bluuebunny/crossref_metadata_2025 huggingface dataset:
Pengaruh Akasia sebagai Bahan Pengikat terhadap Mutu Fisik Tablet Hisap Ekstrak Teh Hijau (Camellia sinensis)
Authors: Ameliana Lidya , Wazni Fitri
Published: May 2017

ABSTRACT

 

Formulation of green tea extract lozenges (Camellia sinensis) have been studied, the lozenges were made by direct compressing method. The purpose of this research is to know the effect of acacia as binding agent to the physical characteristic of the tablets. Fillers were combined using wet granulation with acacia with concentration of 1%, 2%, and 3% respectively. Furthermore, the filler granuls mixed with green tea extract. Physical characteristic of granul including flow rate, angle of repose, particle size distribution, bulk density, tapped density, compressibility index, and moisture content. Then the extract granuls were pressed into tablet on a hydraulic press with diameter 16,71 mm and pressure of 4 ton, and physical characteristic of lozenges were examined. Evaluation on the green tea extract lozenges result including tablet size, tablet weight, hardness, friability, and dissolving time. The result of those evaluations showed that green tea extract lozenges fulfilled the requirement of tablet physical characteristics. The result showed that the increase of acacia concentration will increase hardness and prolonged dissolving time but the increase of acacia concentration will decrease the friability of lozenges.

 

Keywords : green tea extract, lozenges, acacia, physical characteristic, direct   compression.

 

ABSTRAK

 

Telah dilakukan formulasi tablet hisap ekstrak teh hijau (Camellia sinensis), dengan metode cetak langsung. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh penambahan bahan pengikat akasia 1%, 2%, dan 3 % terhadap mutu fisik tablet hisap ekstrak teh hijau. Bahan pengisi dan bahan pengikat dikombinasikan dengan menggunakan granulasi basah dengan akasia sebagai bahan pengikat. Selanjutnya granul bahan pengisi tersebut dicampurkan dengan ekstrak teh hijau. Karakteristik fisik granul yang diuji meliputi laju alir, sudut istirahat, distribusi ukuran partikel, berat jenis nyata, berat jenis mampat, kompresibilitas, dan kandungan kelembaban. Setelah memeriksa karakteristik fisik campuran granul, kemudian dikompres menjadi tablet dengan diameter 16,71 mm dan tekanan 4 ton. Evaluasi pada ekstrak teh hijau meliputi ukuran tablet, massa tablet, kekerasan, kerapuhan, dan waktu larut. Hasil evaluasi menunjukkan bahwa tablet hisap ekstrak teh hijau memenuhi persyaratan karakteristik tablet fisik. Hasil penelitian ini menunjukkan bahwa peningkatan akasia akan meningkatkan kekerasan dan waktu melarut, namun akan mengurangi kerapuhan tablet hisap.

 

Kata kunci : ekstrak teh hijau, tablet hisap, akasia, karakteristik fisik, cetak langsung.
A PEDAGOGIA EXPERIMENTAL E A FORMAÇÃO DE PROFESSORES (1950-1970): ANÁLISE DE DUAS EXPERIÊNCIAS DIDÁTICAS INCOMUNS
Authors: Santos Pablo Silva Machado Bispo dos , Lima Cecilia Neves
Published: May 2017

O presente artigo tem como objetivo principal apresentar e analisar a experiência didática desenvolvida em duas instituições escolares brasileiras de destaque nos anos de 1950-1970:  O Colégio Nova Friburgo e a Escola Guatemala.  Para tanto, foram analisados documentos institucionais diversos e publicações sobre tais instituições.  A perspectiva metodológica empregada foi a da História Cultural, que se caracteriza entre outras coisas, por relativizar o caráter de verdade absoluta contida em um documento, bem como em ampliar o conceito de fonte documental abarcando as dimensões culturais e políticas de sua produção. Ao fim do estudo, foi possível identificar dois elementos-chave:  a) o papel da iniciativa privada na capacitação de professores em redes públicas de ensino; b) a emergência de um padrão de formação de professores baseado na noção de experiência educacional, o qual destinar-se-ia a multiplicar-se por todo o País por intermédio do Ministério da Educação e das redes de ensino.
A Modelagem Matemática como estratégia de ensino e aprendizagem: Contribuições das atividades sobre energia elétrica
Authors: SOARES MARIA ROSANA , Santos Junior Guataçara Dos
Published: May 2017

Este artigo objetiva analisar as contribuições que a Modelagem Matemática pode proporcionar como estratégia de ensino e aprendizagem nas atividades de energia elétrica aos alunos de duas turmas do 1º ano de Ensino Médio de Física. Ela foi aplicada em dois colégios públicos do município de Cambará pela Secretaria da Educação do Paraná – SEED, em que se desenvolveram várias atividades de Modelagem com os participantes objetivando analisar o consumo de energia elétrica dos principais equipamentos eletroeletrônicos utilizados nas residências, o custo mensal de energia e a redução do consumo de energia elétrica residencial. Isso foi desenvolvido à luz da pesquisa qualitativa de cunho interpretativo, em que a coleta de dados se deu por meio da observação, intervenção no trabalho, questionário pós-teste e análise dos dados obtidos na Companhia Paranaense de Energia Elétrica – COPEL[1] e na aplicação da proposta da Modelagem. Logo, infere-se que as atividades desenvolvidas foram eficientes aos alunos, pois eles obtiveram contribuições ao reconhecerem e compreenderem a importância da utilização racional da energia elétrica e também de seu uso consciente, uma vez que os favorece, suas famílias, a economia, o meio social e ambiental, as futuras gerações e os recursos sustentáveis e naturais.Palavras-chave: Modelagem Matemática; Energia Elétrica; Ensino e Aprendizagem.[1] COMPANHIA PARANAENSE DE ENERGIA – COPEL. Residencial: consumo de energia. 2010 e 2014. Disponível em: . Acesso em: 04 mar. 2014.
Feedback stabilization of a simplified model of fluid–structure interaction on a tree
Authors: Ammari Kaïs , Shel Farhat , Vanninathan Muthusamy
Published: May 2017

