bluuebunny/crossref_metadata_2025 huggingface dataset:
Membrane Modification of Ceramic Membrane and its Application in Separation of Waste o/w Emulsion
Authors: Zhou Jian Er , Chang Qi Bing , Wang Yong Qing , Zhang Xiao Zhen , Liang Jian , Wang Xia
Published: July 2015

Membrane modification is an important technology to improve the membrane performance. Ceramic membranes modified with nanometal oxide coating are prepared by homogeneous precipitation or in-situ hydrolysis method. TEM images show that the nanocoating distributes in the surface of the membrane pores. The nanocoating has no the separation function but just changes the surface characters of ceramic membrane. The permeate flux of the modified membrane increase above 20% than the unmodified membrane while treating the stable o/w emulsion with the concentration of 4g/L.
The Electrical Characteristics of GaAs-MgO Interfaces of GaAs MIS Schottky Diodes
Authors: Gao Xian , Tang Ji Long , Fang Dan , Chen Fang , Wang Shuang Peng , Zhao Hai Feng , Fang Xuan , Wang Xiao Hua , Xu Zhi Kun , Ma Xiao Hui , Xu Li , Wei Zhi Peng
Published: July 2015

Many researches pay attention to the metal-semiconductor interface barrier, due to its effect on device. Deliberate growing an interface layer to affect and improve the quality of device, especially metal-insulator-semiconductor (MIS) structures, arouses wide attention. In this paper, Be-doped GaAs was grown on substrate wafer by molecular beam epitaxy (MBE) on purpose before depositing insulator layer, and then MgO film as the dielectric interface layer of Au/GaAs were deposited using atomic layer deposition (ALD) method. The interface electrical characteristics of the metal-insulator-semiconductor (MIS) structures were investigated in detail. The barrier height and ideal factor of GaAs diode parameters were calculated by means of current-voltage (I-V) characteristics. Experimental result showed that along with the increasing of the doping content, the Schottky barrier height increasing, but the ideal factor decrease at first and then increase.
The Synthesis and Property of Neutral Silicone Glass Sealant
Authors: Chen Xin , Yu Bing , Yuan Hua , Cong Hai Lin , Xu Xiao Dan , Yang Shu Jing , Peng Qiao Hong , Yang Rui Xia , Gao Xiao Hui
Published: July 2015

The neutral silicone glass sealant was prepared and the mechanical performance of this silicone glass sealant was researched in this paper. The recipe of neutral silicone glass sealant was studied. Besides, the influence of different cross-linking agents was researched; meanwhile, the effect of plasticizer and reinforcing agent on the mechanical properties of the material was studied. To obtain the best properties of neutral silicone glass sealant, the recipe should be taken further efforts to optimize.
Effect of Sm-Au on Silver Staining Results and it ́s UV-Vis Absorption Spectrum
Authors: Liu Xiao Zhen , Zhang Cheng , Zhu Wan Wan , Liu Xiao Zhou , Chen Jie , Gui Xiu Min
Published: July 2015

Sm particles and gold nanoparticles were prepared respectively. Effects of Sm-Au particles on silver staining results were studied, and UV-Vis absorption spectrum of Sm-Au particles solution was studied. Time and color of sport with Sm-Au particles is longer and darker than that of with gold nanoparticles. The time of sport with Sm-Au particles is as long as 28.5 min, which is 2.6 times as long as with gold nanoparticles. Although amount of gold nanoparticles reduced 80%, the color of sport with Sm-Au particles is darker than that of with gold nanoparticles. In 200.00-800.00 nm, Sm particles solution and gold nanoparticles solution has one absorption peak, respectively, and λmaxis 276 nm, 521 nm respectively. Sm-Au particles solution has two absorption peaks, λmax (Sm)and λmax (Au)are 276 nm and 523 nm respectively. λmaxof Sm particles is constant, and λmaxof Au nanoparticles occurs red moving. Sm particles and gold nanoparticles may have interaction.
The Influence of Mn, Zr and Pb Promoters on the Performance of Cu/ZnO/SBA-15 Catalyst for Hydrogenation of CO2 to Methanol
Authors: Tasfy Sara Faiz Hanna , Zabidi Noor Asmawati Mohd , Shaharun Maizatul S. , Subbarao Duvvuri
Published: July 2015

The present work investigates the hydrogenation of CO2 to methanol via a promoted Cu/ZnO/SBA-15 catalyst. In order to understand the effect of Mn, Zr and Pb promoters on the catalytic activity of Cu/Zn/SBA-15 catalysts, the hydrogenation of CO2 was performed in a stirred high-pressure reactor at 483K, 22.5bar, and a H2/CO2 ration of 3. The physicochemical properties of the catalysts were studied using N2 physical adsorption, TEM and H2-TPR. The characteristics of catalysts depended on the type of promoter and it influenced their catalytic performance. The Mn and Zr promoters resulted in a larger surface area of the catalyst and improved catalytic activity and methanol selectivity. However, an opposite effect was found for the Pb promoter. A 10% improvement on the CO2 conversion and 20% on the methanol selectivity was achieved due to the double promotion effect of Mn and Zr on Cu/ZnO-SBA-15 catalyst.
First-Principles Study of Hydrogen Storage in Fe-Ti System
Authors: Khadraoui Ahlem , Bentayeb Fatima Zohra
Published: July 2015

