bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced alpha‐synuclein in cerebrospinal fluid in synucleinopathies: Evidence from a meta‐analysis
Authors: Sako Wataru , Murakami Nagahisa , Izumi Yuishin , Kaji Ryuji
Published: September 2014

Alpha‐synuclein plays a key role in the pathology of synucleinopathies including Parkinson's disease (PD) and multiple system atrophy (MSA). However, whether alpha‐synuclein level in cerebrospinal fluid (CSF) could distinguish synucleinopathies from progressive supranuclear palsy (PSP) is still a contentious issue. A comprehensive literature search yielded nine eligible studies. We expressed the between‐group difference of the concentration of alpha‐synuclein in CSF as the standardized mean difference. The proportion of variation attributable to heterogeneity was computed and expressed as I2. Nine studies involved 537 controls, 843 PD, 130 MSA, and 98 PSP patients. The overall effect of PD on alpha‐synuclein in CSF was significantly different from normal control or disease control (standardized mean difference = –0.67, P < 0.00001). These studies were heterogeneous (I2 = 40%). Alpha‐synuclein in CSF in MSA was significantly reduced relative to controls with heterogeneous studies (standardized mean difference = –0.75, P < 0.0001; I2 = 62%). In contrast, no significant difference of alpha‐synuclein in CSF was observed between PSP and controls with heterogeneous studies (standardized mean difference = –0.28, P = 0.13; I2 = 53%). Alpha‐synuclein in CSF was significantly reduced in synucleinopathies compared with PSP (“PD vs. PSP”: standardized mean difference = –0.38, P = 0.001; “MSA vs. PSP”: standardized mean difference = –0.66, P < 0.00001). The included studies were homogeneous (I2 = 0%). Our study showed that alpha‐synuclein levels in CSF in synucleinopathies was significantly lower than in PSP. This finding provides insights into the pathophysiological difference between synucleinopathies and PSP as well as possibility of development of a tool for differential diagnosis between MSA and PSP using enzyme‐linked immunosorbent assay (ELISA) and similar methods. © 2014 International Parkinson and Movement Disorder Society
The increasing incidence of foetal echogenic congenital lung malformations: an observational study
Authors: Stocker Linden J. , Wellesley Diana G. , Stanton Michael P. , Parasuraman Rajeswari , Howe David T.
Published: September 2014

Objectives

The aim of this study was to investigate the incidence of congenital lung malformations over the past 19 years. Congenital lung malformations (CLM) are a heterogeneous group of lung abnormalities. The antenatal diagnosis is important for foetal and neonatal management but there have been no studies examining whether the reported incidence of this abnormality is constant.

Methods

A retrospective cross‐sectional study of cases identified from the Wessex Antenatally Detected Anomalies (WANDA) register 1994–2012.

Results

One hundred and thirty‐three cases of CLM in 524 372 live and stillbirths were identified. All but seven were identified on antenatal ultrasound.

During the early registry (1994–1998) the average incidence of CLM was 1.27 per 10 000 births. By the last 4 years (2008–2012) this had risen to 4.15 per 10 000 births, with a progressive increase during the intervening years.

Conclusion

There was over a three‐fold increase in the antenatally detected CLM in the Wessex region 1994–2012. Comparison with the antenatal detection of diaphragmatic hernia suggests that this is a true rise in incidence rather than an artefactual increase due to increased antenatal recognition secondary to improved ultrasound resolution and operator experience. These results have clinical and cost implications for practitioners of foetal medicine, neonatology and paediatric surgery services. © 2014 John Wiley & Sons, Ltd.
Use of solution crystallization analysis by laser light scattering for studying the solution crystallization of various Ziegler–Natta‐catalysed polypropylenes
Authors: Amer Ismael , van Reenen Albert , Brand Margaretha
Published: September 2014

Solution crystallization analysis by laser light scattering (SCALLS) involves the observation of the scattering of diode mercury laser lamp light after it passes through a polymer solution. An increase in turbidity occurs when the hot polymer solution is cooled and the polymer starts to crystallize out of solution. This causes a decrease in the amount of laser light that can pass through the solution and an increase in the amount of scattered light. The reverse of this process leads to the turbidity decreasing with an increase in temperature. According to this concept, it is possible to follow the solution crystallization of various polypropylenes under controlled cooling. In this study, SCALLS was able to differentiate between different isotactic and syndiotactic polypropylenes with similar chemical structures, but different tacticity and molecular weights. Furthermore, SCALLS provided good crystallization information that is similar to that from crystallization analysis fractionation and temperature rising elution fractionation. In addition, SCALLS can be used as a quantitative tool for the measurement of weight fractions during dissolution. © 2014 Society of Chemical Industry
On the vertical structure of wind gusts
Authors: Suomi I. , Gryning S.‐E. , Floors R. , Vihma T. , Fortelius C.
Published: September 2014