In this paper we study the dynamic feedback stability for some simplified model of fluid–structure interaction on a tree. We prove that, under some conditions, the energy of the solutions of the dissipative system decay exponentially to zero when the time tends to infinity. Our technique is based on a frequency domain method and a special analysis for the resolvent.
Asymptotic behavior of a model for order-disorder and phase separation
Authors: Miranville Alain , Saoud Wafa , Talhouk Raafat
Published: May 2017

Our aim in this article is to study the long time behavior, in terms of finite-dimensional attractors, of a coupled Allen–Cahn/Cahn–Hilliard system. In particular, we prove the existence of an exponential attractor and, as a consequence, the existence of the global attractor with finite fractal dimension.
Fast energy decay for wave equations with a localized damping in the n-D half space
Authors: Ikehata Ryo
Published: May 2017

We consider a mixed problem for wave equations with a localized damping in the n-dimensional half space [Formula: see text]. We first propose a new type of Hardy inequality in the whole space by employing the Fourier transform. Then, this inequality combined with a multiplier method developed by [ Sci. Math. Japon. 55 ( 2002 ), 33–42] will be effectively applied to the half space problems of the damped wave equations with a variable coefficient to catch a fast energy decay property. The Fourier transform is partially used to obtain the [Formula: see text]-boundedness of the solution. The method introduced in this paper will compensate lack of an effective Hardy type inequality in the n-dimensional half space.
Advanced Emergency Braking Control Based on a Nonlinear Model Predictive Algorithm for Intelligent Vehicles
Authors: Zhang Ronghui , Li Kening , He Zhaocheng , Wang Haiwei , You Feng
Published: May 2017

Focusing on safety, comfort and with an overall aim of the comprehensive improvement of a vision-based intelligent vehicle, a novel Advanced Emergency Braking System (AEBS) is proposed based on Nonlinear Model Predictive Algorithm. Considering the nonlinearities of vehicle dynamics, a vision-based longitudinal vehicle dynamics model is established. On account of the nonlinear coupling characteristics of the driver, surroundings, and vehicle itself, a hierarchical control structure is proposed to decouple and coordinate the system. To avoid or reduce the collision risk between the intelligent vehicle and collision objects, a coordinated cost function of tracking safety, comfort, and fuel economy is formulated. Based on the terminal constraints of stable tracking, a multi-objective optimization controller is proposed using the theory of non-linear model predictive control. To quickly and precisely track control target in a finite time, an electronic brake controller for AEBS is designed based on the Nonsingular Fast Terminal Sliding Mode (NFTSM) control theory. To validate the performance and advantages of the proposed algorithm, simulations are implemented. According to the simulation results, the proposed algorithm has better integrated performance in reducing the collision risk and improving the driving comfort and fuel economy of the smart car compared with the existing single AEBS.
Detection of Pitting in Gears Using a Deep Sparse Autoencoder
Authors: Qu Yongzhi , He Miao , Deutsch Jason , He David
Published: May 2017

In this paper; a new method for gear pitting fault detection is presented. The presented method is developed based on a deep sparse autoencoder. The method integrates dictionary learning in sparse coding into a stacked autoencoder network. Sparse coding with dictionary learning is viewed as an adaptive feature extraction method for machinery fault diagnosis. An autoencoder is an unsupervised machine learning technique. A stacked autoencoder network with multiple hidden layers is considered to be a deep learning network. The presented method uses a stacked autoencoder network to perform the dictionary learning in sparse coding and extract features from raw vibration data automatically. These features are then used to perform gear pitting fault detection. The presented method is validated with vibration data collected from gear tests with pitting faults in a gearbox test rig and compared with an existing deep learning-based approach.
The Incarnation of Eddie Burrup: A Review of Elizabeth Durack, Art & Life, Selected Writings, Perpetua Durack Clancy (Editor), Brisbane: Connor Court
Authors: Paull John
Published: May 2017

Elizabeth Durack (1915–2000) was a prolific Australian artist. She spent much of her life in Western Australia. Her subject of choice was most often aboriginal life. The book, Elizabeth Durack, Art & Life, Selected Writings (2016, edited by Perpetua Durack Clancy, Brisbane: Connor Court, 276 pp., A$29.95) presents a chronological selection of her writings in nine chapters, one decade per chapter. There are personal letters and extracts from her diaries, along with some published and unpublished essays. The style is frank, sometimes irreverent, and she rails against political correctness. In her 80th year, Elizabeth was gripped with a manic burst of creativity. She produced a remarkable suite of works in the thrall of her new muse, Eddie Burrup. The book throws light on her relationship with Eddie Burrup and the unfolding controversy. The presenting of art works of a white woman as those of an aboriginal man caused grief for some of the local artocrats. The first 80 years of Elizabeth Durack can be regarded as a long art apprenticeship and at the culmination of which she graduated to be Eddie Burrup. In this guise and in the twilight of her life, she produced the masterworks of her career, scores of remarkable paintings. The Eddie Burrup suite of paintings are big and bold, fresh and expansive, and uniquely Australian. They reveal Australia’s ancient landscape as a playground for the spirits and totems of the land. This book reveals some of the story of Elizabeth Durack and Eddie Burrup.
Enteric Methane Emissions Estimate for Livestock in South Africa for 1990–2014
Authors: Moeletsi Mokhele , Tongwane Mphethe , Tsubo Mitsuru
Published: May 2017

