offering a rationale for previous synthetic difficulties.
Synthesis of a naphthalenediimide-based cyclophane for controlling anion–arene interactions
Authors: Li Yongjun , Zhao Yingjie , Jiang Runsheng , Liu Huibiao , Li Yuliang
Published: August 2014

A cationic cyclophane was employed to control the interactions between anions and a naphthalenediimide motif.
Going beyond the self-assembled monolayer: metal intercalated dithiol multilayers and their conductance
Authors: Hamoudi Hicham , Uosaki Kohei , Ariga Katsuhiko , Esaulov Vladimir A.
Published: August 2014

A study of the configuration and the conductivity of the self-assembly of silver intercalated dithiol (DTT) monolayers and multilayers on gold is presented.
Cobalt modified mesoporous graphitic carbon nitride with enhanced visible-light photocatalytic activity
Authors: Qiu Pengxiang , Chen Huan , Jiang Fang
Published: August 2014

Mesoporous graphitic carbon nitride (mpg-C3N4) was synthesized using silica nanoparticles as the hard template, and cobalt modified mpg-C3N4(Co3O4/mpg-C3N4) was preparedviaa facile impregnation method.
Room temperature biosynthesis of crystalline TiO2nanoparticles using Bacillus licheniformis and studies on the effect of calcination on phase structure and optical properties
Authors: Suriyaraj S. P. , Selvakumar R.
Published: August 2014

Extracellular production of oxidase enzyme byBacillus licheniformisat different time intervals during the biosynthesis of highly crystalline TiO2nanoparticles .
History-dependent ion transport through conical nanopipettes and the implications in energy conversion dynamics at nanoscale interfaces
Authors: Li Yan , Wang Dengchao , Kvetny Maksim M. , Brown Warren , Liu Juan , Wang Gangli
Published: August 2014

We report striking time-dependent ion transport characteristics at nanoscale interfaces in current–potential (I–V) measurements and theoretical analyses.
Bioactive nanocomposites of bacterial cellulose and natural hydrocolloids
Authors: Woehl Marco Aurelio , Ono Lucy , Riegel Vidotti Izabel Cristina , Wypych Fernando , Schreiner Wido Herwig , Sierakowski Maria Rita
Published: August 2014

Bacterial cellulose–natural hydrocolloid bionanocomposites were developed as cell growth substrates. The surface free energy of the composites is related to fibroblast viability. Surface properties of the bionanocomposites can be adjusted purely by changing the component proportions.
An experimental setup for the simultaneous measurement of thermoelectric power of two samples from 77 K to 500 K
Authors: Tripathi T. S. , Bala M. , Asokan K.
Published: August 2014

We report on an experimental setup for the simultaneous measurement of the thermoelectric power (TEP) of two samples in the temperature range from 77 K to 500 K using optimum electronic instruments. The setup consists of two rectangular copper bars in a bridge arrangement for sample mounting, two surface mount (SM) chip resistors for creating alternate temperature gradient, and a type E thermocouple in differential geometry for gradient temperature (ΔT) measurement across the samples. In addition, a diode arrangement has been made for the alternate heating of SM resistors using only one DC current source. The measurement accuracy of ΔT increases with the differential thermocouple arrangement. For the calibration of the setup, measurements of TEP on a high purity (99.99%) platinum wire and type K thermocouple wires Chromel and Alumel have been performed from 77 K to 500 K with respect to copper lead wires. Additionally, this setup can be utilized to calibrate an unknown sample against a sample of known absolute TEP.
Note: Magnification of a polarization angle with a Littrow layout brazed grating
Authors: Sasao H. , Arakawa H. , Kubo H. , Kawano Y. , Itami K.
Published: August 2014

