bluuebunny/crossref_metadata_2025 huggingface dataset:
Grape Seed Proanthocyanidin Extract Prevents Ovarian Aging by Inhibiting Oxidative Stress in the Hens
Authors: Liu Xingting , Lin Xin , Mi Yuling , Li Jian , Zhang Caiqiao
Published: January 2018

Oxidative stress is an important inducement in ovarian aging which results in fecundity decline in human and diverse animals. As a potent antioxidant, grape seed proanthocyanidin extract (GSPE) was investigated to ameliorate chicken ovarian aging in this study. Firstly, ovarian antioxidant capacity of hens at different ages (90, 150, 280, and 580 days old) was compared to elucidate its age‐related changes. Subsequently, a D‐gal‐induced (2.5 mg/mL) aging ovarian model was established and the cultured ovarian tissues were treated with GSPE at 5 μg/mL for 72 h to evaluate the putative attenuating effects of GSPE on ovarian aging. Meanwhile, ovaries of D280 (young) and D580 (old) were treated with GSPE for 72 h in culture to verify the protective effects of GSPE on natural aging ovary. The results showed that GSPE could rescue the antioxidant capacity decline by increasing the antioxidase activities and their gene expression in either D‐gal‐induced or natural aging ovaries. Moreover, GSPE could maintain the homeostasis between cell proliferation and apoptosis in the D‐gal‐induced and natural aging ovaries, as well as alleviate D‐gal‐induced nucleus chromatin condensation in the ovarian granulosa cells. In conclusion, GSPE treatment can effectively prevent the ovarian aging process in hens by reducing oxidative stress.
Improved Evaluation of Antivascular Cancer Therapy Using Constrained Tracer-Kinetic Modeling for Multiagent Dynamic Contrast-Enhanced MRI
Authors: Hectors Stefanie J. , Jacobs Igor , Lok Jasper , Peters Johannes , Bussink Johan , Hoeben Freek J. , Keizer Henk M. , Janssen Henk M. , Nicolay Klaas , Schabel Matthias C. , Strijkers Gustav J.
Published: January 2018

Dynamic contrast–enhanced MRI (DCE-MRI) is a promising technique for assessing the response of tumor vasculature to antivascular therapies. Multiagent DCE-MRI employs a combination of low and high molecular weight contrast agents, which potentially improves the accuracy of estimation of tumor hemodynamic and vascular permeability parameters. In this study, we used multiagent DCE-MRI to assess changes in tumor hemodynamics and vascular permeability after vascular-disrupting therapy. Multiagent DCE-MRI (sequential injection of G5 dendrimer, G2 dendrimer, and Gd-DOTA) was performed in tumor-bearing mice before, 2 and 24 hours after treatment with vascular disrupting agent DMXAA or placebo. Constrained DCE-MRI gamma capillary transit time modeling was used to estimate flow F, blood volume fraction vb, mean capillary transit time tc, bolus arrival time td, extracellular extravascular fraction ve, vascular heterogeneity index α−1 (all identical between agents) and extraction fraction E (reflective of permeability), and transfer constant Ktrans (both agent-specific) in perfused pixels. F, vb, and α−1 decreased at both time points after DMXAA, whereas tc increased. E (G2 and G5) showed an initial increase, after which, both parameters restored. Ktrans (G2 and Gd-DOTA) decreased at both time points after treatment. In the control, placebo-treated animals, only F, tc, and Ktrans Gd-DOTA showed significant changes. Histologic perfused tumor fraction was significantly lower in DMXAA-treated versus control animals. Our results show how multiagent tracer-kinetic modeling can accurately determine the effects of vascular-disrupting therapy by separating simultaneous changes in tumor hemodynamics and vascular permeability.

Significance: These findings describe a new approach to measure separately the effects of antivascular therapy on tumor hemodynamics and vascular permeability, which could help more rapidly and accurately assess the efficacy of experimental therapy of this class. Cancer Res; 78(6); 1561–70. ©2018 AACR.
Visual Outcomes Based on Early Response to Anti-Vascular Endothelial Growth Factor Treatment for Diabetic Macular Edema
Authors: Koyanagi Yoshito , Yoshida Shigeo , Kobayashi Yoshiyuki , Kubo Yuki , Nakama Takahito , Ishikawa Keijiro , Nakao Shintaro , Hisatomi Toshio , Ikeda Yasuhiro , Oshima Yuji , Ishibashi Tatsuro , Sonoda Koh-hei
Published: January 2018