Methane (CH4) from enteric fermentation is one of the main anthropogenic greenhouse gas (GHG) emissions in South Africa. Livestock population data from 1990 to 2014 and emission factors were utilized in estimating CH4 emissions as per the 2006 IPCC (Intergovernmental Panel on Climate Change) guidelines. CH4 emissions originating from country-specific emission factors were compared with those calculated using IPCC default emission factors. Trends in emissions were then determined using the Man-Kendall trend test at the 5% significance level. The results showed annual total enteric CH4 emissions exceeding 1171.56 Gg (in 1995) with an average (1990 to 2014) of 1227.96 Gg. Non-dairy cattle are the highest emitters with an average of 873.07 Gg (71.10%) while sheep are the second highest with 227.61 Gg (18.54%). Other contributors are dairy cattle, goats, horses, pigs and donkeys with an average (percentage contribution) of 85.94 Gg (7.00%), 32.06 Gg (2.61%), 4.86 Gg (0.40%), 2.77 Gg (0.23%) and 1.65 Gg (0.13%), respectively. The trend analysis revealed positive trends for all the livestock categories, except sheep and goats which showed negative trends, consequently balancing out. The results obtained for the year 2014 were 37% higher than the enteric CH4 emissions in 1990, 1994 and 2000 inventories and the emissions estimated entirely from IPCC default emission factors. This demonstrates the need for the development of Tier 2 emission factors for key category sectors such as cattle and sheep in South Africa. To fully adhere to the principles of GHG inventory accounting, there has to be total livestock inclusivity and major improvements in activity data collection.
Development of Active and Stable Low Nickel Content Catalysts for Dry Reforming of Methane
Authors: Ha Quan , Armbruster Udo , Atia Hanan , Schneider Matthias , Lund Henrik , Agostini Giovanni , Radnik Jörg , Vuong Huyen , Martin Andreas
Published: May 2017

Methane dry reforming (DRM) was investigated over highly active Ni catalysts with low metal content (2.5 wt %) supported on Mg-Al mixed oxide. The aim was to minimize carbon deposition and metal sites agglomeration on the working catalyst which are known to cause catalyst deactivation. The solids were characterized using N2 adsorption, X-ray diffraction, temperature-programmed reduction, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The results showed that MgO-Al2O3 solid solution phases are obtained when calcining Mg-Al hydrotalcite precursor in the temperature range of 550–800 °C. Such phases contribute to the high activity of catalysts with low Ni content even at low temperature (500 °C). Modifying the catalyst preparation with citric acid significantly slows the coking rate and reduces the size of large octahedrally coordinated NiO-like domains, which may easily agglomerate on the surface during DRM. The most effective Ni catalyst shows a stable DRM course over 60 h at high weight hourly space velocity with very low coke deposition. This is a promising result for considering such catalyst systems for further development of an industrial DRM technology.
The New Sunscreens among Formulation Strategy, Stability Issues, Changing Norms, Safety and Efficacy Evaluations
Authors: Lionetti Nicola , Rigano Luigi
Published: May 2017

The sun-and-skin interactions have controversial sides. Besides important beneficial effects, we need to take into consideration also some serious harmful results. In particular, these are connected to the portion of the solar spectrum traditionally identified as ultraviolet type A and B. The topical application of sunscreens (and the avoidance of extreme exposure to sun rays) is worldwide recognized as the best strategy to avoid sunburn and oedema. Moreover, such strategy can efficiently prevent the onset of skin cancer. Therefore, the first aim of sunscreen products is to efficiently minimize all damage of sun exposure, while, at the same time, keeping good skin tolerability, avoiding safety problems and developing pleasant sensorial properties. Sunscreens, i.e., substances able to reflect and/or absorb, at a partial or complete extent, UV radiation are the key actors in skin protection. They are used to implement the level of primary photoprotection against UV rays. This means that when they absorb the radiation energy, their molecules pass to an excited state and successively re-emit energy in other forms (vibrational, rotational, infrared radiation) to come back to the ground state.
A New Hemihydrate of Valacyclovir Hydrochloride
Authors: Zhang Shuai , Zheng Meiqi , Zhou Mengqing , Chen Tian , Wang Naixing , Zhang Zhaoxia , Zhang Guoqing
Published: May 2017

Several crystal forms of valacyclovir hydrochloride, including two anhydrous and three hydrates, were investigated in this study. At the same time, a new hemihydrate of valacyclovir hydrochloride was first discovered and its properties were characterized by PXRD, TGA, DSC, and Raman in this study. The hemihydrate shows a distinctive PXRD pattern and a melting point of 209 °C with a water weight loss of 2.42% from the thermal analysis. The Raman spectra show a few distinctive peaks in the region of 1250–1400 cm−1 due to different crystal forms. The thermostability testing suggests it is a stable crystal form and remain the same for several months under high temperature and humidity. All these crystal forms show good dissolubility in the water at room temperature with excess 100 mg/mL.
Synthesis and Thermoelectric Properties of Copper Sulfides via Solution Phase Methods and Spark Plasma Sintering
Authors: Tang Yun-Qiao , Ge Zhen-Hua , Feng Jing
Published: May 2017

