bluuebunny/crossref_metadata_2025 huggingface dataset:
The HelCat basic plasma science device
Authors: Gilmore M. , Lynn A. G. , Desjardins T. R. , Zhang Y. , Watts C. , Hsu S. C. , Betts S. , Kelly R. , Schamiloglu E.
Published: November 2014

TheHelicon-Cathode(HelCat) device is a medium-size linear experiment suitable for a wide range of basic plasma science experiments in areas such as electrostatic turbulence and transport, magnetic relaxation, and high power microwave (HPM)-plasma interactions. The HelCat device is based on dual plasma sources located at opposite ends of the 4 m long vacuum chamber – an RF helicon source at one end and a thermionic cathode at the other. Thirteen coils provide an axial magnetic fieldB⩾ 0.220 T that can be configured individually to give various magnetic configurations (e.g. solenoid, mirror, cusp). Additional plasma sources, such as a compact coaxial plasma gun, are also utilized in some experiments, and can be located either along the chamber for perpendicular (to the background magnetic field) plasma injection, or at one of the ends for parallel injection. Using the multiple plasma sources, a wide range of plasma parameters can be obtained. Here, the HelCat device is described in detail and some examples of results from previous and ongoing experiments are given. Additionally, examples of planned experiments and device modifications are also discussed.
Sub-behaviour relations for session-based client/server systems
Authors: BARBANERA FRANCO , DE'LIGUORO UGO
Published: November 2014

We propose a refinement and a simplification of the behavioural semantics of session types, based on the concepts of compliance and sub-behaviour from the theory of web contracts. We introduce three relations on a suitable class of behaviours with higher-order input/output, called ‘session behaviours’. Such relations, depending on each other, represent the idea of sub-behaviour from the point of view of a client, a server or a peer, respectively. A restriction of the intersection of the first two relations characterizes the ‘usual’ sub-behaviour relation from the literature. We then device an algorithmic formal system for three subtyping relations (dubbed CSP-subtyping) for session types that takes into account the role played by a user of a channel during an interaction, so extending Gay and Hole subtyping theory. We show that our session behaviours and sub-behaviour relations provide sound and complete semantics for CSP-subtyping, and for Gay and Hole subtyping as a by-product.
Poly(l-lysine)-Based Copolymers: Synthetic Strategies and Biomedical Applications
Authors: Dimitrov Ivaylo V.
Published: November 2014

Poly(l-lysine)-based materials are extensively studied for potential biomedical applications. Among them, synthetic polymer–poly(l-lysine) hybrids are of particular interest due to the combination of advantageous properties characteristic of both components. In this chapter, the synthetic routes to poly(l-lysine)-based hybrid copolymers of various architectures are described. Contemporary synthetic methods such as controlled radical polymerization, controlled ring-opening polymerization of N-carboxyanhydrides (NCAs) and “click” chemistry as tools for the preparation of complex macromolecular architectures with poly(l-lysine) segments are presented. The potential applications of these materials in gene and drug delivery, tissue engineering and diagnostics are discussed.
Stimuli-Responsive Structures from Cationic Polymers for Biomedical Applications
Authors: Calejo Maria Teresa , Hasirci Nesrin , Bagherifam Shahla , Lund Reidar , Nyström Bo
Published: November 2014

The potential of cationic polymers in biological applications such as drug delivery and tissue engineering is widely recognized. The presence of a positively charged surface can promote cell attachment and interaction with oppositely charged molecules or drugs. This chapter focuses on cationic polymers with stimuli-responsive and self-assembly properties. These smart polymers can undergo reversible changes in response to small variations in the environment, such as pH and temperature, that can be advantageously used, for example, to target specific tissues or cell compartments, or to induce rapid drug release at the regeneration or diseased site. Examples based on cationic hydrogels, micelles and nanoparticles are introduced and discussed from the point of view of their mechanism of action and applicability in drug delivery, gene delivery and tissue engineering.
Cationic Polymers in Drug Delivery
Authors: Karewicz Anna , Szczubiałka Krzysztof , Nowakowska Maria
Published: November 2014

Polycations constitute an important group of polymeric materials widely used in the construction of novel drug delivery systems. The positive charge of these compounds renders them highly soluble in aqueous media and allows for strong electrostatic interactions of these polymers with anionic substances, including drugs and substances contained in the body (proteins and nucleic acids, in particular) as well as negatively charged anatomical structures (e.g., cell membranes, glycocalix or mucosa). A wide spectrum of delivery systems containing polycations has been recently developed and studied, including polyelectrolyte complexes, nano- and microparticles, injectable hydrogels, liposomes and micelles. Cationic polymers are also intensively used as penetration enhancers and release triggers. In this chapter the recent developments in the application of polycations for delivery of various therapeutic agents are summarized and discussed. The potential problems related to their potential cytotoxicity and the possible ways of eliminating unwanted side effects are also presented.
Cationic Polymers for Intracellular Delivery of Proteins
Authors: Coué Grégory , Engbersen Johan F. J.
Published: November 2014