Objective: To examine the relationship between early response to anti-vascular endothelial growth factor (VEGF) treatment and visual prognosis. Methods: We retrospectively separated 20 patients with persistent diabetic macular edema (DME) into two responder status groups based on the reduction of central macular thickness (CMT) from baseline to month 3: a delayed responder group (DRG) (≤25% CMT reduction, n = 11) and an immediate responder group (IRG) (>25% CMT reduction, n = 14). We also separated the patients into two responder status groups based on the logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA): a visual nonimprovement group (VNIG) (≥0 logMAR BCVA improvement, n = 11) and a vi sual improvement group (VIG) (<0 logMAR BCVA improvement, n = 14). Finally, we assessed the correlations between logMAR BCVA changes from baseline to month 3 (ΔBCVAM3) and those from baseline to month 12 (ΔBCVAM12). Results: At month 12, BCVA was significantly more improved in the VIG than the VNIG (p < 0.005), but was not significantly different between the DRG and the IRG (p = 0.75). The Pearson correlation coefficient showed a significant relationship between ΔBCVAM3 and ΔBCVAM12 (r = 0.60, p < 0.005). Conclusions: BCVA showed significantly greater improvement in the VIG than in the VNIG. ΔBCVAM3 may predict the visual outcome at month 12 in DME patients treated with anti-VEGF drugs.
Transbronchial Cryobiopsies for the Diagnosis of Diffuse Parenchymal Lung Diseases: Expert Statement from the Cryobiopsy Working Group on Safety and Utility and a Call for Standardization of the Procedure
Authors: Hetzel Jürgen , Maldonado Fabien , Ravaglia Claudia , Wells Athol U. , Colby Thomas V. , Tomassetti Sara , Ryu Jay H. , Fruchter Oren , Piciucchi Sara , Dubini Alessandra , Cavazza Alberto , Chilosi Marco , Sverzellati Nicola , Valeyre Dominique , Leduc Dimitri , Walsh Simon L.F. , Gasparini Stefano , Hetzel Martin , Hagmeyer Lars , Haentschel Maik , Eberhardt Ralf , Darwiche Kaid , Yarmus Lonny B. , Torrego Alfonso , Krishna Ganesh , Shah Pallav L. , Annema Jouke T. , Herth Felix J.F. , Poletti Venerino
Published: January 2018

Transbronchial cryobiopsies (TBCB) have recently been introduced as a promising and safer alternative to surgical lung biopsy in the diagnostic approach to diffuse parenchymal lung diseases (DPLD). Despite a substantial and expanding body of literature, the technique has not yet been standardized and its place in the diagnostic algorithm of DPLD remains to be defined. In part, this reflects concerns over the diagnostic yield and safety of the procedure, together with the rapid spread of the technique without competency and safety standards; furthermore, there is a substantial procedural variability among centers and interventional pulmonologists. We report this expert statement proposed during the third international conference on “Transbronchial Cryobiopsy in Diffuse Parenchymal Lung Disease” (Ravenna, October 27–28, 2016), which formulates evidence- and expert-based suggestions on the indications, contraindications, patient selection, and procedural aspects of the procedure. The following 5 domains were reviewed: (1) what is the role of TBCB in the diagnostic evaluation of DPLD: patient selection; (2) pathological considerations; (3) contraindications and safety considerations; (4) how should TBCB be performed and in what procedural environment; and (5) who should perform TBCB. Finally, the existence of white paper recommendations may also reassure local hospital credentialing committees tasked with endorsing an adoption of the technique.
Skin Infections due to Bacteria in Solid Organ Transplant Recipients: A Review
Authors: Ilyas Muneeb , Maganty Nishita , Ginsberg Zachary , Sharma Amit
Published: January 2018

Though there is an abundance of information on cutaneous malignancies in transplant recipients, cutaneous infections in solid organ transplant recipients (SOTRs) are underrepresented in the dermatological literature. Our paper provides a comprehensive review of bacterial cutaneous infections within the solid organ transplant population. Cutaneous bacterial infections may lead to significant morbidity and even mortality in this immunosuppressed population. Thus, it is to the benefit of both dermatologists and other transplant care providers to better understand and recognize the features of cutaneous bacterial infections in SOTRs. This paper can aid providers in promptly identifying, diagnosing, and treating bacterial skin infections. This review discusses the diagnosis and treatment of the following bacterial species: Staphylococcus, Streptococcus, Pseudomonas aeruginosa, Escherichia coli, Nocardia, Mycobacteria, and Bartonella henselae.
Double Anterior Stereotactic Cingulotomy for Intractable Oncological Pain
Authors: Strauss Ido , Berger Assaf , Ben Moshe Shlomit , Arad Michal , Hochberg Uri , Gonen Tal , Tellem Rotem
Published: January 2018

Background: Stereotactic anterior cingulotomy has been used in the treatment of patients suffering from refractory oncological pain due to its effects on pain perception. However, the optimal targets as well as suitable candidates and outcome measures have not been well defined. We report our initial experience in the ablation of 2 cingulotomy targets on each side and the use of the Brief Pain Inventory (BPI) as a perioperative assessment tool. Methods: A retrospective review of all patients who underwent stereotactic anterior cingulotomy in our Department between November 2015 and February 2017 was performed. All patients had advanced metastatic cancer with limited prognosis and suffered from intractable oncological pain. Results: Thirteen patients (10 women and 3 men) underwent 14 cingulotomy procedures. Their mean age was 54 ± 14 years. All patients reported substantial pain relief immediately after the operation. Out of the 6 preoperatively bedridden patients, 3 started ambulating shortly after. At the 1-month follow-up, the mean preoperative Visual Analogue Scale score decreased from 9 ± 0.9 to 4 ± 2.7 (p = 0.003). Mean BPI pain severity and interference scores decreased from levels of 29 ± 4 and 55 ± 12 to 16 ± 12 (p = 0.028) and 37 ± 15 (p = 0.043), respectively. During the 1- and 3-month follow-up visits, 9/11 patients (82%) and 5/7 patients (71%) available for follow-up reported substantial pain relief. No patient reported worsening of pain during the study period. Neuropsychological analyses of 6 patients showed stable cognitive functions with a mild nonsignificant decline in focused attention and executive functions. Adverse events included transient confusion or mild apathy in 5 patients (38%) lasting 1-4 weeks. Conclusions: Our initial experience indicates that double stereotactic cingulotomy is safe and effective in alleviating refractory oncological pain.
Survival of Viruses in Water
Authors: Pinon Anthony , Vialette Michèle
Published: January 2018