Large-scale Cu2S tetradecahedrons microcrystals and sheet-like Cu2S nanocrystals were synthesized by employing a hydrothermal synthesis (HS) method and wet chemistry method (WCM), respectively. The morphology of α-Cu2S powders prepared by the HS method is a tetradecahedron with the size of 1–7 μm. The morphology of β-Cu2S is a hexagonal sheet-like structure with a thickness of 5–20 nm. The results indicate that the morphologies and phase structures of Cu2S are highly dependent on the reaction temperature and time, even though the precursors are the exact same. The polycrystalline copper sulfides bulk materials were obtained by densifying the as-prepared powders using the spark plasma sintering (SPS) technique. The electrical and thermal transport properties of all bulk samples were measured from 323 K to 773 K. The pure Cu2S bulk samples sintered by using the powders prepared via HS reached the highest thermoelectric figure of merit (ZT) value of 0.38 at 573 K. The main phase of the bulk sample sintered by using the powder prepared via WCM changed from β-Cu2S to Cu1.8S after sintering due to the instability of β-Cu2S during the sintering process. The Cu1.8S bulk sample with a Cu1.96S impurity achieved the highest ZT value of 0.62 at 773 K.
Structure Property Relationships and Cationic Doping in [Ca24Al28O64]4+ Framework: A Review
Authors: Salasin John , Rawn Claudia
Published: May 2017

Ca12Al14O33 (C12A7, 12CaO·7Al2O3, or [ Ca 12 Al 14 O 32 ] 2 + : O 2 − ) is a material with a clathrate cage framework, positively charged and stabilized by anions occluded within 17% of the cages. The occluded anion is modular and can be elemental, polyatomic, and electronic in nature. This review focuses on the electride C12A7 ( [ Ca 24 Al 28 O 64 ] 4 + : ( 4 * ∂ ) e − ( 2 − ∂ ) O 2 − ), where O2− anions are replaced with electrons, and compliments previous structural and electronic property reviews to illuminate the structure–property relationships. Electride formation is updated with new findings in carbonaceous reduction methods. Most importantly, an extensive compilation of cationic doped C12A7 isostructural compounds is presented as motivation to study doped C12A7 electrides. Cationic dopants have profound impacts on the electronic properties due to changes in the density of states, localized electron behavior, and structural distortions.
An Efficient Reactive Power Control Method for Power Network Systems with Solar Photovoltaic Generators Using Sparse Optimization
Authors: Li Yu , Ishikawa Masato
Published: May 2017

With the incremental introduction of solar photovoltaic (PV) generators into existing power systems, and their fast-growing share in the gross electricity generation, system voltage stability has become a critical issue. One of the major concerns is voltage fluctuation, due to large and random penetration of solar PV generators. To suppress severe system voltage deviation, reactive power control of the photovoltaic system inverter has been widely proposed in recent works; however, excessive use of reactive power control would increase both initial and operating costs. In this paper, a method for efficient allocation and control of reactive power injection using the sparse optimization technique is proposed. Based on a constrained linearized model describing the influence of reactive power injection on voltage magnitude change, the objective of this study is formulated as an optimization problem, which aims to find the best reactive power injection that minimizes the whole system voltage variation. Two types of formulations are compared: the first one is the conventional least-square optimization, while the second one is adopted from a sparse optimization technique, called the constrained least absolute shrinkage and selection operator (LASSO) method. The constrained LASSO method adds ℓ 1 -norm penalty to the total reactive power injection, which contributes to the suppression of the number of control nodes with non-zero reactive power injection. The authors analyzed the effectiveness of the constrained LASSO method using the IEEE 39-bus and 57-bus power network as benchmark examples, under various PV power generation and allocation patterns. The simulation results show that the constrained LASSO method automatically selects the minimum number of inverters required for voltage regulation at the current operating point.
High Performances of Artificial Nacre-Like Graphene Oxide-Carrageenan Bio-Nanocomposite Films
Authors: Zhu Wenkun , Chen Tao , Li Yi , Lei Jia , Chen Xin , Yao Weitang , Duan Tao
Published: May 2017

This study was inspired by the unique multi-scale and multi-level ‘brick-and-mortar’ (B&M) structure of nacre layers. We prepared the B&M, environmentally-friendly graphene oxide-carrageenan (GO-Car) nanocomposite films using the following steps. A natural polyhydroxy polymer, carrageenan, was absorbed on the surface of monolayer GO nanosheets through hydrogen-bond interactions. Following this, a GO-Car hybridized film was produced through a natural drying process. We conducted structural characterization in addition to analyzing mechanical properties and cytotoxicity of the films. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses showed that the nanocomposite films had a similar morphology and structure to nacre. Furthermore, the results from Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Thermogravimetric (TG/DTG) were used to explain the GO-Car interaction. Analysis from static mechanical testers showed that GO-Car had enhanced Young’s modulus, maximum tensile strength and breaking elongation compared to pure GO. The GO-Car nanocomposite films, containing 5% wt. of Car, was able to reach a tensile strength of 117 MPa. The biocompatibility was demonstrated using a RAW264.7 cell test, with no significant alteration found in cellular morphology and cytotoxicity. The preparation process for GO-Car films is simple and requires little time, with GO-Car films also having favorable biocompatibility and mechanical properties. These advantages make GO-Car nanocomposite films promising materials in replacing traditional petroleum-based plastics and tissue engineering-oriented support materials.
Variable-Frequency Ultrasonic Treatment on Microstructure and Mechanical Properties of ZK60 Alloy during Large Diameter Semi-Continuous Casting
Authors: Chen Xingrui , Le Qichi , Wang Xibo , Liao Qiyu , Chu Chaoyang
Published: May 2017