The increasing size of wind turbines, their height and the area swept by their blades have revised the need for understanding the vertical structure of wind gusts. Information is needed for the whole profile. In this study, we analyzed turbulence measurements from a 100 m high meteorological mast at the Danish National Test Station for Large Wind Turbines at Hóvsóre in Denmark. The site represents flat, homogeneous grassland with an average gust factor of 1.4 at 10 m and 1.2 at 100 m level. In a typical surface‐layer gust parametrization, the gust factor is composed of two components, the peak factor and the turbulence intensity, of which the turbulence intensity was found to dominate over the peak factor in determining the effects of stability and height above the surface on the gust factor. The peak factor only explained 15% or less of the vertical decrease of the gust factor, but determined the effect of gust duration on the gust factor. The statistical method to estimate the peak factor did not reproduce the observed vertical decrease in near‐neutral and stable conditions and near‐constant situation in unstable conditions. Despite this inconsistency, the theoretical method provides estimates for the peak factor when comparing gust durations of 1 and 3 s with averaging period lengths of 10 min and 1 h. A new technique to study the timing of maxima at different levels relative to the maximum gust at some level was developed. Results showed that a 10 m level maximum gust was typically preceded by maxima at higher levels and vice versa: a 100 m gust was usually followed by a maximum at lower levels.
An Evaluation of the Stream Simulation Culvert Design Method in Washington State
Authors: Barnard R. J. , Yokers S. , Nagygyor A. , Quinn T.
Published: September 2014

Stream simulation has become an increasingly common culvert design method around the world. It is based on the assumption that geologic and hydraulic conditions in natural channels define passage characteristics for migrating fish and that water crossing structures that imitate these conditions can then achieve those same passage characteristics. This study expands on an initial evaluation of 19 culverts in 2003 to 50 culverts and includes methods and analyses comparing hydraulic characteristics based on cross sections, profile variation, and bed texture between each culvert and its paired reference reach situated in an adjacent section of the natural channel of each stream. Taken as a group, these culverts simulate bed texture, 100‐year recurrence interval flood velocity and 2‐year flood width but did not simulate thalweg complexity or other hydraulic metrics. Culvert span, relative to the bankfull width of the stream, does not by itself determine whether the culvert simulates the reference reach. Of the 50 culverts, many of which experienced record floods, only one showed significant bed degradation. Copyright © 2014 John Wiley & Sons, Ltd.
Application‐specific hybrid symmetric design of key pre‐distribution for wireless sensor networks
Authors: Dargahi Tooska , Javadi Hamid H. S. , Hosseinzadeh Mehdi
Published: September 2014

Wireless sensor networks have been established for a wide range of applications in adversarial environments, which makes secure communication between sensor nodes a challenging issue. To achieve high level of security, each pair of nodes must share a secret key in order to communicate with each other. Because of the random deployment of sensors, a set of keys must be pre‐distributed, so that each sensor node is assigned a set of keys from a key pool before the deployment. The keys stored in each node must be carefully selected to increase the probability of key share between two neighboring nodes. In this paper, we consider a hybrid key pre‐distribution scheme based on the balanced incomplete block design. We present a new approach for choosing key pool in the hybrid symmetric design that improves the connectivity and scalability of the network. We also introduce an extension to the proposed approach to detract memory usage and improve resilience. Experimental results verify the performance and applicability of our approach. Copyright © 2014 John Wiley & Sons, Ltd.
The Images Deficit in the Teaching of Writing
Authors: Coppola Shawna
Published: September 2014

View From the Chalkboard essays share readers' reflections on teaching experiences, advice for new teachers, and perspectives on current issues.
The influence of Argonaute proteins on alternative RNA splicing
Authors: Batsché Eric , Ameyar‐Zazoua Maya
Published: September 2014

Alternative splicing of precursor RNAs is an important process in multicellular species because it impacts several aspects of gene expression: from the increase of protein repertoire to the level of expression. A large body of evidences demonstrates that factors regulating chromatin and transcription impact the outcomes of alternative splicing. Argonaute (AGO) proteins were known to play key roles in the regulation of gene expression at the post‐transcriptional level. More recently, their role in the nucleus of human somatic cells has emerged. Here, we will discuss some of the nuclear functions of AGO, with special emphasis on alternative splicing. The AGO‐mediated modulation of alternative splicing is based on several properties of these proteins: their binding to transcripts on chromatin and their interactions with many proteins, especially histone tail‐modifying enzymes, HP1γ and splicing factors. AGO proteins may favor a decrease in the RNA‐polymerase II kinetics at actively transcribed genes leading to the modulation of alternative splicing decisions. They could also influence alternative splicing through their interaction with core components of the splicing machinery and several splicing factors. We will discuss the modes of AGO recruitment on chromatin at active genes. We suggest that long intragenic antisense transcripts (lincRNA) might be an important feature of genes containing splicing events regulated by AGO. WIREs RNA 2015, 6:141–156. doi: 10.1002/wrna.1264

This article is categorized under:

RNA Processing > Splicing Regulation/Alternative Splicing

Regulatory RNAs/RNAi/Riboswitches > RNAi: Mechanisms of Action
Causes of mortality in anuran amphibians from an ex situ survival assurance colony in Panama
Authors: Pessier Allan P. , Baitchman Eric J. , Crump Paul , Wilson Brad , Griffith Edgardo , Ross Heidi
Published: September 2014