In this study, a first-principles investigation of hydrogen storage in the FeTi intermetallic is carried out. The structural and electronic changes due to hydrogen insertion into the FeTi intermetallic are determined using DFT and pseudo-potential calculations through the code SIESTA (Spanish Initiative for Electronic Simulation of Thousand of Atoms). The pseudopotentials are constructed using Troullier and Martins parametrization which describes correctly the ion-electron interactions. To define the real-space grid, necessary for numerical calculations of the electron density, detailed tests were performed in order to choose the appropriate basis set, the energy cutoff and the k-grid cutoff. The exchange-correlation potential is treated with the generalized gradient approximation (GGA). Lattice data, bonding properties and the density of states provide an explanation for the role played by hydrogen in the chemical bond with the Ti and Fe constituents.
Study on Cu48Zr43Al9 and Cu54Zr40Al6 Amorphous Matrix Alloys by Mechanical Spectroscopy
Authors: Florêncio Odila , Marques Paulo Wilmar Barbosa , Silva Paulo Sergio , Muñoz Chaves Javier Andres , Rodriguez Aliaga L.C. , Botta Filho Walter José
Published: July 2015

Anelastic properties of Bulk Metallic Glasses (BMG) were studied by mechanical spectroscopy using a flexural vibration apparatus. BMG’s samples, with nominal composition Cu48Zr43Al9and Cu54Zr40Al6, were produced by skull push-pull casting technique in rectangular cavity cooper mold. In both samples, the differential scanning calorimeter patterns have evidenced the presence of amorphous structure, although the X-ray diffraction for Cu48Zr43Al9composition has shown a heterogeneous microstructure embedded in the amorphous matrix. Anelastic relaxation spectra were obtained using an acoustic elastometer system with vibration frequency in the kilohertz bandwidth, a heating rate of 1 K/min, vacuum greater than 10-5mBar in the temperature range of 300 K to 620 K. In the flexural apparatus, an acoustic elastometer system, the internal friction (energy loss) and the elastic modulus were obtained by free decay of vibrations and by the squared of the oscilation frequency, respectively. Internal friction spectra were not reproducible among the measurements, which may imply atomic rearrangement in the samples due to consecutive heating. Normalized elastic modulus data showed distinct behavior from the first to the other measurements evidencing irreversible microstructural alterations in the samples possibly associated with mechanical relaxation due to the motion of atoms or clusters in the glassy state.
Characteristics Determination of LM-2500 Naval Gas Turbine in Aspect of Energy Modeling and Simulations
Authors: Pojawa Bogdan
Published: July 2015

The paper presents the results of study concerning the determination of operating characteristics of the examined engine in steady states. The study concerned main propulsion engines of an Oliver Hazard Perry class frigate operated by the Polish Navy. The studies were conducted in the ship's engine room when the ship was at sea. Operating characteristics were determined on the basis of the measurements recorded over the entire load range of the engine, from minimum to rated load. During the studies, the load of both engines of the ship was simultaneous and balanced. In order to facilitate the comparison of the operating characteristics of the tested engines, as well as to make a reference to various weather conditions, the data obtained was reduced to standard reference state. For the aforementioned characteristics approximation relations were determined using statistical analysis. The relations obtained may be utilized in energy modeling and simulations, as well as technical diagnostics concerning this kind of engines.
Analysis of Gaseous Degradation Products Occurring during Biomass-to-Liquid Processes
Authors: Rostek Ewa
Published: July 2015

The article presented the processes of pyrolysis and gasification of biomass leading to the preparation of liquid hydrocarbon fractions in the synthesis of Fischer-Tropsch and processes HTU. Preliminary thermogravimetric testing of biomass samples was conducted on the STA 449 F3 Jupiter® coupled with the gases analyzer – spectrometer QMS 403 Aëolos. These studies were carried out for samples of cereal straw, crushed to a state of dry dust. The temperature regime provided that the samples were heated to the temperature of 750 °C at the heating rate of 10 K/min. Gases (nitrogen, argon or carbon dioxide) were used with flow rates of 60 mL/min. The results, along with discussion, are presented in graphs - TG curves and mass spectrum.
Temperature as a Source of Information about the Technical Condition Viscous Torsion Damper
Authors: Homik Wojciech , Markowski Tadeusz
Published: July 2015

The problem of damping of torsional vibrations of the crankshaft in a multi-cylinder engine is very important from the point of view of durability and reliability of the drive unit of the vessel or ship. Mostly dependent on the technical state of the torsional vibration damper that is located at the free end of the crankshaft. The paper presents selected results of the research that led to the acceptance criterion for assessing the technical condition of the viscous torsion damper.
The Selection of the Parameters of Laser Beam for Constitution of the Corrosion Resistant Surfaces in Parts of the Rubber Vibration Damper
Authors: Ciecińska Barbara , Homik Wojciech , Matuszak Zbigniew
Published: July 2015

Corrosion is an everyday occurrence. It provokes the materials destruction, what directly translates into the durability, survivability and reliability of the equipment, specially of working in the aggressive environments one – e.g. afloat ships or boats. Corrosion is a cause of growth of the requirements of the raw materials needed for production of more and more new products and increase amount of waste come from this production.In the paper authors show the results of the experimental tests and they describe the meaning of the selection of laser bean parameters oriented for surface of chosen steel exposed to even corrosion.
A. Cindrič: OD IMATRIKULACIJE DO PROMOCIJE Ljubljana, Znanstvena založba Filozofske fakultete, 2015
Authors: Ličen Nives
Published: July 2015