Traditional fixed-frequency ultrasonic technology and a variable-frequency ultrasonic technology were applied to refine the as-cast microstructure and improve the mechanical properties of a ZK60 (Mg–Zn–Zr) alloy during large diameter semi-continuous casting. The acoustic field propagation was obtained by numerical simulation. The microstructure of the as-cast samples was characterized by optical and scanning electron microscopy. The variable-frequency ultrasonic technology shows its outstanding ability in grain refinement compared with traditional fixed-ultrasonic technology. The variable-frequency acoustic field promoted the formation of small α-Mg globular grains and changed the distribution and morphology of β-phases throughout the castings. Ultimate tensile strength and elongation are increased to 280 MPa and 8.9%, respectively, which are 19.1% and 45.9% higher than the values obtained from billets without ultrasonic treatment and are 11.6% and 18.7% higher than fixed-frequency ultrasound treated billets. Different refinement efficiencies appear in different districts of billets attributed to the sound attenuation in melt. The variable-frequency acoustic field improves the refinement effect by enhancing cavitation-enhanced heterogeneous nucleation and dendrite fragmentation effects.
Transparent Conducting Film Fabricated by Metal Mesh Method with Ag and Cu@Ag Mixture Nanoparticle Pastes
Authors: Nam Hyun , Seo Duck , Yun Hyung , Thangavel Gurunathan , Park Lee , Nam Su
Published: May 2017

Transparent conducting electrode film is highly desirable for application in touch screen panels (TSPs), flexible and wearable displays, sensors, and actuators. A sputtered film of indium tin oxide (ITO) shows high transmittance (90%) at low sheet resistance (50 Ω/cm2). However, ITO films lack mechanical flexibility, especially under bending stress, and have limitation in application to large-area TSPs (over 15 inches) due to the trade-off in high transmittance and low sheet resistance properties. One promising solution is to use metal mesh-type transparent conducting film, especially for touch panel application. In this work, we investigated such inter-related issues as UV imprinting process to make a trench layer pattern, the synthesis of core-shell-type Ag and Cu@Ag composite nanoparticles and their paste formulation, the filling of Ag and Cu@Ag mixture nanoparticle paste to the trench layer, and touch panel fabrication processes.
Mechanical Behavior and Sliding Wear Studies on Iron Aluminide Coatings Reinforced with Titanium Carbide
Authors: Amiriyan Mahdi , Blais Carl , Savoie Sylvio , Schulz Robert , Gariépy Mario , Alamdari Houshang
Published: May 2017

Wear-resistant iron aluminide-based composites were coated on steel substrates with the High-Velocity Oxy-Fuel (HVOF) technique using ball milled Fe3Al and TiC powders as feedstock. The phase composition, microstructure, microhardness, elastic modulus and dry sliding wear performance of unreinforced Fe3Al and Fe3Al–TiC composite coatings (reinforced with 30 and 50 vol. % TiC particles) were evaluated in order to reveal the relationship between the mechanical and tribological behaviors. Compared to the unreinforced coatings, the composite coating with 30 vol. % TiC particles exhibited much greater hardness and higher elastic modulus. The increase of the elastic modulus of the composite coatings did not result in deterioration of sliding wear behavior. The addition of 50 vol. % TiC resulted in a further increase in hardness, however, both composite coatings showed the same elastic modulus. The fractured cross sectional surface of the unreinforced coating showed a weakly bonded microstructure promoting delamination in wear tests, whereas the composite fractured surface showed strong mechanical bonding between the matrix and carbide particles, leading to better cohesion. The Fe3Al–TiC coatings showed almost three orders of magnitude higher wear resistance under the dry sliding wear test compared to the unreinforced coatings.
Characterization of Germanium Speciation in Sphalerite (ZnS) from Central and Eastern Tennessee, USA, by X-ray Absorption Spectroscopy
Authors: Bonnet Julien , Cauzid Jean , Testemale Denis , Kieffer Isabelle , Proux Olivier , Lecomte Andreï , Bailly Laurent
Published: May 2017

X-ray absorption near edge structure (XANES) spectroscopy was used on zoned sphalerites (ZnS) from two world-class Mississippi Valley Type deposits, the Central and Eastern Tennessee Mining district, USA, in order to investigate germanium oxidation states. Due to the low germanium concentrations of these samples, it was necessary to perform the X-ray absorption spectroscopy (XAS) in fluorescence mode. The overlapping of the Zn Kβ and Ge Kα emission lines meant that a high energy-resolution was required. This was achieved using crystal analysers and allowed a bandwidth of 1.3 eV to be obtained. Experimental spectra were compared to XANES calculations and three configurations of germanium incorporation into sphalerite were identified. The first two, the most prevalent, show germanium (II) and (IV) surrounded by sulphur atoms in tetrahedral coordination, suggesting the replacement of Zn by Ge. In the third configuration, germanium (IV) is surrounded by oxygen atoms. This third configuration is unexpected for a zinc sulphide mineral and it resembles that of argutite (GeO2).
Evaluation of the Mycobactericidal Effect of Thio-functionalized Carbohydrate Derivatives
Authors: Korycka-Machała Małgorzata , Brzostek Anna , Dziadek Bożena , Kawka Malwina , Popławski Tomasz , Witczak Zbigniew , Dziadek Jarosław
Published: May 2017