The success of ex situ survival assurance populations as tools for amphibian conservation depends on the health and reproductive success of founder populations. Necropsy examination and histopathology of animals that die in assurance populations are useful for the identification of population‐limiting disease problems and can help to direct applied research efforts in areas such as amphibian husbandry and nutrition. This study reviewed postmortem findings in 167 frogs from 13 species that died in a large Panamanian rescue and survival assurance population between 2006 and 2011. Common problems identified in long‐term captive animals, especially in Atelopus species, were epithelial squamous metaplasia suggestive of vitamin A deficiency and a polycystic nephropathy resembling lesions seen in laboratory animals with electrolyte imbalances. Metabolic bone disease was a significant contributor to morbidity in captive‐bred juvenile frogs of Gastrotheca cornuta, Hemiphractus fasciatus, and Hylomantis lemur. Findings common to multiple species included poor overall nutritional condition that was sometimes attributable to maladaptation to captive husbandry and epidermal hyperplasia and hyperkeratosis possibly reflecting environmental skin irritation. Infectious diseases and endoparasitism were most common in recently captured animals and included chytridiomycosis and Rhabdias sp. lungworms. Applied research efforts to improve sustainability of survival assurance populations should focus on elucidating optimal husbandry practices for diverse species, improving methods for nutritional supplementation of cultured insects and examination of the role of water composition in disease development. Zoo Biol. 33:516–526, 2014. © 2014 Wiley Periodicals Inc.
Lymphangiogenesis in renal diseases: passive bystander or active participant?
Authors: Yazdani Saleh , Navis Gerjan , Hillebrands Jan-Luuk , van Goor Harry , van den Born Jacob
Published: September 2014

Lymphatic vessels (LVs) are involved in a number of physiological and pathophysiological processes such as fluid homoeostasis, immune surveillance, and resolution of inflammation and wound healing. Lymphangiogenesis, the outgrowth of existing LVs and the formation of new ones, has received increasing attention over the past decade on account of its prominence in organ physiology and pathology, which has been enabled by the development of specific tools to study lymph vessel functions. Several studies have been devoted to renal lymphatic vasculature and lymphangiogenesis in kidney diseases, such as chronic renal transplant dysfunction, primary renal fibrotic disorders, proteinuria, diabetic nephropathy and renal inflammation. This review describes the most recent findings on lymphangiogenesis, with a specific focus on renal lymphangiogenesis and its impact on renal diseases. We suggest renal lymphatics as a possible target for therapeutic interventions in renal medicine to dampen tubulointerstitial tissue remodelling and improve renal functioning.
Expansion wave diffraction over a 90 degree corner
Authors: Mahomed Irshaad , Skews Beric W.
Published: September 2014

The diffraction of an initially one-dimensional plane expansion wave over a 90° corner was explored using experiment and numerical simulation. Unlike studies of shock diffraction, expansion wave diffraction has hardly been documented previously. The planar expansion wave was produced in a shock tube by bursting a diaphragm. Two independent parameters were identified for study: (i) the initial diaphragm shock tube pressure ratio, which determines the strength (pressure ratio) of the expansion, and (ii) the position of the diaphragm from the apex of the 90° corner, which determines the width of the wave. The experimentation only considered variation in the shock tube pressure ratio whereas the simulation varied both parameters. A Navier–Stokes solver with Menter’s shear stress transport$\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}}k\mbox{--}\omega $turbulence model was found to adequately model the overall flow field. A number of major flow features were identified occurring in the vicinity of the corner. These were: a shear layer that originated by flow separation at the apex of the corner; a vortex within a separation bubble that remained attached to the wall, in sharp contrast to what happens in the shock wave diffraction case, where the vortex convects downstream; and a reflected compression wave arising from perturbation signals generated by the diffraction. For a narrow-width expansion wave existing prior to diffraction, the reflected compression wave steepens into an outwardly propagating, weak cylindrical shock wave. Regions of supersonic flow are identified surrounding the bubble and can extend downstream depending on the pressure ratio. Another major flow feature identified in some cases was an oblique shock located near the separation bubble. A large wake region is evident immediately downstream of the bubble and appears to consist of two distinct layers. The experimental results showed large-scale turbulent structures within the separation bubble, and shear layer instability and vortex shedding from the separation bubble were also evident.
The Mesozoic–Cenozoic tectonic evolution of the New Siberian Islands, NE Russia
Authors: BRANDES CHRISTIAN , PIEPJOHN KARSTEN , FRANKE DIETER , SOBOLEV NIKOLAY , GAEDICKE CHRISTOPH
Published: September 2014

On the New Siberian Islands the rocks of the east Russian Arctic shelf are exposed and allow an assessment of the structural evolution of the region. Tectonic fabrics provide evidence of three palaeo-shortening directions (NE–SW, WNW–ESE and NNW–SSE to NNE–SSW) and one set of palaeo-extension directions revealed a NE–SW to NNE–SSW direction. The contractional deformation is most likely the expression of the Cretaceous formation of the South Anyui fold–thrust belt. The NE–SW shortening is the most prominent tectonic phase in the study area. The WNW–ESE and NNW–SSE to NNE–SSW-oriented palaeo-shortening directions are also most likely related to fold belt formation; the latter might also have resulted from a bend in the suture zone. The younger Cenozoic NE–SW to NNE–SSW extensional direction is interpreted as a consequence of rifting in the Laptev Sea.
Sacrifice and Revenge in Euripides' Hecuba
Authors: Mitchell-Boyask Robin N.
Published: September 2014