Ob bližajoči se stoletnici Filozofske fakultete in Univerze v Ljubljani je bila zasnovana zbirka Historia facultatis. Prvo delo v tej zbirki je monografija, ki je nastala ob podrobnem študiju arhivskega gradiva o doktorskih študentih in nosi podnaslov Doktorandi profesorja Franceta Vebra na Oddelku za filozofijo Filozofske fakultete Univerze v Ljubljani v luči arhivskega gradiva 1919–1945.
Comparación de la recarga natural estimada con el balance de agua en el suelo y con el balance de la deposición atmosférica de cloruro en un sistema carbonatado en el área semiárida del Baix Ebre, Cataluña, España.
Authors: Espinosa-Martínez Sara , Custodio Emilio , Loaso-Vierbücher Carlos
Published: July 2015

Se realiza la estimación de la recarga media multianual con el método de balance de la deposición atmosférica de cloruro (BCl) y con el balance de agua en el suelo (BaS) en el área del Baix Ebre (Sur de Cataluña). Es un sistema acuífero complejo formado por una cordillera carbonatada moderadamente lluviosa (los Ports) que transfiere agua a un llano semiárido (Plana de La Galera), según un modelo hidrogeológico conceptual de funcionamiento apoyado en técnicas hidrogeoquímicas e isotópicas ambientales y que considera la escorrentía superficial en la zona montañosa. Según el BCl la tasa media de recarga en los Ports de 340±155 mm.a-1 y 150±55 mm.a-1 en la Plana y según el BaS de 500±60 mm.a-1 en los Ports y 230±25 mm.a-1 en la Plana. Las diferencias dependen de cómo se considera la escorrentía superficial, de la concentración cloruro en la recarga y de las series de datos de precipitación.  
FishPath: aplicación informática de diseño de escalas de peces de hendidura vertical
Authors: Bermúdez María , Rico Ángel , Rodríguez Álvaro , Pena Luís , Rabuñal Juan R. , Puertas Jerónimo , Balairón Luis , Lara Ángel , Aramburu Enrique , Morcillo Felipe , Castillo Miriam
Published: July 2015

Las escalas de peces de hendidura vertical son estructuras hidráulicas diseñadas para permitir la migración de las especies piscícolas a través de obstáculos en ríos. El diseño adecuado de estos dispositivos depende de la interacción entre variables hidráulicas y biológicas, dado que las propiedades hidrodinámicas de la escala deben ajustarse a los requisitos de las especies objetivo. En este artículo se presenta una aplicación informática que analiza la eficiencia de un modelo de escala de acuerdo con criterios biológicos. El modelo propuesto aplica restricciones referidas a la capacidad de natación de los peces, a sus necesidades de calado y a sus requisitos en relación con la energía disipada en forma de turbulencias. Permite así comparar diseños de forma objetiva y determinar cuál será previsiblemente más eficiente. Con esta herramienta se busca facilitar a los técnicos involucrados en el diseño de escalas de peces de hendidura vertical la aplicación sistemática de criterios hidrobiológicos, que incorporen además los resultados de las investigaciones más recientes en este ámbito.
Durabilidade natural da madeira de três espécies florestais em ensaios de campo.
Authors: Melo Rafael Rodolfo de , Stangerlin Diego Martins , Santini Elio José , Haselein Clovis Roberto , Gatto Darci Alberto , Susin Felipe
Published: July 2015

Com o objetivo de avaliar a durabilidade natural da madeira, amostras de alburno e de cerne de Luehea divaricata (açoita-cavalo), Carya illinoinensis (nogueira-pecã) e Platanus x acerifolia (plátano), medindo 2,5 x 2,5 x 30,0 cm (radial x tangencial x longitudinal), foram submetidas a ensaios experimentais em um povoamento de Pinus e em campo aberto. Durante um ano, as amostras foram periodicamente pesadas e avaliadas pelo critério de notas, para determinar o percentual de perda de massa e índice de deterioração, respectivamente. Os resultados mostraram que, independente da espécie e do tipo de lenho, o ambiente dentro da floresta é mais favorável a deterioração da madeira do que fora dele. Apesar da elevada correlações entre a perda de massa e o índice de deterioração foram observadas variações na avaliação da durabilidade da madeira entre esses critérios. Para todas as espécies, a madeira proveniente do alburno foi a mais atacada. Para perda de massa não foi observada diferença entre as espécies avaliadas, entretanto, o índice de deterioração apontou o plátano como a mais atacada.
Crescimento em viveiro de mudas de Schizolobium parahyba (Vell.) S. F. Blake. submetidas a níveis de sombreamento
Authors: Caron Braulio Otomar , Souza Velci Queiróz de , Cantarelli Edison Bisognin , Manfron Paulo Augusto , Behling Alexandre , Eloy Elder
Published: July 2015

