bluuebunny/crossref_metadata_2025 huggingface dataset:
Mesiodens en dentición primaria
Authors: Torres G.
Published: February 2019

Supernumerary teeth are developmental disorders that can appear in any maxillary región. Whilst their etiology is not well-known, it has been postulated that they are the result of a "doubling" of the dental lamina. Mesiodens can cause several complications, such as the crowding, delayed eruption or displacement of dental organs. Diagnosis is carried out clinically and radiographically. For clinical management is reported in a male patient of 5 years with a mesiodens in the maxilla, who was treated at Hospital Dos de Mayo, odontopediatry service. Intraoral examination revealed a molariform supernumerary tooth eruption, and x-ray analysis showed the presence of an dental organ in the midline. Due to the observed displacement of permanent teeth, it was decided that the supernumerary would be removed in the conventional manner. [ABSTRACT FROM AUTHOR]Resumen (español):Los dientes supernumerarios son alteraciones del desarrollo que aparecen en cualquier región de los maxilares. Su etiología no es bien conocida; sin embargo se postula que son el resultado de la "duplicación" de la lámina dental. Los mesiodens pueden causar varias complicaciones como apiñamiento, retraso en la erupción o desplazamiento de los órganos dentarios. El diagnóstico se realiza de manera clínica y radiográfica. Se reporta el caso de manejo clínico en un paciente masculino de 5 años de edad con un mesiodens en el maxilar superior, que acudió al Hospital Dos de Mayo, servicio de odontopediatria. A la exploración intraoral se observó un diente supernumerario molariforme semi erupcionado, y el análisis de radiografía mostró la presencia de un órgano dentario en la línea media. Debido al desplazamiento observado de los órganos dentarios permanentes, se decidió realizar la extracción del supernumerario de manera convencional. [ABSTRACT FROM AUTHOR]
Signs and symptoms of craniomandibular dysfunction in a population of Spanish children
Authors: Sánchez-Sánchez Maria Esperanza
Published: February 2019

The craniomandibular dysfunction (CMD) is a pathology that can appear at early ages. In a sample of 36 childrenresiding in Madrid (Spain), of both sexes, with ages between 7 and 13 years, the prevalence of signs and symptomsof CMD was analyzed. For that purpose, we did a dental and muscular examination, together with temporomandibularjoints, functional and occlusal examination, and completed with a specific questionnaire. The results revealedthat 100% showed some sign or sympthom of CMD. 77,8% of the pacients presented 3 or more CMD signs.The most prevalent were painful muscle palpation (94,4%), together with sliding anteriorly (91,7%), painful jointpalpation (69,4%), wear facets in permanent teeth (41,7%) and altered opening and closing trayectory (38,9%). Onthe other hand, only 38,9% showed any CMD symptom. The most prevalent symptoms were night teeth grinding(27,8%), followed by tooth sensitivity (19,4%) and fullness in the ears (16,7%). We conclude that in our sample,25% presented mild CMD (less that 3 signs or symptoms), 58,3% presented moderate CMD (from 3 to 6 signs orsymptoms) and 16,7% showed severe CMD (more than 6 symptoms). Nevertheless, it’s important to remark thatnone of these pacients came seeking treatment for his CMD and these symptoms were refered only when beingasked. Hence the importance of a comprehensive clinic history to precociously diagnose this pathology and havethe ability to prevent its progression.
Nuestra institución y sus filiales
Authors: Gonzáles Mendoza Julio
Published: February 2019

La Sociedad Peruana de Odontopediatría nació como institución hace ya 65 años con una clara vocación, el de impulsar y difundir la odontopediatría en el Perú,no solo como especialidad sino también como componente importante de la formación de todo Cirujano – Dentista. Nuestra historia inicia con un grupode distinguidos colegas entusiasmados por compartir experiencias clínicas y departir camaradería dentro de un ambiente que promueva el desarrollo de laprofesión. Para esa época no existía en el Perú ni en Sudamérica programas de especialización en el área, se tenía que viajar muy lejos, especialmente al nortedel hemisferio para poder lograr la tan ansiada especialización que permitiera perfeccionar el manejo y la atención odontológica en el paciente pediátrico.
Rehabilitación oral de hipomineralización incisivo molar
Authors: Mejia-Herrera Zahira , Torres-Ramos Gilmer , Huamani-Huayhua Luis
Published: February 2019

El Objetivo es conocer e investigar el manejo odontológico y las posibles opciones de rehabilitación en los casos de Hipomineralización Incisivo Molar. Como metodología se usó el Reporte Clínico de un caso de Hipomineralización Incisivo Molar, en un paciente masculino de 8 años de edad con Diagnostico Sistémico de: Comunicación Interauricular, Retraso Psicomotor Global, Síndrome de Brown, Enfermedad por Reflujo Esofágico, TBC Latente; y Diagnostico Estomatológico de: Hipomineralización Incisivo Molar; atendido en el Instituto Nacional de Salud del Niño, en el servicio de Odontología de Pacientes Medicamente Comprometidos. El paciente presenta Hipomineralización en primeras molares y en incisivos centrales inferiores permanentes; debido a la complejidad de las lesiones a restaurar y la poca capacidad del paciente para mantener la apertura bucal por mucho tiempo se opta por rehabilitar al paciente en sala de operaciones, colocándose coronas de acero preformadas en molares más afectados y restaurando con Resina Composite los molares e incisivos menos afectados. Como resultados, en los controles realizados al paciente se puede observar que ha mejorado la calidad de vida, ya que no presenta más sensibilidad dentinaria, tampoco molestias al comer, encontrando a un paciente y sus padres muy satisfechos con los tratamientos realizados, considerando hasta ahora el tratamiento exitoso, tanto clínico como radiográfico. Conclusión: La ejecución de medidas preventivas individuales puede posponer el inicio del tratamiento restaurador y reducir la incomodidad del paciente a largo plazo. El diagnóstico precoz permite el seguimiento y la instauración de dichas medidas preventivas tan pronto las superficies afectadas sean accesibles.
Tratamiento de dientes permanentes jóvenes con hipoplasia de esmalte. Reporte de caso
Authors: Molina Morales Hugo
Published: February 2019