Recent studies of theHecubahave begun to allay doubts about whether its two disparate halves form a single plot. I shall approach this question from a different angle, finding the unity of theHecubain two areas: first, the similarity of the acts of sacrifice and revenge; and, second, the irresolution of the reason for Polyxena's sacrifice, the restraining winds, until Hecuba has avenged herself on Polymestor. Euripides' drama engages the emotional dynamics of sacrifice and revenge in order to explore the power of theatre to destabilise such societal activites and the ethical distinctions held by its audience. The Theatre of Dionysus thus bears witness to a drama that undermines ethical certitudes and makes problematic the types of institutions that thepolisneeds for stability. When a vote is taken on human sacrifice, when sacrifice fails to control violence, when revenge becomes the chosen recourse to achieve justice, how can apolisrestore order? While the action of theHecubaoccurs beyond the realm of any recognisablepolis, its war-time setting and the undercurrent of references to Athens and its institutions suggest that theHecuba'sanswers could not have been reassuring to its audience.
A PRACTICAL TURN: ELIE HALEVY'S EMBRACE OF POLITICS AND HISTORY
Authors: REVILL JOEL
Published: September 2014

Elie Halévy's legacy is bounded by the two primary objects of his scholarly interest: the history of modern Britain and the study of French socialist doctrines. Taken together, his writings on temperate English politics and occasionally intemperate French socialists cemented his status as a leading French liberal of his generation. Read out of context, the tone of his criticism of wartime socialization and the growth of wartime governments has given him a conservative reputation in some circles and inspired a backlash among historians seeking a more progressive Halévy in his prewar writings. Meanwhile, the depth of his historical study of Britain has elicited several discussions of Halévy's turn from philosophy to history at the end of the 1890s. The portrait of Halévy that emerges in light of his historical studies of England and of French socialism is detailed, accurate, and flattering, but, like any portrait, it is incomplete. Before he was a historian, Halévy was a philosopher, and before he mastered his craft in the early twentieth century, Halévy struggled to find his voice in the late nineteenth.
Determination of carbon and oxygen isotopes of geological samples with a complicated matrix: comparison of different analytical methods
Authors: Cui Lin-Lin , Wang Xu
Published: September 2014

Several automated on-line carbonate reaction devices coupled with isotope ratio mass spectrometers (IRMS) have been frequently used to determine the isotopic compositions of the carbon and oxygen in carbonates because of their high efficiency and small sample size.
Recent development of synthetic preparation methods for guanidines via transition metal catalysis
Authors: Zhang Wen-Xiong , Xu Ling , Xi Zhenfeng
Published: September 2014

This article provides an overview of guanidine synthesisviatransition-metal-catalyzed reactions including cycloaddition, guanylation and tandem guanylation/cyclization.
Probing the magnetic and magnetothermal properties of M(ii)–Ln(iii) complexes (where M(ii) = Ni or Zn; Ln(iii) = La or Pr or Gd)
Authors: Ahmed Naushad , Das Chinmoy , Vaidya Shefali , Srivastava Anant Kumar , Langley Stuart K. , Murray Keith S. , Shanmugam Maheswaran
Published: September 2014

We report the crystal structures of Ni(ii)–Ln(iii) (where Ln = Gd or Pr) complexes and their suitably substituted diamagnetic analogues. Magnetic characterization revealed the nature of the magnetic exchange interactions and the magnetothermal properties.
Synthesis, structure and magnetic properties of phenylhydroxamate-based coordination clusters
Authors: Tirfoin Rémi , Chamoreau Lise-Marie , Li Yanling , Fleury Benoit , Lisnard Laurent , Journaux Yves
Published: September 2014

The successful clustering of nickel(ii) or cobalt(ii) dinuclear complexes into tetra- and hexa-metallic species has been made possible with the use of the phenylhydroxamate bridging ligand. The magnetic properties of these complexes have been studied and modelled.
Catalyst-free one-pot four-component domino reactions in water–PEG-400: highly efficient and convergent approach to thiazoloquinoline scaffolds
Authors: Nagaraju Anugula , Ramulu B. Janaki , Shukla Gaurav , Srivastava Abhijeet , Verma Girijesh Kumar , Raghuvanshi Keshav , Singh Maya Shankar
Published: September 2014

Catalyst-free one-pot sustainable synthesis of thiazoloquinoline and thiazolopyridine scaffolds is achievedviafour-component domino reactions in water–PEG.
Fluorous-inorganic hybrid dielectric materials for solution-processed electronic devices
Authors: Kim Heejin , Jo Sang Ho , Jee Joong-Hwi , Han WooJe , Kim Youngtae , Park Hyung-Ho , Jin Hyoung-Joon , Yoo Byungwook , Lee Jin-Kyun
Published: September 2014

Fluorous-inorganic hybrid dielectric (FIHD) materials in fluorous solvents can be deposited on top of organic semiconductor films by solution casting.
siRNA liposome-gold nanorod vectors for multispectral optoacoustic tomography theranostics
Authors: Taruttis Adrian , Lozano Neus , Nunes Antonio , Jasim Dhifaf A. , Beziere Nicolas , Herzog Eva , Kostarelos Kostas , Ntziachristos Vasilis
Published: September 2014

This study describes the simultaneous in vivo optoacousic imaging and siRNA-mediated gene silencing capabilities of a model theranostic vector system between liposomes and gold nanorods.
Cationic carbosilane dendrimers and oligonucleotide binding: an energetic affair
Authors: Marson D. , Laurini E. , Posocco P. , Fermeglia M. , Pricl S.
Published: September 2014