Water, a frequent vehicle for the transmission of viruses, may permit their survival, but many environmental factors will have an adverse effect on the viral population. Risk evaluation requires identification of these factors and assessment of the inactivation rate of infectious viruses. A higher temperature means a faster reduction of the viral population, as do increased sunlight, higher antimicrobial concentration, or higher oxygen levels. Another documented impact is linked to the presence of indigenous microbial populations: virus survival is higher in sterile water. Environmental factors inactivate viruses through direct or indirect action on one part of the viral structure: genome, capsid, or envelope if present. Viral populations also have resistance mechanisms, generally involving physical shielding from adverse effects; such protective behaviors include aggregation, adhesion, or internalization inside living structures. Because of these phenomena, inactivation kinetics may deviate from traditional log-linear shapes. It is therefore important to account for all factors that may impact on survival, to carefully design experiments to ensure sufficient data, and to select the right modelling approach. Comparison between studies is difficult. It is suggested that laboratory studies include standard conditions of water, and analyze the impact of different factors as precisely as possible. Larger studies in natural environments, though more difficult, are also much needed.
Modern Invasive Hemodynamic Assessment of Pulmonary Hypertension
Authors: Pagnamenta Alberto , Lador Frédéric , Azzola Andrea , Beghetti Maurice
Published: January 2018

Since 1998 pulmonary hypertension has been clinically classified into five well-defined, distinct categories. A definitive diagnosis of pulmonary hypertension requires the invasive confirmation of an elevated mean pulmonary artery pressure of 25 mm Hg or above during a right heart catheterization. From a hemodynamic point of view, pulmonary hypertension is classified into precapillary and postcapillary pulmonary hypertension on the basis of a pulmonary artery wedge pressure threshold value of 15 mm Hg. Pulmonary vascular resistance is better characterized by multi-point pressure/flow measurements than by single-point determination. Multi-point pulmonary vascular resistance calculation could be useful for early disease identification as well as for treatment response assessment. Occlusion analysis of the pulmonary artery pressure decay curve after balloon inflation at the tip of the pulmonary artery catheter permits locating the site of predominantly increased resistance and could be useful in differentiating proximal from distal vasculopathy, especially in chronic thromboembolic pulmonary hypertension. The pulsatile hydraulic load of the pulmonary circulation can be better appreciated by pulmonary vascular impedance or via the resistance-compliance relationship than by means of pulmonary vascular resistance. Determination of right ventriculo-arterial coupling permits assessing the impact of an elevated afterload on right ventricular function, which ultimately determines the symptoms and prognosis of patients with pulmonary hypertension. The clinical utility of combining different invasive hemodynamic approaches is still uncertain and remains to be determined.
Inertial Sensor Technology Can Capture Changes in Dynamic Balance Control during the Y Balance Test
Authors: Johnston William , O’Reilly Martin  , Coughlan Garrett F. , Caulfield Brian
Published: January 2018

Introduction: The Y Balance Test (YBT) is one of the most commonly utilised clinical dynamic balance assessments. Research has demonstrated the utility of the YBT in identifying balance deficits in individuals following lower limb injury. However, quantifying dynamic balance based on reach distances alone fails to provide potentially important information related to the quality of movement control and choice of movement strategy during the reaching action. The addition of an inertial sensor to capture more detailed motion data may allow for the inexpensive, accessible quantification of dynamic balance control during the YBT reach excursions. As such, the aim of this study was to compare baseline and fatigued dynamic balance control, using reach distances and 95EV (95% ellipsoid volume), and evaluate the ability of 95EV to capture alterations in dynamic balance control, which are not detected by YBT reach distances. Methods: As part of this descriptive laboratory study, 15 healthy participants completed repeated YBTs at 20, 10, and 0 min prior to and following a modified 60-s Wingate test that was used to introduce a short-term reduction in dynamic balance capability. Dynamic balance was assessed using the standard normalised reach distance method, while dynamic balance control during the reach attempts was simultaneously measured by means of the 95EV derived from an inertial sensor, worn at the level of the 4th lumbar vertebra. Results: Intraclass correlation coefficients for the inertial sensor-derived measures ranged from 0.76 to 0.92, demonstrating strong intrasession test-retest reliability. Statistically significant alterations (p < 0.05) in both reach distance and the inertial sensor-derived 95EV measure were observed immediately post-fatigue. However, reach distance deficits returned to baseline levels within 10 min, while 95EV remained significantly increased (p < 0.05) beyond 20 min for all 3 reach distances. Conclusion: These findings demonstrate the ability of an inertial sensor-derived measure to quantify alterations in dynamic balance control, which are not captured by traditional reach distances alone. This suggests that the addition of an inertial sensor to the YBT may provide clinicians and researchers with an accessible means to capture subtle alterations in motor function in the clinical setting.
Decreased IFIT2 Expression Promotes Gastric Cancer Progression and Predicts Poor Prognosis of the Patients
Authors: Chen Lujun , Zhai Wensi , Zheng Xiao , Xie Quanqin , Zhou Qi , Tao Min , Zhu Yibei , Wu Changping , Jiang Jingting
Published: January 2018