Sugars with heteroatoms other than oxygen have attained considerable importance in glycobiology and in drug design since they are often more stable in blood plasma due to their resistance to enzymes, such as glycosidases, phosphorylases and glycosyltransferases. The replacement of oxygen atoms in sugars with sulfur forms thio-sugars, which are potentially useful for the treatment of diabetes and some bacterial and viral infections. Here, we evaluated the antibacterial activity of thio-functionalized carbohydrate derivatives. A set of 21 compounds was screened against acid-fast Mycobacterium tuberculosis (Mtb), gram-negative Escherichia coli and gram-positive Staphylococcus aureus. The tested carbohydrate derivatives were most effective against tubercle bacilli, with as many as five compounds (thioglycoside 6, thiosemicarbazone 16A, thiosemicarbazone 20, aminothiadiazole 23, and thiazoline 26) inhibiting its growth with MIC50 ≤ 50 µM/CFU. Only two compounds (aminothiadiazole 23 and thiazoline 26) were able to inhibit the growth of E. coli at concentrations below 1 mM, and one of them, aminothiadiazole 23, inhibited the growth of S. aureus at a concentration ≤1 mM. The five compounds affecting the growth of mycobacteria were either thiodisaccharides (6, 16A, and 20) or thioglycosides (23 and 26). All of these compounds (6, 16A, 20, 23, and 26) were able to inhibit the growth of Mtb deposited within human macrophages. However, three of the five selected compounds (6, 23, and 26) exhibited relatively high cytotoxicity in mouse fibroblasts at micromolar concentrations. The selected thio-sugars are very promising compounds, thus making them candidates for further modifications that would decrease their cytotoxicity against eukaryotic cells without affecting their antimycobacterial potential.
Cation, Anion and Ion-Pair Complexes with a G-3 Poly(ethylene imine) Dendrimer in Aqueous Solution
Authors: Savastano Matteo , Bazzicalupi Carla , Giorgi Claudia , Gratteri Paola , Bianchi Antonio
Published: May 2017

The G-3 poly(ethylene imine) ligand L2 shows a multifaceted coordination ability, being able to bind metal cations, anions and ion-pairs. The equilibrium constants for the formation of metal (Cu2+, Zn2+), anion (SO42−) and ion-pair (Cu2+/SO42−) complexes were determined in 0.1 M Me4NCl aqueous solution at 298.1 ± 0.1 K by means of potentiometric titrations. Thanks to its dendrimeric nature, L2 can form highly nucleated metal complexes, such as Cu5L210+ and Zn4L28+, in successive and well-defined complexation steps. Protonated forms of L2 give rise to relatively weak anion complexes with SO42−, but the addition of Cu2+ significantly enhances the binding ability of the ligand toward this anion below pH 9. In more alkaline solutions, an opposite trend is observed. The coordination properties of L2 are discussed with the support of modelling calculations. According to results, L2 is a promising molecule for the preparation of solid supported materials for the recovery of cations and anions from aqueous media and/or for applications in heterogeneous catalysis.
A Smart Sensor Grid to Enhance Irrigation Techniques in Jordan Using a Novel Event-Based Routing Protocol
Authors: Rantisi Maher , Mapp Glenford , Gemikonakli Orhan
Published: May 2017

Due to rapid changes in climatic conditions worldwide, environmental monitoring has become one of the greatest concerns in the last few years. With the advancement in wireless sensing technology, it is now possible to monitor and track fine-grained changes in harsh outdoor environments. Wireless sensor networks (WSN) provide very high quality and accurate analysis for monitoring of both spatial and temporal data, thus providing the opportunity to monitor harsh outdoor environments. However, to deploy and maintain a WSN in such harsh environments is a great challenge for researchers and scientists. Several routing protocols exist for data dissemination and power management but they suffer from various disadvantages. In our case study, there are very limited water resources in the Middle East, hence soil moisture measurements must be taken into account to manage irrigation and аgriculturаl projects. In order to meet these challenges, a Smart Grid that supports a robust, reactive, event-based routing protocol is developed using Ad hoc On-Demand Multipath Distance Vector (AOMDV) as a starting point. A prototype WSN network of 5 nodes is built and a detailed simulation of 30 nodes is also developed to test the scalability of the new system.
Emerging Evidence on Neutrophil Motility Supporting Its Usefulness to Define Vitamin C Intake Requirements
Authors: Elste Volker , Troesch Barbara , Eggersdorfer Manfred , Weber Peter
Published: May 2017

Establishing intake recommendations for vitamin C remains a challenge, as no suitable functional parameter has yet been agreed upon. In this report, we review the emerging evidence on neutrophil motility as a possible marker of vitamin C requirements and put the results in perspective with other approaches. A recent in vitro study showed that adequate levels of vitamin C were needed for this function to work optimally when measured as chemotaxis and chemokinesis. In a human study, neutrophil motility was optimal at intakes ≥250 mg/day. Interestingly, a Cochrane review showed a significant reduction in the duration of episodes of common cold with regular vitamin C intakes in a similar range. Additionally, it was shown that at a plasma level of 75 µmol/L, which is reached with vitamin C intakes ≥200 mg/day, incidences of cardiovascular disease were lowest. This evidence would suggest that daily intakes of 200 mg vitamin C might be advisable for the general adult population, which can be achieved by means of a diverse diet. However, additional studies are warranted to investigate the usefulness of neutrophil motility as a marker of vitamin C requirements.
Accessing Mefenamic Acid Form II through High-Pressure Recrystallisation
Authors: Abbas Nasir , Oswald Iain , Pulham Colin
Published: May 2017