Many therapeutic proteins exert their pharmaceutical action inside the cytoplasm or onto individual organelles inside the cell. Intracellular protein delivery is considered to be the most direct, fastest and safest approach for curing gene-deficiency diseases, enhancing vaccination and triggering cell transdifferentiation processes, within other curative applications. However, several hurdles have to be overcome. For this purpose the use of polymers, with their ease of modification in physical and chemical properties, is attractive in protein drug carriers. They can protect their therapeutic protein cargo from degradation and enhance their bioavailability at targeted sites. In this chapter, potential and currently used polymers for fabrication of protein delivery systems and their applications for intracellular administration are discussed. Special attention is given to the use of cationic polymers for their ability to promote the cellular uptake of therapeutic proteins.
Cationic Polymers as Gene-Activated Matrices for Biomedical Applications
Authors: Dash Mamoni , Kaplan David L. , Dubruel Peter , Samal Sangram K.
Published: November 2014

The architecture and chemical structure of biomaterials are important aspects of control related to biomimetic functions. The design of such biomaterial matrices has shown enhanced therapeutic potential for biomedical applications. Cationic polymeric systems with positive charges on their backbone or side chains have been framed in various architectures, including hydrogels, 3D porous scaffolds, fibers, nanogels, micelles, nanoparticles and dendrimers. The healing potential of these cationic biomaterials can be enhanced by combining them with DNA to produce gene-activated matrices for biomedical applications. This chapter provides an overview of gene-activated cationic polymer matrices with different architectures and a description of therapeutically relevant biomedical applications.
Interactions of Cationic Polymers with Cells
Authors: Ware Matthew J. , Summers Huw D. , Godin Biana
Published: November 2014

Cationic polymers and their derivatives are being investigated for development of a multitude of biomedical applications. In this chapter we focus on the interactions of cationic polymers with biological milieu, which shape their potential efficacies in drug and gene delivery. The chapter is divided into sections describing interactions of cationic polymers with extracellular components, whole cells and various cell organelles. In the intracellular interactions subsection we focus on the uptake mechanism and intracellular trafficking of polyplexes (complexes of cationic polymers and genetic material). Further, the cytocompatibility of the polymers as related to their structure and gene delivery ability is reviewed. The chapter concludes with a discussion on future research opportunities and clinical applications of cationic polymers in gene and drug delivery.
Cationic Polymers as Carriers through the Blood–Brain Barrier
Authors: Samal Sangram K. , Dash Mamoni , Dubruel Peter , Müllen Klaus , Rajadas Jayakumar
Published: November 2014

The blood–brain barrier (BBB) is an organization lined with brain endothelial cells, bound by extracellular matrix and sealed with paracellular protein complexes that acts as a selective transport and metabolic boundary. The BBB is designed to regulate brain homeostasis and to allow selective transport of molecules that are essential for the proper functioning of the brain. The BBB is an internal defense system that acts as a block to the delivery of nucleic acids and drug molecules to the brain. This defines a challenge for an effective delivery of therapeutics to the central nervous system (CNS). A number of potential biomolecules have failed at their developmental stage for clinical use due to an unsuccessful delivery to the CNS in required amounts. In this perspective, an in-depth research has been undertaken to understand the mechanisms underlying the transportation across the BBB via carriers. Amongst the various strategies, the use of cationic polymer carriers for nucleic acid and drug delivery across the BBB has gained much attention. This chapter reviews the developments of different cationic polymers vectors for delivering genes and drugs across the BBB.
Natural Cationic Polymers for Advanced Gene and Drug Delivery
Authors: Dai Sheng
Published: November 2014

Gene and drug delivery is becoming more and more important in the treatment of complicated human diseases. Proper gene/drug delivery systems can effectively enhance therapeutic efficiency and minimize various side-effects. To date, a variety of delivery systems have been developed. Different from synthetic materials, natural polymers are abundant in nature, renewable, non-toxic, biocompatible and biodegradable. Owing to the presence of positive charges, natural cationic polymers have found important applications in many biological fields, such as drug/gene delivery and tissue engineering. In gene delivery, natural cationic polymers can condense nucleic acids, protect them from degradation, lower the immunogenicity and improve overall transfection efficiency. In drug delivery, cationic functional groups can alter the amphiphilic properties of the polymers to ensure their suitable applications for delivering hydrophobic or protein drugs. After simple chemical modification, the derivatives of natural cationic polymers show improved performance as functional delivery carriers. In this chapter, details on the chemical modification of natural cationic polymers and their applications in gene/drug delivery is discussed.
Effects of Cationic Polymers on Cell Functions
Authors: Chen Guoping
Published: November 2014