Molecular simulations individuate the normalized effective free energy of binding as a critical molecular parameter in designing efficient nanovectors for gene delivery.
A high-molecular-weight and high-Tg poly(ester carbonate) partially based on isosorbide: synthesis and structure–property relationships
Authors: Feng Long , Zhu Wenxiang , Li Chuncheng , Guan Guohu , Zhang Dong , Xiao Yaonan , Zheng Liuchun
Published: September 2014

A new family of high-molecular-weight and high Tg poly(ester carbonate)s partially based on renewable isosorbide were prepared by incorporating 1,4-butanediol and dimethyl terephthalate into poly(isosorbide carbonate).
First principles investigation of NO2 and SO2 adsorption on γ-Al2O3 supported mono- and diatomic metal clusters
Authors: Artuc Zuleyha , Ustunel Hande , Toffoli Daniele
Published: September 2014

Atomistic simulations of NO2 and SO2 adsorption on γ-Al2O3 supported mono and diatomic clusters of Pt and Rh show that enhanced sulfur tolerance with respect to pristine metallic surfaces or extended nanoparticles, can be achieved.
Effects of HRT and nitrite/ammonia ratio on anammox discovered in a sequencing batch biofilm reactor
Authors: Yu Ying-Cui , Tao Yu , Gao Da-Wen
Published: September 2014

There are three key aspects of substrate effect on anaerobic ammonia oxidizing (anammox) bacteria: (1) substrate concentration-based nitrogen loading rate (NLR), (2) hydraulic retention time (HRT)-based NLR and (3) nitrite/ammonia ratio.
Mechanically reinforced composite aerogel blocks by self-growing nanofibers
Authors: Yi Xibin , Zhang Linlin , Wang Fengyun , Shen Xiaodong , Cui Sheng , Zhang Jing , Wang Xiuchun
Published: September 2014

Here we report the preparation of mechanically reinforced composite aerogels using self-growing nanofibers.
Photoluminescence study of optically active diaminopyridine intercalated graphene oxide
Authors: Gupta Abhisek , Shaw Bikash Kumar , Saha Shyamal Kumar
Published: September 2014

The optical property of a diaminopyridine intercalated GO composite with interlayer separation ∼1.03 nm was investigated by both experimental and theoretical approaches.
Regulating signal enhancement with coordination-coupled deprotonation of a hydrazone switch
Authors: Foy Justin T. , Ray Debdas , Aprahamian Ivan
Published: September 2014

Regulating signal amplification using a switchable catalytic cycle.
Construction of mass-controllable mesoporous NiCo2S4 electrodes for high performance supercapacitors
Authors: Peng Tao , Qian Zhongyu , Wang Jun , Song Dalei , Liu Jinyuan , Liu Qi , Wang Peng
Published: September 2014

Shape-preserved NiCo2S4 was obtained from NiCo2O4via a facile anion exchange reaction (AER). The unique electrode showed excellent performance, which makes it a promising electrode for supercapacitors.
Solution-based DNA-templating of sub-10 nm conductive copper nanowires
Authors: Pate Jonathan , Zamora Felix , Watson Scott M. D. , Wright Nicholas G. , Horrocks Benjamin R. , Houlton Andrew
Published: September 2014

Electroless metal deposition at DNA ‘template’ molecules in bulk solution, compared to previous surface-based routes, produces conductive, sub-10 nm, nanowires.
Emission dynamic meso‐simulation model to evaluate traffic strategies in congested urban networks
Authors: Gori Stefano , La Spada Simone , Mannini Livia , Nigro Marialisa
Published: September 2014

Road vehicle emissions have become a main aspect related to the quality of life and sustainability. The aim of this study is to develop a method to estimate pollutant emissions that takes into account the daily variations of traffic flow conditions and parameters relative to the different state of vehicles and that can easily be applied to evaluate the results of both on‐line and off‐line traffic management strategies in wide congested urban networks. The method has been tested in the real case of the city of Brindisi (Italy), demonstrating its reliability and efficiency.
Narrow band wavelength selective filter using grating assisted single ring resonator
Authors: Prabhathan P. , Murukeshan V. M.
Published: September 2014

This paper illustrates a filter configuration which uses a single ring resonator of larger radius connected to a grating resonator at its drop port to achieve single wavelength selectivity and switching property with spectral features suitable for on-chip wavelength selection applications. The proposed configuration is expected to find applications in silicon photonics devices such as, on-chip external cavity lasers and multi analytic label-free biosensors. The grating resonator has been designed for a high Q-factor, high transmittivity, and minimum loss so that the wavelength selectivity of the device is improved. The proof-of-concept device has been demonstrated on a Silicon-on-Insulator (SOI) platform through electron beam lithography and Reactive Ion Etching (RIE) process. The transmission spectrum shows narrow band single wavelength selection and switching property with a high Free Spectral Range (FSR) ∼60 nm and side band rejection ratio >15 dB
In situ biaxial rotation at low-temperatures in high magnetic fields
Authors: Selby N. S. , Crawford M. , Tracy L. , Reno J. L. , Pan W.
Published: September 2014