Tratamiento de dientes permanentes jóvenes con hipoplasia de esmalte. Reporte de caso
LAS CARACTERÍSTICAS OCLUSALES DE LA DENTICIÓN DECIDUA Y EL ESTADO NUTRICIONAL EN NIÑOS DE SAÑOS CHICO, HUANCAYO–2006
Authors: Torres Maita Liz María
Published: February 2019

Occlusal characteristics of the deciduous dentition and nutritional status in Saños Chico´children, Huancayo-2006
¿CUÁNDO Y POR QUÉ EL EMPLEO EN NIÑOS DE LA PRÓTESIS FIJA Y SEMI FIJA EN EL MAXILAR SUPERIOR?
Authors: Silva-Reggiardo Eduardo
Published: February 2019

When and Why fixed and semifixed prostheses should be used in the upper maxila in children?
TRATAMIENTO DE UNA PIEZA DENTARIA PERMANENTE FRACTURADA EN PACIENTE CON PARÁLISIS CEREBRAL
Authors: Chávez Corrales Antonio
Published: February 2019

Treatment of a fractured permanent dental tooth in patient with cerebral palsy
Sin historia no hay identidad
Authors: Silva-Reggiardo Eduardo
Published: February 2019

Editorial
Evaluación del aprendizaje de los estudiantes de las carreras de medicina y odontología dentro de un modelo de atención interdisciplinario a nivel hospitalario, Centro Hospitalario Pereira Rossell, Montevideo Uruguay
Authors: Hermida Bruno María Laura
Published: February 2019

Evaluation of the learning process of medicine and dentistry students within an assistential interdisciplinary teaching model at a hospital level, Hospital Center Pereira Rossell, Montevideo Uruguay
Pautas para la salud Bucal en los primeros años de vida
Authors: Palma Camila
Published: February 2019

Guidelines for Oral Health During Early Childhood
Nitrogen Application Improved Photosynthetic Productivity, Chlorophyll Fluorescence, Yield and Yield Components of Two Oat Genotypes under Saline Conditions
Authors: Song Xudong , Zhou Guisheng , Ma Bao-Luo , Wu Wei , Ahmad Irshad , Zhu Guanglong , Yan Weikai , Jiao Xiurong
Published: February 2019

: Understanding the interaction between salinity and nitrogen (N) nutrition is of great economic importance to improve plant growth and grain yield for oat plants. The objective of this study was to investigate whether N application could alleviate the negative effect of salinity (NaCl) stress on oat physiological parameters and yield performance. Two oat genotypes with contrasting salt tolerance response (6-SA120097, a salt-tolerant genotype SA and 153-ND121147, salt-sensitive ND) were grown under four N rates (0, 100, 200, and 400 mg N pot−1) in non-saline and saline (100 mM NaCl) conditions. The results showed that salinity, N fertilization and their interaction significantly affected the photosynthetic rate, transpiration rate, agronomic nitrogen use efficiency (aNUE), physiological nitrogen efficiency (pNUE) and apparent nitrogen recovery (ANR), seed number, and grain yield. Saline stress reduced gas exchange rate, nitrogen use efficiency (NUE), grain yield, and yield components. N fertilization increased photosynthetic productivity and chlorophyll fluorescence, resulting in improved grain yields and yield components for both genotypes. On average, the photosynthetic rate was increased by 38.7%, 74.1%, and 98.8% for SA and by 49.8%, 77.6%, and 110% for ND, respectively, under the N rates of 100, 200, and 400 mg N pot−1, as compared with non-fertilized treatment. In addition, grain yield was increased by 80.6% for genotype SA and 88.7% for genotype ND under higher N application rate (200 mg N pot−1) in comparison with the non-nitrogen treatment. Our experimental results showed that an increase of N supply can alleviate the negative effects induced by salinity stress and improved plant growth and yield by maintaining the integrity of the photosynthesis and chlorophyll fluorescence processes of oat plants, which provides a valuable agronomic strategy for improving oat production in salt-affected soils.
Evaluation of the NovaLisa™ Leishmania Infantum IgG ELISA in A Reference Diagnostic Laboratory in A Non-Endemic Country
Authors: Stensvold Christen Rune , Høst Amalie Vang , Belkessa Salem , Nielsen Henrik Vedel
Published: February 2019

