bluuebunny/crossref_metadata_2025 huggingface dataset:
Endoscopic Retrograde Cholangiopancreatography followed by Laparoscopic Cholecystectomy versus Laparacosopic Cholecystectomy and Common Bile Duct Exploration in Concomitant Gallstone and Common Bile Duct Stone
Authors: Ranty Stefanus Satrio , Stephanie Anggilia , Mudjaddid E , Syam Ari Fahrial
Published: April 2017

Aim: Cholecystolithiasis is frequently accompanied with choledocholithiasis, with the incidence ranged from 8-20%. The current management of concomitant cholecystolithiasis and choledocholithiasis is varied, either Endoscopic Retrograde Cholangiopancreatography (ERCP) followed by Laparoscopic Cholecystectomy (LC) or LC followed by ERCP, or single-step procedure, i.e. LC with common bile duct exploration (LCBDE). This evidence-based case report (EBCR) will compare the efficacy, effectiveness, and safety between the ERCP+LC and LCBDE.Method: The article search was done through PubMed, EBSCO, dan Cochrane at 1st December 2015 using keywords ERCP, LC, gallstone, common bile duct. Two meta-analyses and two randomized clinical trial were found and critical appraisal was done to all four articles.Results: All four studies showed similar stone clearance for both procedures. One meta-analysis showed better clearance in single procedure (OR = 1,56; 95% CI: 1,05-2,33; p: 0,03; heterogeneity: I2 = 42%). Mortality and morbidity rate, complication, and the need of another procedure were no difference between single-step and two-step procedure. Length of stay and cost effectiveness were better in single-step procedure in all studies.Conclusion: Single-step procedure may show better result in stone clearance, cost-effectiveness, and length of stay. However, this procedure may be limited, thus can only be done in health center with sufficient resources. ERCP followed by LC is still the preferred procedure, especially in patient with worse performance status and limited health center.
Expression of Hepcidin and Growth Differentiation Factor 15 (GDF-15) Levels in Thalassemia Patients with Iron Overload and Positive Anti Hepatitis C Virus
Authors: Indrasari Nuri Dyah , Timan Ina Susianti , Amalia Pustika
Published: April 2017

Background: Thalassemia patients who undergo life-long recurrent blood transfusion will experience iron overload in various organs including the liver and possibly suffer from chronic hepatitis C infection which may lead to liver impairment. The liver produces hepcidin, a hormone which plays role in the regulation of iron level in the blood. Various factors may influence hepcidin level in the blood. Chronic hepatitis C causes iron overload and liver impairment. Liver impairment and haemolytic anaemia due to haemoglobinopathy will suppress hepcidin production. Anaemia stimulates growth differentiation factor 15 (GDF-15) to increase erythropoiesis and suppress hepcidin production. Iron overload causes increase in hepcidin level. Presence of factors which decrease or increase hepcidin production will express various levels of hepcidin. This study aimed to identify the expression of hepcidin and GDF-15 levels in thalassemia patients with iron overload and positive anti-HCV. Information on hepcidin and GDF-15 levels are beneficial in the management of iron overload in thalassemia with positive anti-HCV.Method: This study was a descriptive analytic study in thalassemia patients who had received recurrent blood transfusion ≥ 12 times, suffered from iron overload (transferrin saturation 55% and ferritin 1,000 ng/mL), which consisted of 31 individuals with positive anti-HCV and 27 individuals with negative anti-HCV. This study was performed in Thalassemia Centre Department of Child Health and Department of Clinical Pathology, Faculty of Medicine, Universitas Indonesia, Cipto Mangunkusumo Hospital, in October 2011–January 2012. Serum hepcidin and GDF-15 examinations were performed using enzyme-linked immunosorbent assay (ELISA) method. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) examinations were performed using colorimetry method. Data on ferritin and transferrin saturation were obtained from medical records in the last 3 months. Data was analysed using SPSS Windows version 17 software.Results: Characteristics of subjects in this study included ferritin level, transferrin saturation, AST, and ALT were 5,289 (SD 2,492) ng/mL, 96.7 (SD 9.2)%, 41.8 (SD 26.7) U/L, and 50.6 (24.9) U/L, respectively.  It was obtained that the hepcidin levels were within the normal limits with median of 51.5 (19-166) pg/mL, while GDF-15 levels were higher than the normal range with median of 1,936 (643-2,475) pg/mL. There was no significant difference of hepcidin and GDF-15 levels between positive and negative anti-HCV groups, with p value of 0.842 and 0.115, respectively.Conclusion: We obtained that the hepcidin levels were within normal limits and GDF-15 levels were higher than the normal range. There was no significant difference of hepcidin and GDF-15 levels between positive and negative anti-HCV group.
Screening and Management of Colon Polyp as Colorectal Cancer Prevention
Authors: Ayundini Gratcia , Simadibrata Marcellus
Published: April 2017

Colon polyp is a term used for abnormality from bulging tissue above surrounding colonic mucosal layer. Adenoma polyp was the commonly found polyp that progress to colorectal cancer. Most of those patients was asymptomatic. Undetected and unmanaged polyp was a risk factors of colorectal cancer event.
Endoscopic Dilatation versus Oesophageal Stent in Benign Oesophageal Stricture
Authors: Caputra Hadyanto , Awang Iqbal I , Nugroho Prionggodigdo , Syam Ari Fahrial
Published: April 2017