O estudo do crescimento e desenvolvimento de plantas em diferentes ambientes oferece respostas sobre as melhores condições para as espécies serem cultivadas. Objetivou-se avaliar o crescimento inicial até 80 dias em mudas de Schizolobium parahyba (guapuruvu) submetidas aos níveis de sombreamento: 0% (pleno sol), 30, 50 e 70%. Os resultados demonstram que o sombreamento interferiu positivamente no crescimento em altura das mudas, apresentando tendência nos maiores níveis, não causando danos às plantas, fato comprovado pela não diferença das variáveis: matéria seca, diâmetro de colo e número de pares de folhas. É favorável a produção de mudas com qualidade até o 45o dia de submissão ao sombreamento, devendo ser transplantadas após esse período.
Estimativa da biomassa comercial de brotos de Ilex paraguariensis A.St.-Hil.
Authors: Vuaden Elisabete , Fleig Frederico Dimas , Selle Gerson Luiz , Lana Mayara Dalla , Silva Gustavo Fernandes da , Vargas Jonas Flores
Published: July 2015

Este estudo teve como objetivo desenvolver modelos que permitam estimar a biomassa comercial verde dos brotos de erva-mate (Ilex paraguariensis) após a poda, aos 10 anos de idade. Em setembro de 2007, 40 erveiras foram podadas, um ano após a primeira poda, em 2008, estas foram avaliadas dendrometricamente e sua biomassa comercial determinada a partir da colheita de 16 indivíduos, para as demais, a biomassa comercial foi estimada pelo somatório da biomassa dos brotos. Como resultado obteve-se que: a biomassa comercial dos brotos pode ser estimada como função do comprimento folhado dos mesmos, com modelos específicos para brotos curtos: √bc = 0,8682 + 0,0113 . cf2, brotos médios simples e compostos: ln bc = -2,1600 + 1,3861 . ln cf e brotos longos compostos: ln bc = -0,6288 + 1,0584. ln ∑cf; os modelos utilizados para a estimativa da biomassa comercial dos brotos que utilizam o comprimento folhado e somatório do comprimento folhado como variáveis independentes, subestimam os valores de biomassa com uma margem de erro de apenas 2,6 %.
Utilização da farinha de babaçu como extensor alternativo na produção de painéis compensados
Authors: Ferreira Érika da Silva , Brito Edvá Oliveira , Iwakiri Setsuo , Rosso Silviana , Batista Djeison Cesar
Published: July 2015

O objetivo desta pesquisa foi avaliar a potencialidade de uso da farinha de babaçu sob diferentes percentuais (0, 50, 75 e 100%) como extensor alternativo à farinha de trigo para produção de painéis compensados. Foram produzidos 32 painéis compostos por cinco lâminas de madeira de Araucaria angustifolia (Bertol.) Kuntze, sendo utilizadas as resinas uréia-formaldeído - UF e fenol-formaldeído - FF, com três repetições por tratamento. As seguintes formulações (em partes por peso) foram utilizadas: resina uréia-formaldeído - 100, extensor - 50, água - 50, catalisador - 7 e, resina fenol-formaldeído - 100, extensor - 18, água - 22. Os resultados de resistência da linha de cola obtidos para os painéis produzidos tanto com a resina uréia-formaldeído, quanto com a resina fenol-formaldeído, apontaram para a viabilidade de uso do extensor a base de farinha de babaçu em substituição parcial ou total do extensor convencional a base de farinha de trigo na produção de painéis compensados multilaminados.
La méthode philosophique en question
Authors: Prunea-Bretonnet Tinca
Published: July 2015

Cet article se propose d’analyser les courants et les doctrines méthodologiques représentés à l’Académie de Berlin entre 1746 et 1761 en prenant en compte les deux orientations principales qui s’y affrontent : d’une part, le wolffianisme soutenu en premier lieu par Formey, qui argumente l’emploi d’une méthode d’inspiration mathématique en philosophie, et, de l’autre, le camp newtonien et anti-wolffien, représenté notamment Maupertuis et Béguelin, qui affirme l’hétérogénéité de la mathématique et de la philosophie et la nécessité d’en tenir compte sur le plan méthodologique. Ce débat est intimement dépendant des prises de position de Crusius et de Wolff et leur analyse s’avère indispensable. Il formule également le cadre conceptuel de la Preisaufgabe pour l’année 1763, jouant un rôle déterminant dans l’élaboration des réponses, ainsi qu’en témoignent les mémoires de Mendelssohn et de Kant, discutés dans la dernière partie du texte. L’Académie de Berlin apparaît ainsi comme un acteur décisif dans les controverses philosophiques de l’époque et dans la redéfinition méthodologique amorcée.
Modeled Osteopathic Manipulative Treatments: A Review of Their in Vitro Effects on Fibroblast Tissue Preparations
Authors: Zein-Hammoud Manal , Standley Paul R.
Published: July 2015

A key osteopathic tenet involves the body’s ability to self-heal. Osteopathic manipulative treatment (OMT) has been evolved to improve this healing capacity. The authors' in vitro work has focused on modeling 2 common OMT modalities: myofascial release (MFR) and counterstrain. Their studies have evaluated the effects of these modalities on wound healing, cytokine secretion, and muscle repair. The key components of the host response to mechanical forces are fibroblasts, which are the main fascial cells that respond to different types of strain by secreting anti-inflammatory chemicals and growth factors, thus improving wound healing and muscle repair processes. The purpose of this review is to discuss the cellular and molecular mechanisms by which MFR and other OMT modalities work, in particular, the role of strained fibroblasts in inflammation, wound healing, and muscle repair and regeneration. Changing MFR parameters, such as magnitude, duration, direction, and frequency of strain, might uniquely affect the physiologic response of fibroblasts, muscle contraction, and wound healing. If such results are clinically translatable, the mechanisms underlying the clinical outcomes of OMT modalities will be better understood, and these treatments will be more widely accepted as evidence-based, first-line therapies.
Bilateral Shoulder Dislocation Presenting as a Unilateral Shoulder Dislocation: Case Report
Authors: Auerbach Brett , Bitterman Adam , Mathew Cristin , Healy William
Published: July 2015