A new method to magnify a small polarization angle with brazed gratings has been developed. In the method, difference in diffraction efficiency for S and P polarization components is used. The magnification dependence on the incident angle can be small by arranging the grating in Littrow layout. A magnification with a factor ∼2.7 has been demonstrated for a 10.6 μm CO2 laser beam as expected from a calculation. The method is applicable in many polarimetry fields.
Formation mechanism of threading-dislocation array in AlN layers grown on 6H-SiC (0001) substrates with 3-bilayer-high surface steps
Authors: Okumura Hironori , Kimoto Tsunenobu , Suda Jun
Published: August 2014

We grew AlN layers on 6H-SiC (0001) substrates with three Si-C bilayer high (0.75 nm) steps. In the AlN layers, most of the threading dislocations (TDs) were arranged in rows. The TD row consisted of arrays of a half-loop dislocation, which was formed by an AlN/SiC interfacial dislocation along the step edges of the SiC substrate surfaces and a TD pair at both ends. The configuration of the interfacial dislocation was highly relevant with two-dimensional AlN nuclei at the initial stage of growth. We concluded that the half-loop dislocation arrays were generated in the AlN nucleus coalescence over the SiC step edges.
Rare event molecular dynamics simulations of plasma induced surface ablation
Authors: Sharia Onise , Holzgrafe Jeffrey , Park Nayoung , Henkelman Graeme
Published: August 2014

The interaction of thermal Ar plasma particles with Si and W surfaces is modeled using classical molecular dynamics (MD) simulations. At plasma energies above the threshold for ablation, the ablation yield can be calculated directly from MD. For plasma energies below threshold, the ablation yield becomes exponentially low, and direct MD simulations are inefficient. Instead, we propose an integration method where the yield is calculated as a function of the Ar incident kinetic energy. Subsequent integration with a Boltzmann distribution at the temperature of interest gives the thermal ablation yield. At low plasma temperatures, the ablation yield follows an Arrhenius form in which the activation energy is shown to be the threshold energy for ablation. Interestingly, equilibrium material properties, including the surface and bulk cohesive energy, are not good predictors of the threshold energy for ablation. The surface vacancy formation energy is better, but is still not a quantitative predictor. An analysis of the trajectories near threshold shows that ablation occurs by different mechanisms on different material surfaces, and both the mechanism and the binding of surface atoms determine the threshold energy.
Transient reflectivity as a probe of ultrafast carrier dynamics in semiconductors: A revised model for low-temperature grown GaAs
Authors: Wells Nathan P. , Belden Paul M. , Demers Joseph R. , Lotshaw William T.
Published: August 2014

We revisit pump-probe transient reflectivity (PPTR) as a probe of ultrafast carrier dynamics in photoconductive materials, using low-temperature grown GaAs (LT-GaAs) as an exemplar. The carrier dynamics in a series of annealed LT-GaAs wafers were measured by PPTR. The wafer growth and anneal conditions were tailored to produce a material system with a sub-picosecond carrier lifetime. The PPTR signals from these wafers are bipolar with time constants on the order of 100 fs and 1 ps, consistent with previous literature reports on LT-GaAs. We examined the utility of numerical simulations of the pump-probe transients described in [V. Ortiz et al., J. Appl. Phys. 102, 043515 (2007)] to model our experimental results. We discovered a discrepancy between the model's predictions and experiment with respect to the scaling of the PPTR response with injected carrier density, and show that this discrepancy is rooted in how the model accounts for the index of refraction change due to band filling (BF) and band gap renormalization (BGR). We demonstrate that any model that includes a non-negligible BGR effect is inconsistent with our experimental observations of LT-GaAs. We present a revised model to simulate PPTR signals that account for BF and incorporate optical absorption from mid-gap states. This model can reproduce the experimental results on LT-GaAs and enables comparative assessments of alternate trapping and recombination hypotheses. For LT-GaAs, we compared point defects and nanoparticles as sites for Shockley-Read-Hall recombination, with the result that nanoparticle trapping and recombination centers most accurately reproduce the PPTR probe of carrier dynamics in LT-GaAs.