Aim: Oesophageal stricture is one of the causes of dysphagia. It is a condition in which the lumen of oesophagus is narrowed by fibrotic tissue in the oesophageal wall. It is usually caused by inflammation or any other cause that leads to necrotizing of tissue. It is mainly differentiated into benign or malignant. The aim of this article is to answer the clinical question on the effectiveness of oesophageal stenting compared to endoscopic dilatation in patient with benign oesophageal stricture due to ingestion of corrosive substances, who had undergone several endoscopic dilatations.Method: We conducted search of relevant articles using PubMed search engine to answer the clinical question. Keywords being used during the search process were: ("oesophageal stricture"[All Fields] OR "oesophageal stenosis"[All Fields] AND (("dilatation"[All Fields] AND ("stents"[MeSH Terms] OR "stents"[All Fields] OR "stent"[All Fields]). Results were further converged by adding specific filters, which were full text articles and clinical trial.Results: The chosen article was further appraised in order to identify its validity and eligibility to answer the clinical question. We chose to use CONSORT (statement to improve the quality of reporting of RCTs) to facilitate the critical appraisal and interpretation of RCTs.Conclusion: Stenting was associated with greater dysphagia, co-medication and adverse events. No randomized controlled trials which compared biodegradable stents with other stents or with balloon dilatation was identified. Lack of adequately robust evidence for effectiveness and cost-effectiveness formed the rationale of this trial.
Correlation Between Esophageal Varices and Lok Score as a Non-invasive Parameter in Liver Cirrhosis Patients
Authors: Sungkar Iqbal , Dairi Leonardo Basa , Siregar Gontar Alamsyah
Published: April 2017

Background: Bleeding from gastro-esophageal varices is the most serious and life-threatening complication of cirrhosis. Endoscopic surveillance of esophageal varices in cirrhotic patients is expensive and uncomfortable for the patients. Therefore, there is a particular need for non-invasive predictors for esophageal varices. The aim of the present study was to evaluate association of esophageal varices and Lok Score as non-invasive parameter in liver cirrhosis patients.Method: This is a cross-sectional study of patients admitted at the Adam Malik hospital Medan between September to December 2014 with a diagnosis of cirrhosis based on clinical, biochemical, ultrasound, and gastroscopy. Lok Score was calculated for all patients, tabulated and analyzed.Results: Among 76 patients with esophageal varices, 55.3% was due to hepatitis B virus (HBV). The majority of patients were Child C with only 13,2% being Child Pugh class A. Majority of the population had F2 esophageal varices (42,1%), F1 (32,9%), and F3 (25%). There is significance difference between Lok Score and grading of esophageal varices, Lok score is higher in Large esophageal varices compared with small esophageal varises (0.92 ± 0.14 vs. 0.70 ± 0.29; p = 0.001). Lok Score cut-off value of 0,9141 was highly predictive in the diagnosis large esophageal varices with a sensitivity of 74.5%, specificity of 72%, positive predictive value of 84%, negative predictive value 58%, and accuracy was 73.7%.Conclusion: Lok Score was significantly associated with esophageal varices. Lok score is a good non-invasive predictor of large esophageal varices in cirrhotic patients.
Le mythe des deux solitudes. Des relations entre les psychiatres francophones et anglophones dans le Montréal des années 1950
Authors: Klein Alexandre
Published: April 2017

Cet article étudie, à partir d'archives institutionnelles et de revues médicales, les relations qu'ont entretenues les psychiatres francophones et anglophones dans le Montréal des années 1950. Il montre la multiplicité ainsi que la multiplication des échanges et des collaborations entre les deux communautés au cours de la période allant de 1948 à 1961. Il entend ainsi contribuer à la déconstruction d'une historiographie traditionnelle qui distingue et oppose les psychiatries québécoises anglophone et francophone comme deux systèmes parallèles, comme deux solitudes.
The Social Environment of Daily Life and Perceptions of Police and/or Court Discrimination among African, Caribbean, and Black Youth
Authors: Peirone Amy , Maticka-Tyndale Eleanor , Gbadebo Kenny , Kerr Jelani
Published: April 2017

Recent deaths of African-Americans at the hands of police and the creation of the protest movement Black Lives Matter has brought public attention to claims of racial profiling and police discrimination in the United States. In Canada, concerns about racial profiling centre on the disproportionate number of visible minority, particularly African-diasporic, individuals targeted in “street checks” or “carding.” This study used multivariate block logistic regression to compare the explanatory power of variables measuring different aspects of the social environment of daily life drawn from three theoretical frameworks (broken windows, routine activities, and critical race theory) when considering contact with police and perceptions of police and court discrimination in a sample of African-diasporic youth (N=529) who self-identify as African, Caribbean, or Black in a mid-sized city in Ontario, Canada. All measures of the social environment contributed significantly to explaining contact and perceived discrimination. In addition, the significant increase in the variance explained for both contact and perceived discrimination with each successive block supports the conclusion that consideration of the social environment of daily life contributes to an understanding of youth–police contact and youth perceptions of police and courts. The study's findings add to the discussion of inequality and youth–police contacts and experiences, as well as to the Canadian criminological literature exploring relationships between police and racialized youth.
Effect of age on feed efficiency and carcass yield characteristics of indigenous bull
Authors: Sultana N , Huque KS , Rahman MZ , Das NG
Published: April 2017