Background/Aims: The status of interferon (IFN) signaling pathway has been shown to be closely associated with the response of immune checkpoint blockade therapy against advanced human cancers. IFN-induced protein with tetratricopeptide repeats 2 (IFIT2), also known as IFN-stimulated gene 54 (ISG54), is one of the most highly responsive ISGs, which can inhibit the proliferation and migration of cancer cells, and regulate viral replication, resulting in anti-cancer and anti-viral effects. In the present study, we aimed to investigate the role of IFIT2 in human gastric cancer. Methods: Immunohistochemistry assay was used to investigate the correlation between the IFIT2 expression in cancer tissues and clinical parameters of gastric cancer patients. Knockdown of IFIT2 was performed using RNAi to assess the role of IFIT2 in the regulation of biological behaviors in human gastric cancer cell lines. Results: IFIT2 expression in gastric cancer tissues was significantly associated with tumor stage and postoperative prognoses of the patients. Moreover, decreased IFIT2 expression in human gastric cancer cell lines SGC-7901 and AGS significantly increased the cell viability, cell migration and the ratios of cells in S phase. Conclusion: Our present study demonstrated that the decreased IFIT2 expression could promote the gastric cancer progression and predict poor therapeutic outcomes of the patients.
Oocyte Cytoplasmic Gas6 and Heparan Sulfate (HS) are Required to Establish the Open Chromatin State in Nuclei During Remodeling and Reprogramming
Authors: Kim Kyeoung-Hwa , Kim Eun-Young , Lee Su-Yeon , Ko Jung-Jae , Lee Kyung-Ah
Published: January 2018

Background/Aims: Previously, we found that silencing of growth arrest-specific gene 6 (Gas6) in oocytes impaired cytoplasmic maturation, resulting in failure of sperm chromatin decondensation (SCD) and pronuclear (PN) formation after fertilization. Thus, we conducted this study to determine the effect of Gas6 RNAi on downstream genes and to elucidate the working mechanism of Gas6 on oocyte cytoplasmic maturation and SCD. Methods: Using RT-PCR, Western blot and immunofluorescence, the expression levels of various target genes and the localization of heparan sulfate (HS) were analyzed after Gas6 RNAi. The roles of Gas6 in HS biosynthesis, production of ATP and GSH, ROS generation and ΔΨm were also investigated. SCD and micrococcal nuclease (MNase) analyses were used to examine the effects of HS on the open chromatin state in sperm and somatic cell nuclei, respectively. Results: Disruption of Gas6 expression led to the inhibition of HS biosynthesis through the reduction of several HS biosynthetic enzymes. The rescue experiment, HS treatment in vitro, significantly recovered SCD and PN formation, confirming that HS had the ability to induce sperm head remodeling during fertilization. Interestingly, excessive mitochondrial activation in Gas6-depleted MII oocytes caused ROS generation and glutathione (GSH) degradation via mitochondrial activation, such as elevated ΔΨm and ATP production. Indeed, HS-treated NIH3T3 cell nuclei showed an open chromatin state, as determined by diffuse DAPI staining and increased sensitivity to MNase. Conclusion: We propose that the addition of HS to sperm and/or oocyte maturation would improve the efficiency of in vitro fertilization and somatic cell nuclear transfer (SCNT) reprogramming.
Enlarged Basal Ganglia Perivascular Spaces are Associated with Pulsatile Components of Blood Pressure
Authors: Del Brutto Oscar H. , Mera Robertino M. ,   for the Atahualpa Project Investigators
Published: January 2018

Background/Aims: Pathogenetic mechanisms involved in enlargement of basal ganglia perivascular spaces (BG-PVSs) are controversial. Here, we assessed whether pulsatile or steady components of blood pressure (BP) are associated with enlarged BG-PVS. Methods: We evaluated the association between BG-PVS and pulsatile and steady components of BP in Atahualpa residents aged ≥60 years, by the use of regression models and receiver operator characteristics (ROC) curve analysis, after taking into account the effect of demographics, cardiovascular risk factors, and other signatures of cerebral small vessel disease (SVD). Results: Of 437 candidates, 363 (83%) were included. MRI showed >10 enlarged BG-PVS in 103 (28%) subjects. In univariate analysis, the association between enlarged BG-PVS and systolic pressure (SP) and pulse pressure (PP) were highly significant, while the association with diastolic pressure (DP) was not. ROC curve analysis showed a higher area under the curve for PP than for DP (p < 0.05). The area under the curve for SP was also higher than that of DP, but not significantly better due to overlapping 95% CI. Conclusion: Enlarged BG-PVS are associated with pulsatile components of BP, although some of the effect is taken away by the strong interaction between BG-PVS and other signatures of SVD.
A New Approach for Classification of Fault in Transmission Line with Combination of Wavelet Multi Resolution Analysis and Neural Networks
Authors: Srinivasa Rao Y , Kumar G. Ravi , Kesava Rao G.
Published: January 2018

