Construction of as prototype D-Statcom for voltage sag mitigation

This paper presents the design of a prototype distribution static compensator (D-STATCOM) for load compensation in an unbalanced distribution system. The DSTATCOM is intended to replace the widely used static Var compensator (SVC). The compensation scheme of the DSTATCOM is derived using the symmetrical component method.In this work, the 12-pulse D-STATCOM configuration with IGBT has been designed and the graphic based models of the DSTATCOM have been developed using the PSCAD/EMTDC electromagnetic transient simulation program. Accordingly,simulation is first carried out to illustrate the use of DSTATCOM in mitigating voltage sag in a distribution system. The D-STATCOM has been developed using DSP controller to achieve excellent overall performance. Simulation results prove that the D-STATCOM is capable of mitigating voltage sag by controlling PWM of the system using DSP board

Manufacturing and mechanical characterization of multiwalled carbon nanotubes/quartz nanocomposite

Monolithic refractory ceramic materials have outstanding heat resistant properties at elevated temperature and possess high stiffness but are generally brittle. To toughen a typical matrix of natural traditional monolithic quartz ceramic, functionalized multiwalled carbon nanotubes (FMWNTs) were added to the matrix as filler for the first time and processed by a wet method using conventional powder processing; involving consolidation by pressureless sintering technique, to obtain the novel nanocomposite. The effect of the varied amount of carbon nanotubes (0.01, 0.1, 0.5, 1 & 4 wt.%) on densification and mechanical properties of the composites were studied. 1 wt.% FMWNTs/quartz (QF-1) possesses moderate tensile and compressive strengths, modest Young’s modulus and toughness, and high fracture strain in tension. Good combination of strengths and toughness in QF-1 nanocomposite, suggest the possibility of using 1 wt.% FMWNTs as an additive in the preparation of silica/silica-based refractory mixture for optimum mechanical properties

Effect of Psychological Empowerment and Transformational Leadership on Organizational Commitment

According to recent literature that relates to organizational leadership, transformational leadership consists of three important elements: idealized influence, individual consideration and intellectual stimulation. Extant studies in this area highlighted that the ability of the leaders in implementing these transformational processes (to execute organizational functions) may have a significant impact on individual outcome especially organizational commitment. Although this relationship has been studied, the mediating role of transformational leadership has taken a less prominent role in organizational leadership model. Recent studies on organizational leadership have emphasized that transformational leadership has three important characteristics: idealized influence, individual consideration and intellectual stimulation. The purpose of this paper is to examine the influence of empowerment in the relationship between transformational leadership and organizational commitment; by using 77 USAble questionnaires gathered from employees who worked at a foreign manufacturing company in Free Trade Zone, Malaysia. Results of SmartPLS path model analysis confirm that empowerment does act as an important mediating variable in the relationship between transformational leadership and organizational commitment in the organizational sample. In the succeeding sections, discussion, implications and conclusion are elaborated

Effect of Female Sex Hormones on Cardiorespiratory System: Theoretical Review

This study aimed at analyzing the effect of the female sex hormones upon  the cardiorespiratory system. And the results showed that the cardiac output measurement showed no significant increase during both phases of menstrual cycle before exercise but there was an insignificant increase soon after exercise owing to sympathetic over activity. The observed increase in the peripheral blood flow during mid-follicular phase before and after exercise revealed that influence of estrogen increases the arterial distensibility. The observed increase in the respiratory efficiency test during early luteal phase before and soon after exercise revealed the influence of progesterone, which is considered to be a potent stimulator of respiration, and added up effect of hormones and exercise-induced changes

A new hybrid dual active bridge modular multilevel based DC-DC converter for HVDC networks