Anti-Leishmania antibodies may be detectable in patients with leishmaniasis. Here, we compared a commercial enzyme-linked immunosorbent assay (ELISA) for the detection of anti-Leishmania antibodies, with an immunofluorescence antibody test (IFAT) that is no longer commercially available. Eighty-six serum samples from 73 patients were tested. The results obtained by the NovaLisa™ Leishmania infantum IgG ELISA, interpreted according to the instructions of the manufacturer, but with a modified cut-off for borderline positive values, were compared with the IFAT results that were already available. Moreover, Leishmania Western blot IgG results were available for 43 of the samples. The overall concordance of ELISA and IFAT was 67%. The ELISA and IFAT tests scored as 24% and 15% of the samples being positive, respectively, while 13% and 33% scored as borderline-positive, respectively. Using a Western blot (WB) as the reference, the sensitivities and specificities for the positive plus borderline-positive samples combined was 95.5% (95% confidence interval (CI), 77.2–99.9%) and 81.0% (95% CI, 58.1–94.6%) for ELISA, and 95.5% (95% CI, 77.2–99.9%) and 42.9% (95% CI, 21.8–66.0%) for IFAT, respectively. Overall, the ELISA proved to be a cost-effective alternative to the IFAT, due to its higher accuracy and specificity, and with a consequently lower number of confirmatory WB tests being required. Lastly, we also present data on the associations between seroconversion and the type of leishmaniasis.
Effect of the Relative Position of the Face Milling Tool towards the Workpiece on Machined Surface Roughness and Milling Dynamics
Authors: Pimenov Danil Yurievich , Hassui Amauri , Wojciechowski Szymon , Mia Mozammel , Magri Aristides , Suyama Daniel I. , Bustillo Andres , Krolczyk Grzegorz , Gupta Munish Kumar
Published: February 2019

In face milling one of the most important parameters of the process quality is the roughness of the machined surface. In many articles, the influence of cutting regimes on the roughness and cutting forces of face milling is considered. However, during flat face milling with the milling width B lower than the cutter’s diameter D, the influence of such an important parameter as the relative position of the face mill towards the workpiece and the milling kinematics (Up or Down milling) on the cutting force components and the roughness of the machined surface has not been sufficiently studied. At the same time, the values of the cutting force components can vary significantly depending on the relative position of the face mill towards the workpiece, and thus have a different effect on the power expended on the milling process. Having studied this influence, it is possible to formulate useful recommendations for a technologist who creates a technological process using face milling operations. It is possible to choose such a relative position of the face mill and workpiece that will provide the smallest value of the surface roughness obtained by face milling. This paper shows the influence of the relative position of the face mill towards the workpiece and milling kinematics on the components of the cutting forces, the acceleration of the machine spindle in the process of face milling (considering the rotation of the mill for a full revolution), and on the surface roughness obtained by face milling. Practical recommendations on the assignment of the relative position of the face mill towards the workpiece and the milling kinematics are given.
Study on Fluorine Pollution in a Slag Yard
Authors: Wei Lide , Wei Changfu , Sui Sugang
Published: February 2019

This paper suggests a large-scale three-dimensional numerical simulation method to investigate the fluorine pollution near a slag yard. The large-scale three-dimensional numerical simulation method included an experimental investigation, laboratory studies of solute transport during absorption of water by soil, and large-scale three-dimensional numerical simulations of solute transport. The experimental results showed that the concentrations of fluorine from smelting slag and construction waste soil were well over the discharge limit of 0.1 kg/m3 recommended by Chinese guidelines. The key parameters of the materials used for large-scale three-dimensional numerical simulations were determined based on an experimental investigation, laboratory studies, and soil saturation of survey results and back analyses. A large-scale three-dimensional numerical simulation of solute transport was performed, and its results were compared to the experiment results. The simulation results showed that the clay near the slag had a high saturation of approximately 0.9, consistent with the survey results. Comparison of the results showed that the results of the numerical simulation of solute transport and the test results were nearly identical, and that the numerical simulation results could be used as the basis for groundwater environmental evaluation.
Assessment of Energy Saving Potential by Replacing Conventional Materials by Cross Laminated Timber (CLT)—A Case Study of Office Buildings in China
Authors: Dong Yu , Cui Xue , Yin Xunzhi , Chen Yang , Guo Haibo
Published: February 2019

This research evaluates the operational heating and cooling energy consumption of cross-laminated timber (CLT) office buildings in China. The evaluations involve a comparison of the energy consumption of a reference RC structure and CLT system office buildings. Computational simulation results are based on IES-VE 2019 and show that the estimated heating energy saving ratio of CLT buildings in Harbin, Beijing, Shanghai, and Kunming to the reference structure are 11.97%, 22.11%, 30.94%, and 23.30% respectively. However, the CLT buildings consume more energy for cooling in the summer. The results of the research show significantly higher heating energy reductions for CLT buildings in the Cold Region and Severe Cold Regions of China. Thus, the application of the CLT system is better suited to northern China than southern China. The results of the research can be used in further assessment of the use of CLT systems in different climatic regions in China.
Electrochemical Sensor Based on Molecularly Imprinted Polymer for the Detection of Cefalexin
Authors: Feier Bogdan , Blidar Adrian , Pusta Alexandra , Carciuc Paula , Cristea Cecilia
Published: February 2019

In this study, a new electrochemical sensor was developed for the detection of cefalexin (CFX), based on the use of a molecularly imprinted polymer (MIP) obtained by electro‒polymerization in an aqueous medium of indole-3-acetic acid (I3AA) on a glassy carbon electrode (GCE) and on boron-doped diamond electrode (BDDE). The two different electrodes were used in order to assess how their structural differences and the difference in the potential applied during electrogeneration of the MIP translate to the performances of the MIP sensor. The quantification of CFX was performed by using the electrochemical signal of a redox probe before and after the rebinding of the template. The modified electrode was characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influence of different parameters on the fabrication of the sensor was tested, and the optimized method presented high selectivity and sensitivity. The MIP-based electrode presented a linear response for CFX concentration range of 10 to 1000 nM, and a limit of detection of 3.2 nM and 4.9 nM was obtained for the BDDE and the GCE, respectively. The activity of the sensor was successfully tested in the presence of some other cephalosporins and of other pharmaceutical compounds. The developed method was successfully applied to the detection of cefalexin from real environmental and pharmaceutical samples.
Liposomal Irinotecan for Treatment of Colorectal Cancer in a Preclinical Model
Authors: Huang Jiao-Ren , Lee Mei-Hsien , Li Wen-Shan , Wu Han-Chun
Published: February 2019