Shoulder dislocations are a common condition seen by orthopedic surgeons and emergency medicine physicians. Shoulder dislocations typically present unilaterally and are anterior in nature. Bilateral simultaneous posterior shoulder dislocations are typically associated with seizure or electrocution and are more common than bilateral simultaneous anterior dislocations, which occur because of trauma or fall. In a traumatic setting, a shoulder dislocation may be accompanied by a distracting injury, and a thorough examination must be conducted to avoid overlooking concomitant diagnosis. The authors highlight the case of a patient who presented to the emergency department with the rare incidence of traumatic bilateral anterior shoulder dislocations, which resolved after 2 closed reductions. Orthopedic surgery and emergency medicine teams must maintain a high index of suspicion for injury to the contralateral limb to avoid missing pathologic changes due to distracting injuries.
Subglacial hydrology as a control on emergence,scale, and spacing of ice streams
Authors: Kyrke‐Smith T. M. , Katz R. F. , Fowler A. C.
Published: July 2015

Observations have long associated ice streams with the presence of meltwater at the bed. More recently, theoretical models have been able to reproduce ice stream behavior as a consequence of the coupled dynamics of ice and subglacial meltwater. In this paper we analyze the properties of ice streams that form in a coupled model of ice flow and subglacial hydrology. We see that there is a natural length scale defining ice stream separation and width. This arises as a result of the balance between effective pressure gradients driving meltwater away from ice streams and the enhanced water production in the streams due to the fast ice flow. We further discuss how the model interacts with topography, and we show that small perturbations to a uniform bed have a strong effect on where ice streams emerge in the model. However, in many cases ice streams then evolve to be closer to the dimensions defined by the natural length scale of the unperturbed system. The nondimensional parameter that defines this length scale is therefore of fundamental importance in the model.
Simulating depth‐averaged, one‐dimensional turbidity current dynamics using natural topographies
Authors: Traer M. M. , Fildani A. , McHargue T. , Hilley G. E.
Published: July 2015

This study simulates turbidity currents through natural submarine topographies using a steady, one‐dimensional, depth‐averaged model to determine if modeled flows might traverse the length of channel forms observed at the seafloor or in shallow seismic data sets. To accomplish this, we calculated flow dynamics based on 50,000 sets of initial conditions drawn randomly between prescribed bounds and identified those conditions that allowed flows to traverse the naturally observed systems. We also used flow height and velocity to rule out initial conditions that produced flows that would be broadly accepted as unrealistic. We found that a small percentage (2.3–9.7%) of flows traversed the measured portion of these natural systems and maintained plausible peak depth‐averaged velocities when laboratory‐derived clear‐water entrainment rules were used. However, even these flows reached peak heights that were many times (10–200) greater than that of the channel bottom to levee crest relief. When clear‐water entrainment was removed from the model, a larger percentage of flows (34.5–41.6%) traversed the measured channel geometries, maintained lower ranges of flow height, and typically had higher flow velocities. Alternate entrainment relationships allowed flows to maintain realistic flow heights and velocities. We speculate that the unrealistic flows produced using clear‐water entrainment rules arise because flow loss through stripping and/or overbank collapse is neglected in this one‐dimensional model, or extrapolating laboratory‐measured clear‐water entrainment rules to the field is problematic.
Bacterial Capsules and Evasion of Immune Responses
Authors: Merino Susana , Tomás Juán M
Published: July 2015

The bacterial surface contains various structures that are capable of activating the host defences and consequently inducing host immune responses. Bacterial capsules are one of the most external structures on the bacterial surface, which may completely surround all the antigenic molecules or may be coexpressed with other bacterial antigens. They are involved in a wide range of biological processes, such as prevention of desiccation, adherence and resistance to nonspecific and specific host immunity.

Gram‐negative and Gram‐positive capsular polysaccharides contribute to the bacterial resistance of host immune responses by different mechanisms. Usually, capsular polysaccharides that mask the underlying cell surface structures activate weakly or not at all the immune system, whereas bacterial capsules coexpressed with other bacterial antigens activate the immune system but mask opsonines and prevent complement attack complex formation, as well as phagocytosis.

Key Concepts

Bacterial capsules completely surround bacterial cell and enhance the ability of bacteria to cause disease.

Polysaccharides are polymeric carbohydrate structures, formed of one or more sugar residues repeating units joined together by glycosidic bonds.

Antigenic variation modifies microorganism's surface structures and allows them to overcome the immune response.

Phagocytosis is the process by which certain cells called phagocytes engulf and digest a solid particle as bacteria.

The complement system is a part of the innate immune system and consists of a number of plasma small proteins which circulating as inactive precursors and after their activation cascade are able to serve as opsonins.
Graft Rejection: Immunological Suppression
Authors: Afzali Behdad , Lechler Robert , Lombardi Giovanna
Published: July 2015

Transplantation of solid organs is the treatment of choice for most patients with end‐stage organ diseases. In the absence of pharmacological immunosuppression, recognition of foreign (allogeneic) histocompatibility proteins expressed on donor cells by the recipient's immune system results in rejection of the transplanted tissue(s). One‐year renal transplant survival is now routinely over 90% in most centres, largely the result of improvements in immunosuppressive drugs. In this article, we review commonly used immunosuppressive medications and discuss their pharmacological modes of action. Given that the long‐term graft outcomes remain poor, despite improvements in early transplant survival, we discuss, in addition, novel experimental strategies for the induction of tolerance to transplanted tissues that have translational relevance to human organ recipients.