An appropriate fault detection and classification of power system transmission line using discrete wavelet transform and artificial neural networks is performed in this paper. The analysis is carried out by applying discrete wavelet transform for obtained fault phase currents. The work represented in this paper are mainly concentrated on classification of fault and this classification is done based on the obtained energy values after applying discrete wavelet transform by taking this values as an input for the neural network. The proposed system and analysis is carried out in Matlab Simulink.
Modified Look-Up Table for Enhancement of Torque Response in Direct Torque Controlled Induction Machine
Authors: Wee Yen Goh , Nik Idris Nik Rumzi , Jidin Auzani , Sutikno Tole
Published: January 2018

Basically, the direct torque control (DTC) drive system is operated at light load. At light load, supplying the drive system with rated flux will decrease the efficiency of the system. To maximize the efficiency of drive system, an optimal flux has been applied during steady-state but when a torque is suddenly needed, for example during acceleration, the dynamic of the torque response would be degraded. Therefore, a modification to the voltage vector as well as look-up table has been proposed for the torque response improvement. The proposed voltage vector is generated by adding two adjacent conventional voltage vectors and implemented by using duty ratio. The duty ratio is used to estimate the activation time of each conventional voltage vector in order to produce the proposed voltage vector.
Three-Phase Three-Level Soft Switching Dc-Dc Converter for Industrial Applications
Authors: Prasad J. Sivavara , Obulesh Y.P. , Sai Babu Ch.
Published: January 2018

In high power DC applications, the single-phase DC-DC converter will face large voltage and current stress in each control switch and thereby the power handling capacity is less. To overcome this problem, three-phase DC-DC converter is used and it is suitable for high power applications with reduced number of switches as compared with the conventional topologies. The asymmetrical duty cycle control is considered to operate the switches under soft switching and hence the switching losses are reduced. The transformer leakage inductances are used along with junction capacitances in order to form resonance and hence ZVS commutation is possible in a wider load range. The modified phase shift control method is used for the proposed converter.The operational modes and design equations of the proposed converter have been observed. The simulation is carried out with a load of 1000W for validating the proposed work.
Topological Comparison of Dual-Input DC-DC Converters
Authors: Lavanya A. , Kumar K. Vijaya , Navamani J. Divya
Published: January 2018

Dual input dc-dc converters have two input voltage sources  or one input source and an energy storage system like ultra capacitor, PV, battery, super capacitors and a single output load. In order to process the power in hybrid energy systems using reduced part count, researchers have proposed several multi-input dc-dc power converter topologies to transfer power from different input voltage sources to the output. This paper compares non-isolated dual-input converter topologies topologically ,based on the components count, various fields of application and  different modes of operation for hybrid systems mainly used in electric vehicles  and renewable energy systems composed of energy storage systems (ESSs) with different voltage-current characteristics. Dual input dc-dc converter topologies considered in this paper are investigated using MATLAB and PSIM software and output voltage and inductor current waveforms are shown.
Carrier Shifting Algorithms for the Mitigation of Circulating Current in Diode Clamped MLI fed Induction Motor Drive
Authors: Santhakumar C. , Shivakumar R. , Bharatiraja C. , Sanjeevikumar P.
Published: January 2018

Reduction of circulating current is one of the major considerations in inverter fed electrical drives. Diode clamped MLI enables higher output current per phase, thereby rating of the drive gets increased effectively. Various methods of triggering in the inverter legs creates better voltage profile and leads to the enabling of circulating current in the drive system.  The induced circulating current flows through the apparatus neutral (N) and supply ground (G) is caused by the existence of parasitic capacitance. This circulating current may cause potential danger especially when parasitic capacitance poses large. In the past, different modulation techniques and conversion topologies have been introduced to minimize the flow of circulating current. However, these techniques lead to complexity, high cost, low voltage profile and efficiency due to lower modulation parameters. This paper proposes PS, POD, PD carrier shifting PWM algorithms for diode clamped MLI to tumbling the circulating current within the each phase of inverter legs. The performances of proposed algorithm, in terms of circulating current, THD, losses and efficiencies are analyzed theoreticallyand are validated via simulation and experimental results.
Efficient Approach to LVRT Capability of DFIG-Based Wind Turbines under Symmetrical and Asymmetrical Voltage Dips Using Dynamic Voltage Restorer
Authors: Azizi Kiarash , Farsadi Murtaza , Farhadi Kangarlu Mohammad
Published: January 2018

The capability of low-voltage ride-through (LVRT) of doubly fed induction generator (DFIG) has been considered as an essence for grid code requirements. Any unbalance on the grid side causes the rotor current of the generator to rise which leads to saturate the dc-link of the back-to-back converter or even destroy it. To meet this requirement, a dynamic voltage restorer (DVR) without dc-link energy storage elements is utilized to compensate any disturbance imposed to the DFIG wind turbine system. On the time of any disturbance or fault, DFIG and DVR are properly controlled in order to compensate the specified faulty phase uninterruptedly. DVR is connected in series to the grid and by injecting instantaneous compensating voltage, prevents the stator voltage from rapid changing; consequently, the rotor side converter can accomplish its normal operation. As voltage dips are the most common grid faults subjected to DFIGs, this paper investigates both symmetrical and asymmetrical voltage dips caused by grid faults. The independent and instantaneous phase voltage compensation, less volume, weight, and cost are the merits to utilize the proposed DVR along with DFIG wind turbines. PSCAD/EMTDC based simulations verifies the capabilities of the proposed technique for the LVRT capability of DFIG.
Vibration Analysis of Tapered Pole Linear Switched Reluctance Machine
Authors: N C Lenin , S V Arvind
Published: January 2018