Colorectal cancer (CRC) is the most frequently diagnosed cancer and leading cause of cancer-related deaths worldwide. Because of the use of first-line CRC treatments, such as irinotecan (IRI), is hindered by dose-limiting side effects, improved drug delivery systems may have major clinical benefits for CRC treatment. In this study, we generate and characterize liposomal irinotecan (Lipo-IRI), a lipid-based nanoparticle, which shows excellent bioavailability and pharmacokinetics. Additionally, this formulation allows IRI to be maintained in active form and prolongs its half-life in circulation compared to IRI in solution. Compared with IRI statistically, the level of prostaglandin E2 (PGE2) in colonic tissue decreases, and Bifidobacterium spp. (beneficial intestinal microbiota) content increases in the Lipo-IRI-treated group. Moreover, no damage is observed by the hematoxylin and eosin staining of the normal tissue samples from the Lipo-IRI-treated group. In a xenograft mouse model, CRC tumors shrink markedly following Lipo-IRI treatment, and mice receiving a targeted combination of Lipo-IRI and liposomal doxorubicin (Lipo-Dox) extend their survival rate significantly. Overall, our results demonstrate that this formulation of Lipo-IRI shows a great potential for the treatment of colorectal cancer.
Nicotine Induces Resistance to Erlotinib Therapy in Non-Small-Cell Lung Cancer Cells Treated with Serum from Human Patients
Authors: Imabayashi Tatsuya , Uchino Junji , Osoreda Hisayuki , Tanimura Keiko , Chihara Yusuke , Tamiya Nobuyo , Kaneko Yoshiko , Yamada Tadaaki , Takayama Koichi
Published: February 2019

Previously, we reported that nicotine reduces erlotinib sensitivity in a xenograft model of PC9, an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI)-sensitive non-small-cell lung cancer cell line. The present study examined whether smoking induces erlotinib resistance in vitro. We assessed resistance to EGFR-TKIs by treating cancer cell lines with erlotinib, afatinib, or osimertinib, and serum collected from smokers within 30 min of smoking and that from a non-smoker as a control. We also assessed erlotinib resistance by treating PC9 cells exposed to serum from a smoker or a non-smoker, or serum from an erlotinib user. Treatment of the cancer cell lines with serum from smokers induced significant erlotinib resistance, compared with the control (p < 0.05). Furthermore, serum samples with a high concentration of cotinine (a nicotine exposure indicator) demonstrated stronger erlotinib resistance than those with low concentrations. Similar to the observations with erlotinib treatment of cell lines, the analysis of serum from erlotinib users revealed that smokers demonstrated significantly reduced sensitivity to erlotinib (p < 0.001). In conclusion, our present results support the hypothesis that smoking contributes to resistance to erlotinib therapy in non-small-cell lung cancer.
Gliosarcoma Is Driven by Alterations in PI3K/Akt, RAS/MAPK Pathways and Characterized by Collagen Gene Expression Signature
Authors: Wojtas Bartosz , Gielniewski Bartlomiej , Wojnicki Kamil , Maleszewska Marta , Mondal Shamba S. , Nauman Pawel , Grajkowska Wieslawa , Glass Rainer , Schüller Ulrich , Herold-Mende Christel , Kaminska Bozena
Published: February 2019

Gliosarcoma is a very rare brain tumor reported to be a variant of glioblastoma (GBM), IDH-wildtype. While differences in molecular and histological features between gliosarcoma and GBM were reported, detailed information on the genetic background of this tumor is lacking. We intend to fill in this knowledge gap by the complex analysis of somatic mutations, indels, copy number variations, translocations and gene expression patterns in gliosarcomas. Using next generation sequencing, we determined somatic mutations, copy number variations (CNVs) and translocations in 10 gliosarcomas. Six tumors have been further subjected to RNA sequencing analysis and gene expression patterns have been compared to those of GBMs. We demonstrate that gliosarcoma bears somatic alterations in gene coding for PI3K/Akt (PTEN, PI3K) and RAS/MAPK (NF1, BRAF) signaling pathways that are crucial for tumor growth. Interestingly, the frequency of PTEN alterations in gliosarcomas was much higher than in GBMs. Aberrations of PTEN were the most frequent and occurred in 70% of samples. We identified genes differentially expressed in gliosarcoma compared to GBM (including collagen signature) and confirmed a difference in the protein level by immunohistochemistry. We found several novel translocations (including translocations in the RABGEF1 gene) creating potentially unfavorable combinations. Collected results on genetic alterations and transcriptomic profiles offer new insights into gliosarcoma pathobiology, highlight differences in gliosarcoma and GBM genetic backgrounds and point out to distinct molecular cues for targeted treatment.
K-Modulated Co Nanoparticles Trapped in La-Ga-O as Superior Catalysts for Higher Alcohols Synthesis from Syngas
Authors: Guo Shaoxia , Liu Guilong , Han Tong , Zhang Ziyang , Liu Yuan
Published: February 2019