Key Concepts

The major limitation of solid organ transplantation is long‐term immunosuppression, which either results in excessive mortality and morbidity or is insufficient to prevent chronic rejection of transplanted tissues.

An understanding of transplant rejection and pharmacological targets of immunosuppression is a key to devising novel strategies of preventing rejection by inducing transplant tolerance.
Bone Homeostasis: Extracellular Calcium Levels and Their Control in Humans
Authors: McDonald Fraser
Published: July 2015

Calcium (Ca2+) is an essential ion within the human body. It is extraordinary as an ion whose homeostasis is controlled and managed by many organs (bone, intestine, kidney, skin and thyroid). For a student, Ca2+is a clear example of the complexities of biological control, integrating many systems. The understanding of the basic principles of control of this ion is a very sound foundation for consideration of other biological control mechanisms. The ion is responsible for the correct coordination of many functions (including excitable (muscle and nerve) and nonexcitable (endocrine in particular but also cellular enzymatic functions) tissue) and constitutes a large part of the inorganic component of the skeleton in the form of hydroxyapatite crystals. Calcium levels are kept within a narrow and specific range (7.5–11.5 mg/dL−1in health; varying with age) and are regulated principally by three hormones – parathyroid hormone, calcitonin and cholecalciferol (vitamin D3). Other paracrine substances can also have a major effect. Excessive variations can lead to abnormalities of nerve function and porous bones (hypocalcaemia) or pathological calcification (hypercalcaemia).

Key Concepts

Ca2+is a unique ion maintaining both the independent functional capacity of the organism being part of the rigid endoskeleton and having unique microlevel qualities controlling, very precisely, cell function.

Release and uptake of Ca2+from the skeleton is undertaken by osteoblasts (bone depositing cells), osteoclasts (bone dissolving cells) and may have some influence from osteocytes (osteoblasts when surrounded by bones) and bone lining cells (thin cells possibly controlling ion exchange with bone).

Its characteristic role at cellular level can control ‘immediate’ cellular events such as exocytosis and contraction.

It is responsible for intercellular adherence.

It can influence chromosome functions.

It is integral to activation of enzyme systems.

As an ion whose serum levels are controlled closely, it demonstrates clearly basic principles of homeostasis that can serve as a foundation for understanding control of other ions/metabolites.

The control of serum Ca2+demonstrates very clearly the interaction of several systems that are required to function correctly.

Ca2+is a major coordinator of programmed cell death as well as a significant second messenger.
Cystinuria
Authors: Goldfarb David S
Published: July 2015

Cystinuria accounts for 1% of kidney stones in adults and up to 5–7% of stones in children. The two genes responsible for the disorder,
SLC3A1
and
SLC7A9
. The genes code, respectively, for proteins called rBAT and b
0,+
AT, both of which are necessary for the proximal tubule of the nephron to reabsorb cystine filtered by the glomerulus. The identification of
SLC3A1
made cystinuria the first disorder of amino acid transport with an identified gene. Most patients are affected by autosomal recessive inheritance, but a mutation in one allele of
SLC
7
A9
may sometimes be sufficient to form stones, constituting autosomal dominant inheritance with variable penetrance.
l
‐Cystine is poorly soluble and precipitates in the urinary tract to form stones which are often large and recurrent. Stone removal with urologic interventions such as ureteroscopy may be required. Prevention of stone recurrence is directed at increasing the solubility of cystine. New inhibitors of cystine crystal growth have been identified and may be effective
in vitro
and
in vivo
in a knock‐out mouse model.

Key Concepts

Cystinuria accounts for 1% of kidney stones in adults and up to 5–7% of stones in children.

The genes responsible for cystinuria,
SLC3A1
and
SLC7A9
, code, respectively, for proteins called rBAT and b
0,+
AT, both of which are necessary for the proximal tubule of the nephron to reabsorb cystine filtered by the glomerulus.

The amino acid
l
‐cystine is a homodimer of two molecules of the amino acid cysteine, linked by a disulfide bond.

Amino acids are present in the plasma, filtered by the glomerulus and reabsorbed by the proximal tubule. Normally, the amount of cystine in the urine is <1% of filtered cystine but in cystinuria, there may be more than 100% of filtered cystine.

Most patients are affected by autosomal recessive inheritance, but a mutation in one allele of
SLC
7
A9
may sometimes be sufficient to form stones, constituting autosomal dominant inheritance with variable penetrance.

The only clinical manifestation of cystinuria is kidney stones. Cystine is poorly soluble and precipitates in the urinary tract to form stones which are often large and recurrent.

Stone removal with urologic interventions such as ureteroscopy may be required.

Prevention of stone recurrence is directed at increasing the solubility of cystine. Increased fluid intake increases urine volume and dilutes cystine. Ingestion of alkali increases urine pH and increases cystine solubility. Restriction of dietary animal protein and salt will decrease the amount of cystine in the urine.

Two thiol drugs,
d
‐penicillamine and tiopronin, break the disulfide bridge of cystine and form drug–cysteine complexes which are soluble in the urine.