The study was conducted with the objectives to understand the effect of age of native Pabna bulls on feed conversion ratio (FCR), digestibility and carcass yield characteristics. Fifteen Pabna bulls having five  in each age groups of 6 to12, 13 to 24 and 25 to 36 months  were fed   ad libitum mix silages of Splendida (Setaria splendida) and Andrpogan (Andropogon gyunus) grasses (1:1 fresh) and supplemented with a concentrate mixture at 1% of live weight (LW) for a period of 72 days. With the increase of age, and subsequently LW (initial LW: 98.2, 182.6 and 288 kg, respectively), there was significant decrease in dry matter (DM) intake as % LW (<0.05; 2.94, 2.61 and 2.36, respectively) and increased daily gain (<0.01; 294, 519 and 597 g/d, respectively). However, the feed conversion ratio (FCR) (>0.05; 10.88, 10.10 and 12.24, respectively) and DM digestibility (>0.05; 51.0, 48.1 and 49.1 %, respectively) of bulls were remained unchanged. In case of carcass yield characteristics, significantly lower yield grade (<0.01; 1.79, 1.27 and 0.20, respectively) of bulls of 25 to 36 years produced higher closely trimmed boneless retail cuts (CTBRC) (<0.01; 50.47, 51.64 and 54.14 %, respectively), retail cut (<0.01; 76.14, 78.55 and 83.48 %, respectively) and meat quality index (MQI) (<0.01; 67.28, 67.89 and 69.07, respectively) compared to younger bulls. It may, therefore, be recommended that beef cattle farming with native Pabna bulls of 24 to 36 months will give more daily LW gain and produce more CTBRC at a similar FCR compared to younger ones.Bang. J. Anim. Sci. 2017. 46 (1): 17-23
Preservative effects of aqueous and ether extracts of Aframomum melegueta on West African soft cheese
Authors: Badmos AA , Imam AA , Annongu AA , Yusuff AT , Kayode RMO , Salami KO , Ahutu IA , Lawal AO
Published: April 2017

The Total Bacterial Count, proximate composition, and sensory evaluation of West African Soft Cheese supplemented with aqueous and ether extracts of the spice Aframomum melegueta (at 0%, 1%, 2% and 3% each) were determined with a completely randomized design.  Effects of the spice were monitored for 3 days. The results revealed that 3% concentration of the ether extract of the spice was the most inhibitory (p<0.05) of microbial growth for the duration of the experiment and it also significantly improved the fat, ash and protein contents of the cheese. The study recommended the addition of 3 % ether extract of  A. melegueta as an additive to fortify West African soft cheese.Bang. J. Anim. Sci. 2017. 46 (1): 51-56
Effects of Industrial Wastewater on the Yield and Trace Element Contents of Red amaranth
Authors: Sultana N , Nawshin N , Muktadir H , Chowdhury MAH , Baten MA
Published: April 2017

Assessment the effect of industrial wastewater on the yield and trace element contents of red amaranth was carried out by this study. Thirty wastewater samples were collected from five major environment-polluting industries namely pharmaceuticals, dyeing, leather, food, and plastic industries at three different locations. Atomic Absorption Spectrophotometer was used for analyzing the trace elements in the wastewater-irrigated samples of red amaranth. Higher mean concentrations of Pb, Cd, Ni, Cr, As, Zn, and Cu in red amaranth were 0.97, 0.20, 1.23, 52.72, 0.52, 0.85, and 2.62 ?g g-1. The percentage of yield reduction in red amaranth were 11.06, 12.73, 14.07, 3.46, 7.82 % for T2, T3, T4, T5 and T6 respectively compared to distilled water control (T1). The results concludes that the wastewater samples of pharmaceuticals, dyeing, leather and plastic industries were more polluted than the wastewater of food industries. Vegetables grown in industrial areas contain trace elements viz. Cr, Ni and Cu which would be health hazardous for consumer.J. Environ. Sci. & Natural Resources, 9(2): 27-30 2016
Impacts of Brick Fields on Environment and Social Economy at Bagatipara, Natore, Bangladesh
Authors: Jerin MF , Mondol SK , Sarker BC , Rimi RH , Aktar S
Published: April 2017

This study investigated environmental and socio-economic impacts of brick fields at Bagatipara upazila of Natore district, Bangladesh. A questionnaire survey was conducted at selected community members living at or near brick field areas with aim to assess impacts of brick fields on air, water, soil, vegetation as well as socio-economic conditions. Findings of this study were based on randomly selected respondents perception on change of any resource or condition. Crop loss, decreased soil fertility and subsequent reductions in crop production were reported. Trees around brickfields were dusted badly and water quality of nearby water bodies deteriorated because of emerged dust and ash from brick fields. Noticeable negative impacts on aquaculture were found. Except few, majority of the respondents were suffering from various diseases like eye irritation, skin diseases and respiratory problems. Despite creating work opportunities for local people, brick fields of the study area adversely affected environment and social economy.J. Environ. Sci. & Natural Resources, 9(2): 31-34 2016
Effect of Different Plucking Systems on Yield and Root Starch Reserve in Two Cultivars of Tea (Camellia sinensis L.)
Authors: Ahmed T , Costa WAJM De , Wijeratne MA
Published: April 2017