Owing to the outstanding catalytic performance for higher alcohol synthesis, Ga-Co catalysts have attracted much attention. In view of their unsatisfactory stability and alcohol selectivity, herein, K-modulated Co nanoparticles trapped in La-Ga-O catalysts were prepared by the reduction of La1−xKxCo0.65Ga0.35O3 perovskite precursor. Benefiting from the atomic dispersion of all the elements in the precursor, during the reduction of La1−xKxCo0.65Ga0.35O3, Co nanoparticles could be confined into the K-modified La-Ga-O composite oxides, and the confinement of La-Ga-O could improve the anti-sintering performance of Co nanoparticles. In addition, the addition of K modulated parts of La-Ga-O into La2O3, which ameliorated the anti-carbon deposition performance. Finally, the addition of K increased the dispersion of cobalt and provided more electron donors to metallic Co, resulting in a high activity and superior selectivity to higher alcohols. Benefiting from the above characteristics, the catalyst possesses excellent activity, good selectivity, and superior stability.
Effect of Preparation Method of Co-Ce Catalysts on CH4 Combustion
Authors: Darda Sofia , Pachatouridou Eleni , Lappas Angelos , Iliopoulou Eleni
Published: February 2019

Transition metal oxides have recently attracted considerable attention as candidate catalysts for the complete oxidation of methane, the main component of the natural gas, used in various industrial processes or as a fuel in turbines and vehicles. A series of novel Co-Ce mixed oxide catalysts were synthesized as an effort to enhance synergistic effects that could improve their redox behavior, oxygen storage ability and, thus, their activity in methane oxidation. The effect of synthesis method (hydrothermal or precipitation) and Co loading (0, 2, 5, and 15 wt.%) on the catalytic efficiency and stability of the derived materials was investigated. Use of hydrothermal synthesis results in the most efficient Co/CeO2 catalysts, a fact related with their improved physicochemical properties, as compared with the materials prepared via precipitation. In particular, a CeO2 support of smaller crystallite size and larger surface area seems to enhance the reducibility of the Co3O4/CeO2 materials, as evidenced by the blue shift of the corresponding reduction peaks (H2-TPR, H2-Temperature Programmed Reduction). The limited methane oxidation activity over pure CeO2 samples is significantly enhanced by Co incorporation and further improved by higher Co loadings. The optimum performance was observed over a 15 wt% Co/CeO2 catalyst, which also presented sufficient tolerance to water presence.
Observed Spatiotemporal Trends in Intense Precipitation Events across United States: Applications for Stochastic Weather Generation
Authors: Joshi Sanjeev , Garbrecht Jurgen , Brown David
Published: February 2019

An increasing focus of climate change studies is the projection of storm events characterized by heavy, very heavy, extreme, and/or intense precipitation. Projected changes in the spatiotemporal distributions of such intense precipitation events remain uncertain due to large measures of variability in both the definition and evidence of increased intensity in the upper percentile range of observed daily precipitation distributions, particularly on a regional basis. As a result, projecting changes in future precipitation at the upper tail of the distribution (i.e., the heavy to heaviest events), such as through the use of stochastic weather generator programs, remains challenging. One approach to address this challenge is to better define what constitutes intense precipitation events and the degree of location-specific adjustment needed for the weather generator programs to appropriately account for potential increases in precipitation intensity due to climate change. In this study, we synthesized information on categories of intense precipitation events and assessed reported trends in the categories at national and regional scales within the context of applying this information to stochastic weather generation. Investigations of adjusting weather generation models to include long-term regional trends in intense precipitation events are limited, and modeling trends in site-specific future precipitation distributions forecasted by weather generator programs remains challenging. Probability exceedance curves and variations between simulated and observed distributions can help in modeling and assessment of trends in future extreme precipitation events that reflect changes in precipitation intensity due to climate change.
Study of a Nano-SiO2 Microsphere-Modified Basalt Flake Epoxy Resin Coating
Authors: Luo Lida , Ma Qian , Wang Qingwei , Ding Linfeng , Gong Ziyan , Jiang Weizhong
Published: February 2019

Basalt flakes (BFs) have been widely used in recent years as a novel anticorrosion material in the marine industry to prevent the corrosion of metal substrates. In this study, BFs were modified with 1–7‰ nano-SiO2 microspheres, and a modified BF epoxy coating was successfully prepared. Experimental results showed that the BF epoxy resin coating modified with 3‰ nano-SiO2 microspheres exhibited excellent chemical durability (surface weight loss rate of 2.2% in the alkali solution and only 1.1% in the acid solution at room temperature after 480 h), low water infiltration (water absorption of 0.72% after 480 h), and good mechanical performance (tensile strength of approximately 33.4 MPa). This study proves the feasibility of using nano-SiO2 microspheres to modify BF epoxy resin coating and enhance the chemical durability and mechanical properties provided by the coating.
Design of Nano-Structured Micro-Thermoelectric Generator: Load Resistance and Inflections in the Efficiency
Authors: Badillo-Ruiz Carlos Alberto , Olivares-Robles Miguel Angel , Chanona-Perez Jose Jorge
Published: February 2019