We report the design, construction, and characterization of a biaxial sample rotation stage for use in a cryogenic system for orientation-dependent studies of anisotropic electronic transport phenomena at low temperatures and high magnetic fields. Our apparatus allows for continuous rotation of a sample about two axes, both independently and simultaneously.
Critical nucleus composition in a multicomponent system
Authors: Philippe T. , Blavette D. , Voorhees P. W.
Published: September 2014

The properties of a critical nucleus are derived using the capillarity theory in the framework of classical nucleation. An analytical solution for the composition of a critical nucleus is given for low supersaturation. The theory is valid for any multicomponent systems. It is found that the deviation in nucleus composition from the equilibrium tie-line is mainly due to the difference in the Hessian of the Gibbs energy of the phases and the magnitude of the deviation in composition from equilibrium is order of the supersaturation. Despite our analysis strictly holds for low supersaturation, this suggests strong deviations near the spinodal line.
Development of graphene nanoplatelet embedded polymer microcantilever for vapour phase explosive detection applications
Authors: Ray Prasenjit , Pandey Swapnil , Ramgopal Rao V.
Published: September 2014

In this work, a graphene based strain sensor has been reported for explosive vapour detection applications by exploiting the piezoresistive property of graphene. Instead of silicon based cantilevers, a low cost polymeric micro-cantilever platform has been used to fabricate this strain sensor by embedding the graphene nanoplatelet layer inside the beam. The fabricated devices were characterized for their mechanical and electromechanical behaviour. This device shows a very high gauge factor which is around ∼144. Also the resonant frequency of these cantilevers is high enough such that the measurements are not affected by environmental noise. These devices have been used in this work for reliable detection of explosive vapours such as 2,4,6-Trinitrotoluene down to parts-per-billion concentrations in ambient conditions.
M3D-K simulations of sawteeth and energetic particle transport in tokamak plasmas
Authors: Shen Wei , Fu G. Y. , Sheng Zheng-Mao , Breslau J. A. , Wang Feng
Published: September 2014

Nonlinear simulations of sawteeth and related energetic particle transport are carried out using the kinetic/magnetohydrodynamic (MHD) hybrid code M3D-K. MHD simulations show repeated sawtooth cycles for a model tokamak equilibrium. Furthermore, test particle simulations are carried out to study the energetic particle transport due to a sawtooth crash. The results show that energetic particles are redistributed radially in the plasma core, depending on pitch angle and energy. For trapped particles, the redistribution occurs for particle energy below a critical value in agreement with existing theories. For co-passing particles, the redistribution is strong with little dependence on particle energy. In contrast, the redistribution level of counter-passing particles decreases with increasing particle energy.
Nano-scale NiSi and n-type silicon based Schottky barrier diode as a near infra-red detector for room temperature operation
Authors: Roy S. , Midya K. , Duttagupta S. P. , Ramakrishnan D.
Published: September 2014

The fabrication of nano-scale NiSi/n-Si Schottky barrier diode by rapid thermal annealing process is reported. The characterization of the nano-scale NiSi film was performed using Micro-Raman Spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The thickness of the film (27 nm) has been measured by cross-sectional Secondary Electron Microscopy and XPS based depth profile method. Current–voltage (I–V) characteristics show an excellent rectification ratio (ION/IOFF = 105) at a bias voltage of ±1 V. The diode ideality factor is 1.28. The barrier height was also determined independently based on I–V (0.62 eV) and high frequency capacitance–voltage technique (0.76 eV), and the correlation between them has explained. The diode photo-response was measured in the range of 1.35–2.5 μm under different reverse bias conditions (0.0–1.0 V). The response is observed to increase with increasing reverse bias. From the photo-responsivity study, the zero bias barrier height was determined to be 0.54 eV.
Low temperature near band edge recombination dynamics in ZnO nanorods
Authors: Urgessa Z. N. , Botha J. R. , Eriksson M. O. , Mbulanga C. M. , Dobson S. R. , Tankio Djiokap S. R. , Karlsson K. F. , Khranovskyy V. , Yakimova R. , Holtz Per-Olof
Published: September 2014

The recombination dynamics of neutral donor bound excitons (DoX: I4, I6/6a) and near band edge defect-related emission in solution grown ZnO nanorods are investigated using steady state and time-resolved photoluminescence (PL) measurements. The effects of annealing are also studied. Low temperature steady state PL shows a systematic removal of the I4 line after annealing at 450 °C and the subsequent domination of I6a in these PL spectra. Additionally, the time decay of the I4, I6/6a, free exciton (FX), and basal plane stacking fault-related (BSF) PL transitions are studied as a function of annealing temperature. For the various annealing temperatures studied, the PL decay is described by a bi-exponential profile with a fast component (contribution from the surface) and slow component (related to bulk recombination). The fast component dominates in the case of as-grown and low temperature annealed samples (anneal temperatures up to 300 °C), suggesting the presence of surface adsorbed impurities. For samples annealed above 400 °C, the effects of the surface are reduced. The sample annealed at 850 °C produced an overall enhancement of the crystal quality. The underlying mechanisms for the observed PL characteristics are discussed based on near surface band bending caused by surface impurities.
Fabrication of ultra-high aspect ratio silicon nanopores by electrochemical etching
Authors: Schmidt Torsten , Zhang Miao , Yu Shun , Linnros Jan
Published: September 2014