A study was carried out to monitor the effect of different plucking systems on root starch reserve and yield of tea in two cultivars (drought tolerant TRI2025 and moderately drought tolerant TRI2026). Depending on the severity of plucking, four plucking systems were used as treatments namely, mother-leaf plucking, fish-leaf plucking, janam-leaf plucking and estate practice. The cultivar TRI2026 showed significantly higher yield than the drought tolerant cultivar TRI2025. Estate practice produced greater yield in TRI2025 than the other treatments, while in TRI2026 the highest yield was found in fish-leaf plucking system. Although cultivars had no significant effect on root starch reserves, however significantly different found in treatments. About one year after commencing the experiment, for both cultivars higher root starch observed under mother-leaf plucking and the lowest was in janam-leaf plucking.J. Environ. Sci. & Natural Resources, 9(2): 91-95 2016
PM2.5 Characteristics in Qingdao and across Coastal Cities in China
Authors: Wu Ruidong , Zhou Xuehua , Wang Linpeng , Wang Zhe , Zhou Yang , Zhang Jingzhu , Wang Wenxing
Published: April 2017

A year-long study was performed to comprehensively investigate the mass concentration, water-soluble ions, organic and elemental carbons, and elemental components of atmospheric fine particles from March 2006 to February 2007 in Qingdao. The results showed that PM2.5 concentration was over twice the National Ambient Air Quality Standards of 35 μg/m3 (GB3095-2012), with the highest value in winter (110 μg/m3) and the lowest in summer (42.8 μg/m3). Non-sea salt-SO42− (nss-SO42−), NO3−, and NH4+ were the dominant water-soluble ions in PM2.5, and showed the highest concentrations in autumn, winter and autumn, respectively, and all had the lowest concentrations in summer. Organic carbon (OC) and elemental carbon (EC) had the lowest levels in summer and the highest values in winter and autumn, respectively. The lower acetic/formic acid (A/F) ratio in summer suggested a predominant secondary formation of water-soluble organic acids. Cl-depletion mainly occurred in summer, along with the largest sea salt proportion in particles in a year when winds came from the southeastern sea. The enrichment factors (EFs) of elements followed an increasing order: Si, Al, Ti, Mg, Ca, Fe, Na, Sr, K, Mn, Ba, V, Cr, Ni, Co, Sc, Cu, As, Cl, Zn, Pb, S, Br, Cd, and Se. The higher EFs from 10.1 to 10,487 for Sr, K, Mn, Ba, V, Cr, Ni, Co, Sc, Cu, Cl, Zn, Pb, S, Br, Cd, and Se suggested the significant influence of anthropogenic sources in the area. Mass closure showed that (NH4)2SO4, organic matter, and NH4NO3 were the main components, and contributed 31.0%, 25.2%, and 14.0% of PM2.5 mass in Qingdao, respectively. Source apportionment results showed that secondary sulfate, nitrate, and coal combustion were the main sources. Based on this study and previous publications, the PM2.5 characteristics—including seasonality in mass and chemical species concentrations and Cl-depletion in summer—were obtained across coastal cities in China.
Diversity of Amyloid Motifs in NLR Signaling in Fungi
Authors: Loquet Antoine , Saupe Sven
Published: April 2017

Amyloid folds not only represent the underlying cause of a large class of human diseases but also display a variety of functional roles both in prokaryote and eukaryote organisms. Among these roles is a recently-described activity in signal transduction cascades functioning in host defense and programmed cell death and involving Nod-like receptors (NLRs). In different fungal species, prion amyloid folds convey activation signals from a receptor protein to an effector domain by an amyloid templating and propagation mechanism. The discovery of these amyloid signaling motifs derives from the study of [Het-s], a fungal prion of the species Podospora anserina. These signaling pathways are typically composed of two basic components encoded by adjacent genes, the NLR receptor bearing an amyloid motif at the N-terminal end and a cell death execution protein with a HeLo pore-forming domain bearing a C-terminal amyloid motif. Activation of the NLR receptor allows for amyloid folding of the N-terminal amyloid motifs which then template trans-conformation of the homologous motif in the cell death execution protein. A variety of such motifs, which differ by their sequence signature, have been described in fungi. Among them, the PP-motif bears resemblance with the RHIM amyloid motif involved in the necroptosis pathway in mammals suggesting an evolutionary conservation of amyloid signaling from fungi to mammals.
The Androgen Receptor and VEGF: Mechanisms of Androgen-Regulated Angiogenesis in Prostate Cancer
Authors: Eisermann Kurtis , Fraizer Gail
Published: April 2017

Prostate cancer progression is controlled by the androgen receptor and new blood vessel formation, or angiogenesis, which promotes metastatic prostate cancer growth. Angiogenesis is induced by elevated expression of vascular endothelial growth factor (VEGF). VEGF is regulated by many factors in the tumor microenvironment including lowered oxygen levels and elevated androgens. Here we review evidence delineating hormone mediated mechanisms of VEGF regulation, including novel interactions between the androgen receptor (AR), epigenetic and zinc-finger transcription factors, AR variants and the hypoxia factor, HIF-1. The relevance of describing the impact of both hormones and hypoxia on VEGF expression and angiogenesis is revealed in recent reports of clinical therapies targeting both VEGF and AR signaling pathways. A better understanding of the complexities of VEGF expression could lead to improved targeting and increased survival time for a subset of patients with metastatic castration-resistant prostate cancer.
Characterization of MoVTeNbOx Catalysts during Oxidation Reactions Using In Situ/Operando Techniques: A Review
Authors: Lwin Soe , Diao Weijian , Baroi Chinmoy , Gaffney Anne , Fushimi Rebecca
Published: April 2017