In recent years the interest for the harvest of energy with micro thermoelectric generators ( μ TEG) has increased, due to its advantages compared to technologies that use fossil fuels. There are three ways to improve the performance of the device, by modifying its structure, type of material and operation control. In this study, the role of the load resistance R L on the performance of a μ TEG with nanostructured materials is investigated. The interaction of the load resistance with the thermoelements exhibits interesting features, arising from the coupling of the temperature-dependent electrical and thermal transport properties at different temperature ranges and the architecture of nanostructured thermoelectric materials. This coupling results in inflections on the efficiency, i.e., maximum and minimum values of the efficiency at higher temperatures, 600–900 K. We show the explicit dependence of the performance of the μ TEG in terms of the load resistance and discuss the underlying physics. The unusual features of the efficiency of nanostructured thermoelectric materials are a result of the behavior of the power factor and the nonequilibrium properties of the system. We also analyze the effect of the geometric shape of the thermoelements on the device. We determine the performance of the μ TEG, evaluating the generation power and its efficiency. The results show that the efficiency of the device can decrease or increase depending on the value of R L , while the power decreases with an increase of the load resistance.
Peltier Supercooling in Transient Thermoelectrics: Spatial Temperature Profile and Characteristic Cooling Length
Authors: Ruiz-Ortega Pablo , Olivares-Robles Miguel
Published: February 2019

Thermoelectric coolers (TECs) can reach temperatures below that obtained with a steady-state current by applying an electrical current pulse which enables a transitory state in a Peltier device. This effect is known as supercooling. In this paper, we study characteristics parameters, such as the minimum cooling temperature and spatial temperature profile, in a TEC operated under current pulses and a cooling load ( Q c ) . Numerical analysis for a one-dimensional thermoelectric model of the cooling system is developed, and a novel MATLAB programming code is proposed for the transient state based on finite element analysis. We also investigate the influence of the thermoelement’s length upon the cooling mechanism. A new parameter called the “characteristic cooling length” is proposed to describe the length in which the minimum cooling temperature occurs along the elements of a TEM. Results show the transient temperature profiles along the elements of the semiconductor P-type element, and a “characteristic cooling length” is characterized. We also propose a general principle, and the lowest cooling temperature values are obtained for a semiconductor’s small length and variable pulse cooling load under current pulse operation. The present study will serve as guidance for the geometric design of TECs under current pulse operations.
Transport and Energetic Properties of a Ring of Interacting Spins Coupled to Heat Baths
Authors: Xu Xiansong , Choo Kenny , Balachandran Vinitha , Poletti Dario
Published: February 2019

We study the heat and spin transport properties in a ring of interacting spins coupled to heat baths at different temperatures. We show that interactions, by inducing avoided crossings, can be a means to tune both the total heat current flowing between the ring and the baths, and the way it flows through the system. In particular, we recognize three regimes in which the heat current flows clockwise, counterclockwise, and in parallel. The temperature bias between the baths also induces a spin current within the ring, whose direction and magnitude can be tuned by the interaction. Lastly, we show how the ergotropy of the nonequilibrium steady state can increase significantly near the avoided crossings.
A 13-bit 3-MS/s Asynchronous SAR ADC with a Passive Resistor Based Loop Delay Circuit
Authors: Ju Hyungyu , Lee Minjae
Published: February 2019

An asynchronous successive approximation register (SAR) ADC incorporates a passive resistor based delay cell to reduce power consumption and accommodate the SAR ADC with a reconfigurable sampling frequency or tapered bit period without repeated delay calibration. The ADC aims to have a sampling frequency of several MS/s. The proposed delay cell adopts resistance controlled delay architecture to generate a delay of nanoseconds with high linearity. The resistance controlled delay cell is based on a passive resistor instead of a MOS transistor using a triode region to avoid the nonlinear delay characteristic of active devices. From the analysis of the linearity of delay cell, the passive resistor based delay cell achieves a delay error of about 5 percent. The prototype ADC to validate the proposed passive resistor based delay cell is fabricated in 40 n m CMOS. The ADC occupies 0.054 m m 2 and achieves an SNDR of 57.4 dB under 67 μ W power dissipation at a 1.1 V supply with a 3 MHz sampling frequency.
Mixed Convection Stagnation-Point Flow of a Nanofluid Past a Permeable Stretching/Shrinking Sheet in the Presence of Thermal Radiation and Heat Source/Sink
Authors: Jamaludin Anuar , Nazar Roslinda , Pop Ioan
Published: February 2019

In this study we numerically examine the mixed convection stagnation-point flow of a nanofluid over a vertical stretching/shrinking sheet in the presence of suction, thermal radiation and a heat source/sink. Three distinct types of nanoparticles, copper (Cu), alumina (Al2O3) and titania (TiO2), were investigated with water as the base fluid. The governing partial differential equations were converted into ordinary differential equations with the aid of similarity transformations and solved numerically by utilizing the bvp4c programme in MATLAB. Dual (upper and lower branch) solutions were determined within a particular range of the mixed convection parameters in both the opposing and assisting flow regions and a stability analysis was carried out to identify which solutions were stable. Accordingly, solutions were gained for the reduced skin friction coefficients, the reduced local Nusselt number, along with the velocity and temperature profiles for several values of the parameters, which consists of the mixed convection parameter, the solid volume fraction of nanoparticles, the thermal radiation parameter, the heat source/sink parameter, the suction parameter and the stretching/shrinking parameter. Furthermore, the solutions were presented in graphs and discussed in detail.
The Application of Analytical Hierarchy Process in Combination with PESTEL-SWOT Analysis to Assess the Hydrocarbons Sector in Cyprus
Authors: Tsangas Michail , Jeguirim Mejdi , Limousy Lionel , Zorpas Antonis
Published: February 2019