Cationic polymers can affect cell functions such as cell adhesion, proliferation and differentiation through electrostatic interaction with cells or mediated by protein adsorption. Their effects have been compared with cell culture polystyrene plates. The effects on chondrogenic and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells have been elucidated by culturing the cells under the presence of cationic polymers in soluble and grafted conditions. Cationic polymers show promotive effects on both osteogenic and chondrogenic differentiation, while polystyrene plates are good for osteogenic differentiation. This chapter summarizes and highlights the recent developments of cationic polymers on the functions of stem cells.
An Introduction to Ambient Ionization Mass Spectrometry
Authors: Monge María Eugenia , Fernández Facundo M.
Published: November 2014

Ambient ionization/sampling mass spectrometry (or “ambient mass spectrometry” for short) is a subdiscipline of mass spectrometry that enables direct, high-throughput, surface analysis of native samples. Two flagship ambient mass spectrometry techniques: direct analysis in real time (DART) and desorption electrospray ionization (DESI) have not only enabled experiments previously not possible, but have also been surrounded by a plethora of other techniques, each with their own advantages and specific applications. This chapter introduces the kind of experiments that are the cornerstone of ambient mass spectrometry, and provides a set of select examples to introduce the reader new to the area to the field.
Secondary Electrospray Ionization
Authors: Berchtold Christian
Published: November 2014

This chapter details the technique called extractive electrospray ionization (EESI) and describes its state-of-the-art developmental, mechanical and experimental aspects and shows its most important applications. EESI is a sensitive, matrix-tolerant secondary electrospray ionization technique, which is in the focus of ongoing investigations. The strength of EESI is its ability to ionize various compounds directly out of the sample without preparation or chromatographic separation. Although it appears to be not always the most sensitive method, it has shown enormous capabilities for various applications such as breath or skin analysis, the classification of perfumes, detection of melamine in milk and identification of the freshness of frozen meat or fruit.
Laser Ablation Electrospray Ionization Mass Spectrometry: Mechanisms, Configurations and Imaging Applications
Authors: Nemes Peter , Vertes Akos
Published: November 2014

Laser ablation electrospray ionization (LAESI) combines the microsampling capabilities of mid-IR lasers with the high ion yields of electrosprays to produce sample-specific ions from biomedical and other specimens of high water content. To facilitate fundamental understanding of this technique, four critical aspects of the underlying physical phenomena are discussed. Fast imaging experiments and fluid dynamic calculations indicate that the sampling process by mid-IR laser ablation is governed by particulate ejection due to the recoil pressure of the expanding laser plume. Spray diagnostic studies show that control over the spraying regimes of the electrospray offers clues to achieve high ion yields. Tailoring the merging of the laser ablation plume with the electrospray offers additional ways to improve sensitivity. Measured internal energies of the ions produced by LAESI and regular electrospray ionization show them to be indistinguishable. Since its inception in 2007, LAESI has been implemented in diverse configurations, including conventional reflection and transmission geometries, heat-assisted LAESI for enhanced detection of apolar molecules, optical fiber-based laser-pulse delivery for improved focusing, and plume collimation for heightened sensitivity. LAESI supports several spatial profiling and molecular imaging modalities for biological tissues. Rastering the surface with the laser beam and collecting spectra point-by-point is the basis of constructing lateral images for ions associated with hundreds of metabolites and lipids. Because ablation by consecutive laser pulses can sample subsurface layers for analysis, depth profiling can also be performed. Combining lateral imaging with depth profiling is the basis of the three-dimensional reconstruction of molecular distributions in tissues. To improve the fidelity of molecular imaging, we introduced and implemented a cell-by-cell imaging strategy that promises to reveal new information on cellular transport and signaling processes in tissues.
Electrospray Laser Desorption Ionization Mass Spectrometry
Authors: Huang Min-Zong , Jhang Siou-Sian , Chan Ya-Ting , Cheng Sy-Chi , Cheng Chun-Nian , Shiea Jentaie
Published: November 2014

Electrospray laser desorption ionization mass spectrometry (ELDI/MS), an ambient mass spectrometric technique that combines laser desorption with postionization via electrospray, was developed to rapidly characterize analytes ranging from small organic to large biomolecules. The technique requires essentially no sample pretreatment. The analytes are desorbed through pulsed laser irradiation in the absences of organic matrices like those used in matrix-assisted laser desorption ionization (MALDI). The desorbed molecules subsequently enter an electrospray plume and are postionized through reactions with charged solvent species such as protons, cluster solvent ions, and charged droplets (also termed as species produced from an acidic methanol electrospray solution). This chapter provides a full-scale review of the ELDI technique including its development, underlying principles of operation, ionization mechanism, unique features, related techniques, and applications.
Inlet and Vacuum Ionization from Ambient Conditions
Authors: Trimpin Sarah , Wang Beixi
Published: November 2014