The Vibration is one of the major problem in linear switched reluctance motors (LSRMs). This paper present a detailed analysis of vibration in a two phase LSRM and proposes a new structure to reduce the effect. The experimental results of this paper prove that the proposed structure is well suited for conveyor application.
Effect of PWM Duty Cycle and Frequency of Power Supply to the LED Bulb Efficacy
Authors: Pawawoi Andi , Prabowo Wahyu
Published: January 2018

In this paper described the effect of frequency and duty cycle of the PWM power supply LED bulb light efficacy. Efficacy LED bulb is measured by measuring the light flux and power consumed at standard conditions, the bulb is supplied directly from the network. Then efficacy, the luminous flux and power the bulb is also measured under the conditions given PWM power supply at some frequency and duty cycle value. In the same light flux levels between the two treatment, the use of PWM power supply can increase the efficacy of the light bulb up to 66.2%, with a value of 117.52 light efficacy lumen / Watt. At the level of light flux which is slightly lower, the use of PWM power supply to the LED bulb with a specific frequency and power supply can achieve the efficacy of 397.14 lumens / Watt
Harmonic Elimination Using STATCOM for SEIG Fed Induction Motor Load
Authors: Gorantla Satyanarayana , Ravi Kumar Goli
Published: January 2018

Non-linear loads connected to distribution system induce harmonics in to source components and the presence of harmonics in source components affects the performance of other sensitive loads connected at the same point. Induction motor load for drive system should be operated with variable frequency and variable voltage for its speed control. To vary the voltage and frequency, induction motor is fed from an inverter. This total drive set-up constitutes non-linear load type and will be the source of harmonics. This paper depicts the suppression of harmonics with STATCOM in distribution system when induction motor load is fed from SEIG (singly excited inductin generator). STATCOM is controlled with simple synchronous reference frame theory and the results are shown for source current, load current. THD in source current and load current was also shown for the said system. System for single-phase and three-phase induction motor drive was developed and results are shown using MATLAB/SIMULINK software.
A Simplified Space Vector Pulse Width Modulation Method Including Over Modulation Operation for Five Level Cascaded H-bridge Inverter with FPGA Implementation
Authors: Sirisha Bogimi , Kumar P. Satish
Published: January 2018

This paper presents simplified control strategy of Space Vector Pulse Width Modulation method  including over modulation region  with linear transfer characteristic for cascaded H-bridge inverters. Because of large number of switching states of the cascaded H- Bridge inverter, the over modulation operation is very complex. And also requires incorporation of  both under modulation and over modulation algorithms. The proposed control method is effective in terms of selecting the optimal switching states with reduced computational complexity using simplified linear calculations which makes it easier for digital implementation. The performance of the proposed method  is simulated and tested experimentally through Spartan 3A FPGA processor for five level Cascaded H-bridge Inverter. The simulation results and harmonic analysis of voltage and current at various modulation indexes as are presented which are in well agreement.
Pulse Width Modulation Based Decentralized Street LED Light Dimming System
Authors: Attia Hussain , Omar Amjad , Takruri Maen , Ali Halah Y.
Published: January 2018

The high power consumption of conventional street lighting systems, and the consequences on environmental ecosystem due to continuous turning ON of light, have led researchers to seek solutions to this problem. LED light dimming system has been presented in many studies using computerized systems with or without wireless monitoring facility. The demerits of these systems include complexity, high cost and unfixed data transfer speed. This paper proposes to reduce power consumption of street lighting through a decentralized light dimming system that is based on Pulse Width Modulation (PWM). This is in addition to replacing conventional high power lamps with lower power LED lamps. The dimming control circuit of this system is fixed on each pole and controlled individually resulting in faster and more reliable response. The proposed system uses the available infrastructure and is suitable for small or main streets regardless of the number of light poles. It is also flexible in its coverage distance due to the freedom of motion detector selection. The advantages of using LED lighting on the environment as compared to conventional lighting are explained. Simulations reveal the effectiveness of the proposed system on energy saving and on the environment.
A Simplified PWM Technique for Isolated DC-DC Converter Fed Switched Capacitor Multi-Level Inverter for Distributed Generation
Authors: BM Mmanjunath , D V Ashok Kumar , M Vijaya Kumar
Published: January 2018

This paper presents a novel simplied PWM technique to drive switched capacitor type multi-level inverter fed from isolated type DC-DC converter for distributed generation. Distributed generation (DG) is renowned power generation at point of utility with no environmental aects and reduces transmission line losses. Photo-voltaic system is considered as renewable energy source for DG and the low voltage from PV system is boosted to required voltage using an isolated type single-input multi-output (SIMO) DC-DC converter. DC output from isolated SIMO DC-DC converter is fed to switched capacitor type multi-level inverter (SC-MLI) to feed the AC load. Isolated SIMO DC-DC converter apart from boosting the DG output voltage, also eliminates the problem of voltage unbalancing in SC-MLI topology. Closed loop operation of SIMO DC-DC converter employs only single PI controller instead of three controllers was presented in this paper. Modes of operation of SC-MLI and Novel PWM switching pattern was explained. Simulation of proposed system was developed using MATLAB/SIMULINK software. The prototype was developed for the proposed system and hardware results are also shown.
Design and Analysis of Capacitive Power Transfer System with and without the Impedance Matching Circuit
Authors: Rahman F.K.A. , Saat Shakir , Yusop Yusmarnita , Husin Huzaimah , Aziz Y.
Published: January 2018