New potential drugs, identified by atomic force microscopy, have been identified as novel mimics of cystine that can inhibit cystine crystal growth. They appear effective
in vitro
and
in vivo
in a mouse model in which
Slc3a1
has been knocked out.
Mass Spectrometry: Analysis of Two‐Dimensional Protein Gels
Authors: Paradela Alberto
Published: July 2015

Introduced two decades ago, two‐dimensional gel electrophoresis (2‐DE) in combination with mass spectrometry has since been a powerful tool to analyse and to describe the enormous complexity hidden in the proteomes. Massively used by the academic community in the last two decades, it has lost its privileged status in favour of other high‐throughput approaches, such as liquid chromatography coupled to mass spectrometry (LC‐MS). Nevertheless, 2‐DE is still a useful tool to describe both in qualitative and quantitative terms the complexity of the proteome, offering some advantages over ‘peptide‐centric’ approaches such as LC‐MS and a more ‘realistic’ view of common post‐translational processes that modify both the structure and function of proteins, including alternative splicing processes and common post‐translational modifications such as phosphorylation and glycosylation. In addition, continuous improvements in gel imaging software have greatly improved the utility of 2‐DE for quantitative experiments.

Key Concepts

Analysis of complex proteomes demand the use of high‐resolution separation techniques.

Immobilised pH gradients increase the resolution power of two‐dimensional gel electrophoresis (2‐DE) while reducing experimental variability.

2‐DE gel‐based protein analysis has lost predominance in favour of peptide‐centric experimental approaches.

2‐DE is a powerful experimental approach to compare complex proteomes quantitatively.

2‐D DIGE significantly reduces artefactual gel‐to‐gel variability.

Development of soft‐ionisation techniques made it possible to analyse peptides and proteins by means of mass spectrometry.

MALDI TOF TOF mass spectrometers are best suited for the analysis of 2‐DE protein spots.

High performance liquid chromatography can be directly coupled to ESI‐based mass spectrometers.
In VivoAnalysis of Membrane Fusion
Authors: Palfreyman Mark T , Jorgensen Erik M
Published: July 2015

Membranes provide a barrier that allows chemical reactions to be isolated from the environment. The plasma membrane, for example, delineates self from nonself, and thus must have played an essential role in the evolution of life. Yet under numerous circumstances it is equally important that membranes be breached. Numerous forces oppose the spontaneous fusion of membranes; thus, specialised proteins have evolved to fuse membranes. The most well‐understood fusion proteins are the viral fusion proteins and the SNARE proteins used in the secretory pathway. Recent discoveries have added to the list of fusogens for which necessity and sufficiency have been demonstrated. The list now includes the fusion family proteins, used in cell–cell fusion, and the dynamin‐related proteins, used in organelle fusion. Despite, the diverse structures of fusion proteins, it is likely that they all function to drive membranes through a series of common lipid intermediates. In this article, we review the mechanisms of fusion for biological membranes, and highlight the similarities and differences in these processes.

Key Concepts

Fusion proteins can be divided into three major classes: the secretory pathway uses SNARE proteins, cell–cell fusion uses proteins related to viral fusogens and organellar fusion is driven by dynamin‐related GTPases.

Fusion proteins are thought to lead membranes through the common set of lipid intermediates: lipid stalk, hemifusion diaphragm and pore formation.

Fusion proteins, either SNAREs or viral proteins, play an active role in all steps of the fusion process.

Multimerisation of fusogens improves efficiency and in many instances is a requirement for fusion.

Diverse proteins act as the fusogens in cell–cell fusion; many remain undiscovered.
Terrorism
Authors: Weimann Gabriel
Published: July 2015

Modern terrorists became aware of the new opportunities for exerting mass psychological impact using the latest means of mass communication. Academic observers remarked increasingly on the theater‐like nature of terrorist operations. According to this notion, modern terrorism can be understood in terms of the production requirements of theatrical engagements. Several terrorist organizations realized the potential of media‐oriented terror, in terms of effectively reaching huge audiences. Postmodern terrorists are taking advantage of the fruits of globalization and modern technology—especially the most advanced communication technologies. The Internet and its numerous platforms are becoming more popular among terrorists: in addition to launching their own websites, terrorists harness the interactive capabilities of the Internet using chatrooms, instant messaging, blogs, video‐sharing websites, and postings on Facebook, MySpace, Twitter, and YouTube.
Communitarianism
Authors: van Leeuwen Bart
Published: July 2015

Communication generates and sustains community by expressing shared understandings. Communitarianism represents a school of political thought, developed in the 1980s, that argues for the moral and political relevance of such shared understandings and communal solidarity, thereby challenging the abstract and individualist tendencies of contemporary liberalism. Communitarianism argues that culture and shared values constitute the identity of individuals. Therefore it defends a politics of the common good. Communitarian politics has been argued for at different levels of society: the national, the local, and the intermediate subnational level. In the first case it overlaps with, or touches upon, nationalism and in the last case with a politics of difference or multiculturalism.
Online Elections
Authors: Gibson Rachel K.
Published: July 2015