The discovery that laser ablation of a common MALDI matrix at atmospheric pressure without use of a voltage produced ions with nearly identical charge states to ESI led to a series of new ionization methods that we have given the general term inlet and vacuum ionization. The initial thought that the laser was necessary for matrix-assisted ionization gave way to ionization requiring a heated inlet with a pressure-drop region and then to a matrix that could be a solvent or no matrix. This in turn led to laser ablation in vacuum producing multiply charged ions without an inlet, and finally to the present where we have found matrices that lift molecules into the gas phase as ions without any external energy source. Our mechanistic view of this new ionization process developed into ionization methods for use in mass spectrometry will be discussed. These methods are simple to use, safe, robust, and sensitive. Several approaches for high-throughput analyses of compounds irrespective of their molecular weight will be presented using low- and high-performance mass spectrometers.
Songs from the Outback: The Effectiveness of Music in Treating Articulation Disorders in Children Aged 2–5 Years with Cleft Palate and Velopharyngeal Dysfunction
Authors: Kilcoyne Sarah C. , Carrington Helen , Walker-Smith Katie , Morris Helen , Condon Anita
Published: November 2014

The Royal Children's Hospital Speech Pathology Department (RCH SPD) provides services to children with Cleft Palate (CP) and velopharyngeal dysfunction (VPD) in a geographical region that is more than twice the size of Texas, with 30% of the children residing in regional areas. The geographical distribution of the population means that many families are unable to access local speech therapy. To address this problem, the RCH SPD and Music Therapy departments (MTD) collaborated to create a clinical resource for regional children and families. The package is intended to facilitate an increase in children's consonant inventory, frequency of vocalizations, vocabulary, and communicative opportunity and increase oral airflow during speech. It is also intended to facilitate family-centered care and increase the parent and child's motivation to participate in speech therapy activities within the home environment. The clinical resource has now been distributed to 70 children with cleft palate in Queensland. This paper presents results of preliminary evaluation of the program and explores the use of music to facilitate speech sound stimulation for children with CP and VPD aged 2–5 years. This resource will be of interest to speech therapists and families with limited or no access to services.
Intubation-Related Dysphonia Following Extreme Preterm Birth: Case Studies in Behavioural Voice Intervention
Authors: Reynolds Victoria , Meldrum Suzanne , Simmer Karen , Vijayasekaran Shyan , French Noel
Published: November 2014

Many more children than ever before survive and thrive following preterm birth (Saigal & Doyle, 2008). To date, research has focussed on medical, developmental, neurological, and behavioral outcomes. As the number of surviving children increases and survivors reach school age and beyond, it has become apparent that many children experience difficulties with voice production (French et al., 2013). Following preterm birth, endotracheal intubation may be necessary to deliver surfactant or relieve respiratory distress during the neonatal period (Ho, Subramaniam, Henderson-Smart, & Davis, 2002). Intubation injury to the larynx and resultant dysphonia are well described in the literature (Bray, Cavalli, Eze, Mills, & Hartley, 2010). This article presents a brief review of the literature relevant to intubation-related injury following preterm birth and 2 case studies of voice outcomes following a trial of behavioral voice therapy in extremely preterm children who were intubated.
Activist-Mothers Maybe, Sisters Surely? Black British Feminism, Absence and Transformation
Authors: Anim-Addo Joan
Published: November 2014

This article, drawing on selected feminist magazines of the 1980s, particularly Feminist Arts News (FAN) and GEN, offers a textual ‘braiding’ of narratives to re-present a history of Black British feminism. I attempt to chart a history of Black British feminist inheritance while proposing the politics of (other)mothering as a politics of potential, pluralistic and democratic community building, where Black thought and everyday living carry a primary and participant role. The personal—mothering our children—is the political, affording a nurturing of alterity through a politics of care that is fundamentally antiracist and antisexist. I attempt to show how Black feminist thought can significantly contribute to democracy in the present and how Black British history and thought, as fundamentally antiracist and anticolonial, can generate a reinvention much needed in the present of a shared British history. I argue for feminist intervention premised upon a politics of care, addressing through activist mothering the urgency of Black absence from prestigious institutions. Such debilitating absence in Britain inhibits the development of scholarship, distorts feminist history and seriously concerns potential Black feminists. From diverse texts, I develop a genealogical narrative supplemented through memory work. This ‘gathering and re-using’ privileges Black women's theorising as a crucial component of the methodological metissage, which includes auto-theorising to develop ideas of resemblance in relation to Black British feminism and feminist kinship. The resultant ‘braiding’, I suggest after Lionnet, questions the absence of intersubjective spaces for reflection on Black British feminist praxis, indicating a direction for British feminists of all complexions. Attentive to the 1980s as historical context while invoking the maternal, I consider what is required to engage generationally, counterwrite the academy and pursue a dynamic process of transformation within a transnational feminism that challenges Black British absence from academic knowledge production, while nurturing its presence.
Photovoltaic thermal air collectors: A review
Authors: Kamthania Deepali , Tiwari G. N.
Published: November 2014