This paper presents the design and analysis of a relatively new wireless power transfer technique using capacitive coupling, named Capacitive power transfer (CPT). In general, CPT system has been introduced as an attractive alternative to the former inductive coupling method. This is because CPT uses lesser number of components, simpler topology, enhanced EMI performance and better strength to surrounding metallic elements. In this work, aluminium sheet is used as a capacitive coupling at transmitter and receiver side. Moreover, a Class-E resonant inverter together with π1a impedance matching network has been proposed because of its ability to perform the dc-to-ac inversion well. It helps the CPT system to achieve maximum power transfer. The CPT system is designed and simulated by using MATLAB/Simulink software. The validity of the proposed concept is then verified by conducting a laboratory experimental of CPT system. The proposed system able to generate a 9.5W output power through a combined interface capacitance of 2.44nF, at an operating frequency of 1MHz, with 95.10% efficiency. The proposed CPT system with impedance matching network also allows load variation in the range of 20% from its nominal value while maintaining the efficiency over 90%.
Wind-PV Hybrid Energy Source Fed Three Level NPC with Quasi Z Source Network
Authors: R Palanisamy , K Vijayakumar
Published: January 2018

Multilevel inverters find use in industrial drive applications and grid based power generation. Owing to the increasing power demand and rising conventional generation costs a new alternative in renewable energy source is gaining popularity and acceptance. A Wind-PV hybrid renewable energy source is proposed which increases power reliability and improves standalone generation efficiency. A Quasi Z source network allows inverter shoot through possibility while boosting the dc voltage fed to the Neutral Point Clamped MLI. Simulation results were obtained for two levels VSI and further simulations for 3 level quasi NPC-TLI verified using Matlab Simulink and hardware implementation results verified by using DSP controller
High Performance Maximum Power Point Tracking on Wind Energy Conversion System
Authors: Hendrawati Dwiana , Soeprijanto Adi , Ashari Mochamad
Published: January 2018

This paper presents the maximum power point tracking (MPPT) to extract the power of wind energy conversion system (WECS) using the Firefly Algorithm (FA) algorithm. This paper aims to present the FA as one of the accurate algorithms in MPPT techniques. Recently, researchers tend to apply the MPPT digital technique with the P n O algorithm to track MPP. On the other hand, this Paper implements the FA included in the digital classification to improve the performance of the MPPT technique. Therefore, the FA tracking results are verified with P n O to show the accuracy of the MPPT algorithm. The results obtained show that performance is higher when using the FA algorithm
Differential Evolution Algorithm with Triangular Adaptive Control Parameter for SHEPWM Switching Pattern Optimization
Authors: Yusuf Ismail , Hiendro Ayong , Pontia Wigyarianto F. Trias , Khwee Kho Hie
Published: January 2018

Differential evolution (DE) algorithm has been applied as a powerful tool to find optimum switching angles for selective harmonic elimination pulse width modulation (SHEPWM) inverters. However, the DE’s performace is very dependent on its control parameters. Conventional DE generally uses either trial and error mechanism or tuning technique to determine appropriate values of the control paramaters. The disadvantage of this process is that it is very time comsuming. In this paper, an adaptive control parameter is proposed in order to speed up the DE algorithm in optimizing SHEPWM switching angles precisely. The proposed adaptive control parameter is proven to enhance the convergence process of the DE algorithm without requiring initial guesses. The results for both negative and positive modulation index (M) also indicate that the proposed adaptive DE is superior to the conventional DE in generating SHEPWM switching patterns
Hysteresis Control 3-Level SI-NPC Inverter with Wind Energy System
Authors: Selvakumar K. , Palanisamy R. , Vijayakumar K , Karthikeyan D , Selvabharathi D. , Kubendran V.
Published: January 2018

The system is a 3-level Neutral point clamped hysteresis current controlled Inverter with Wind energy as power source. The input DC Power for the multi-level inverter is drawn from wind turbine generator connected through a rectifier circuit. An inductor has been introduced for smoothening the DC output from the rectifier. The inverter uses Neutral Point Clamped topology. The switching pulses for the inverter are achieved by hysteresis current control technique. This system is advantageous over the conventional SPWM based system as the hysteresis current control allows to reduce the low frequency harmonics while also allowing to control the fundamental amplitude depending on frequency. The outputs for the system are verified using MATLAB simulations. The hardware for Hysteresis current control for the inverter is implemented by using a dSPIC microcontroller. The proposed system can be implemented in households for supplying backup power in case of power shortage and can also be used as a primary power source if wind flow is abundant. It is easy to implement, economical and provides clean energy
A Concept of Virtual-Flux Direct Power Control of Three-Phase AC-DC Converter
Authors: Mohd Yusoff Nor Azizah , M. Razali Azziddin , Abdul Karim Kasrul , Sutikno Tole , Jidin Auzani
Published: January 2018