Light alkanes are abundant in shale gas resources. The bulk mixed metal oxide MoVTe(Sb)NbOx catalysts play a very important role in dehydrogenation and selective oxidation reactions of these short hydrocarbons to produce high-value chemicals. This catalyst system mainly consists of M1 and less-active M2 crystalline phases. Due to their ability to directly monitor the catalysts under the relevant industrial conditions, in situ/operando techniques can provide information about the nature of active sites, surface intermediates, and kinetics/mechanisms, and may help with the synthesis of new and better catalysts. Sophisticated catalyst design and understanding is necessary to achieve the desired performance (activity, selectivity, lifetime, etc.) at reasonable reaction conditions (temperature, pressure, etc.). This article critically reviews the progress made in research of these MoVTe(Sb)NbOx catalysts in oxidation reactions mainly through in situ/operando techniques and suggests the future direction needed to realize the industrialization of these catalysts.
Unprecedented Multifunctionality of Grubbs and Hoveyda–Grubbs Catalysts: Competitive Isomerization, Hydrogenation, Silylation and Metathesis Occurring in Solution and on Solid Phase
Authors: Martinez-Amezaga Maitena , Delpiccolo Carina , Méndez Luciana , Dragutan Ileana , Dragutan Valerian , Mata Ernesto
Published: April 2017

This contribution showcases the interplay of several non-metathetic reactions (isomerization, silylation and “hydrogen-free” reduction) with metathesis in systems comprising a functionalized olefin and a soluble or resin-immobilized silane. These competing, one-pot reactions occur under activation by second-generation Ru-alkylidene catalysts. Different olefinic substrates were used to study the influence of the substitution pattern on the reaction outcome. Emphasis is placed upon the rarely reported yet important transformations implying a solid phase-supported silane reagent. Catalytic species involved in and reaction pathways accounting for these concurrent processes are evidenced. An unexpected result of this research was the clearly proved partial binding of the olefin to the resin, thereby removing it from the reacting ensemble.
Heisenberg and Entropic Uncertainty Measures for Large-Dimensional Harmonic Systems
Authors: Puertas-Centeno David , Toranzo Irene , Dehesa Jesús
Published: April 2017

The D-dimensional harmonic system (i.e., a particle moving under the action of a quadratic potential) is, together with the hydrogenic system, the main prototype of the physics of multidimensional quantum systems. In this work, we rigorously determine the leading term of the Heisenberg-like and entropy-like uncertainty measures of this system as given by the radial expectation values and the Rényi entropies, respectively, at the limit of large D. The associated multidimensional position-momentum uncertainty relations are discussed, showing that they saturate the corresponding general ones. A conjecture about the Shannon-like uncertainty relation is given, and an interesting phenomenon is observed: the Heisenberg-like and Rényi-entropy-based equality-type uncertainty relations for all of the D-dimensional harmonic oscillator states in the pseudoclassical ( D → ∞ ) limit are the same as the corresponding ones for the hydrogenic systems, despite the so different character of the oscillator and Coulomb potentials.
Dielectric Properties of Biomass/Biochar Mixtures at Microwave Frequencies
Authors: Ellison Candice , McKeown Murat , Trabelsi Samir , Boldor Dorin
Published: April 2017

Material dielectric properties are important for understanding their response to microwaves. Carbonaceous materials are considered good microwave absorbers and can be mixed with dry biomasses, which are otherwise low-loss materials, to improve the heating efficiency of biomass feedstocks. In this study, dielectric properties of pulverized biomass and biochar mixtures are presented from 0.5 GHz to 20 GHz at room temperature. An open-ended coaxial-line dielectric probe and vector network analyzer were used to measure dielectric constant and dielectric loss factor. Results show a quadratic increase of dielectric constant and dielectric loss with increasing biochar content. In measurements on biochar, a strong dielectric relaxation is observed at 8 GHz as indicated by a peak in dielectric loss factor at that frequency. Biochar is found to be a good microwave absorber and mixtures of biomass and biochar can be utilized to increase microwave heating rates for high temperature microwave processing of biomass feedstocks. These data can be utilized for design, scale-up and simulation of microwave heating processes of biomass, biochar, and their mixtures.
Evaluation Method for Real-Time Dynamic Line Ratings Based on Line Current Variation Model for Representing Forecast Error of Intermittent Renewable Generation
Authors: Sugihara Hideharu , Funaki Tsuyoshi , Yamaguchi Nobuyuki
Published: April 2017

Due the high penetration of intermittent renewable energy sources (IRESs), transmission line currents show large fluctuations and thus significant uncertainty. This makes it difficult to operate a power system without violating transmission capacity constraints. This paper evaluates the dynamic line ratings (DLRs) of overhead lines based on changes in the line current owing to the high penetration of intermittent renewable energy sources. In particular, by focusing on extremely large (but rare) forecasting errors in the intermittent renewable energy source output, which are generally inevitable in most forecasting methods, a model for representing the forecasting error in line with current variation due to intermittent renewable energy source output is developed. The model is based on a shape parameter that represents the equivalent current variation required for the same temperature increase as that due to the extremely large forecasting error. Finally, based on the annual minute-by-minute irradiance data, preventive control of the transmission network with dynamic line ratings is evaluated using worst-case parameter values.
Output Voltage Quality Evaluation of Stand-alone Four-Leg Inverters Using Linear and Non-Linear Controllers
Authors: Luís Ricardo , Silva José , Quadrado José
Published: April 2017