Renewable energy resources have enormous potential and can meet the present world energy need. One of the most promising renewable energy technologies is photovoltaic technology. This article presents an overview on the development and application aspects for the hybrid photovoltaic/thermal (PVT) collector systems since last 30 yr. Different types of solar thermal collector and new materials for PV cells have been developed for efficient solar energy utilization. The review covers detailed description and thermal model of hybrid photovoltaic thermal systems, using air as the working fluid. Numerical model analysis and qualitative evaluation of thermal and electrical output in terms of an overall thermal energy and exergy for various silicon and non-silicon based modules have been carried out. Based on the thorough review, it is clear that PVT modules are very promising devices and future work should be carried out to improve efficiency aiming towards global expansion and utilization of environment friendly renewable energy devices.
Invited Article: SUBGLACIOR: An optical analyzer embedded in an Antarctic ice probe for exploring the past climate
Authors: Grilli R. , Marrocco N. , Desbois T. , Guillerm C. , Triest J. , Kerstel E. , Romanini D.
Published: November 2014

This article describes the advances made in the development of a specific optical spectrometer based on the Optical Feedback-Cavity Enhanced Absorption Spectroscopy technique for exploring past climate by probing the original composition of the atmosphere stored in the ice sheet of a glacier. Based on significant technological progresses and unconventional approaches, SUBGLACIOR will be a revolutionary tool for ice-core research: the optical spectrometer, directly embedded in the drilling probe, will provide in situ real-time measurements of deuterium isotopic variations (δ2H ) and CH4 concentrations down to 3500 m of ice depth within a single Antarctic season. The instrument will provide simultaneous and real-time vertical profiles of these two key climate signatures in order to evaluate if a target site can offer ice cores as old as 1.5 million years by providing direct insight into past temperatures and climate cycles. The spectrometer has a noise equivalent absorption coefficient of 2.8 × 10−10 cm−1 Hz−1/2, corresponding to a detection limit of 0.2 ppbv for CH4 and a precision of 0.2‰ on the δ2H of H2O within 1 min acquisition time.
Communication: Global minimum search of ${\rm Ag}^+_{10}$ Ag 10+ with molecular beam optical spectroscopy
Authors: Shayeghi A. , Johnston R. L. , Schäfer R.
Published: November 2014

The present study is focused on the optical properties of the \documentclass[12pt]{minimal}\begin{document}${\rm Ag}^+_{10}$\end{document} Ag 10+ cluster in the photon energy range ℏω = 1.9–4.4 eV. Absorption spectra are recorded by longitudinal molecular beam depletion spectroscopy and compared to optical response calculations using time-dependent density functional theory. Several cluster isomers obtained by the new pool-based parallel implementation of the Birmingham Cluster Genetic Algorithm, coupled with density functional theory, are used in excited state calculations. The experimental observations, together with additional simulations of ion mobilities for the several geometries found within this work using different models, clearly identify the ground state isomer of \documentclass[12pt]{minimal}\begin{document}${\rm Ag}^+_{10}$\end{document} Ag 10+ to be composed of two orthogonal interpenetrating pentagonal bipyramids, having overall D2d symmetry.
Does surface roughness amplify wetting?
Authors: Malijevský Alexandr
Published: November 2014

Any solid surface is intrinsically rough on the microscopic scale. In this paper, we study the effect of this roughness on the wetting properties of hydrophilic substrates. Macroscopic arguments, such as those leading to the well-known Wenzel's law, predict that surface roughness should amplify the wetting properties of such adsorbents. We use a fundamental measure density functional theory to demonstrate the opposite effect from roughness for microscopically corrugated surfaces, i.e., wetting is hindered. Based on three independent analyses we show that microscopic surface corrugation increases the wetting temperature or even makes the surface hydrophobic. Since for macroscopically corrugated surfaces the solid texture does indeed amplify wetting there must exist a crossover between two length-scale regimes that are distinguished by opposite response on surface roughening. This demonstrates how deceptive can be efforts to extend the thermodynamical laws beyond their macroscopic territory.
Metastability, spectrum, and eigencurrents of the Lennard-Jones-38 network
Authors: Cameron Maria K.
Published: November 2014

We develop computational tools for spectral analysis of stochastic networks representing energy landscapes of atomic and molecular clusters. Physical meaning and some properties of eigenvalues, left and right eigenvectors, and eigencurrents are discussed. We propose an approach to compute a collection of eigenpairs and corresponding eigencurrents describing the most important relaxation processes taking place in the system on its way to the equilibrium. It is suitable for large and complex stochastic networks where pairwise transition rates, given by the Arrhenius law, vary by orders of magnitude. The proposed methodology is applied to the network representing the Lennard-Jones-38 cluster created by Wales's group. Its energy landscape has a double funnel structure with a deep and narrow face-centered cubic funnel and a shallower and wider icosahedral funnel. However, the complete spectrum of the generator matrix of the Lennard-Jones-38 network has no appreciable spectral gap separating the eigenvalue corresponding to the escape from the icosahedral funnel. We provide a detailed description of the escape process from the icosahedral funnel using the eigencurrent and demonstrate a superexponential growth of the corresponding eigenvalue. The proposed spectral approach is compared to the methodology of the Transition Path Theory. Finally, we discuss whether the Lennard-Jones-38 cluster is metastable from the points of view of a mathematician and a chemical physicist, and make a connection with experimental works.
Generalized discrete orbit function transforms of affine Weyl groups
Authors: Czyżycki Tomasz , Hrivnák Jiří
Published: November 2014