High-pressure crystallisation has been successfully used as an alternative technique to prepare Form II of a non-steroidal anti-inflammatory drug, mefenamic acid (MA). A single crystal of Form II, denoted as high-pressure Form II, was grown at 0.3 GPa from an ethanolic solution by using a diamond anvil cell. A comparison of the crystal structures shows that the efficient packing of molecules in Form II was enabled by the structural flexibility of MA molecules. Compression studies performed on a single crystal of Form I resulted in a 14% decrease of unit cell volume up to 2.5 GPa. No phase transition was observed up to this pressure. A reconstructive phase transition is required to induce conformational changes in the structure, which was confirmed by the results of crystallisation at high pressure.
A Machine Learning Based Reconstruction Method for Satellite Remote Sensing of Soil Moisture Images with In Situ Observations
Authors: Xing Chenjie , Chen Nengcheng , Zhang Xiang , Gong Jianya
Published: May 2017

Surface soil moisture is an important environment variable that is dominant in a variety of research and application areas. Acquiring spatiotemporal continuous soil moisture observations is therefore of great importance. Weather conditions can contaminate optical remote sensing observations on soil moisture, and the absence of remote sensors causes gaps in regional soil moisture observation time series. Therefore, reconstruction is highly motivated to overcome such contamination and to fill in such gaps. In this paper, we propose a novel image reconstruction algorithm that improved upon the Satellite and In situ sensor Collaborated Reconstruction (SICR) algorithm provided by our previous publication. Taking artificial neural networks as a model, complex and highly variable relationships between in situ observations and remote sensing soil moisture is better projected. With historical data for the network training, feedforward neural networks (FNNs) project in situ soil moisture to remote sensing soil moisture at better performances than conventional models. Consequently, regional soil moisture observations can be reconstructed under full cloud contamination or under a total absence of remote sensors. Experiments confirmed better reconstruction accuracy and precision with this improvement than with SICR. The new algorithm enhances the temporal resolution of high spatial resolution remote sensing regional soil moisture observations with good quality and can benefit multiple soil moisture-based applications and research.
Evaluation of the Plant Phenology Index (PPI), NDVI and EVI for Start-of-Season Trend Analysis of the Northern Hemisphere Boreal Zone
Authors: Karkauskaite Paulina , Tagesson Torbern , Fensholt Rasmus
Published: May 2017

Satellite remote sensing of plant phenology provides an important indicator of climate change. However, start of the growing season (SOS) estimates in Northern Hemisphere boreal forest areas are known to be challenged by the presence of seasonal snow cover and limited seasonality in the greenness signal for evergreen needleleaf forests, which can both bias and impede trend estimates of SOS. The newly developed Plant Phenology Index (PPI) was specifically designed to overcome both problems. Here we use Moderate Resolution Imaging Spectroradiometer (MODIS) data (2000–2014) to analyze the ability of PPI for estimating start of season (SOS) in boreal regions of the Northern Hemisphere, in comparison to two other widely applied indices for SOS retrieval: the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI). Satellite-based SOS is evaluated against gross primary production (GPP)-retrieved SOS derived from a network of flux tower observations in boreal areas (a total of 81 site-years analyzed). Spatiotemporal relationships between SOS derived from PPI, EVI and NDVI are furthermore studied for different boreal land cover types and regions. The overall correlation between SOS derived from VIs and ground measurements was rather low, but PPI performed significantly better (r = 0.50, p < 0.01) than EVI and NDVI which both showed a very poor correlation (r = 0.11, p = 0. 16 and r = 0.08, p = 0.24). PPI, EVI and NDVI overall produce similar trends in SOS for the Northern Hemisphere showing an advance in SOS towards earlier dates (0.28, 0.23 and 0.26 days/year), but a pronounced difference in trend estimates between PPI and EVI/NDVI is observed for different land cover types. Deciduous needleleaf forest is characterized by the largest advance in SOS when considering all indices, yet PPI showed less dramatic changes as compared to EVI/NDVI (0.47 days/year as compared to 0.62 and 0.74). PPI SOS trends were found to be higher for deciduous broadleaf forests and savannas (0.54 and 0.56 days/year). Taken together, the findings of this study suggest improved performance of PPI over NDVI and EVI in retrieval of SOS in boreal regions and precautions must be taken when interpreting spatio-temporal patterns of SOS from the latter two indices.
A Note on Medium- and Long-Term Global Energy Prospects and Scenarios
Authors: Bollino Carlo , Asdrubali Francesco , Polinori Paolo , Bigerna Simona , Micheli Silvia , Guattari Claudia , Rotili Antonella
Published: May 2017