Natural gas reserves have been recently found offshore of Cyprus. Hence, a new energy sector is under development, creating potential for raised welfare for the small insular EU member. Several social and economic benefits could be achieved from the resources’ exploitation. However, natural gas is a non-renewable energy source, connected with the major environmental issues of fossil fuels. The research goal of this work was to evaluate the sustainability of the new hydrocarbons sector. This was attained using a set of indicators, developed from the combination of PESTEL (Political, Economic, Technical, Social, Environmental, Legal) and SWOT (Strengths, Weaknesses, Opportunities, Threats) analyses. These were quantified using the Analytical Hierarchy Process (AHP) weighting method. They were pairwise compared and evaluated, resulting to a size for each one. The judgements of four evaluators, representing diverse interested parties, were used. The strengths and opportunities of the sector were found to be more than the weaknesses and threats. The relevant indicators quantification demonstrates also that the value of the positives is higher than the negatives. Therefore, if the first are enhanced and the latter are mitigated, there is sustainability potential. The sectors environmental issues are evaluated as the most important, followed by the economic. The other takes lower but comparatively significant values, and must be handled accordingly. These results lead to useful conclusions and could be exploited for decision-making and policies formulation.
Increasing the Utilization of Transmission Lines Capacity by Quasi-Dynamic Thermal Ratings
Authors: Song Fan , Wang Yanling , Yan Hongbo , Zhou Xiaofeng , Niu Zhiqiang
Published: February 2019

The power grid is under pressure to maintain a reliable supply because of constrained budgets and environmental policies. In order to effectively make use of existing transmission lines, it is important to accurately evaluate the line capacity. Dynamic thermal rating (DTR) offers a way to increase the utilization of capacity under real-time meteorological data. However, DTR relies on a number of sensors and the cost is high. Therefore, a method of improving the utilization of capacity by quasi-dynamic thermal rating (QDR) is proposed in this paper. QDR at different confidence levels and time scales is determined through the statistical analysis of line ampacity driven by key parameters, and the key parameters is identified by control variate method. In addition, the operation risk and tension loss is evaluated. The results show that QDR can increase the utilization of line capacity and in the absence of along-line measuring devices, QDR is more accurate, reliable and cost-saving. The managers can determine the appropriate confidence level according to the operation risk and tension loss that the system can bear, and shorten the time scale with the permission of the operation and control complexity.
Characterization of Wave Energy Potential for the Baltic Sea with Focus on the Swedish Exclusive Economic Zone
Authors: Nilsson Erik , Rutgersson Anna , Dingwell Adam , Björkqvist Jan-Victor , Pettersson Heidi , Axell Lars , Nyberg Johan , Strömstedt Erland
Published: February 2019

In this study, a third-generation wave model is used to examine the wave power resource for the Baltic Sea region at an unprecedented one-kilometer-scale resolution for the years 1998 to 2013. Special focus is given to the evaluation and description of wave field characteristics for the Swedish Exclusive Economic Zone (SEEZ). It is carried out to provide a more detailed assessment of the potential of waves as a renewable energy resource for the region. The wave energy potential is largely controlled by the distance from the coast and the fetch associated with the prevailing dominant wave direction. The ice cover is also shown to significantly influence the wave power resource, especially in the most northern basins of the SEEZ. For the areas in focus here, the potential annual average wave energy flux reaches 45 MWh/m/year in the two sub-basins with the highest wave energies, but local variations are up to 65 MWh/m/year. The assessment provides the basis for a further detailed identification of potential sites for wave energy converters. An outlook is given for additional aspects studied within a broad multi-disciplinary project to assess the conditions for offshore wave energy conversion within the SEEZ.
Induction Motor Broken Rotor Bar Detection Based on Rotor Flux Angle Monitoring
Authors: Nemec Mitja , Ambrožič Vanja , Fišer Rastko , Nedeljković David , Drobnič Klemen
Published: February 2019

This paper presents a method for the detection of broken rotor bars in an induction motor. After introducing a simplified dynamic model of an induction motor with broken cage bars in a rotor field reference frame which allows for observation of its internal states, a fault detection algorithm is proposed. Two different motor estimation models are used, and the difference between their rotor flux angles is extracted. A particular frequency component in this signal appears only in the case of broken rotor bars. Consequently, the proposed algorithm is robust enough to load oscillations and/or machine temperature change, and also indicates the fault severity. The method has been verified at different operating points by simulations as well as experimentally. The fault detection is reliable even in cases where traditional methods give ambiguous verdicts.
Monitoring of Defects of a Photovoltaic Power Plant Using a Drone
Authors: Libra Martin , Daneček Milan , Lešetický Jan , Poulek Vladislav , Sedláček Jan , Beránek Václav
Published: February 2019

Drone infrared camera monitoring of photovoltaic (PV) power plants allows us to quickly see a large area and to find the worst defects in PV panels, namely cracked PV cells with broken contacts. Roofs are suitable for the integration of PV power plants into buildings. The power plant at the Czech University of Life Sciences in Prague, which was monitored by this method, does not show any significant defects, and the produced electric energy exceeds the expected values. On the contrary, the PV power plant in Ladná has visible defects, and the data monitoring system Solarmon-2.0 also indicates defects. Our newly developed data monitoring system Solarmon-2.0 has been successfully used in 65 PV power plants in the Czech Republic and in many PV power plants throughout the world. Data are archived and interpreted in our dispatch area at the Czech University of Life Sciences in Prague. The monitoring system can report possible failure(s) if the measured amount of energy differs from the expected value(s). The relation of the measured values of PV power to the PV panel temperature is justified, which is consistent with the physical theory of semiconductors.
Experimental Investigation on Performance of a Compression Ignition Engine Fueled with Waste Cooking Oil Biodiesel–Diesel Blend Enhanced with Iron-Doped Cerium Oxide Nanoparticles
Authors: Hawi Meshack , Elwardany Ahmed , Ismail Mohamed , Ahmed Mahmoud
Published: February 2019