The affine Weyl groups with their corresponding four types of orbit functions are considered. Two independent admissible shifts, which preserve the symmetries of the weight and the dual weight lattices, are classified. Finite subsets of the shifted weight and the shifted dual weight lattices, which serve as a sampling grid and a set of labels of the orbit functions, respectively, are introduced. The complete sets of discretely orthogonal orbit functions over the sampling grids are found and the corresponding discrete Fourier transforms are formulated. The eight standard one-dimensional discrete cosine and sine transforms form special cases of the presented transforms.
Effect of pre-treatment on solvents extraction and physico-chemical properties of castor seed oil
Authors: Dasari Swaroopa Rani , Goud Vaibhav V.
Published: November 2014

Extraction of castor oil from castor seed was carried out by Soxhlet method using polar and non-polar commercial solvents at the optimum conditions obtained from the preliminary oil extraction study. The solvents used were hexane, pentane, petroleum ether, cyclohexane, ethylacetate, methanol, and isopropanol. The effect of different process parameters such as temperature, solute to solvent ratio, and extraction time were studied to optimize and compare the extraction efficiency of different solvents. The higher oil yields of 56.07% and 55.22% were obtained by using polar solvents, i.e., ethyl acetate and methanol, respectively. The physico-chemical properties of the castor oil extracted using different solvents were also estimated to determine its quality potential using ASTM methods. Similarly, the performance of seed pre-treatment on the oil yield and the suitability of methanol as a possible extracting and reactive solvent for biodiesel production was also investigated. The pre-treatment of castor seed has slightly increased the oil yield and decreased the values of acid value (3.92 to 0.925 mg KOH/g) and pour point (−15 to −21 °C) significantly. Apart from that, thermal and oxidative stability analysis was performed using thermo gravimetric analysis and differential scanning calorimetry under nitrogen and air atmosphere, respectively. The fatty acid profile of castor oil was determined by using gas chromatography. The 1H nuclear magnetic resonance spectroscopy was employed for two castor oil samples (extracted after and before heat-treatment of seeds) to compare and identify the different protons in present the oil. The obtained physico-chemical properties indicate that oil meets the prescribed biodiesel feedstock quality standards and further justifying that methanol can be a capable solvent for simultaneous extraction and transesterification.
Electrical flicker-noise generated by filling and emptying of impurity states in injectors of quantum-cascade lasers
Authors: Yamanishi Masamichi , Hirohata Tooru , Hayashi Syohei , Fujita Kazuue , Tanaka Kazunori
Published: November 2014

Free running line-widths (>100 kHz), much broader than intrinsic line-widths ∼100 Hz, of existing quantum-cascade lasers are governed by strong flicker frequency-noise originating from electrical flicker noise. Understanding of microscopic origins of the electrical flicker noises in quantum-cascade lasers is crucially important for the reduction of strength of flicker frequency-noise without assistances of any type of feedback schemes. In this article, an ad hoc model that is based on fluctuating charge-dipoles induced by electron trappings and de-trappings at indispensable impurity states in injector super-lattices of a quantum-cascade laser is proposed, developing theoretical framework based on the model. The validity of the present model is evaluated by comparing theoretical voltage-noise power spectral densities based on the model with experimental ones obtained by using mid-infrared quantum-cascade lasers with designed impurity-positioning. The obtained experimental results on flicker noises, in comparison with the theoretical ones, shed light on physical mechanisms, such as the inherent one due to impurity states in their injectors and extrinsic ones due to surface states on the ridge-walls and due to residual deep traps, for electrical flicker-noise generation in existing mid-infrared quantum-cascade lasers. It is shown theoretically that quasi-delta doping of impurities in their injectors leads to strong suppression of electrical flicker noise by minimization of the dipole length at a certain temperature, for instance ∼300 K and, in turn, is expected to result in substantial narrowing of the free running line-width down below 10 kHz.
Nanocomposite formed by titanium ion implantation into alumina
Authors: Spirin R. E. , Salvadori M. C. , Teixeira F. S. , Sgubin L. G. , Cattani M. , Brown I. G.
Published: November 2014