The paper presents recent and future trends of the world energy market, as highlighted by medium- and long-term projections. Energy demand and energy consumptions projected by IEA (International Energy Agency) are examined, in comparison with projections provided by other international agencies and companies in the energy sector. In particular, energy resources, energy consumption and economic growth both in developing and developed countries are presented, with a particular attention to the role of energy efficiency, nuclear power, unconventional fossil resources and renewable energies. Sustainable development issues, according to the global climate agreement signed at COP21, are also presented. The outlook period extends up to 2040. The results confirm a worldwide interest in renewable and unconventional resources for the forthcoming decades, as well as efforts to increase the energy efficiency potential in all end-use sectors to reduce the overall environmental impact of energy production.
Fair Dynamic Spectrum Allocation Using Modified Game Theory for Resource-Constrained Cognitive Wireless Sensor Networks
Authors: Byun Sang-Seon , Gil Joon-Min
Published: May 2017

This paper considers the deployment of a cognitive radio scheme in wireless sensor networks to achieve (1) fair spectrum allocation, (2) maximum spectrum utilization, and (3) priority-based sensor transmissions, while (4) avoiding unnecessary spectrum handover (or handoff). This problem is modelled as a bi-objective optimization problem. We apply modified game theory and a cooperative approach to identify an approximate optimal solution in reasonable time. We perform a series of numerical experiments to show that our scheme achieves fair spectrum allocation (in terms of proportional fairness) while observing transmission priorities and minimizing unnecessary spectrum handover.
Antigenic and Biological Characterization of ORF2–6 Variants at Early Times Following PRRSV Infection
Authors: Evans Alyssa , Loyd Hyelee , Dunkelberger Jenelle , Van Tol Sarah , Bolton Marcus , Dorman Karin , Dekkers Jack , Carpenter Susan
Published: May 2017

Genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) challenges efforts to develop effective and broadly acting vaccines. Although genetic variation in PRRSV has been extensively documented, the effects of this variation on virus phenotype are less well understood. In the present study, PRRSV open reading frame (ORF)2–6 variants predominant during the first six weeks following experimental infection were characterized for antigenic and replication phenotype. There was limited genetic variation during these early times after infection; however, distinct ORF2–6 haplotypes that differed from the NVSL97-7895 inoculum were identified in each of the five pigs examined. Chimeric viruses containing all or part of predominant ORF2–6 haplotypes were constructed and tested in virus neutralization and in vitro replication assays. In two pigs, genetic variation in ORF2–6 resulted in increased resistance to neutralization by autologous sera. Mapping studies indicated that variation in either ORF2–4 or ORF5–6 could confer increased neutralization resistance, but there was no single amino acid substitution that was predictive of neutralization phenotype. Detailed analyses of the early steps in PRRSV replication in the presence and absence of neutralizing antibody revealed both significant inhibition of virion attachment and, independently, a significant delay in the appearance of newly synthesized viral RNA. In all pigs, genetic variation in ORF2–6 also resulted in significant reduction in infectivity on MARC-145 cells, suggesting variation in ORF2–6 may also be important for virus replication in vivo. Together, these data reveal that variation appearing early after infection, though limited, alters important virus phenotypes and contributes to antigenic and biologic diversity of PRRSV.
Increase in Extracellular Hydration Status after Initiating Peritoneal Dialysis Electively
Authors: Panorchan Kwanpeemai , Davenport Andrew
Published: May 2017

Renal replacement therapy is designed to treat uremic symptoms and correct hypervolemia. We hypothesized that starting peritoneal dialysis (PD) should reduce overhydration, and we measured body composition and hydration status using bio-impedance in PD patients prior to training and then at the first assessment of peritoneal membrane function. We studied 100 consecutive patients with a planned start to PD, without peritoneal infections or mechanical catheter problems, mean age 54.7 ± 17.1 years, 57% male and 25% diabetic. Extracellular water (ECW) overhydration increased from -0.06 (-1.21 to 0.97) L to 0.96 (0.50 to 3.01) L, p < 0.001. Fat mass increased from 22.7 ± 11.1 to 23.7 ± 11.3 kg, p = 0.007). The change in ECW/ total body water (TBW) was associated with age (β 0.065, p < 0.001), increasing comorbidity (β 1.107, p = 0.005), faster peritoneal protein transport (β 1.84, p < 0.04), and negatively with serum albumin (β -0.208, p < 0.001), and residual renal function (β -0.725, p = 0.026). Patients who had an increase in ECW/TBW had higher C-reactive protein (CRP) both before starting (16.8 ± 24.1 vs 7.7 ± 18.9 mg/L), and when established on PD (15.0 ± 31.8 vs 4.6 ± 5.1 mg/L), p < 0.05. Rather than a reduction in ECW hydration status, overhydration increased after starting PD. This was greater for older more comorbid patients and those with an inflammatory milieu and lower residual renal function. These factors should be considered when deciding upon initial PD prescriptions to limit ECW over-hydration before information on peritoneal membrane function becomes available.
Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions
Authors: Heredia Adrián A , Peñéñory Alicia B
Published: May 2017

Alkynyl selenides were synthesized by a straightforward one-pot and three-step methodology, without the need of diselenides as starting reagents, under an oxygen atmosphere and using PEG 200 as the solvent. This procedure involves the in situ generation of dialkyl diselenides through a K3PO4-assisted reaction of an alkyl selenocyanate obtained by a nucleophilic substitution reaction between KSeCN and alkyl halides. Successive reaction with terminal alkynes in the presence oft-BuOK affords the corresponding alkyl alkynyl selenide in moderate to good yields. Finally, this methodology allowed the synthesis of 2-alkylselanyl-substituted benzofuran and indole derivatives starting from convenient 2-substituted acetylenes.