We report on the formation of ultra-high aspect ratio nanopores in silicon bulk material using photo-assisted electrochemical etching. Here, n-type silicon is used as anode in contact with hydrofluoric acid. Based on the local dissolution of surface atoms in pre-defined etching pits, pore growth and pore diameter are, respectively, driven and controlled by the supply of minority charge carriers generated by backside illumination. Thus, arrays with sub-100 nm wide pores were fabricated. Similar to macropore etching, it was found that the pore diameter is proportional to the etching current, i.e., smaller etching currents result in smaller pore diameters. To find the limits under which nanopores with controllable diameter still can be obtained, etching was performed at very low current densities (several μA cm−2). By local etching, straight nanopores with aspect ratios above 1000 (∼19 μm deep and ∼15 nm pore tip diameter) were achieved. However, inherent to the formation of such narrow pores is a radius of curvature of a few nanometers at the pore tip, which favors electrical breakdown resulting in rough pore wall morphologies. Lowering the applied bias is adequate to reduce spiking pores but in most cases also causes etch stop. Our findings on bulk silicon provide a realistic chance towards sub-10 nm pore arrays on silicon membranes, which are of great interest for molecular filtering and possibly DNA sequencing.
Meso-scale measurement of the electrical spreading resistance in highly anisotropic media
Authors: Koren E. , Knoll A. W. , Lörtscher E. , Duerig U.
Published: September 2014

The spreading resistance of circular contacts with a radius in the range from 60 nm to 500 nm has been measured in highly oriented pyrolytic graphite which is known to exhibit an extremely large electrical conductance anisotropy due to the layered structure. The experimental data are compatible with a diffusive transport model characterized by an inverse scaling of the spreading resistance with contact radius with an effective resistivity of ρeff = 5.7 ± 0.3 × 10−5 Ω m. Based on a scaling theory of the conduction in anisotropic media, we infer a ratio of the in-plane to out-of-plane conductance of 3.6 × 104 in agreement with literature. Accordingly, the radius of the effective area probed is on the order of 100 μm, which is much larger than the radius of contact, whereas the penetration depth into the sample is around 1 nm to 5 nm corresponding to 3–15 graphite layers. Remarkably, no deviation from the scaling model is observed despite the fact that only a small number of graphite layers are involved in the conduction.
The dominant factors affecting the memory characteristics of (Ta2O5)x(Al2O3)1−x high-k charge-trapping devices
Authors: Gong Changjie , Yin Qiaonan , Ou Xin , Lan Xuexin , Liu Jinqiu , Sun Chong , Wang Laiguo , Lu Wei , Yin Jiang , Xu Bo , Xia Yidong , Liu Zhiguo , Li Aidong
Published: September 2014

The prototypical charge-trapping memory devices with the structure p-Si/Al2O3/(Ta2O5)x(Al2O3)1−x/Al2O3/Pt(x = 0.5, 0.3, and 0.1) were fabricated by using atomic layer deposition and RF magnetron sputtering techniques. A memory window of 7.39 V with a charge storage density of 1.97 × 1013 cm−2 at a gate voltage of ±11 V was obtained for the memory device with the composite charge trapping layer (Ta2O5)0.5(Al2O3)0.5. All memory devices show fast program/erase speed and excellent endurance and retention properties, although some differences in their memory performance exist, which was ascribed to the relative individual band alignments of the composite (Ta2O5)x(Al2O3)1−x with Si.
Capacity modulation of a cascade heat pump with the variation of compressor speed and electronic expansion valve opening
Authors: Jeong Kwangmoo , Choi Jong Min
Published: September 2014

With the increased awareness on excessive energy consumption, increasing fuel cost and negative environmental impact (ozone depletion and global warming) of the major heat generation systems and processes, the ability of heat pumps to generate high temperature with very efficient use of energy and minimal environmental impact has gained lots of awareness over the years. Some domestic and most industrial heating and refrigeration applications demand very high temperature lifts. Single-stage cycles do not practically support these applications since their performance and reliability decrease greatly. High temperature generation can be successfully executed through the use of cascade heat pump. This study analyzes the effects of compressor speed and electronic expansion valve (EEV) opening on the performance of the cascade heat pump in heating mode. The rate of increase of capacity with high-stage (HS) EEV opening at higher HS compressor speed is larger than it at high low-stage (LS) compressor speed. The slope of the capacity with the HS EEV opening was much steeper at small opening range than that at large opening range. When the LS compressor speed increased, the maximum Coefficient of Performance (COP) occurred at larger HS EEV opening than the standard opening. The COP variation at the range of low HS compressor speed had smaller dependency on the LS EEV opening than that at the range of high HS compressor speed.
Effect of tunneling layers on the performances of floating-gate based organic thin-film transistor nonvolatile memories
Authors: Wang Wei , Han Jinhua , Ying Jun , Xiang Lanyi , Xie Wenfa
Published: September 2014