The impact of the Internet on politics in general and within the electoral arena in particular has been the subject of increasing academic study and debate. In this entry we examine those debates at two levels. First, on the supply side we look at the effects of the new interactive Web technologies on campaigns and parties and particularly how they affect the centralized and professionalized model of operation that has dominated until now. Does the digital era challenge the power of elites and place more power in the hands of grassroots supporters? Second, we turn to changes at the mass level and outline the main argument that the arrival of the Internet has inspired among scholars of participation—namely whether use of the Web increases people's engagement with politics and their likelihood to turn out to vote. We conclude by locating online elections and the change associated with them in the wider context of digital politics.
Stereotype
Authors: Sibley Chris G. , Osborne Danny
Published: July 2015

Stereotypes are specialized schemas adapted for the social world that people use to understand and predict the behavior of others. These predictions often contain substantial inaccuracies and cause people to see what they expect to see. Stereotyping unfolds over a two‐stage sequential process. First, cues in the environment automatically activate stereotypes. Controlled processes may then inhibit the application of the activated stereotype, and this is more likely to occur if the person is not under excessive cognitive load. Stereotypes tend to be based on specific content relating to judgments of warmth and competence. These two social judgments reflect the perceived intention of others toward us (are they friend or foe?) and their capacity to act on their intentions. Groups seen as competing with the ingroup or the dominant reference group will tend to be stereotyped as colder and as having more negative intentions toward the ingroup. Groups seen as higher in status will tend to be stereotyped as higher in competence and more able to act on their intentions. The combination of warmth–competence stereotypes in turn elicits different forms of discriminatory behaviors directed toward the group.
Gender and Politics
Authors: Wahl‐Jorgensen Karin , Ye Weihua
Published: July 2015

The relationship between gender and politics has unfolded in the context of male domination. Questions of representation and its consequences for political gender equality have always been central to understanding this relationship, as women politicians have consistently been underrepresented and subjected to essentialist constructions of femininity. But a shift toward more complex representations is making gender less salient than before, as female politicians are entering legislatures around the world in larger numbers.
Political Communication Research in the Middle East
Authors: Leihs Nadia , Roeder‐Tzellos Maria
Published: July 2015

This entry identifies the typical characteristics of authoritarian media systems. The press and broadcasting institutions of the MENA region have long been the mouthpieces of the national ruling elites and restricted by different mechanisms of control like direct and indirect censorship. Due to the high interconnectedness of politics and journalism, Arab journalists have developed professional values different from those of their western colleagues. The advent of transnational media, namely Arab satellite news channels, not only impacted these role conceptions but also laid the foundations for an evolving transnational public sphere. The space for political communication was further enhanced by the introduction of social network sites (SNSs) which provided for the articulation of dissident views and political mobilization.
Citizenship
Authors: Pasquino Gianfranco
Published: July 2015

The concept of citizenship and its practical implementation have a long and rich history. Both are tied at the same time with a political community and with a battery of rights to be enjoyed and duties to be performed. Citizenship is made of objective and subjective components: belonging and identity. The granting and the conquest of civil, political, and social rights have significantly contributed to the contemporary definition of citizenship. A cosmopolitan view of rights has made its recent appearance and has been translated into the concept of universal human rights. Almost at the same time, multiculturalism has challenged a central tenet of citizenship, that is, the equality each and all citizens before the law. The idea of group rights has been used to justify exceptions and practices that the liberal‐democratic theory and experience would consider highly objectionable. Transnational migrations, globalization, and the process of political unification of Europe suggest the need to (re)think in terms of supranational citizenship, its implication, its problems.
Production of Hydrogen with Solar Energy
Authors: Schoonman Joop
Published: July 2015

One of the main requirements for a future Hydrogen Economy is a clean and efficient process for producing hydrogen using renewable energy sources. Hydrogen is a promising energy carrier because of its high energy content and clean combustion. In particular, the production of hydrogen from water and solar energy, i.e., photocatalysis and photoelectrolysis are methods for both renewable and sustainable energy production. Systems based on a photocatalyst powder suspended in an aqueous solution comprise single particles, layered materials, composite particles, or particle mixtures. The oxidation and reduction reactions take place at the same surface of a single particle. In order to avoid recombination processes, co‐catalysts are deposited on the surface of the photocatalyst to ensure that oxygen and hydrogen evolve at spatially separate surface sites. While water splitting can be carried out with coupled solar cells‐commercial water electrolyzers, the direct photoelectrolysis with a semiconductor photoelectrode is a more elegant and cheaper approach and the direct photoelectrolysis is the Holy Grail of electrochemistry, using the power of light. Here, the photoactive semiconductor is immersed in water and the photogenerated electrons and holes are directly used to reduce and oxidize water, respectively, in a PhotoElectroChemical cell (PEC cell).

This article focuses on the materials science and engineering of photocatalysts, co‐catalysts, and photoelectrodes and will illustrate that the activities in the field of solar energy conversion into hydrogen are numerous. The principle of the PEC cell will be presented along with materials requirements for application in a PEC cell. Characterizations of the physical and chemical properties of state‐of‐the‐art and novel materials guide materials scientists to optimal photocatalysts and photoelectrodes. Engineering on an atomic scale is achieved by cation and anion doping effects, deviations from stoichiometry, and, in case of ternary and more complex materials, deviations from molecularity. Defect chemical aspects will be presented. To date, the decreasing length scale to the nanoscale of the functional materials for photocatalytical and photoelectrochemical applications attracts widespread attention. Besides water, also aqueous solutions of hydrobromic acid and hydrogen sulfide have been explored for hydrogen production using solar radiation. The large‐scale conversion of hydrogen sulfide from the Black Sea would be beneficial from an environmental and energy point of view.