The effect of iron-doped cerium oxide (FeCeO2) nanoparticles as a fuel additive was experimentally investigated with waste cooking oil methyl ester (WCOME) in a four-stroke, single cylinder, direct injection diesel engine. The study aimed at the reduction of harmful emissions of diesel engines including oxides of nitrogen (NOx) and soot. Two types of nanoparticles were used: cerium oxide doped with 10% iron and cerium oxide doped with 20% iron, to further investigate the influence of the doping level on the nanoparticle activity. The nanoparticles were dispersed in the tested fuels at a dosage of 90 ppm with the aid of an ultrasonic homogenizer. Tests were conducted at a constant engine speed of 2000 rpm and varying loads (from 0 to 12 N.m) with neat diesel (D100) and biodiesel–diesel blends of 30% WCOME and 70% diesel by volume (B30). The engine combustion, performance, and emission characteristics for the fuel blends with nanoparticles were compared with neat diesel as the base fuel. The test results showed improvement in the peak cylinder pressure by approximately 3.5% with addition of nanoparticles to the fuel. A reduction in NOx emissions by up to 15.7% were recorded, while there was no noticeable change in unburned hydrocarbon (HC) emissions. Carbon monoxide (CO) emission was reduced by up to 24.6% for B30 and 15.4% for B30 with nano-additives. Better engine performance was recorded for B30 with 20% FeCeO2 as compared to 10% FeCeO2, in regard to cylinder pressure and emissions. The brake specific fuel consumption was lower for the fuel blend of B30 with 10% FeCeO2 nanoparticles, in low-to-medium loads and comparable to D100 at high loads. Hence, a higher brake thermal efficiency was recorded for the blend in low-to-medium loads compared to D100.
Contrasting Differences in Responses of Streamflow Regimes between Reforestation and Fruit Tree Planting in a Subtropical Watershed of China
Authors: Xu Zhipeng , Liu Wenfei , Wei Xiaohua , Fan Houbao , Ge Yizao , Chen Guanpeng , Xu Jin
Published: February 2019

Fruit tree planting is a common practice for alleviating poverty and restoring degraded environment in developing countries. Yet, its environmental effects are rarely assessed. The Jiujushui watershed (261.4 km2), located in the subtropical Jiangxi Province of China, was selected to assess responses of several flow regime components on both reforestation and fruit tree planting. Three periods of forest changes, including a reference (1961 to 1985), reforestation (1986 to 2000) and fruit tree planting (2001 to 2016) were identified for assessment. Results suggest that the reforestation significantly decreased the average magnitude of high flow by 8.78%, and shortened high flow duration by 2.2 days compared with the reference. In contrast, fruit tree planting significantly increased the average magnitude of high flow by 27.43%. For low flows, reforestation significantly increased the average magnitude by 46.38%, and shortened low flow duration by 8.8 days, while the fruit tree planting had no significant impact on any flow regime components of low flows. We conclude that reforestation had positive impacts on high and low flows, while to our surprise, fruit tree planting had negative effects on high flows, suggesting that large areas of fruit tree planting may potentially become an important driver for some negative hydrological effects in our study area.
iNOS Gene Ablation Prevents Liver Fibrosis in Leptin-Deficient ob/ob Mice
Authors: Becerril Sara , Rodríguez Amaia , Catalán Victoria , Ramírez Beatriz , Unamuno Xabier , Gómez-Ambrosi Javier , Frühbeck Gema
Published: February 2019

The role of extracellular matrix (ECM) remodeling in fibrosis progression in nonalcoholic fatty liver disease (NAFLD) is complex and dynamic, involving the synthesis and degradation of different ECM components, including tenascin C (TNC). The aim was to analyze the influence of inducible nitric oxide synthase (iNOS) deletion on inflammation and ECM remodeling in the liver of ob/ob mice, since a functional relationship between leptin and iNOS has been described. The expression of molecules involved in inflammation and ECM remodeling was analyzed in the liver of double knockout (DBKO) mice simultaneously lacking the ob and the iNOS genes. Moreover, the effect of leptin was studied in the livers of ob/ob mice and compared to wild-type rodents. Liver inflammation and fibrosis were increased in leptin-deficient mice. As expected, leptin treatment reverted the obesity phenotype. iNOS deletion in ob/ob mice improved insulin sensitivity, inflammation, and fibrogenesis, as evidenced by lower macrophage infiltration and collagen deposition as well as downregulation of the proinflammatory and profibrogenic genes including Tnc. Circulating TNC levels were also decreased. Furthermore, leptin upregulated TNC expression and release via NO-dependent mechanisms in AML12 hepatic cells. iNOS deficiency in ob/ob mice improved liver inflammation and ECM remodeling-related genes, decreasing fibrosis, and metabolic dysfunction. The activation of iNOS by leptin is necessary for the synthesis and secretion of TNC in hepatocytes, suggesting an important role of this alarmin in the development of NAFLD.