Multi-terminal high voltage DC transmission currently represents a leading technology in long-distance power transmission systems. Among the main technical challenges facing such technology, DC fault isolation, permitting different grounding schemes, providing interoperability, and high DC voltage stepping between different HVDC networks, and allowing high-speed power reversal without power interruption especially when connecting the pre-existing voltage source converters (VSC) and line commutated converters (LCC)-based HVDC networks. This paper introduces a new modular multilevel converter (MMC) based front-to-front DC-DC converter to interconnect two different types (LCC/VSC) of HVDC networks. The proposed topology comprises a voltage source MMC (VS-MMC) and a current source MMC (CS-MMC), while both are coupled via an AC link including the isolating transformer. The proposed topology can successfully provide an uninterruptible bi-directional power flow, high DC voltage stepping with a DC fault blocking capability, and low number of semiconductors due to the usage of only half-bridge SMs. The system design is provided with a detailed mathematical analysis. Furthermore, two active power control methodologies are proposed and compared. The first control technique is simpler and entails lower passive elements, while the second technique ensures a zero reactive power over the full range of active power flow. Furthermore, Losses analysis and comparison are provided between the two proposed control techniques. Finally, Control-Hardware-in-the-Loop (CHiL) test validation is employed to confirm the validity of the proposed system under healthy as well as different fault scenarios

Discovery of precursor and mature microRNAs and their putative gene targets using high-throughput sequencing in pineapple (Ananas comosus var. comosus)

MicroRNAs (miRNAs) are a class of small, endogenous non-coding RNAs that negatively regulate gene expression, resulting in the silencing of target mRNA transcripts through mRNA cleavage or translational inhibition. MiRNAs play significant roles in various biological and physiological processes in plants. However, the miRNA-mediated gene regulatory network in pineapple, the model tropical non-climacteric fruit, remains largely unexplored. Here, we report a complete list of pineapple mature miRNAs obtained from high-throughput small RNA sequencing and precursor miRNAs (pre-miRNAs) obtained from ESTs. Two small RNA libraries were constructed from pineapple fruits and leaves, respectively, using Illumina's Solexa technology. Sequence similarity analysis using miRBase revealed 579,179 reads homologous to 153 miRNAs from 41 miRNA families. In addition, a pineapple fruit transcriptome library consisting of approximately 30,000 EST contigs constructed using Solexa sequencing was used for the discovery of pre-miRNAs. In all, four pre-miRNAs were identified (MIR156, MIR399, MIR444 and MIR2673). Furthermore, the same pineapple transcriptome was used to dissect the function of the miRNAs in pineapple by predicting their putative targets in conjunction with their regulatory networks. In total, 23 metabolic pathways were found to be regulated by miRNAs in pineapple. The use of high-throughput sequencing in pineapples to unveil the presence of miRNAs and their regulatory pathways provides insight into the repertoire of miRNA regulation used exclusively in this non-climacteric model plant

Interactions between integrated pest management, pollinator introduction, and landscape context on avocado Persea americana productivity

Pest management and insect pollination are important services that support crop production but are most often studied in isolation in cropping systems. Avocado Persea americana Mill. is an economically important crop in East Africa, which suffers from pest threats and potential drawbacks of the global pollinator crisis. The integration of pest and pollinator management is a growing research trend as a potential solution for sustainable crop production with minimum adverse effects on the environment and biodiversity. This study assessed potential interactions between landscape context, honeybee Apis mellifera L. introduction and integrated pest management (IPM) on avocado pests Bactrocera dorsalis (Hendel) and Thaumatotibia leucotreta (Meyrick), pollinators, and productivity in Kenya. Results showed an interaction between honeybee introduction and IPM on A. mellifera, with the highest mean abundance on the farms with both honeybee colonies and IPM. The abundance and diversity of non-Apis flower visitors were not affected by IPM and honeybee introduction across the landscapes. Pollinator introduction and IPM implementation resulted in a 941% fruit set increase and up to 97% fruit abscission within the high vegetation productivity class. Pest abundance significantly decreased on the farms with IPM, resulting in a 6% increase of final fruit weight compared with the farms without IPM. Overall, integration of pest and pollinator management did not synergistically increase the final avocado yield but represented a potential strategy to reduce pest densities while preserving wild visitors and benefiting from secondary products of honeybee colonies.The German Federal Ministry for Economic Cooperation and Development (BMZ) commissioned and administered through the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) Fund for International Agricultural Research (FIA) and Norwegian Agency for Development Cooperation, the Section for research, innovation, and higher education, UK’s Foreign, Commonwealth and Development Office (FCDO), Swedish International Development Cooperation Agency (Sida), the Swiss Agency for Development and Cooperation (SDC), the German Academic Exchange Services (DAAD), Federal Democratic Republic of Ethiopia, and the Kenyan Government.https://www.schweizerbart.de/journals/entomologiadm2022Zoology and Entomolog