Composites of titanium nanoparticles in alumina were formed by ion implantation of titanium into alumina, and the surface electrical conductivity measured in situ as the implantation proceeded, thus generating curves of sheet conductivity as a function of dose. The implanted titanium self-conglomerates into nanoparticles, and the spatial dimensions of the buried nanocomposite layer can thus be estimated from the implantation depth profile. Rutherford backscattering spectrometry was performed to measure the implantation depth profile, and was in good agreement with the calculated profile. Transmission electron microscopy of the titanium-implanted alumina was used for direct visualization of the nanoparticles formed. The measured conductivity of the buried layer is explained by percolation theory. We determine that the saturation dose, φ0, the maximum implantation dose for which the nanocomposite material still remains a composite, is φ0 = 2.2 × 1016 cm−2, and the corresponding saturation conductivity is σ0 = 480 S/m. The percolation dose φc, below which the nanocomposite still has basically the conductivity of the alumina matrix, was found to be φc = 0.84 × 1016 cm−2. The experimental results are discussed and compared with a percolation theory model.
Superconducting proximity effect in inverted InAs/GaSb quantum well structures with Ta electrodes
Authors: Yu Wenlong , Jiang Yuxuan , Huan Chao , Chen Xunchi , Jiang Zhigang , Hawkins Samuel D. , Klem John F. , Pan Wei
Published: November 2014

We present our recent electronic transport results in top-gated InAs/GaSb quantum well hybrid structures with superconducting Ta electrodes. We show that the transport across the InAs−Ta junction depends largely on the interfacial transparency, exhibiting distinct zero-bias behavior. For a relatively resistive interface, a broad conductance peak is observed at zero bias. When a transparent InAs−Ta interface is achieved, a zero-bias conductance dip appears with two coherent-peak-like features forming at bias voltages corresponding to the superconducting gap of Ta. The conductance spectra of the transparent InAs−Ta junction at different gate voltages can be fit well using the standard Blonder-Tinkham-Klapwijk theory.
Influence of carrier overflow on the forward-voltage characteristics of InGaN-based light-emitting diodes
Authors: Han Dong-Pyo , Kim Hyunsung , Shim Jong-In , Shin Dong-Soo , Kim Kyu-Sang
Published: November 2014

We investigate the influence of carrier overflow on the forward-voltage characteristics of the InGaN-based blue light-emitting-diode (LED) by comparing the temperature-dependent characteristics of the electroluminescence (EL) efficiency, the EL spectra, and the current-voltage relation over a wide range of temperature (50–300 K). Based on these experimental results, we demonstrate that the simple ohmic potential drop in the Shockley diode equation is not sufficient to explain the experimental data when the severe carrier overflow to the p-(Al)GaN layer induces the efficiency droop in the LED device. The anomalous relation between current and voltage at cryogenic temperatures is explained by the space-charge-limited current formed by the overflown electrons, rather than by the increase of a constant series resistance in the p-(Al)GaN layer.
Patterning via optical-saturable transformations: A review and simple simulation model
Authors: Cantu Precious , Andrew Trisha L. , Menon Rajesh
Published: November 2014

Most of the nanoscale fabrication in the semiconductor industry is based on patterning with scanning-electron beam lithography (SEBL). Although this approach is very versatile and has very high resolution, it is intrinsically a serial writing process, and therefore, relatively slow. Our group has been investigating alternative nano-fabrication techniques, adapted from ideas of saturating optical transitions such as those used in stimulated emission-depletion microscopy and related methods, and optical interference lithography. Linewidths and resolutions on the scale of a few tens of nanometers and below are highly desirable for various applications in nanotechnology. However, the spatial resolution of optical lithography is restricted by diffraction. In the past, we developed absorbance modulation to overcome this limit. This approach utilizes photochromic molecules that can be optically switched between two thermally stable states, one opaque and the other transparent. However, absorbance modulation is limited to surface (2-D) patterning. Here, we report on an alternative approach that exploits unique combinations of spectrally selective reversible and irreversible photochemical transitions to achieve deep subwavelength resolution with potential extension to 3-dimensions. This approach, which we refer to as patterning via optical-saturable transformations have the potential for massive parallelism, enabling the creation of nanostructures and devices at a speed far surpassing what is possible with SEBL. The aim of our research is to translate the success in circumventing Abbe's diffraction limit in optical microscopy to optical lithography.
Institutional Entrepreneurship, Power, and Knowledge in Innovation Systems: Institutionalization of Regenerative Medicine in Tampere, Finland
Authors: Sotarauta Markku , Mustikkamäki Nina
Published: November 2014

In this paper we ask what is the place of institutional entrepreneurship in a (regional) innovation system. The main research questions addressed are (a) how does a new science-based concentration of innovation become institutionalized in an innovation system; (b) who are the institutional entrepreneurs and what do they actually do in their efforts to institutionalize new beliefs, practices, and activities within a system; and (c) what knowledge do institutional entrepreneurs need and what kind of power do they exercise in the institutionalization process. We add new knowledge to studies focusing on innovation systems by revealing how new elements are attached into it. We also add power and knowledge to the study of institutional entrepreneurship and institutional change. The empirical analysis identifies the main phases of institutionalization, key actors in different phases, and their strategies of influence. This paper is based on the analysis of secondary data and twenty-eight interviews with key actors.
On the development of Korean SAY evidentials and their extended pragmatic functions
Authors: Ahn Mikyung , Yap Foong Ha
Published: November 2014