This paper presents the design and experimental voltage quality evaluation of controllers for the output voltages of 3-phase four-leg voltage source inverters. These inverters are needed in stand-alone power systems to supply linear and non-linear, balanced or unbalanced loads with constant RMS value voltages at fixed frequency. Comparisons include closed loop outer voltage controllers based on predictive, sliding mode and decoupled proportional-integral controllers in dqo synchronous space, fitted with an inner hysteretic current loop vector controller in α β γ space. The 3-phase four-leg VSI output voltages waveform quality is analysed under unbalanced and non-linear loads.
Hysteresis Analysis and Control of a Metal-Polymer Hybrid Soft Actuator
Authors: Schimmack Manuel , Feistauer Eduardo E. , Amancio-Filho Sergio T. , Mercorelli Paolo
Published: April 2017

The number of applications of stimulus-responsive polymers is growing at an impressive rate. The motivation of this contribution is to use a commercially available low-budget silver-coated polyamide (PA6) as a thermo-responsive metal-polymer hybrid soft actuator. Polyamide is a hygroscopic polymer; therefore, its mechanical and physical-chemical properties are affected by exposition to humidity or immersion in water. The effect of water absorption content on the PA6 and silver-coated PA6 monofilament properties, such as mass change and resistance, were evaluated. Moreover, the influence of swelling and shrinking effects on the surface morphology, caused by variations of moisture and water immersion, was investigated. Based on these variations, the dynamics of the resistance of the hybrid material were analyzed in the context of the proposed hysteresis model. An identification procedure of the hysteresis is presented along with an approximation of the upper and lower bound based on a constrained least square approach. A switching logic algorithm for this hybrid dynamic system is introduced, which makes it possible to structure the non-linear function in a switching mode. Finally, a non-linear integral sliding manifold is proposed and tested to control the resulting force of the actuator.hysteresis model. An identification procedure of the hysteresis is presented along with an approximation of the upper and lower bound based on a constrained least square approach. A switching logic algorithm for this hybrid dynamic system is introduced, which makes it possible to structure the non-linear function in a switching mode. Finally, a non-linear integral sliding manifold is proposed and tested to control the resulting force of the actuator.
Condition Assessment of Paper Insulation in Oil-Immersed Power Transformers Based on the Iterative Inversion of Resistivity
Authors: Ruan Jiangjun , Jin Shuo , Du Zhiye , Xie Yiming , Zhu Lin , Tian Yu , Gong Ruohan , Li Guannan , Xiong Min
Published: April 2017

The resistivity of oil impregnated paper will decrease during its aging process. This paper takes paper resistivity as an assessment index to evaluate the insulation condition of oil impregnated paper in power transformer. The feasibility of this method are discussed in two aspects: reliability and sensitivity. Iterative inversion of paper resistivity was combined with finite element simulation. Both the bisection method and Newton’s method were used as iterative methods. After the analysis and comparison, Newton’s method was selected as the first option of paper resistivity iteration for its faster convergence. In order to consider the spatial distribution characteristic of paper aging and enhance the calculation accuracy, the resistivity calculation is expanded to a multivariate iteration based on Newton’s method, in order to consider the spatial distribution characteristic of paper aging and improve the calculation accuracy. This paper presents an exploratory research on condition assessment of oil impregnated paper insulation, and provides some reference to the security and economy operation of power transformers.
Molecular Structure and Electronic Properties of Triolein Molecule under an External Electric Field Related to Streamer Initiation and Propagation
Authors: Wang Yachao , Wang Feipeng , Li Jian , Huang Zhengyong , Liang Suning , Zhou Jinghan
Published: April 2017

Natural ester has been widely studied as an alternative dielectric liquid to mineral oil in recent years. Unsaturated triacylglycerol molecules are the main components of natural ester; therefore, in this paper, we investigate the molecular structure and electronic properties of the triolein molecule, an oleic-type triacylglycerol molecule, as a representative component of natural ester oils. The effects of external electric fields at the electric field intensity related to streamer initiation and propagation on the bond lengths, dipole moment, total energy, infrared spectra, and orbital energy of the triolein molecule are investigated using density functional theory (DFT). In addition, the excitation energies, transition wavelengths, and oscillator strengths of the first eight excited states of the triolein molecule under external electric fields are calculated by time-dependent DFT. The results show that the bond lengths, dipole moments, total energy, and infrared spectra change obviously under external electric fields. With increasing external electric field intensity, the energy of the highest occupied molecular orbital increases, and the gap between that and the energy of the lowest unoccupied molecular orbital decreases, which make the molecule susceptible to excitation. The calculations contribute to an understanding of the causes behind the degradation of the insulation properties of natural ester oils.
Comparative Study of Breakdown Voltage of Mineral, Synthetic and Natural Oils and Based Mineral Oil Mixtures under AC and DC Voltages
Authors: Beroual Abderrahmane , Khaled Usama , Mbolo Noah Phanuel , Sitorus Henry
Published: April 2017