This paper presents a proposed technique of virtual-flux direct power control (VF-DPC) as the improvement in control method from the basic of conventional direct power control (DPC) for front-end three-phase pulse width modulated (PWM) in ac-dc converter. Three sensors in order to measure the three phase input voltage have been eliminated in the proposed method of virtual flux (VF) regarding from the estimation technique. Theoritical principles of VF-DPC are discussed in this paper. The steady-state performance of VF-DPC and conventional DPC are evaluated and presented in this work to estinguish for the excellent performance. It is shown that the VF-DPC exhibits the several advantages, particularly in providing low total harmonic distortion with almost sinusoudal of input current and unity power factor (pf) operation under balanced three phase voltage supply. The simulation results from both methods through Matlab simulation have demonstrated the outstanding performance of the new proposed control technique from VF-DPC.
Maximum Power Point Tracking for a Grid Connected Photovoltaic System using Sliding Mode Control
Authors: Sattianadan D. , Kalyanasundaram V. , Vidyasagar S. , Nayak Deepak Kumar , Jha Roopam
Published: January 2018

This paper presents a method to track the maximum power point for an isolated grid connected photovoltaic system. The method used to achieve this goal is sliding mode control. A high frequency flyback converter topology working in continuous conduction mode is used to boost the voltage and also provides galvanic isolation between input and output side. An inverter is used to invert the power for a grid connected operation. Therefore, the primary objective of this study is to design a sliding mode controller which can track maximum power driving a high frequency flyback converter and demonstrate its practicality as a higly efficient maximum power point tracker. This system is modelled and tested in MATLAB SIMULINK. To verify the results a practical implementation of sliding mode controller with high frequency flyback transformer is performed in a hardware setup
Collateral Channel Size and Tortuosity Predict Retrograde Percutaneous Coronary Intervention Success for Chronic Total Occlusion
Authors: Huang Ching-Chang , Lee Chih-Kuo , Meng Shih-Wei , Hung Chi-Sheng , Chen Ying-Hsien , Lin Mao-Shin , Yeh Chih-Fan , Kao Hsien-Li
Published: January 2018

Background—

There is little evidence on how to select an interventional collateral channel (CC) in retrograde chronic total occlusion (CTO) percutaneous coronary intervention. We aimed to identify independent angiographic predictors of CC tracking and technical success in retrograde CTO percutaneous coronary intervention.

Methods and Results—

From January 2012 to December 2015, a total of 216 consecutive retrograde CTO percutaneous coronary intervention attempts by a high-volume operator in a tertiary university-affiliated hospital were enrolled. The clinical, angiographic, and procedural details were collected. The characteristics analyzed included channel type, size, tortuosity, angle of attack, length to emerging point, and the Multicenter CTO Registry of Japan score. The Multicenter CTO Registry of Japan score was 4.2±0.8. A total of 242 CCs were attempted for intervention. CC tracking success rate was 83.5%, and the technical success rate (per CC) was 81.4%. The per-patient technical success rate was 91.2%, and the major procedural complication rate was 4.6%. The atrioventricular groove, epicardial, and septal CCs were used in 36 (14.9%), 84 (34.7%), and 122 (50.4%) tracking attempts, respectively. In multivariable analysis, only large channel size and lack of tortuosity were significant independent predictors of CC tracking and technical success. A new scoring system was developed, while large size was given 1 point and lack of tortuosity was given 2 points. The receiver-operating characteristic area by the new model to predict CC tracking and technical success were 0.800 and 0.752, respectively.

Conclusions—

In retrograde CTO percutaneous coronary intervention, only size and tortuosity of a CC are independent angiographic predictors of CC tracking and technical success.
Comparison of a Simple Angiographic Approach With a Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery Score–Based Approach for Left Main Coronary Artery Stenting
Authors: Lee Pil Hyung , Lee Jong-Young , Lee Cheol Whan , Kim Seon-Ok , Ahn Jung-Min , Park Duk-Woo , Kang Soo-Jin , Lee Seung-Whan , Kim Young-Hak , Park Seong-Wook , Park Seung-Jung
Published: January 2018

Background—

The applicability of Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery scores to left main coronary artery disease (CAD) has been questioned. A simplified alternative is needed for guiding decision making.

Methods and Results—

We evaluated the prognostic value of a simplified angiographic classification in comparison with a Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery score–based approach for patients with left main CAD undergoing drug-eluting stent implantation. The proposed approach classified left main CAD as either extensive (n=819), defined as left main bifurcation lesions with an involvement of ostial left circumflex artery or as any left main lesion plus multivessel CAD, or limited (n=453), defined as ostial/midshaft lesions or left main bifurcation lesions without an involvement of ostium of left circumflex artery, alone or plus 1-vessel disease. The databases from 4 prospective Premier of Randomized Comparison of Bypass Surgery versus Angioplasty Using Sirolimus-Eluting Stent in Patients with Left Main Coronary Artery Disease studies were pooled, and the primary outcome was a major adverse cardiac event, defined as death, myocardial infarction, or repeat revascularization. During follow-up (median 38 months; interquartile range, 36–61 months), the risk for major adverse cardiac event was significantly higher with extensive than with limited left main CAD (adjusted hazard ratio, 2.13; 95% confidence interval, 1.54−2.94;
P
<0.001). The risk for a composite outcome of death or myocardial infarction was also higher with extensive left main CAD (adjusted hazard ratio, 1.75; 95% confidence interval, 1.08−2.85;
P
=0.02). However, Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery score tertiles did not effectively stratify these 2 outcome measures.

Conclusions—

Compared with Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery scores, the simpler angiographic approach provided better discrimination for future cardiovascular events in patients with left main CAD undergoing drug-eluting stent implantation.