Mid-infrared water pollutant sensor based on SPR-PCF

In this paper, a highly sensitive water pollutant optical sensor is proposed and analyzed. The suggested sensor consists of photonic crystal fiber with a core surrounded by four elliptical holes infiltrated with the studied analyte (pure/polluted water sample). In addition, two gold nanorods are mounted horizontally at the inner surfaces of two horizontal elliptical holes. The proposed sensor can efficiently detect dissolved pollutants in water such as nitric acid (HNO3) with concentrations of 14, 23 and 35% and H2O2 with concentrations of 7, 15 and 30%. The dissolved pollutants in water (analyte) have refractive indices (RIs) in the range of 1.350–1.355 in the mid infrared regime from λ = 2200 nm to λ = 3500 nm. A fully vectorial finite element method (FVFEM) is employed for the modal analysis of the reported structure. The geometrical parameters are studied to maximize the RI sensitivity where a high sensitivity of 36,000 nm/RIU is achieved between the studied RIs of 1.350 and 1.355. The obtained RI sensitivity is higher than those of the recent reported sensors in the literature especially those operating in the mid infrared wavelengths

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Matrix metalloproteinase 2 is a target of the RAN-GTP pathway and mediates migration, invasion and metastasis in human breast cancer

RAS-related nuclear protein(RAN) is a nuclear shuttle and normally regulates events in the cell cycle. When overexpressed in cultured cells, it causes increases in cell migration/invasion in vitro and its overexpression is associated with early breast cancer patient deaths in vivo. However, the underlying mechanism is unknown. The effect of RAN overexpression on potential targets MMP2, ATF3, CXCR3 was investigated by Real-Time PCR/Western blots in the triple receptor negative breast cancer(TRNBC) cell line MDA-MB231 and consequent biological effects were measured by cell adhesion, cell migration and cell invasion assays. Results showed that knockdown of RAN lead to a reduction of MMP2 and its potential regulators ATF3 and CXCR3. Moreover, knockdown of ATF3 or CXCR3 downregulated MMP2 without affecting RAN, indicating that RAN regulates MMP2 through ATF3 and CXCR3. Knockdown of RAN and MMP2 reduced cell adhesion, cell migration and cell growth in agar, whilst overexpression of MMP2 reversed the knockdown of RAN. Furthermore, immunohistochemical staining for RAN and MMP2 are positively associated with each other in the same tumour and separately with patient survival times in breast cancer specimens, suggesting that a high level of RAN may be a pre-requisite for MMP2 overexpression and metastasis. Moreover, positive immunohistochemical staining for both RAN and MMP-2 reduces further patient survival times over that for either protein separately. Our results suggest that MMP2 expression can stratify progression of breast cancers with a high and low incidence of RAN, both RAN and MMP2 in combination can be used for a more accurate patient prognosis. SIMPLE SUMMARY: Ran is an important regulator of normal cell growth and behaviour. We have established in cell line models of breast cancer (BC) a molecular pathway between RAN and its protein-degrading effector MMP-2 and properties related to metastasis in culture. Using immunohistochemistry (IHC) staining of primary BCs, we have shown that RAN and MMP-2 are on their own significantly associated with patient demise from metastatic BC. Moreover, when staining for MMP-2 is added to that for RAN in the primary tumours, there is a significant decrease in patient survival time over that for either protein alone. Thus a combination of staining for RAN and MMP2 is an excellent marker for poor prognosis in breast cancer