This paper examines the development of five hearsay evidential markers in Korean, namely,tako,tamye,tamyense,tanunandtanta, and traces their extended pragmatic functions in discourse. We first identify their functions over time, from Middle Korean to Modern and Contemporary Korean, then quantitatively analyze the usage frequency of these functions, diachronically from the 16th century to the early 20th century using the UNICONC historical corpus, and synchronically in present-day Korean using theSejongcontemporary written and spoken corpus. From a pragmatic perspective, we examine how Korean speakers use these hearsay evidential markers to convey the interpersonal and intersubjective stances of interlocutors in natural conversations. Based on the differential rates of grammaticalization of these markers, and on their usage frequency, we also examine the relationship between evidentiality marking and finiteness; more specifically, we analyze the sequences and mechanisms of change whereby different types of non-finite evidential structures develop into finite evidential constructions. Our findings have broader theoretical and crosslinguistic implications for understanding the mechanisms of insubordination, whereby dependent structures become independent, and whereby lexically transparent constructions develop into grammaticalized markers of speakers’ stance.
Deep relationships among California languages
Authors: Haynie Hannah J.
Published: November 2014

The Hokan and Penutian language classifications, introduced by Dixon & Kroeber (1913), remain controversial nearly a century after they were first proposed. Recently developed computational methods for identifying historical relationships between languages are promising tools for assessing distant linguistic relationship proposals such as these. This paper uses a variation of the linguistic relatedness metric and multilateral clustering procedure developed by Kessler (1999, 2001) to study California language phylogenetics. The purpose is twofold: to evaluate the utility of this methodology for identifying deep relationships, and to re-examine the evidence for Hokan and Penutian groupings. While this paper illustrates several advantages of the methodology employed, it ultimately fails to provide any additional support for Hokan or Penutian. I conclude that while this result may be influenced by the sensitivity of the methodology to the composition of the input sample, it ultimately casts further doubt on the genealogical nature of the Hokan and Penutian classificatory groups.
On the relationship between clause combination, grammatical hierarchy and discourse-pragmatic coherence
Authors: Green Clarence
Published: November 2014

The aim of this study is to explore the relationship between the forms of clause combination and their systematic patterns of explicit inter-clausal coherence. The study is conducted within the theoretical framework of the Adaptive Approach. The Adaptive Approach conceives of combined clauses as a hierarchy of conventionalized units for discourse coherence management. The grammatical properties of the different combined clauses determine their position on the hierarchy, and these properties are claimed to correlate with whether the construction is more, or less, of a cohesive unit for packaging multiple propositions. The study pursues the hypothesis that clauses higher on the hierarchy, being the more cohesive grammatical constructions, should tend to manage coherence between the propositions they combine (i.e. the clausal constituents) through fewer explicit discourse-pragmatic ties than the clauses considered less cohesive grammatical constructions. An analysis of cohesive ties in 450 combined clauses, representing 9 different English clause types, bears out these expectations. This is a significant result indicating that an inverse relationship exists between the level of grammatical integration and the frequency of inter-clausal cohesive ties. It is argued to be a quantifiable consequence of grammatical hierarchy, reflecting a continuum of coherence management from discourse to grammar.
Possible signature of Alfvén wave dissipation in the localized magnetic funnels of the equatorial solar corona
Authors: Dwivedi Bhola N. , Srivastava Abhishek Kumar , Mohan Anita
Published: November 2014

We analyse the Hinode/EIS 2″-spectroscopic scan data containing the spectral line formed at typical inner coronal temperature. The strong Fe xii 195.120 Å line shows the existence of funnel-like expanding flux-tubes which exhibit the signature of blue-/red-shifted plasma motions in the off-limb equatorial corona. These coronal funnels expand in the form of open magnetic field channels up to inner coronal heights. They are most likely the parts of large-scale and closed magnetic fields (loops) which exist at higher heights in the diffused equatorial corona. We also find the signature of decreasing line-widths with altitude in observed coronal funnels (e.g., funnel 1), which is the lower part of a curved loop system. This provides the most likely signature of Alfvén wave dissipation in lower part of this loop system. We also examine the blue-shifted and diffused coronal loop boundary and interfaced region (funnel 3) which shows increasing Fe xii 195.120 Å line-width along it. Therefore, it exhibits the most likely signature of Alfvén wave growth in this region which is slightly curved and rising higher in the corona. Density measurements in these funnels show that it falls off with height, but more rapidly in the second funnel. We conjecture the almost constant line-width trend as a most likely signature of Alfvén wave dissipation in this density-stratified second coronal funnel, which is also the lower part of a large-scale closed loop system. Both dissipative and growing Alfvén waves can change the non-thermal component and thus the full width at half-maximum of the Fe xii 195.120 Å line. We find the clues of Alfvén wave dissipation along the expanding field lines of the coronal funnel (lower parts of the loop system) imparting its energy to the outflowing plasma and thereby contributing to the formation of the nascent solar wind in the inner corona.