This paper deals with a comparative study of AC and DC breakdown voltages of based mineral oil mixtures with natural and synthetic esters mainly used in high voltage power transformers. The goal was to analyze the performances of oil mixtures from the dielectric withstand point of view and to predict the behavior of transformers originally filled with mineral oil and re-filled with synthetic or natural ester oils when emptied for maintenance. The study concerns mixtures based on 20%, 50%, and 80% of natural and synthetic ester oils. AC breakdown voltages were measured using a sphere-sphere electrode system according to IEC 60156 specifications; the same specification was adopted for DC measurements since there is no standard specifications for this voltage waveform. A statistical analysis of the mean values, standard deviations, and histograms of breakdown voltage data was carried out. The Normal and Weibull distribution functions were used to analyze the experimental data and the best function that the data followed was used to estimate the breakdown voltage with risk of 1%, 10%, and 50% probability. It was shown that whatever the applied voltage waveforms, ester oils always have a significantly higher breakdown voltage than mineral oil. The addition of only 20% of natural or synthetic ester oil was sufficient to considerably increase the breakdown voltage of mineral oil. The dielectric strength of such a mixture is much higher than that of mineral oil alone and can reach that of ester oils. From the point of view of dielectric strength, the mixtures constitute an option for improving the performance of mineral oil. Thus, re-filling of transformers containing up to 20% mineral oil residues with ester oils, does not present any problem; it is even advantageous when considering only the breakdown voltage. Under AC, the mixtures with natural ester always follow the behavior of vegetable oil alone. With the exception of the 20% mixture of natural ester in DC, the breakdown voltage values of all the tested mixtures were in accordance with the normal distribution, which made it possible to define the breakdown voltages for the risk levels of 1%, 10%, and 50% of probability.
Generalized Energy Flow Analysis Considering Electricity Gas and Heat Subsystems in Local-Area Energy Systems Integration
Authors: Shi Jiaqi , Wang Ling , Wang Yingrui , Zhang Jianhua
Published: April 2017

To alleviate environmental pollution and improve the efficient use of energy, energy systems integration (ESI)—covering electric power systems, heat systems and natural gas systems—has become an important trend in energy utilization. The traditional power flow calculation method, with the object as the power system, will prove difficult in meeting the requirements of the coupled energy flow analysis. This paper proposes a generalized energy flow (GEF) analysis method which is suitable for an ESI containing electricity, heat and gas subsystems. First, the models of electricity, heat, and natural gas networks in the ESI are established. In view of the complexity of the conventional method to solve the gas network including the compressor, an improved practical equivalent method was adopted based on different control modes. On this basis, a hybrid method combining homotopy and the Newton-Raphson algorithm was executed to compute the nonlinear equations of GEF, and the Jacobi matrix reflecting the coupling relationship of multi-energy was derived considering the grid connected mode and island modes of the power system in the ESI. Finally, the validity of the proposed method in multi-energy flow calculation and the analysis of interacting characteristics was verified using practical cases.
A Bi-Level Coordinated Optimization Strategy for Smart Appliances Considering Online Demand Response Potential
Authors: Ning Jia , Tang Yi , Chen Qian , Wang Jianming , Zhou Jianhua , Gao Bingtuan
Published: April 2017

Demand response (DR) is counted as an effective method when there is a large-capacity power shortage in the power system, which may lead to peak loads or a rapid ramp. This paper proposes a bi-level coordinated optimization strategy by quantitating the DR potential (DRP) of smart appliances to descend the steep ramp and balance the power energy. Based on dynamic characteristics of the smart appliances, the mathematic models of online DRP are presented. In the upper layer, a multi-agent coordinated distribution method is proposed to allocate the demand limit to each agent from the dispatching center considering the online DRP. In the lower layer, an optimal smart appliances-controlling strategy is presented to guarantee the total household power consumption of each agent below its demand limit considering the consumers’ comfort and response times. Simulation results indicate the feasibility of the proposed strategy.
Unsynchronized Phasor-Based Protection Method for Single Line-to-Ground Faults in an Ungrounded Offshore Wind Farm with Fully-Rated Converters-Based Wind Turbines
Authors: Jing Liuming , Son Dae-Hee , Kang Sang-Hee , Nam Soon-Ryul
Published: April 2017

This paper proposes a protection method for single line-to-ground (SLG) faults in an ungrounded offshore wind farm with fully-rated converter-based wind turbines. The proposed method uses the unsynchronized current phasors measured by unit protections installed at the connection point of the fully-rated converter (FRC)-based wind turbines (WTs). Each unit protection collects the unsynchronized current phasors from two adjacent nodes and synchronizes them by aligning the positive-sequence current to the same phase angle. The faulted section is identified by comparing the phase angles of the synchronized zero-sequence currents from adjacent nodes. Simulations of an ungrounded offshore wind farm with relay models were carried out using power system computer-aided design (PSCAD)/ electromagnetic transients including direct current (EMTDC).
IEC 61850 Configuration Solution to Distributed Intelligence in Distribution Grid Automation
Authors: Zhu Zhengyi , Xu Bingyin , Brunner Christoph , Yip Tony , Chen Yu
Published: April 2017