Two types of floating-gate based organic thin-film transistor nonvolatile memories (FG-OTFT-NVMs) were demonstrated, with poly(methyl methacrylate co glycidyl methacrylate) (P(MMA-GMA)) and tetratetracontane (TTC) as the tunneling layer, respectively. Their device performances were measured and compared. In the memory with a P(MMA-GMA) tunneling layer, typical unipolar hole transport was obtained with a relatively small mobility of 0.16 cm2/V s. The unidirectional shift of turn-on voltage (Von) due to only holes trapped/detrapped in/from the floating gate resulted in a small memory window of 12.5 V at programming/erasing voltages (VP/VE) of ±100 V and a nonzero reading voltage. Benefited from the well-ordered molecule orientation and the trap-free surface of TTC layer, a considerably high hole mobility of 1.7 cm2/V s and a visible feature of electrons accumulated in channel and trapped in floating-gate were achieved in the memory with a TTC tunneling layer. High hole mobility resulted in a high on current and a large memory on/off ratio of 600 at the VP/VE of ±100 V. Both holes and electrons were injected into floating-gate and overwritten each other, which resulted in a bidirectional Von shift. As a result, an enlarged memory window of 28.6 V at the VP/VE of ±100 V and a zero reading voltage were achieved. Based on our results, a strategy is proposed to optimize FG-OTFT-NVMs by choosing a right tunneling layer to improve the majority carrier mobility and realize ambipolar carriers injecting and trapping in the floating-gate.
In situ oxalic acid injection to accelerate arsenic remediation at a superfund site in New Jersey
Authors: Wovkulich Karen , Stute Martin , Mailloux Brian J. , Keimowitz Alison R. , Ross James , Bostick Benjamin , Sun Jing , Chillrud Steven N.
Published: September 2014

Environmental context
Arsenic is one of the most common contaminants at US Superfund sites; therefore, establishing techniques to accelerate As remediation could benefit many sites. In a pilot scale study, we determined that addition of oxalic acid to the subsurface has the potential to increase arsenic release from sediments and possibly improve remediation efficiency by pump and treat techniques. Because pump and treat remediation can require many decades to sufficiently decrease contaminant levels, methods for improving remediation could lead to substantial savings in time and resources.

Abstract
Arsenic is a prevalent contaminant at a large number of US Superfund sites; establishing techniques that accelerate As remediation could benefit many sites. Hundreds of tonnes of As were released into the environment by the Vineland Chemical Co. in southern New Jersey during its manufacturing lifetime (1949–1994), resulting in extensive contamination of surface and subsurface soils and sediments, groundwater, and the downstream watershed. Despite substantial intervention at this Superfund site, sufficient aquifer clean up could require many decades if based on traditional pump and treat technologies only. Laboratory column experiments have suggested that oxalic acid addition to contaminated aquifer solids could promote significant As release from the solid phase. To evaluate the potential of chemical additions to increase As release in situ and boost treatment efficiency, a forced gradient pilot scale study was conducted on the Vineland site. During spring and summer 2009, oxalic acid and bromide tracer were injected into a small portion (~50m2) of the site for 3 months. Groundwater samples indicate that introduction of oxalic acid led to increased As release. Between 2.9 and 3.6kg of As were removed from the sampled wells as a result of the oxalic acid treatment during the 3-month injection. A comparison of As concentrations on sediment cores collected before and after treatment and analysed using X-ray fluorescence spectroscopy suggested reduction in As concentrations of ~36% (median difference) to 48% (mean difference). Although further study is necessary, the addition of oxalic acid shows potential for accelerating treatment of a highly contaminated site and decreasing the As remediation time-scale.
Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen
Authors: Rizoulis Athanasios , Al Lawati Wafa M. , Pancost Richard D. , Polya David A. , van Dongen Bart E. , Lloyd Jonathan R.
Published: September 2014

Environmental context The use of groundwater with elevated concentrations of arsenic for drinking, cooking or irrigation has resulted in the worst mass poisoning in human history. This study shows that organic compounds that can be found in arsenic rich subsurface sediments may be used by indigenous microorganisms, contributing to the release of arsenic from the sediments into the groundwater. This study increases our understanding of the range of organic substrates (and their sources) that can potentially stimulate arsenic mobilisation into groundwaters. Abstract Microbial activity is generally accepted to play a critical role, with the aid of suitable organic carbon substrates, in the mobilisation of arsenic from sediments into shallow reducing groundwaters. The nature of the organic matter in natural aquifers driving the reduction of AsV to AsIII is of particular importance but is poorly understood. In this study, sediments from an arsenic rich aquifer in Cambodia were amended with two 13C-labelled organic substrates. 13C-hexadecane was used as a model for potentially bioavailable long chain n-alkanes and a 13C-kerogen analogue as a proxy for non-extractable organic matter. During anaerobic incubation for 8 weeks, significant FeIII reduction and AsIII mobilisation were observed in the biotic microcosms only, suggesting that these processes were microbially driven. Microcosms amended with 13C-hexadecane exhibited a similar extent of FeIII reduction to the non-amended microcosms, but marginally higher AsIII release. Moreover, gas chromatography–mass spectrometry analysis showed that 65% of the added 13C-hexadecane was degraded during the 8-week incubation. The degradation of 13C-hexadecane was microbially driven, as confirmed by DNA stable isotope probing (DNA-SIP). Amendment with 13C-kerogen did not enhance FeIII reduction or AsIII mobilisation, and microbial degradation of kerogen could not be confirmed conclusively by DNA-SIP fractionation or 13C incorporation in the phospholipid fatty acids. These data are, therefore, consistent with the utilisation of long chain n-alkanes (but not kerogen) as electron donors for anaerobic processes, potentially including FeIII and AsV reduction in the subsurface.