To solve the configuration issue when using International Electrotechnical Commission (IEC) 61850 for distributed intelligence in Distribution Automation Systems (DAS), this paper proposes the configuration solution in terms of semantic models and processing methods. Firstly, the special requirements of the DAS configuration are analyzed, consisting of the system boundary of a configuration project, the topology configuration for distributed applications, and the automatic identification of the Intelligent Electronic Devices (IED). The new models of Process, Line, and other elements are then presented based on the System Configuration Language (SCL) to describe the distribution network topology. The planned contents are allocated into a new format of the Configured IED Description (CID) file to realize the distributed applications. A register service is designed, which fulfills the automatic identification of IEDs when they are remotely placed into a DAS. The service checks the configuration status in real-time and automates the whole configuration engineering process. The case study shows that the proposed solution allows an IED to detect the real-time topology and re-establish the data flow configuration with peer IEDs independently from the master station; thus the distributed applications can be performed more autonomously and efficiently.
Design and Evaluation of an Efficient Three-Phase Four-Leg Voltage Source Inverter with Reduced IGBTs
Authors: Luo Yixiao , Liu Chunhua , Yu Feng , Lee Christopher H.T.
Published: April 2017

This paper presents a new three-phase four-leg voltage source inverter (VSI), which achieves a high cost effectiveness for mega-watt level system applications. The proposed four-leg inverter adopts the integrated topology with thyristors and insulated-gate bipolar transistors (IGBTs), which aims to reduce the number of IGBTs. In order to handle the zero sequence current, a neutral leg via incorporating IGBTs is artfully integrated with the regular phase legs. Furthermore, the modelling principles are elaborated and analyzed, which emphasizes switching states and voltage vectors in six segments based on the states of thyristors. Finally, by using the carrier-based pulse width modulation (PWM) method, the closed-loop current control of the proposed inverter is verified by both simulation and experimentation.
From Open Data to Open Analyses—New Opportunities for Environmental Applications?
Authors: Klein Thomas , Nilsson Mats , Persson Anders , Håkansson Bertil
Published: April 2017

In this study, we explore the potential of open and accessible data in combination with interactive cloud-processing capabilities for applications in environmental monitoring and policies. During the last few years, the amount of open Earth observation and open national data has increased substantially. In parallel, access to analysis capabilities for such data has improved. The search and extraction of data from larger Earth observations archives and the processing of larger amounts of data have hitherto been an obstacle for many potential users. With the availability of new cloud solutions such as Google Earth Engine, NASA Earth Exchange, or ESA Cloud Toolbox, accessing and processing of large datasets have become easier for a wider range of users. In this communication, we briefly summarize these recent trends and illustrate their potential by four application showcases from terrestrial and aquatic environmental monitoring. We accessed and processed data from US and European Earth observation satellite archives with Google Earth Engine. As a complement, we also used open Swedish national data and open source desktop tools. We hope that our positive user experiences can encourage other environmental data users to further explore the new opportunities for easy access to open data and cloud-based processing capabilities.
Effect of Auxins and Associated Metabolic Changes on Cuttings of Hybrid Aspen
Authors: Yan Shao , Yang Rui , Wang Fang , Sun Li , Song Xing
Published: April 2017

In the present study, an attempt was made to induce rooting from single-node cuttings of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) with different concentrations of Indole-3-acetic acid (IAA), Indole-3-Butytric acid (IBA) and 1-Naphthylacetic acid (NAA). Among the three auxins used, 0.54 mM NAA showed more effective induction on rooting as compared to IAA and IBA at the whole level. Thereafter, 0.54 mM NAA was used further for the anatomical and biochemical investigation. The results showed that it took 12 days from the differentiation of primordium to the appearance of young adventitious roots under NAA application. It was found that endogenous IAA, Zeatin riboside (ZR) and Gibberellic Acid (GA3) levels increased, but Abscisic acid (ABA) decreased in cuttings with NAA treatment. In contrast to the endogenous IAA level, NAA resulted in a decrease in IAA-oxidase (IAAO) activity. Similarly, the decreased peroxidase (POD) activity, consistent with down-regulation of expressed levels of POD1 and POD2, was observed in NAA-treated cuttings. Moreover, NAA resulted in a higher activity in polyphenol oxidase (PPO) compared with control cuttings. Collectively, the study highlighted that 0.54 mM NAA is efficient on rooting in hybrid aspen, and its effect on metabolic changes during rooting was discussed, which can provide valuable information for propagating hybrid aspen.
Microbial Production of Malic Acid from Biofuel-Related Coproducts and Biomass
Authors: West Thomas
Published: April 2017

The dicarboxylic acid malic acid synthesized as part of the tricarboxylic acid cycle can be produced in excess by certain microorganisms. Although malic acid is produced industrially to a lesser extent than citric acid, malic acid has industrial applications in foods and pharmaceuticals as an acidulant among other uses. Only recently has the production of this organic acid from coproducts of industrial bioprocessing been investigated. It has been shown that malic acid can be synthesized by microbes from coproducts generated during biofuel production. More specifically, malic acid has been shown to be synthesized by species of the fungus Aspergillus on thin stillage, a coproduct from corn-based ethanol production, and on crude glycerol, a coproduct from biodiesel production. In addition, the fungus Ustilago trichophora has also been shown to produce malic acid from crude glycerol. With respect to bacteria, a strain of the thermophilic actinobacterium Thermobifida fusca has been shown to produce malic acid from cellulose and treated lignocellulosic biomass. An alternate method of producing malic acid is to use agricultural biomass converted to syngas or biooil as a substrate for fungal bioconversion. Production of poly(β-l-malic acid) by strains of Aureobasidium pullulans from agricultural biomass has been reported where the polymalic acid is subsequently hydrolyzed to malic acid. This review examines applications of malic acid, metabolic pathways that synthesize malic acid and microbial malic acid production from biofuel-related coproducts, lignocellulosic biomass and poly(β-l-malic acid).